[flang-commits] [flang] [flang] Add EXECUTE_COMMAND_LINE runtime and lowering intrinsics implementation (PR #74077)

[Yi Wu via flang-commits]

https://github.com/yi-wu-arm updated https://github.com/llvm/llvm-project/pull/74077

>From 49da4a6d4730cfc8cd9bcd28e7dc6f0f6f1b2cb6 Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 13:57:46 +0300
Subject: [PATCH 01/22] add execute_command_line

Signed-off-by: Jeff Hammond <jeff.science at gmail.com>
---
 flang/lib/Optimizer/Builder/IntrinsicCall.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index 0a023bc6b21ea..8218096c84243 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -209,6 +209,14 @@ static constexpr IntrinsicHandler handlers[]{
        {"boundary", asBox, handleDynamicOptional},
        {"dim", asValue}}},
      /*isElemental=*/false},
+    {"execute_command_line",
+     &I::genExecuteCommandLine,
+     {{{"command", asBox},
+       {"wait", asAddr, handleDynamicOptional},
+       {"exitstat", asAddr, handleDynamicOptional},
+       {"cmdstat", asAddr, handleDynamicOptional},
+       {"cmdmsg", asBox, handleDynamicOptional}}},
+     /*isElemental=*/false},
     {"exit",
      &I::genExit,
      {{{"status", asValue, handleDynamicOptional}}},

>From e31c6f39122117a37e09a43a9fd13f05a7d70912 Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 14:41:02 +0300
Subject: [PATCH 02/22] this is definitely not completely correct

---
 .../execute_command_line-optional.f90         |  54 +++++++
 .../Lower/Intrinsics/execute_command_line.f90 | 138 ++++++++++++++++++
 2 files changed, 192 insertions(+)
 create mode 100644 flang/test/Lower/Intrinsics/execute_command_line-optional.f90
 create mode 100644 flang/test/Lower/Intrinsics/execute_command_line.f90

diff --git a/flang/test/Lower/Intrinsics/execute_command_line-optional.f90 b/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
new file mode 100644
index 0000000000000..b2c589a774466
--- /dev/null
+++ b/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
@@ -0,0 +1,54 @@
+! Test execute_command_line with dynamically optional arguments.
+! RUN: bbc -emit-fir %s -o - | FileCheck %s
+
+
+! CHECK-LABEL: func @_QPtest(
+! CHECK-SAME:  %[[ARG_0:.*]]: !fir.boxchar<1> {fir.bindc_command = "command", fir.optional},
+! CHECK-SAME:  %[[ARG_1:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_command = "wait", fir.optional},
+! CHECK-SAME:  %[[ARG_2:.*]]: !fir.ref<i32> {fir.bindc_command = "length", fir.optional},
+! CHECK-SAME:  %[[ARG_3:.*]]: !fir.ref<i32> {fir.bindc_command = "cmdstat", fir.optional},
+! CHECK-SAME:  %[[ARG_4:.*]]: !fir.boxchar<1> {fir.bindc_command = "cmdmsg", fir.optional}) {
+subroutine test(command, wait, length, cmdstat, cmdmsg)
+  integer, optional :: cmdstat, length
+  character(*), optional :: command, wait, cmdmsg
+  ! Note: command is not optional in execute_command_line and must be present
+  call execute_command_line(command, wait, length, cmdstat, cmdmsg)
+! CHECK:  %[[VAL_0:.*]]:2 = fir.unboxchar %[[ARG_5]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK:  %[[VAL_1:.*]]:2 = fir.unboxchar %[[ARG_0]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK:  %[[VAL_2:.*]]:2 = fir.unboxchar %[[ARG_1]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK:  %[[VAL_3:.*]] = fir.embox %[[VAL_1]]#0 typeparams %[[VAL_1]]#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.box<!fir.char<1,?>>
+! CHECK:  %[[VAL_4:.*]] = fir.is_present %[[VAL_2]]#0 : (!fir.ref<!fir.char<1,?>>) -> i1
+! CHECK:  %[[VAL_5:.*]] = fir.embox %[[VAL_2]]#0 typeparams %[[VAL_2]]#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.box<!fir.char<1,?>>
+! CHECK:  %[[VAL_6:.*]] = fir.absent !fir.box<!fir.char<1,?>>
+! CHECK:  %[[VAL_7:.*]] = arith.select %[[VAL_4]], %[[VAL_5]], %[[VAL_6]] : !fir.box<!fir.char<1,?>>
+! CHECK:  %[[VAL_8:.*]] = fir.is_present %[[ARG_2]] : (!fir.ref<i32>) -> i1
+! CHECK:  %[[VAL_9:.*]] = fir.embox %[[ARG_2]] : (!fir.ref<i32>) -> !fir.box<i32>
+! CHECK:  %[[VAL_10:.*]] = fir.absent !fir.box<i32>
+! CHECK:  %[[VAL_11:.*]] = arith.select %[[VAL_8]], %[[VAL_9]], %[[VAL_10]] : !fir.box<i32>
+! CHECK:  %[[VAL_12:.*]] = fir.is_present %[[VAL_0]]#0 : (!fir.ref<!fir.char<1,?>>) -> i1
+! CHECK:  %[[VAL_13:.*]] = fir.embox %[[VAL_0]]#0 typeparams %[[VAL_0]]#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.box<!fir.char<1,?>>
+! CHECK:  %[[VAL_14:.*]] = fir.absent !fir.box<!fir.char<1,?>>
+! CHECK:  %[[VAL_15:.*]] = arith.select %[[VAL_12]], %[[VAL_13]], %[[VAL_14]] : !fir.box<!fir.char<1,?>>
+! CHECK:  %[[VAL_16:.*]] = fir.convert %[[ARG_4]] : (!fir.ref<!fir.logical<4>>) -> i64
+! CHECK:  %[[CONST_0:.*]] = arith.constant 0 : i64
+! CHECK:  %[[VAL_17:.*]] = arith.cmpi ne, %[[VAL_16]], %[[CONST_0]] : i64
+! CHECK:  %[[VAL_18:.*]] = fir.if %[[VAL_17]] -> (i1) {
+! CHECK:    %[[VAL_28:.*]] = fir.load %[[ARG_4]] : !fir.ref<!fir.logical<4>>
+! CHECK:    %[[VAL_29:.*]] = fir.convert %[[VAL_28]] : (!fir.logical<4>) -> i1
+! CHECK:    fir.result %[[VAL_29]] : i1
+! CHECK:  } else {
+! CHECK:    %[[CONST_1:.*]] = arith.constant true
+! CHECK:    fir.result %[[CONST_1]] : i1
+! CHECK:  }
+! CHECK:  %[[VAL_20:.*]] = fir.convert %[[VAL_3]] : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
+! CHECK:  %[[VAL_21:.*]] = fir.convert %[[VAL_7]] : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
+! CHECK:  %[[VAL_22:.*]] = fir.convert %[[VAL_11]] : (!fir.box<i32>) -> !fir.box<none>
+! CHECK:  %[[VAL_23:.*]] = fir.convert %[[VAL_15]] : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
+! CHECK:  %[[VAL_25:.*]] = fir.call @_FortranAGetEnvVariable(%[[VAL_20]], %[[VAL_21]], %[[VAL_22]], %[[VAL_18]], %[[VAL_23]], %{{.*}}, %{{.*}}) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK:  %[[VAL_26:.*]] = fir.convert %[[ARG_3]] : (!fir.ref<i32>) -> i64
+! CHECK:  %[[CONST_2:.*]] = arith.constant 0 : i64
+! CHECK:  %[[VAL_27:.*]] = arith.cmpi ne, %[[VAL_26]], %[[CONST_2]] : i64
+! CHECK:  fir.if %[[VAL_27]] {
+! CHECK:    fir.store %[[VAL_25]] to %[[ARG_3]] : !fir.ref<i32>
+! CHECK:  }
+end subroutine
diff --git a/flang/test/Lower/Intrinsics/execute_command_line.f90 b/flang/test/Lower/Intrinsics/execute_command_line.f90
new file mode 100644
index 0000000000000..f9b11ad7d772a
--- /dev/null
+++ b/flang/test/Lower/Intrinsics/execute_command_line.f90
@@ -0,0 +1,138 @@
+! RUN: bbc -emit-fir %s -o - | FileCheck --check-prefixes=CHECK,CHECK-32 -DDEFAULT_INTEGER_SIZE=32 %s
+! RUN: flang-new -fc1 -fdefault-integer-8 -emit-fir %s -o - | FileCheck --check-prefixes=CHECK,CHECK-64 -DDEFAULT_INTEGER_SIZE=64 %s
+
+! CHECK-LABEL: func @_QPcommand_only(
+! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"}) {
+subroutine command_only(command)
+    character(len=32) :: command
+    call execute_command_line(command)
+! CHECK-NOT: fir.call @_FortranAGetEnvVariable
+! CHECK-NEXT: return
+end subroutine command_only
+
+! CHECK-LABEL: func @_QPcommand_and_wait_only(
+! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
+! CHECK-SAME: %[[waitArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_command = "wait", fir.optional},
+subroutine command_and_wait_only(command, wait)
+    character(len=32) :: command, wait
+    call execute_command_line(command, wait)
+! CHECK: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
+! CHECK-NEXT: %[[waitUnbox:.*]]:2 = fir.unboxchar %[[waitArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT: %[[waitCast:.*]] = fir.convert %[[waitUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
+! CHECK-NEXT: %[[commandBox:.*]] = fir.embox %[[commandCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
+! CHECK-NEXT: %[[waitBox:.*]] = fir.embox %[[waitCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
+! CHECK-NEXT: %true = arith.constant true
+! CHECK-NEXT: %[[exitstat:.*]] = fir.absent !fir.box<none>
+! CHECK-NEXT: %[[cmdmsg:.*]] = fir.absent !fir.box<none>
+! CHECK-NEXT: %[[sourceFileString:.*]] = fir.address_of(@_QQcl{{.*}}) : !fir.ref<!fir.char<1,[[sourceFileexitstat:.*]]>>
+! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 11]] : i32
+! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
+! CHECK-NEXT: %[[wait:.*]] = fir.convert %[[waitBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
+! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
+! CHECK-NEXT: %{{[0-9]+}} = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-NEXT: return
+end subroutine command_and_wait_only
+
+! CHECK-LABEL: func @_QPcommand_and_exitstat_only(
+! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
+! CHECK-SAME: %[[exitstatArg:.*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_command = "exitstat"}) {
+subroutine command_and_exitstat_only(command, exitstat)
+    character(len=32) :: command
+    integer :: exitstat
+    call execute_command_line(command, EXITSTAT=exitstat)
+! CHECK: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
+! CHECK-NEXT: %[[commandBox:.*]] = fir.embox %[[commandCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
+! CHECK-NEXT: %[[exitstatBox:.*]] = fir.embox %arg1 : (!fir.ref<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<i[[DEFAULT_INTEGER_SIZE]]>
+! CHECK-NEXT: %true = arith.constant true
+! CHECK-NEXT: %[[wait:.*]] = fir.absent !fir.box<none>
+! CHECK-NEXT: %[[cmdmsg:.*]] = fir.absent !fir.box<none>
+! CHECK: %[[sourceFileString:.*]] = fir.address_of(@_QQcl.{{.*}}) : !fir.ref<!fir.char<1,[[sourceFileexitstat:.*]]>>
+! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 9]] : i32
+! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
+! CHECK-NEXT: %[[exitstat:.*]] = fir.convert %[[exitstatBox]] : (!fir.box<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<none>
+! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
+! CHECK-NEXT: %{{.*}} = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+end subroutine command_and_exitstat_only
+
+! CHECK-LABEL: func @_QPcommand_and_cmdstat_only(
+! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
+! CHECK-SAME: %[[cmdstatArg:.*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_command = "cmdstat"}) {
+subroutine command_and_cmdstat_only(command, cmdstat)
+    character(len=32) :: command
+    integer :: cmdstat
+    call execute_command_line(command, CMDSTAT=cmdstat)
+! CHECK: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
+! CHECK-NEXT: %[[commandBox:.*]] = fir.embox %[[commandCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
+! CHECK-NEXT: %true = arith.constant true
+! CHECK-NEXT: %[[wait:.*]] = fir.absent !fir.box<none>
+! CHECK-NEXT: %[[exitstat:.*]] = fir.absent !fir.box<none>
+! CHECK-NEXT: %[[cmdmsg:.*]] = fir.absent !fir.box<none>
+! CHECK-NEXT: %[[sourceFileString:.*]] = fir.address_of(@_QQcl.{{.*}}) : !fir.ref<!fir.char<1,[[sourceFileexitstat:.*]]>>
+! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 9]] : i32
+! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
+! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
+! CHECK-32-NEXT: %[[cmdstat:.*]] = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-64-NEXT: %[[cmdstat32:.*]] = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-64: %[[cmdstat:.*]] = fir.convert %[[cmdstat32]] : (i32) -> i64
+! CHECK: fir.store %[[cmdstat]] to %[[cmdstatArg]] : !fir.ref<i[[DEFAULT_INTEGER_SIZE]]>
+end subroutine command_and_cmdstat_only
+
+! CHECK-LABEL: func @_QPcommand_and_cmdmsg_only(
+! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
+! CHECK-SAME: %[[cmdmsgArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "cmdmsg"}) {
+subroutine command_and_cmdmsg_only(command, cmdmsg)
+    character(len=32) :: command, cmdmsg
+    call execute_command_line(command, CMDMSG=cmdmsg)
+! CHECK: %[[cmdmsgUnbox:.*]]:2 = fir.unboxchar %[[cmdmsgArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT: %[[cmdmsgCast:.*]] = fir.convert %[[cmdmsgUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
+! CHECK-NEXT: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
+! CHECK-NEXT: %[[commandBox:.*]] = fir.embox %[[commandCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
+! CHECK-NEXT: %[[cmdmsgBox:.*]] = fir.embox %[[cmdmsgCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
+! CHECK-NEXT: %true = arith.constant true
+! CHECK-NEXT: %[[wait:.*]] = fir.absent !fir.box<none>
+! CHECK-NEXT: %[[exitstat:.*]] = fir.absent !fir.box<none>
+! CHECK-NEXT: %[[sourceFileString:.*]] = fir.address_of(@_QQcl.{{.*}}) : !fir.ref<!fir.char<1,[[sourceFileexitstat:.*]]>>
+! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 11]] : i32
+! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
+! CHECK-NEXT: %[[cmdmsg:.*]] = fir.convert %[[cmdmsgBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
+! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
+! CHECK-NEXT: %{{[0-9]+}} = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-NEXT: return
+end subroutine command_and_cmdmsg_only
+
+! CHECK-LABEL: func @_QPall_arguments(
+! CHECK-SAME: %[[commandArg:[^:]*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
+! CHECK-SAME: %[[waitArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_command = "wait", fir.optional},
+! CHECK-SAME: %[[exitstatArg:[^:]*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_command = "exitstat"},
+! CHECK-SAME: %[[cmdstatArg:.*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_command = "cmdstat"},
+! CHECK-SAME: %[[cmdmsgArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "cmdmsg"}) {
+subroutine all_arguments(command, wait, exitstat, cmdstat, cmdmsg)
+    character(len=32) :: command, wait, cmdmsg
+    integer :: exitstat, cmdstat
+    call execute_command_line(command, wait, exitstat, cmdstat, cmdmsg)
+! CHECK: %[[cmdmsgUnbox:.*]]:2 = fir.unboxchar %[[cmdmsgArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT: %[[cmdmsgCast:.*]] = fir.convert %[[cmdmsgUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
+! CHECK-NEXT: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
+! CHECK-NEXT: %[[waitUnbox:.*]]:2 = fir.unboxchar %[[waitArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT: %[[waitCast:.*]] = fir.convert %[[waitUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
+! CHECK-NEXT: %[[commandBoxed:.*]] = fir.embox %[[commandCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
+! CHECK-NEXT: %[[waitBoxed:.*]] = fir.embox %[[waitCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
+! CHECK-NEXT: %[[exitstatBoxed:.*]] = fir.embox %[[exitstatArg]] : (!fir.ref<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<i[[DEFAULT_INTEGER_SIZE]]>
+! CHECK-NEXT: %[[cmdmsgBoxed:.*]] = fir.embox %[[cmdmsgCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
+! CHECK: %[[sourceFileString:.*]] = fir.address_of(@_QQcl.[[fileString:.*]]) : !fir.ref<!fir.char<1,[[fileStringexitstat:.*]]>>
+! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 22]] : i32
+! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBoxed]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
+! CHECK-NEXT: %[[wait:.*]] = fir.convert %[[waitBoxed]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
+! CHECK-NEXT: %[[exitstat:.*]] = fir.convert %[[exitstatBoxed]] : (!fir.box<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<none>
+! CHECK-NEXT: %[[cmdmsg:.*]] = fir.convert %[[cmdmsgBoxed]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
+! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[fileStringexitstat]]>>) -> !fir.ref<i8>
+! CHECK-32-NEXT: %[[cmdstat:.*]] = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-64-NEXT: %[[cmdstat32:.*]] = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-64: %[[cmdstat:.*]] = fir.convert %[[cmdstat32]] : (i32) -> i64
+! CHECK: fir.store %[[cmdstat]] to %[[cmdstatArg]] : !fir.ref<i[[DEFAULT_INTEGER_SIZE]]>
+end subroutine all_arguments

>From 60a826e12df697d1389ae8d6011df4bd86c384c0 Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 14:46:57 +0300
Subject: [PATCH 03/22] definitely not right either

---
 .../flang/Optimizer/Builder/Runtime/Execute.h | 32 +++++++++++++++
 .../lib/Optimizer/Builder/Runtime/Execute.cpp | 41 +++++++++++++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 flang/include/flang/Optimizer/Builder/Runtime/Execute.h
 create mode 100644 flang/lib/Optimizer/Builder/Runtime/Execute.cpp

diff --git a/flang/include/flang/Optimizer/Builder/Runtime/Execute.h b/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
new file mode 100644
index 0000000000000..000565f20c5dc
--- /dev/null
+++ b/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
@@ -0,0 +1,32 @@
+//===-- Command.cpp -- generate command line runtime API calls ------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_OPTIMIZER_BUILDER_RUNTIME_EXECUTE_H
+#define FORTRAN_OPTIMIZER_BUILDER_RUNTIME_EXECUTE_H
+
+namespace mlir {
+class Value;
+class Location;
+} // namespace mlir
+
+namespace fir {
+class FirOpBuilder;
+} // namespace fir
+
+namespace fir::runtime {
+
+/// Generate a call to the ExecuteCommandLine runtime function which implements
+/// the GET_EXECUTE_ARGUMENT intrinsic.
+/// \p value, \p length and \p errmsg must be fir.box that can be absent (but
+/// not null mlir values). The status value is returned.
+mlir::Value genExecuteCommandLine(fir::FirOpBuilder &, mlir::Location,
+                                  mlir::Value number, mlir::Value value,
+                                  mlir::Value length, mlir::Value errmsg);
+
+} // namespace fir::runtime
+#endif // FORTRAN_OPTIMIZER_BUILDER_RUNTIME_EXECUTE_H
diff --git a/flang/lib/Optimizer/Builder/Runtime/Execute.cpp b/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
new file mode 100644
index 0000000000000..8c612966aabdb
--- /dev/null
+++ b/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
@@ -0,0 +1,41 @@
+//===-- Execute.cpp -- generate command line runtime API calls ------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "flang/Optimizer/Builder/Runtime/Execute.h"
+#include "flang/Optimizer/Builder/FIRBuilder.h"
+#include "flang/Optimizer/Builder/Runtime/RTBuilder.h"
+#include "flang/Runtime/command.h"
+
+using namespace Fortran::runtime;
+
+// Certain runtime intrinsics should only be run when select parameters of the
+// intrisic are supplied. In certain cases one of these parameters may not be
+// given, however the intrinsic needs to be run due to another required
+// parameter being supplied. In this case the missing parameter is assigned to
+// have an "absent" value. This typically happens in IntrinsicCall.cpp. For this
+// reason the extra indirection with `isAbsent` is needed for testing whether a
+// given parameter is actually present (so that parameters with "value" absent
+// are not considered as present).
+inline bool isAbsent(mlir::Value val) {
+  return mlir::isa_and_nonnull<fir::AbsentOp>(val.getDefiningOp());
+}
+
+mlir::Value fir::runtime::genExecuteCommandLine(
+    fir::FirOpBuilder &builder, mlir::Location loc, mlir::Value number,
+    mlir::Value value, mlir::Value length, mlir::Value errmsg) {
+  auto runtimeFunc =
+      fir::runtime::getRuntimeFunc<mkRTKey(ExecuteCommandLine)>(loc, builder);
+  mlir::FunctionType runtimeFuncTy = runtimeFunc.getFunctionType();
+  mlir::Value sourceFile = fir::factory::locationToFilename(builder, loc);
+  mlir::Value sourceLine =
+      fir::factory::locationToLineNo(builder, loc, runtimeFuncTy.getInput(5));
+  llvm::SmallVector<mlir::Value> args =
+      fir::runtime::createArguments(builder, loc, runtimeFuncTy, number, value,
+                                    length, errmsg, sourceFile, sourceLine);
+  return builder.create<fir::CallOp>(loc, runtimeFunc, args).getResult(0);
+}

>From aa31e9b49a3c7a5a0d1b3be4afeb936915d374bd Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 14:49:22 +0300
Subject: [PATCH 04/22] definitely not right either

---
 .../flang/Optimizer/Builder/IntrinsicCall.h   |  1 +
 flang/lib/Optimizer/Builder/IntrinsicCall.cpp | 43 +++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/flang/include/flang/Optimizer/Builder/IntrinsicCall.h b/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
index 06db8cf9e9dc9..83d7315c1f1a1 100644
--- a/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
+++ b/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
@@ -214,6 +214,7 @@ struct IntrinsicLibrary {
   mlir::Value genDshiftr(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue genEoshift(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   void genExit(llvm::ArrayRef<fir::ExtendedValue>);
+  void genExecuteCommandLine(mlir::ArrayRef<fir::ExtendedValue> args);
   mlir::Value genExponent(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue genExtendsTypeOf(mlir::Type,
                                       llvm::ArrayRef<fir::ExtendedValue>);
diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index 8218096c84243..4c504e0b04f23 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -2775,6 +2775,49 @@ IntrinsicLibrary::genEoshift(mlir::Type resultType,
   return readAndAddCleanUp(resultMutableBox, resultType, "EOSHIFT");
 }
 
+// EXECUTE_COMMAND_LINE
+void IntrinsicLibrary::genExecuteCommandLine(
+    llvm::ArrayRef<fir::ExtendedValue> args) {
+  assert(args.size() == 5);
+  mlir::Value number = fir::getBase(args[0]);
+  const fir::ExtendedValue &value = args[1];
+  const fir::ExtendedValue &length = args[2];
+  const fir::ExtendedValue &status = args[3];
+  const fir::ExtendedValue &errmsg = args[4];
+
+  if (!number)
+    fir::emitFatalError(loc, "expected NUMBER parameter");
+
+  // If none of the optional parameters are present, do nothing.
+  if (!isStaticallyPresent(value) && !isStaticallyPresent(length) &&
+      !isStaticallyPresent(status) && !isStaticallyPresent(errmsg))
+    return;
+
+  mlir::Type boxNoneTy = fir::BoxType::get(builder.getNoneType());
+  mlir::Value valBox =
+      isStaticallyPresent(value)
+          ? fir::getBase(value)
+          : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
+  mlir::Value lenBox =
+      isStaticallyPresent(length)
+          ? fir::getBase(length)
+          : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
+  mlir::Value errBox =
+      isStaticallyPresent(errmsg)
+          ? fir::getBase(errmsg)
+          : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
+  mlir::Value stat = fir::runtime::genExecuteCommandLine(
+      builder, loc, number, valBox, lenBox, errBox);
+  if (isStaticallyPresent(status)) {
+    mlir::Value statAddr = fir::getBase(status);
+    mlir::Value statIsPresentAtRuntime =
+        builder.genIsNotNullAddr(loc, statAddr);
+    builder.genIfThen(loc, statIsPresentAtRuntime)
+        .genThen([&]() { builder.createStoreWithConvert(loc, stat, statAddr); })
+        .end();
+  }
+}
+
 // EXIT
 void IntrinsicLibrary::genExit(llvm::ArrayRef<fir::ExtendedValue> args) {
   assert(args.size() == 1);

>From a417c5a3abf83c6d661f8fe43e63c86b62f28f61 Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 14:54:14 +0300
Subject: [PATCH 05/22] more correct

---
 .../include/flang/Optimizer/Builder/Runtime/Execute.h  | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/flang/include/flang/Optimizer/Builder/Runtime/Execute.h b/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
index 000565f20c5dc..c35f46fa88d42 100644
--- a/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
+++ b/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
@@ -22,11 +22,13 @@ namespace fir::runtime {
 
 /// Generate a call to the ExecuteCommandLine runtime function which implements
 /// the GET_EXECUTE_ARGUMENT intrinsic.
-/// \p value, \p length and \p errmsg must be fir.box that can be absent (but
-/// not null mlir values). The status value is returned.
+/// \p wait, \p exitstat, \p cmdstat and \p cmdmsg must be fir.box that can be 
+/// absent (but not null mlir values). The status exitstat and cmdstat are
+/// returned, along with the message cmdmsg.
 mlir::Value genExecuteCommandLine(fir::FirOpBuilder &, mlir::Location,
-                                  mlir::Value number, mlir::Value value,
-                                  mlir::Value length, mlir::Value errmsg);
+                                  mlir::Value command, mlir::Value wait,
+                                  mlir::Value exitstat, mlir::Value cmdstat,
+                                  mlir::Value cmdmsg);
 
 } // namespace fir::runtime
 #endif // FORTRAN_OPTIMIZER_BUILDER_RUNTIME_EXECUTE_H

>From 36811c71091940267fb4f2d9b15aabd0234704e6 Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 14:59:19 +0300
Subject: [PATCH 06/22] more correct

---
 flang/lib/Optimizer/Builder/Runtime/Execute.cpp | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/flang/lib/Optimizer/Builder/Runtime/Execute.cpp b/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
index 8c612966aabdb..1942c6e943fb8 100644
--- a/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
+++ b/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
@@ -26,16 +26,18 @@ inline bool isAbsent(mlir::Value val) {
 }
 
 mlir::Value fir::runtime::genExecuteCommandLine(
-    fir::FirOpBuilder &builder, mlir::Location loc, mlir::Value number,
-    mlir::Value value, mlir::Value length, mlir::Value errmsg) {
+    fir::FirOpBuilder &builder, mlir::Location loc, mlir::Value command,
+    mlir::Value wait, mlir::Value exitstat, mlir::Value cmdstat,
+    mlir::Value cmdmsg) {
   auto runtimeFunc =
       fir::runtime::getRuntimeFunc<mkRTKey(ExecuteCommandLine)>(loc, builder);
   mlir::FunctionType runtimeFuncTy = runtimeFunc.getFunctionType();
   mlir::Value sourceFile = fir::factory::locationToFilename(builder, loc);
   mlir::Value sourceLine =
-      fir::factory::locationToLineNo(builder, loc, runtimeFuncTy.getInput(5));
+      fir::factory::locationToLineNo(builder, loc, runtimeFuncTy.getInput(6));
   llvm::SmallVector<mlir::Value> args =
-      fir::runtime::createArguments(builder, loc, runtimeFuncTy, number, value,
-                                    length, errmsg, sourceFile, sourceLine);
+      fir::runtime::createArguments(builder, loc, runtimeFuncTy, command, wait,
+                                    exitstat, cmdstat, cmdmsg, sourceFile,
+                                    sourceLine);
   return builder.create<fir::CallOp>(loc, runtimeFunc, args).getResult(0);
 }

>From 6cc9e3f9e581209c54d8c4f476023f406135dddb Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 15:02:07 +0300
Subject: [PATCH 07/22] remove trailing space

---
 flang/include/flang/Optimizer/Builder/Runtime/Execute.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/flang/include/flang/Optimizer/Builder/Runtime/Execute.h b/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
index c35f46fa88d42..ee431caaeefd4 100644
--- a/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
+++ b/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
@@ -22,7 +22,7 @@ namespace fir::runtime {
 
 /// Generate a call to the ExecuteCommandLine runtime function which implements
 /// the GET_EXECUTE_ARGUMENT intrinsic.
-/// \p wait, \p exitstat, \p cmdstat and \p cmdmsg must be fir.box that can be 
+/// \p wait, \p exitstat, \p cmdstat and \p cmdmsg must be fir.box that can be
 /// absent (but not null mlir values). The status exitstat and cmdstat are
 /// returned, along with the message cmdmsg.
 mlir::Value genExecuteCommandLine(fir::FirOpBuilder &, mlir::Location,

>From 46664b767681f64f3fd6e213e90a9f7a5a7b9131 Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 15:03:31 +0300
Subject: [PATCH 08/22] 5 args not 6

---
 flang/lib/Optimizer/Builder/Runtime/Execute.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/flang/lib/Optimizer/Builder/Runtime/Execute.cpp b/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
index 1942c6e943fb8..261dcb529b7c8 100644
--- a/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
+++ b/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
@@ -34,7 +34,7 @@ mlir::Value fir::runtime::genExecuteCommandLine(
   mlir::FunctionType runtimeFuncTy = runtimeFunc.getFunctionType();
   mlir::Value sourceFile = fir::factory::locationToFilename(builder, loc);
   mlir::Value sourceLine =
-      fir::factory::locationToLineNo(builder, loc, runtimeFuncTy.getInput(6));
+      fir::factory::locationToLineNo(builder, loc, runtimeFuncTy.getInput(5));
   llvm::SmallVector<mlir::Value> args =
       fir::runtime::createArguments(builder, loc, runtimeFuncTy, command, wait,
                                     exitstat, cmdstat, cmdmsg, sourceFile,

>From 01d6167916959e47e16273579b058168b515e4f4 Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 15:10:41 +0300
Subject: [PATCH 09/22] i have no idea what i am doing

---
 flang/lib/Optimizer/Builder/IntrinsicCall.cpp | 62 +++++++++++--------
 1 file changed, 37 insertions(+), 25 deletions(-)

diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index 4c504e0b04f23..1f151964a1d29 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -2779,41 +2779,53 @@ IntrinsicLibrary::genEoshift(mlir::Type resultType,
 void IntrinsicLibrary::genExecuteCommandLine(
     llvm::ArrayRef<fir::ExtendedValue> args) {
   assert(args.size() == 5);
-  mlir::Value number = fir::getBase(args[0]);
-  const fir::ExtendedValue &value = args[1];
-  const fir::ExtendedValue &length = args[2];
-  const fir::ExtendedValue &status = args[3];
-  const fir::ExtendedValue &errmsg = args[4];
+  mlir::Value command = fir::getBase(args[0]);
+  const fir::ExtendedValue &wait = args[1];
+  const fir::ExtendedValue &exitstat = args[2];
+  const fir::ExtendedValue &cmdstat = args[3];
+  const fir::ExtendedValue &cmdmsg = args[4];
 
-  if (!number)
-    fir::emitFatalError(loc, "expected NUMBER parameter");
+  if (!command)
+    fir::emitFatalError(loc, "expected COMMAND parameter");
 
   // If none of the optional parameters are present, do nothing.
-  if (!isStaticallyPresent(value) && !isStaticallyPresent(length) &&
-      !isStaticallyPresent(status) && !isStaticallyPresent(errmsg))
+  if (!isStaticallyPresent(wait) && !isStaticallyPresent(exitstat) &&
+      !isStaticallyPresent(cmdstat) && !isStaticallyPresent(cmdmsg))
     return;
 
   mlir::Type boxNoneTy = fir::BoxType::get(builder.getNoneType());
-  mlir::Value valBox =
-      isStaticallyPresent(value)
-          ? fir::getBase(value)
+  mlir::Value waitBox =
+      isStaticallyPresent(wait)
+          ? fir::getBase(wait)
           : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
-  mlir::Value lenBox =
-      isStaticallyPresent(length)
-          ? fir::getBase(length)
+  mlir::Value exitstatBox =
+      isStaticallyPresent(exitstat)
+          ? fir::getBase(exitstt)
           : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
-  mlir::Value errBox =
-      isStaticallyPresent(errmsg)
-          ? fir::getBase(errmsg)
+  mlir::Value cmdstatBox =
+      isStaticallyPresent(cmdstat)
+          ? fir::getBase(cmdstat)
+          : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
+  mlir::Value cmdmsgBox =
+      isStaticallyPresent(cmdmsg)
+          ? fir::getBase(cmdmsg)
           : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
   mlir::Value stat = fir::runtime::genExecuteCommandLine(
-      builder, loc, number, valBox, lenBox, errBox);
-  if (isStaticallyPresent(status)) {
-    mlir::Value statAddr = fir::getBase(status);
-    mlir::Value statIsPresentAtRuntime =
-        builder.genIsNotNullAddr(loc, statAddr);
-    builder.genIfThen(loc, statIsPresentAtRuntime)
-        .genThen([&]() { builder.createStoreWithConvert(loc, stat, statAddr); })
+      builder, loc, command, waitBox, cmdstatBox, exitstatBox, cmdmsgBox);
+  if (isStaticallyPresent(exitstat)) {
+    mlir::Value exitstatAddr = fir::getBase(exitstat);
+    mlir::Value exitstatIsPresentAtRuntime =
+        builder.genIsNotNullAddr(loc, exitstatAddr);
+    builder.genIfThen(loc, exitstatIsPresentAtRuntime)
+        .genThen([&]() { builder.createStoreWithConvert(loc, exitstat, exitstatAddr); })
+        .end();
+  }
+  if (isStaticallyPresent(cmdstat)) {
+    mlir::Value cmdstatAddr = fir::getBase(cmdstat);
+    mlir::Value cmdstatIsPresentAtRuntime =
+        builder.genIsNotNullAddr(loc, cmdstatAddr);
+    builder.genIfThen(loc, cmdstatIsPresentAtRuntime)
+        .genThen([&]() { builder.createStoreWithConvert(loc, cmdstat, cmdstatAddr); })
         .end();
   }
 }

>From b6ea7a7f4492ca18aec1192e91b17bc308bc1ec8 Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 15:21:10 +0300
Subject: [PATCH 10/22] runtime part of this

---
 flang/include/flang/Runtime/execute.h | 33 +++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 flang/include/flang/Runtime/execute.h

diff --git a/flang/include/flang/Runtime/execute.h b/flang/include/flang/Runtime/execute.h
new file mode 100644
index 0000000000000..a988963cb1799
--- /dev/null
+++ b/flang/include/flang/Runtime/execute.h
@@ -0,0 +1,33 @@
+//===-- include/flang/Runtime/command.h -------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_RUNTIME_EXECUTE_H_
+#define FORTRAN_RUNTIME_EXECUTE_H_
+
+#include "flang/Runtime/entry-names.h"
+
+#include <cstdint>
+
+namespace Fortran::runtime {
+class Descriptor;
+
+extern "C" {
+
+// 16.9.83 EXECUTE_COMMAND_LINE
+// Execute a command line.
+// Returns a EXITSTAT, CMDSTAT, and CMDMSG as described in the standard.
+std::int32_t RTNAME(ExecuteCommandLine)(
+    const Descriptor *command = nullptr, const Descriptor *wait = nullptr,
+    const Descriptor *exitstat = nullptr, const Descriptor *cmdstat = nullptr,
+    const Descriptor *cmdmsg = nullptr, const char *sourceFile = nullptr,
+    int line = 0);
+
+}
+} // namespace Fortran::runtime
+
+#endif // FORTRAN_RUNTIME_EXECUTE_H_

>From 7ffafe46fec5e0751becbfd269bf6d460d01b428 Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 15:26:10 +0300
Subject: [PATCH 11/22] WIP

---
 flang/runtime/execute.cpp | 139 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 flang/runtime/execute.cpp

diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
new file mode 100644
index 0000000000000..31f2a63a00d4d
--- /dev/null
+++ b/flang/runtime/execute.cpp
@@ -0,0 +1,139 @@
+//===-- runtime/execute.cpp -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "flang/Runtime/execute.h"
+#include "environment.h"
+#include "stat.h"
+#include "terminator.h"
+#include "tools.h"
+#include "flang/Runtime/descriptor.h"
+#include <cstdlib>
+#include <limits>
+
+namespace Fortran::runtime {
+
+// Returns the length of the \p string. Assumes \p string is valid.
+static std::int64_t StringLength(const char *string) {
+  std::size_t length{std::strlen(string)};
+  if constexpr (sizeof(std::size_t) < sizeof(std::int64_t)) {
+    return static_cast<std::int64_t>(length);
+  } else {
+    std::size_t max{std::numeric_limits<std::int64_t>::max()};
+    return length > max ? 0 // Just fail.
+                        : static_cast<std::int64_t>(length);
+  }
+}
+
+static bool IsValidCharDescriptor(const Descriptor *value) {
+  return value && value->IsAllocated() &&
+      value->type() == TypeCode(TypeCategory::Character, 1) &&
+      value->rank() == 0;
+}
+
+static bool IsValidIntDescriptor(const Descriptor *length) {
+  auto typeCode{length->type().GetCategoryAndKind()};
+  // Check that our descriptor is allocated and is a scalar integer with
+  // kind != 1 (i.e. with a large enough decimal exponent range).
+  return length->IsAllocated() && length->rank() == 0 &&
+      length->type().IsInteger() && typeCode && typeCode->second != 1;
+}
+
+static void FillWithSpaces(const Descriptor &value, std::size_t offset = 0) {
+  if (offset < value.ElementBytes()) {
+    std::memset(
+        value.OffsetElement(offset), ' ', value.ElementBytes() - offset);
+  }
+}
+
+static std::int32_t CopyToDescriptor(const Descriptor &value,
+    const char *rawValue, std::int64_t rawValueLength, const Descriptor *errmsg,
+    std::size_t offset = 0) {
+
+  std::int64_t toCopy{std::min(rawValueLength,
+      static_cast<std::int64_t>(value.ElementBytes() - offset))};
+  if (toCopy < 0) {
+    return ToErrmsg(errmsg, StatValueTooShort);
+  }
+
+  std::memcpy(value.OffsetElement(offset), rawValue, toCopy);
+
+  if (rawValueLength > toCopy) {
+    return ToErrmsg(errmsg, StatValueTooShort);
+  }
+
+  return StatOk;
+}
+
+static std::int32_t CheckAndCopyToDescriptor(const Descriptor *value,
+    const char *rawValue, const Descriptor *errmsg, std::size_t &offset) {
+  bool haveValue{IsValidCharDescriptor(value)};
+
+  std::int64_t len{StringLength(rawValue)};
+  if (len <= 0) {
+    if (haveValue) {
+      FillWithSpaces(*value);
+    }
+    return ToErrmsg(errmsg, StatMissingArgument);
+  }
+
+  std::int32_t stat{StatOk};
+  if (haveValue) {
+    stat = CopyToDescriptor(*value, rawValue, len, errmsg, offset);
+  }
+
+  offset += len;
+  return stat;
+}
+
+static void StoreLengthToDescriptor(
+    const Descriptor *length, std::int64_t value, Terminator &terminator) {
+  auto typeCode{length->type().GetCategoryAndKind()};
+  int kind{typeCode->second};
+  Fortran::runtime::ApplyIntegerKind<Fortran::runtime::StoreIntegerAt, void>(
+      kind, terminator, *length, /* atIndex = */ 0, value);
+}
+
+template <int KIND> struct FitsInIntegerKind {
+  bool operator()([[maybe_unused]] std::int64_t value) {
+    if constexpr (KIND >= 8) {
+      return true;
+    } else {
+      return value <= std::numeric_limits<Fortran::runtime::CppTypeFor<
+                          Fortran::common::TypeCategory::Integer, KIND>>::max();
+    }
+  }
+};
+
+static bool FitsInDescriptor(
+    const Descriptor *length, std::int64_t value, Terminator &terminator) {
+  auto typeCode{length->type().GetCategoryAndKind()};
+  int kind{typeCode->second};
+  return Fortran::runtime::ApplyIntegerKind<FitsInIntegerKind, bool>(
+      kind, terminator, value);
+}
+
+std::int32_t RTNAME(ExecuteCommandLine)(const Descriptor *command,
+    const Descriptor *wait, const Descriptor *exitstat,
+    const Descriptor *cmdstat, const Descriptor *cmdmsg, const char *sourceFile,
+    int line) {
+  Terminator terminator{sourceFile, line};
+
+  if (command) {
+    RUNTIME_CHECK(terminator, IsValidCharDescriptor(command));
+  }
+
+  if (wait) {
+    RUNTIME_CHECK(terminator, IsValidLogicalDescriptor(wait));
+  }
+
+  // TODO
+
+  return StatOk;
+}
+
+} // namespace Fortran::runtime

>From 2e9685bdec4d36ee69a82ee073254f6f9fe5e001 Mon Sep 17 00:00:00 2001
From: Jeff Hammond <jeff.science at gmail.com>
Date: Wed, 18 Oct 2023 15:27:55 +0300
Subject: [PATCH 12/22] where is the pattern for IsValidLogicalDescriptor

---
 flang/runtime/execute.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
index 31f2a63a00d4d..d5515b3e2d7bb 100644
--- a/flang/runtime/execute.cpp
+++ b/flang/runtime/execute.cpp
@@ -43,6 +43,12 @@ static bool IsValidIntDescriptor(const Descriptor *length) {
       length->type().IsInteger() && typeCode && typeCode->second != 1;
 }
 
+static bool IsValidLogicalDescriptor(const Descriptor *wait) {
+  return wait && wait->IsAllocated() &&
+      wait->type() == TypeCode(TypeCategory::Logical, 1) &&
+      wait->rank() == 0;
+}
+
 static void FillWithSpaces(const Descriptor &value, std::size_t offset = 0) {
   if (offset < value.ElementBytes()) {
     std::memset(

>From df35e093dba7e9f7899b48e2cf7d9b7bf05cb895 Mon Sep 17 00:00:00 2001
From: Yi Wu <yi.wu2 at arm.com>
Date: Mon, 20 Nov 2023 10:08:01 +0000
Subject: [PATCH 13/22] some small fixes to make it build

---
 .../flang/Optimizer/Builder/Runtime/Execute.h |  8 +--
 flang/include/flang/Runtime/execute.h         | 10 ++--
 flang/lib/Optimizer/Builder/CMakeLists.txt    |  1 +
 flang/lib/Optimizer/Builder/IntrinsicCall.cpp | 42 ++++-----------
 .../lib/Optimizer/Builder/Runtime/Execute.cpp | 23 ++++----
 flang/runtime/CMakeLists.txt                  |  1 +
 flang/runtime/execute.cpp                     | 53 ++++++++++++-------
 .../execute_command_line-optional.f90         |  5 +-
 .../Lower/Intrinsics/execute_command_line.f90 | 24 +++++----
 9 files changed, 85 insertions(+), 82 deletions(-)

diff --git a/flang/include/flang/Optimizer/Builder/Runtime/Execute.h b/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
index ee431caaeefd4..f660419d70304 100644
--- a/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
+++ b/flang/include/flang/Optimizer/Builder/Runtime/Execute.h
@@ -25,10 +25,10 @@ namespace fir::runtime {
 /// \p wait, \p exitstat, \p cmdstat and \p cmdmsg must be fir.box that can be
 /// absent (but not null mlir values). The status exitstat and cmdstat are
 /// returned, along with the message cmdmsg.
-mlir::Value genExecuteCommandLine(fir::FirOpBuilder &, mlir::Location,
-                                  mlir::Value command, mlir::Value wait,
-                                  mlir::Value exitstat, mlir::Value cmdstat,
-                                  mlir::Value cmdmsg);
+void genExecuteCommandLine(fir::FirOpBuilder &, mlir::Location,
+                           mlir::Value command, mlir::Value wait,
+                           mlir::Value exitstat, mlir::Value cmdstat,
+                           mlir::Value cmdmsg);
 
 } // namespace fir::runtime
 #endif // FORTRAN_OPTIMIZER_BUILDER_RUNTIME_EXECUTE_H
diff --git a/flang/include/flang/Runtime/execute.h b/flang/include/flang/Runtime/execute.h
index a988963cb1799..397c82db82eb5 100644
--- a/flang/include/flang/Runtime/execute.h
+++ b/flang/include/flang/Runtime/execute.h
@@ -21,12 +21,10 @@ extern "C" {
 // 16.9.83 EXECUTE_COMMAND_LINE
 // Execute a command line.
 // Returns a EXITSTAT, CMDSTAT, and CMDMSG as described in the standard.
-std::int32_t RTNAME(ExecuteCommandLine)(
-    const Descriptor *command = nullptr, const Descriptor *wait = nullptr,
-    const Descriptor *exitstat = nullptr, const Descriptor *cmdstat = nullptr,
-    const Descriptor *cmdmsg = nullptr, const char *sourceFile = nullptr,
-    int line = 0);
-
+std::int32_t RTNAME(ExecuteCommandLine)(const Descriptor *command = nullptr,
+    bool wait = false, const Descriptor *exitstat = nullptr,
+    const Descriptor *cmdstat = nullptr, const Descriptor *cmdmsg = nullptr,
+    const char *sourceFile = nullptr, int line = 0);
 }
 } // namespace Fortran::runtime
 
diff --git a/flang/lib/Optimizer/Builder/CMakeLists.txt b/flang/lib/Optimizer/Builder/CMakeLists.txt
index 5e5daffd3ed7d..2d28b10f01fde 100644
--- a/flang/lib/Optimizer/Builder/CMakeLists.txt
+++ b/flang/lib/Optimizer/Builder/CMakeLists.txt
@@ -19,6 +19,7 @@ add_flang_library(FIRBuilder
   Runtime/Command.cpp
   Runtime/Derived.cpp
   Runtime/EnvironmentDefaults.cpp
+  Runtime/Execute.cpp
   Runtime/Inquiry.cpp
   Runtime/Intrinsics.cpp
   Runtime/Numeric.cpp
diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index 9447d3325a1aa..9100cf0a4394b 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -25,6 +25,7 @@
 #include "flang/Optimizer/Builder/Runtime/Character.h"
 #include "flang/Optimizer/Builder/Runtime/Command.h"
 #include "flang/Optimizer/Builder/Runtime/Derived.h"
+#include "flang/Optimizer/Builder/Runtime/Execute.h"
 #include "flang/Optimizer/Builder/Runtime/Inquiry.h"
 #include "flang/Optimizer/Builder/Runtime/Intrinsics.h"
 #include "flang/Optimizer/Builder/Runtime/Numeric.h"
@@ -212,9 +213,9 @@ static constexpr IntrinsicHandler handlers[]{
     {"execute_command_line",
      &I::genExecuteCommandLine,
      {{{"command", asBox},
-       {"wait", asAddr, handleDynamicOptional},
-       {"exitstat", asAddr, handleDynamicOptional},
-       {"cmdstat", asAddr, handleDynamicOptional},
+       {"wait", asValue, handleDynamicOptional},
+       {"exitstat", asBox, handleDynamicOptional},
+       {"cmdstat", asBox, handleDynamicOptional},
        {"cmdmsg", asBox, handleDynamicOptional}}},
      /*isElemental=*/false},
     {"exit",
@@ -2797,19 +2798,14 @@ void IntrinsicLibrary::genExecuteCommandLine(
   if (!command)
     fir::emitFatalError(loc, "expected COMMAND parameter");
 
-  // If none of the optional parameters are present, do nothing.
-  if (!isStaticallyPresent(wait) && !isStaticallyPresent(exitstat) &&
-      !isStaticallyPresent(cmdstat) && !isStaticallyPresent(cmdmsg))
-    return;
-
   mlir::Type boxNoneTy = fir::BoxType::get(builder.getNoneType());
-  mlir::Value waitBox =
-      isStaticallyPresent(wait)
-          ? fir::getBase(wait)
-          : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
+
+  mlir::Value waitBool = isStaticallyPresent(wait)
+                             ? fir::getBase(wait)
+                             : builder.createBool(loc, false);
   mlir::Value exitstatBox =
       isStaticallyPresent(exitstat)
-          ? fir::getBase(exitstt)
+          ? fir::getBase(exitstat)
           : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
   mlir::Value cmdstatBox =
       isStaticallyPresent(cmdstat)
@@ -2819,24 +2815,8 @@ void IntrinsicLibrary::genExecuteCommandLine(
       isStaticallyPresent(cmdmsg)
           ? fir::getBase(cmdmsg)
           : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
-  mlir::Value stat = fir::runtime::genExecuteCommandLine(
-      builder, loc, command, waitBox, cmdstatBox, exitstatBox, cmdmsgBox);
-  if (isStaticallyPresent(exitstat)) {
-    mlir::Value exitstatAddr = fir::getBase(exitstat);
-    mlir::Value exitstatIsPresentAtRuntime =
-        builder.genIsNotNullAddr(loc, exitstatAddr);
-    builder.genIfThen(loc, exitstatIsPresentAtRuntime)
-        .genThen([&]() { builder.createStoreWithConvert(loc, exitstat, exitstatAddr); })
-        .end();
-  }
-  if (isStaticallyPresent(cmdstat)) {
-    mlir::Value cmdstatAddr = fir::getBase(cmdstat);
-    mlir::Value cmdstatIsPresentAtRuntime =
-        builder.genIsNotNullAddr(loc, cmdstatAddr);
-    builder.genIfThen(loc, cmdstatIsPresentAtRuntime)
-        .genThen([&]() { builder.createStoreWithConvert(loc, cmdstat, cmdstatAddr); })
-        .end();
-  }
+  fir::runtime::genExecuteCommandLine(builder, loc, command, waitBool,
+                                      cmdstatBox, exitstatBox, cmdmsgBox);
 }
 
 // EXIT
diff --git a/flang/lib/Optimizer/Builder/Runtime/Execute.cpp b/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
index 261dcb529b7c8..71ee3996ac0da 100644
--- a/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
+++ b/flang/lib/Optimizer/Builder/Runtime/Execute.cpp
@@ -9,7 +9,7 @@
 #include "flang/Optimizer/Builder/Runtime/Execute.h"
 #include "flang/Optimizer/Builder/FIRBuilder.h"
 #include "flang/Optimizer/Builder/Runtime/RTBuilder.h"
-#include "flang/Runtime/command.h"
+#include "flang/Runtime/execute.h"
 
 using namespace Fortran::runtime;
 
@@ -25,19 +25,20 @@ inline bool isAbsent(mlir::Value val) {
   return mlir::isa_and_nonnull<fir::AbsentOp>(val.getDefiningOp());
 }
 
-mlir::Value fir::runtime::genExecuteCommandLine(
-    fir::FirOpBuilder &builder, mlir::Location loc, mlir::Value command,
-    mlir::Value wait, mlir::Value exitstat, mlir::Value cmdstat,
-    mlir::Value cmdmsg) {
+void fir::runtime::genExecuteCommandLine(fir::FirOpBuilder &builder,
+                                         mlir::Location loc,
+                                         mlir::Value command, mlir::Value wait,
+                                         mlir::Value exitstat,
+                                         mlir::Value cmdstat,
+                                         mlir::Value cmdmsg) {
   auto runtimeFunc =
       fir::runtime::getRuntimeFunc<mkRTKey(ExecuteCommandLine)>(loc, builder);
   mlir::FunctionType runtimeFuncTy = runtimeFunc.getFunctionType();
   mlir::Value sourceFile = fir::factory::locationToFilename(builder, loc);
   mlir::Value sourceLine =
-      fir::factory::locationToLineNo(builder, loc, runtimeFuncTy.getInput(5));
-  llvm::SmallVector<mlir::Value> args =
-      fir::runtime::createArguments(builder, loc, runtimeFuncTy, command, wait,
-                                    exitstat, cmdstat, cmdmsg, sourceFile,
-                                    sourceLine);
-  return builder.create<fir::CallOp>(loc, runtimeFunc, args).getResult(0);
+      fir::factory::locationToLineNo(builder, loc, runtimeFuncTy.getInput(6));
+  llvm::SmallVector<mlir::Value> args = fir::runtime::createArguments(
+      builder, loc, runtimeFuncTy, command, wait, exitstat, cmdstat, cmdmsg,
+      sourceFile, sourceLine);
+  builder.create<fir::CallOp>(loc, runtimeFunc, args);
 }
diff --git a/flang/runtime/CMakeLists.txt b/flang/runtime/CMakeLists.txt
index 68ae97bed4e32..cd2bc51098d24 100644
--- a/flang/runtime/CMakeLists.txt
+++ b/flang/runtime/CMakeLists.txt
@@ -104,6 +104,7 @@ set(sources
   edit-input.cpp
   edit-output.cpp
   environment.cpp
+  execute.cpp
   extensions.cpp
   extrema.cpp
   file.cpp
diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
index d5515b3e2d7bb..5966daf84f5a4 100644
--- a/flang/runtime/execute.cpp
+++ b/flang/runtime/execute.cpp
@@ -13,6 +13,8 @@
 #include "tools.h"
 #include "flang/Runtime/descriptor.h"
 #include <cstdlib>
+// #include <iostream>
+// #include <string>
 #include <limits>
 
 namespace Fortran::runtime {
@@ -43,12 +45,6 @@ static bool IsValidIntDescriptor(const Descriptor *length) {
       length->type().IsInteger() && typeCode && typeCode->second != 1;
 }
 
-static bool IsValidLogicalDescriptor(const Descriptor *wait) {
-  return wait && wait->IsAllocated() &&
-      wait->type() == TypeCode(TypeCategory::Logical, 1) &&
-      wait->rank() == 0;
-}
-
 static void FillWithSpaces(const Descriptor &value, std::size_t offset = 0) {
   if (offset < value.ElementBytes()) {
     std::memset(
@@ -96,12 +92,12 @@ static std::int32_t CheckAndCopyToDescriptor(const Descriptor *value,
   return stat;
 }
 
-static void StoreLengthToDescriptor(
-    const Descriptor *length, std::int64_t value, Terminator &terminator) {
-  auto typeCode{length->type().GetCategoryAndKind()};
+static void StoreIntToDescriptor(
+    const Descriptor *intVal, std::int64_t value, Terminator &terminator) {
+  auto typeCode{intVal->type().GetCategoryAndKind()};
   int kind{typeCode->second};
   Fortran::runtime::ApplyIntegerKind<Fortran::runtime::StoreIntegerAt, void>(
-      kind, terminator, *length, /* atIndex = */ 0, value);
+      kind, terminator, *intVal, /* atIndex = */ 0, value);
 }
 
 template <int KIND> struct FitsInIntegerKind {
@@ -123,18 +119,39 @@ static bool FitsInDescriptor(
       kind, terminator, value);
 }
 
-std::int32_t RTNAME(ExecuteCommandLine)(const Descriptor *command,
-    const Descriptor *wait, const Descriptor *exitstat,
-    const Descriptor *cmdstat, const Descriptor *cmdmsg, const char *sourceFile,
-    int line) {
+std::int32_t RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
+    const Descriptor *exitstat, const Descriptor *cmdstat,
+    const Descriptor *cmdmsg, const char *sourceFile, int line) {
   Terminator terminator{sourceFile, line};
 
-  if (command) {
-    RUNTIME_CHECK(terminator, IsValidCharDescriptor(command));
-  }
+  int exitstatVal;
+  int cmdstatVal;
 
   if (wait) {
-    RUNTIME_CHECK(terminator, IsValidLogicalDescriptor(wait));
+    // RUNTIME_CHECK(terminator, IsValidLogicalDescriptor(wait));
+    // if (wait)
+  } else {
+    if (command) {
+      RUNTIME_CHECK(terminator, IsValidCharDescriptor(command));
+      exitstatVal = std::system(command->OffsetElement());
+    }
+  }
+
+  if (exitstat) {
+    RUNTIME_CHECK(terminator, IsValidIntDescriptor(exitstat));
+    StoreIntToDescriptor(exitstat, exitstatVal, terminator);
+  }
+
+  if (cmdstat) {
+    RUNTIME_CHECK(terminator, IsValidIntDescriptor(cmdstat));
+    StoreIntToDescriptor(cmdstat, 0, terminator);
+  }
+
+  if (cmdmsg) {
+    RUNTIME_CHECK(terminator, IsValidCharDescriptor(cmdmsg));
+    std::array<char, 5> str;
+    str.fill('f');
+    CopyToDescriptor(*cmdmsg, str.data(), str.size(), nullptr);
   }
 
   // TODO
diff --git a/flang/test/Lower/Intrinsics/execute_command_line-optional.f90 b/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
index b2c589a774466..be63bc75f2ebf 100644
--- a/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
+++ b/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
@@ -10,7 +10,8 @@
 ! CHECK-SAME:  %[[ARG_4:.*]]: !fir.boxchar<1> {fir.bindc_command = "cmdmsg", fir.optional}) {
 subroutine test(command, wait, length, cmdstat, cmdmsg)
   integer, optional :: cmdstat, length
-  character(*), optional :: command, wait, cmdmsg
+  logical :: wait
+  character(*), optional :: command, cmdmsg
   ! Note: command is not optional in execute_command_line and must be present
   call execute_command_line(command, wait, length, cmdstat, cmdmsg)
 ! CHECK:  %[[VAL_0:.*]]:2 = fir.unboxchar %[[ARG_5]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
@@ -44,7 +45,7 @@ subroutine test(command, wait, length, cmdstat, cmdmsg)
 ! CHECK:  %[[VAL_21:.*]] = fir.convert %[[VAL_7]] : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
 ! CHECK:  %[[VAL_22:.*]] = fir.convert %[[VAL_11]] : (!fir.box<i32>) -> !fir.box<none>
 ! CHECK:  %[[VAL_23:.*]] = fir.convert %[[VAL_15]] : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
-! CHECK:  %[[VAL_25:.*]] = fir.call @_FortranAGetEnvVariable(%[[VAL_20]], %[[VAL_21]], %[[VAL_22]], %[[VAL_18]], %[[VAL_23]], %{{.*}}, %{{.*}}) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK:  %[[VAL_25:.*]] = fir.call @_FortranAExecuteCommandLine(%[[VAL_20]], %[[VAL_21]], %[[VAL_22]], %[[VAL_18]], %[[VAL_23]], %{{.*}}, %{{.*}}) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
 ! CHECK:  %[[VAL_26:.*]] = fir.convert %[[ARG_3]] : (!fir.ref<i32>) -> i64
 ! CHECK:  %[[CONST_2:.*]] = arith.constant 0 : i64
 ! CHECK:  %[[VAL_27:.*]] = arith.cmpi ne, %[[VAL_26]], %[[CONST_2]] : i64
diff --git a/flang/test/Lower/Intrinsics/execute_command_line.f90 b/flang/test/Lower/Intrinsics/execute_command_line.f90
index f9b11ad7d772a..8ceae841440bc 100644
--- a/flang/test/Lower/Intrinsics/execute_command_line.f90
+++ b/flang/test/Lower/Intrinsics/execute_command_line.f90
@@ -6,7 +6,7 @@
 subroutine command_only(command)
     character(len=32) :: command
     call execute_command_line(command)
-! CHECK-NOT: fir.call @_FortranAGetEnvVariable
+! CHECK-Next: fir.call @_FortranAExecuteCommandLine
 ! CHECK-NEXT: return
 end subroutine command_only
 
@@ -14,7 +14,9 @@ end subroutine command_only
 ! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
 ! CHECK-SAME: %[[waitArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_command = "wait", fir.optional},
 subroutine command_and_wait_only(command, wait)
-    character(len=32) :: command, wait
+    character(len=32) :: command
+    logical::wait
+    wait = .false.
     call execute_command_line(command, wait)
 ! CHECK: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
 ! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
@@ -30,7 +32,7 @@ subroutine command_and_wait_only(command, wait)
 ! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
 ! CHECK-NEXT: %[[wait:.*]] = fir.convert %[[waitBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
 ! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
-! CHECK-NEXT: %{{[0-9]+}} = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-NEXT: %{{[0-9]+}} = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
 ! CHECK-NEXT: return
 end subroutine command_and_wait_only
 
@@ -53,7 +55,7 @@ subroutine command_and_exitstat_only(command, exitstat)
 ! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
 ! CHECK-NEXT: %[[exitstat:.*]] = fir.convert %[[exitstatBox]] : (!fir.box<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<none>
 ! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
-! CHECK-NEXT: %{{.*}} = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-NEXT: %{{.*}} = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
 end subroutine command_and_exitstat_only
 
 ! CHECK-LABEL: func @_QPcommand_and_cmdstat_only(
@@ -74,8 +76,8 @@ subroutine command_and_cmdstat_only(command, cmdstat)
 ! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 9]] : i32
 ! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
 ! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
-! CHECK-32-NEXT: %[[cmdstat:.*]] = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
-! CHECK-64-NEXT: %[[cmdstat32:.*]] = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-32-NEXT: %[[cmdstat:.*]] = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-64-NEXT: %[[cmdstat32:.*]] = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
 ! CHECK-64: %[[cmdstat:.*]] = fir.convert %[[cmdstat32]] : (i32) -> i64
 ! CHECK: fir.store %[[cmdstat]] to %[[cmdstatArg]] : !fir.ref<i[[DEFAULT_INTEGER_SIZE]]>
 end subroutine command_and_cmdstat_only
@@ -100,7 +102,7 @@ subroutine command_and_cmdmsg_only(command, cmdmsg)
 ! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
 ! CHECK-NEXT: %[[cmdmsg:.*]] = fir.convert %[[cmdmsgBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
 ! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
-! CHECK-NEXT: %{{[0-9]+}} = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-NEXT: %{{[0-9]+}} = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
 ! CHECK-NEXT: return
 end subroutine command_and_cmdmsg_only
 
@@ -111,8 +113,10 @@ end subroutine command_and_cmdmsg_only
 ! CHECK-SAME: %[[cmdstatArg:.*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_command = "cmdstat"},
 ! CHECK-SAME: %[[cmdmsgArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "cmdmsg"}) {
 subroutine all_arguments(command, wait, exitstat, cmdstat, cmdmsg)
-    character(len=32) :: command, wait, cmdmsg
+    character(len=32) :: command, cmdmsg
+    logical :: wait
     integer :: exitstat, cmdstat
+    wait=.false.
     call execute_command_line(command, wait, exitstat, cmdstat, cmdmsg)
 ! CHECK: %[[cmdmsgUnbox:.*]]:2 = fir.unboxchar %[[cmdmsgArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
 ! CHECK-NEXT: %[[cmdmsgCast:.*]] = fir.convert %[[cmdmsgUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
@@ -131,8 +135,8 @@ subroutine all_arguments(command, wait, exitstat, cmdstat, cmdmsg)
 ! CHECK-NEXT: %[[exitstat:.*]] = fir.convert %[[exitstatBoxed]] : (!fir.box<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<none>
 ! CHECK-NEXT: %[[cmdmsg:.*]] = fir.convert %[[cmdmsgBoxed]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
 ! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[fileStringexitstat]]>>) -> !fir.ref<i8>
-! CHECK-32-NEXT: %[[cmdstat:.*]] = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
-! CHECK-64-NEXT: %[[cmdstat32:.*]] = fir.call @_FortranAGetEnvVariable(%[[command]], %[[wait]], %[[exitstat]], %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-32-NEXT: %[[cmdstat:.*]] = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
+! CHECK-64-NEXT: %[[cmdstat32:.*]] = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
 ! CHECK-64: %[[cmdstat:.*]] = fir.convert %[[cmdstat32]] : (i32) -> i64
 ! CHECK: fir.store %[[cmdstat]] to %[[cmdstatArg]] : !fir.ref<i[[DEFAULT_INTEGER_SIZE]]>
 end subroutine all_arguments

>From 94ac4756eb2b9b008ed7f1c9edff06c82821c1eb Mon Sep 17 00:00:00 2001
From: Yi Wu <yi.wu2 at arm.com>
Date: Tue, 21 Nov 2023 12:14:01 +0000
Subject: [PATCH 14/22] Add simple support of async and sync execution, might
 not work on Windows

---
 flang/include/flang/Runtime/execute.h |   4 +-
 flang/runtime/execute.cpp             | 127 ++++++++++++++------------
 2 files changed, 72 insertions(+), 59 deletions(-)

diff --git a/flang/include/flang/Runtime/execute.h b/flang/include/flang/Runtime/execute.h
index 397c82db82eb5..0c8086fa8ecf0 100644
--- a/flang/include/flang/Runtime/execute.h
+++ b/flang/include/flang/Runtime/execute.h
@@ -21,8 +21,8 @@ extern "C" {
 // 16.9.83 EXECUTE_COMMAND_LINE
 // Execute a command line.
 // Returns a EXITSTAT, CMDSTAT, and CMDMSG as described in the standard.
-std::int32_t RTNAME(ExecuteCommandLine)(const Descriptor *command = nullptr,
-    bool wait = false, const Descriptor *exitstat = nullptr,
+void RTNAME(ExecuteCommandLine)(const Descriptor *command = nullptr,
+    bool wait = true, const Descriptor *exitstat = nullptr,
     const Descriptor *cmdstat = nullptr, const Descriptor *cmdmsg = nullptr,
     const char *sourceFile = nullptr, int line = 0);
 }
diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
index 5966daf84f5a4..458f2f6c964f3 100644
--- a/flang/runtime/execute.cpp
+++ b/flang/runtime/execute.cpp
@@ -13,24 +13,18 @@
 #include "tools.h"
 #include "flang/Runtime/descriptor.h"
 #include <cstdlib>
-// #include <iostream>
-// #include <string>
+#include <future>
 #include <limits>
+#ifdef _WIN32
+#define LEAN_AND_MEAN
+#define NOMINMAX
+#include <windows.h>
+#else
+#include <unistd.h>
+#endif
 
 namespace Fortran::runtime {
 
-// Returns the length of the \p string. Assumes \p string is valid.
-static std::int64_t StringLength(const char *string) {
-  std::size_t length{std::strlen(string)};
-  if constexpr (sizeof(std::size_t) < sizeof(std::int64_t)) {
-    return static_cast<std::int64_t>(length);
-  } else {
-    std::size_t max{std::numeric_limits<std::int64_t>::max()};
-    return length > max ? 0 // Just fail.
-                        : static_cast<std::int64_t>(length);
-  }
-}
-
 static bool IsValidCharDescriptor(const Descriptor *value) {
   return value && value->IsAllocated() &&
       value->type() == TypeCode(TypeCategory::Character, 1) &&
@@ -71,27 +65,6 @@ static std::int32_t CopyToDescriptor(const Descriptor &value,
   return StatOk;
 }
 
-static std::int32_t CheckAndCopyToDescriptor(const Descriptor *value,
-    const char *rawValue, const Descriptor *errmsg, std::size_t &offset) {
-  bool haveValue{IsValidCharDescriptor(value)};
-
-  std::int64_t len{StringLength(rawValue)};
-  if (len <= 0) {
-    if (haveValue) {
-      FillWithSpaces(*value);
-    }
-    return ToErrmsg(errmsg, StatMissingArgument);
-  }
-
-  std::int32_t stat{StatOk};
-  if (haveValue) {
-    stat = CopyToDescriptor(*value, rawValue, len, errmsg, offset);
-  }
-
-  offset += len;
-  return stat;
-}
-
 static void StoreIntToDescriptor(
     const Descriptor *intVal, std::int64_t value, Terminator &terminator) {
   auto typeCode{intVal->type().GetCategoryAndKind()};
@@ -111,30 +84,75 @@ template <int KIND> struct FitsInIntegerKind {
   }
 };
 
-static bool FitsInDescriptor(
-    const Descriptor *length, std::int64_t value, Terminator &terminator) {
-  auto typeCode{length->type().GetCategoryAndKind()};
-  int kind{typeCode->second};
-  return Fortran::runtime::ApplyIntegerKind<FitsInIntegerKind, bool>(
-      kind, terminator, value);
-}
-
-std::int32_t RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
+void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     const Descriptor *exitstat, const Descriptor *cmdstat,
     const Descriptor *cmdmsg, const char *sourceFile, int line) {
   Terminator terminator{sourceFile, line};
 
   int exitstatVal;
   int cmdstatVal;
+  pid_t pid;
+  std::array<char, 30> cmdstr;
+  cmdstr.fill(' ');
+
+  // cmdstat specified in 16.9.73
+  // It is assigned the value −1 if the processor does not support command
+  // line execution, a processor-dependent positive value if an error
+  // condition occurs, or the value −2 if no error condition occurs but WAIT
+  // is present with the value false and the processor does not support
+  // asynchronous execution. Otherwise it is assigned the value 0
+  enum CMD_STAT {
+    ASYNC_NO_SUPPORT_ERR = -2,
+    NO_SUPPORT_ERR = -1,
+    CMD_EXECUTED = 0,
+    FORK_ERR = 1,
+    EXECL_ERR = 2,
+    SIGNAL_ERR = 3
+  };
+
+  if (command) {
+    RUNTIME_CHECK(terminator, IsValidCharDescriptor(command));
+  }
 
   if (wait) {
-    // RUNTIME_CHECK(terminator, IsValidLogicalDescriptor(wait));
-    // if (wait)
+    // either wait is not specified or wait is true: synchronous mode
+    exitstatVal = std::system(command->OffsetElement());
+    cmdstatVal = CMD_EXECUTED;
   } else {
-    if (command) {
-      RUNTIME_CHECK(terminator, IsValidCharDescriptor(command));
-      exitstatVal = std::system(command->OffsetElement());
+// Asynchronous mode, Windows doesn't support fork()
+#ifdef _WIN32
+    STARTUPINFO si;
+    PROCESS_INFORMATION pi;
+
+    ZeroMemory(&si, sizeof(si));
+    si.cb = sizeof(si);
+    ZeroMemory(&pi, sizeof(pi));
+
+    if (CreateProcess(nullptr, const_cast<char *>(cmd), nullptr, nullptr, FALSE,
+            0, nullptr, nullptr, &si, &pi)) {
+      if (!GetExitCodeProcess(pi.hProcess, (DWORD)&exitstatVal)) {
+        cmdstatVal = (uint32_t)GetLastError();
+        std::strncpy(cmdstr.data(), "GetExitCodeProcess failed.", 26);
+      } else {
+        cmdstatVal = CMD_EXECUTED;
+      }
+    } else {
+      cmdstatVal = (uint32_t)GetLastError();
+      std::strncpy(cmdstr.data(), "CreateProcess failed.", 21);
     }
+
+#else
+    pid = fork();
+    if (pid < 0) {
+      std::strncpy(cmdstr.data(), "Fork failed", 11);
+      cmdstatVal = FORK_ERR;
+    } else if (pid == 0) {
+      exitstatVal =
+          execl("/bin/sh", "sh", "-c", command->OffsetElement(), (char *)NULL);
+      cmdstatVal = CMD_EXECUTED;
+      std::strncpy(cmdstr.data(), "Command executed.", 17);
+    }
+#endif
   }
 
   if (exitstat) {
@@ -144,19 +162,14 @@ std::int32_t RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
 
   if (cmdstat) {
     RUNTIME_CHECK(terminator, IsValidIntDescriptor(cmdstat));
-    StoreIntToDescriptor(cmdstat, 0, terminator);
+    StoreIntToDescriptor(cmdstat, cmdstatVal, terminator);
   }
 
   if (cmdmsg) {
     RUNTIME_CHECK(terminator, IsValidCharDescriptor(cmdmsg));
-    std::array<char, 5> str;
-    str.fill('f');
-    CopyToDescriptor(*cmdmsg, str.data(), str.size(), nullptr);
+    FillWithSpaces(*cmdmsg);
+    CopyToDescriptor(*cmdmsg, cmdstr.data(), cmdstr.size(), nullptr);
   }
-
-  // TODO
-
-  return StatOk;
 }
 
 } // namespace Fortran::runtime

>From ecfd50dd5b63f2b29e49c8adae16ea5853943e8c Mon Sep 17 00:00:00 2001
From: Yi Wu <yi.wu2 at arm.com>
Date: Thu, 23 Nov 2023 15:52:08 +0000
Subject: [PATCH 15/22] some changes to match the standard 16.9.73

exitstat: If sync, assigned processor-dependent exit status. Otherwise unchanged.
cmdstast: Assigned 0 as specifed in standard, if error then overwrite.
If a condition occurs that would assign a nonzero value to CMDSTAT but
the CMDSTAT variable is not present, error termination is initiated.
---
 flang/runtime/execute.cpp | 109 +++++++++++++++++++++-----------------
 1 file changed, 61 insertions(+), 48 deletions(-)

diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
index 458f2f6c964f3..d8a37dd19764d 100644
--- a/flang/runtime/execute.cpp
+++ b/flang/runtime/execute.cpp
@@ -89,18 +89,12 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     const Descriptor *cmdmsg, const char *sourceFile, int line) {
   Terminator terminator{sourceFile, line};
 
-  int exitstatVal;
-  int cmdstatVal;
-  pid_t pid;
-  std::array<char, 30> cmdstr;
-  cmdstr.fill(' ');
-
   // cmdstat specified in 16.9.73
-  // It is assigned the value −1 if the processor does not support command
-  // line execution, a processor-dependent positive value if an error
-  // condition occurs, or the value −2 if no error condition occurs but WAIT
-  // is present with the value false and the processor does not support
-  // asynchronous execution. Otherwise it is assigned the value 0
+  // −1 if the processor does not support command line execution,
+  // a processor-dependent positive value if an error condition occurs
+  // −2 if no error condition occurs but WAIT is present with the value false
+  // and the processor does not support asynchronous execution. Otherwise it is
+  // assigned the value 0
   enum CMD_STAT {
     ASYNC_NO_SUPPORT_ERR = -2,
     NO_SUPPORT_ERR = -1,
@@ -113,63 +107,82 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
   if (command) {
     RUNTIME_CHECK(terminator, IsValidCharDescriptor(command));
   }
+  if (exitstat) {
+    RUNTIME_CHECK(terminator, IsValidIntDescriptor(exitstat));
+    // If sync, assigned processor-dependent exit status. Otherwise unchanged
+  }
+
+  if (cmdstat) {
+    RUNTIME_CHECK(terminator, IsValidIntDescriptor(cmdstat));
+    // If a condition occurs that would assign a nonzero value to CMDSTAT but
+    // the CMDSTAT variable is not present, error termination is initiated.
+    // Assigned 0 as specifed in standard, if error then overwrite
+    StoreIntToDescriptor(cmdstat, CMD_EXECUTED, terminator);
+  }
+
+  if (cmdmsg) {
+    RUNTIME_CHECK(terminator, IsValidCharDescriptor(cmdmsg));
+  }
 
   if (wait) {
     // either wait is not specified or wait is true: synchronous mode
-    exitstatVal = std::system(command->OffsetElement());
-    cmdstatVal = CMD_EXECUTED;
+    int exitstatVal = std::system(command->OffsetElement());
+    StoreIntToDescriptor(exitstat, exitstatVal, terminator);
   } else {
-// Asynchronous mode, Windows doesn't support fork()
+// Asynchronous mode
 #ifdef _WIN32
     STARTUPINFO si;
     PROCESS_INFORMATION pi;
-
     ZeroMemory(&si, sizeof(si));
     si.cb = sizeof(si);
     ZeroMemory(&pi, sizeof(pi));
 
-    if (CreateProcess(nullptr, const_cast<char *>(cmd), nullptr, nullptr, FALSE,
-            0, nullptr, nullptr, &si, &pi)) {
-      if (!GetExitCodeProcess(pi.hProcess, (DWORD)&exitstatVal)) {
-        cmdstatVal = (uint32_t)GetLastError();
-        std::strncpy(cmdstr.data(), "GetExitCodeProcess failed.", 26);
-      } else {
-        cmdstatVal = CMD_EXECUTED;
-      }
+    // append "cmd.exe /c " to the begining of command
+    const char *cmd = command->OffsetElement();
+    const char *prefix = "cmd.exe /c ";
+    char *newCmd = (char *)malloc(strlen(prefix) + strlen(cmd) + 1);
+    if (newCmd != NULL) {
+      std::strcpy(newCmd, prefix);
+      std::strcat(newCmd, cmd);
     } else {
-      cmdstatVal = (uint32_t)GetLastError();
-      std::strncpy(cmdstr.data(), "CreateProcess failed.", 21);
+      terminator.Crash("Memory allocation failed for newCmd");
+    }
+
+    // Convert the narrow string to a wide string
+    int size_needed = MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, NULL, 0);
+    wchar_t *wcmd = new wchar_t[size_needed];
+    if (MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, wcmd, size_needed) != 0) {
+      terminator.Crash(
+          "Char to wider char conversion failed with error code: %lu.",
+          GetLastError());
     }
+    free(newCmd);
 
+    if (!CreateProcess(nullptr, wcmd, nullptr, nullptr, FALSE, 0, nullptr,
+            nullptr, &si, &pi)) {
+      if (!cmdstat) {
+        terminator.Crash(
+            "CreateProcess failed with error code: %lu.", GetLastError());
+      } else {
+        StoreIntToDescriptor(cmdstat, (uint32_t)GetLastError(), terminator);
+        CopyToDescriptor(*cmdmsg, "CreateProcess failed.", 21, nullptr);
+      }
+    }
+    delete[] wcmd;
 #else
-    pid = fork();
+    pid_t pid = fork();
     if (pid < 0) {
-      std::strncpy(cmdstr.data(), "Fork failed", 11);
-      cmdstatVal = FORK_ERR;
+      if (!cmdstat) {
+        terminator.Crash("Fork failed with error code: %d.", FORK_ERR);
+      } else {
+        StoreIntToDescriptor(cmdstat, FORK_ERR, terminator);
+        CopyToDescriptor(*cmdmsg, "Fork failed", 11, nullptr);
+      }
     } else if (pid == 0) {
-      exitstatVal =
-          execl("/bin/sh", "sh", "-c", command->OffsetElement(), (char *)NULL);
-      cmdstatVal = CMD_EXECUTED;
-      std::strncpy(cmdstr.data(), "Command executed.", 17);
+      execl("/bin/sh", "sh", "-c", command->OffsetElement(), (char *)NULL);
     }
 #endif
   }
-
-  if (exitstat) {
-    RUNTIME_CHECK(terminator, IsValidIntDescriptor(exitstat));
-    StoreIntToDescriptor(exitstat, exitstatVal, terminator);
-  }
-
-  if (cmdstat) {
-    RUNTIME_CHECK(terminator, IsValidIntDescriptor(cmdstat));
-    StoreIntToDescriptor(cmdstat, cmdstatVal, terminator);
-  }
-
-  if (cmdmsg) {
-    RUNTIME_CHECK(terminator, IsValidCharDescriptor(cmdmsg));
-    FillWithSpaces(*cmdmsg);
-    CopyToDescriptor(*cmdmsg, cmdstr.data(), cmdstr.size(), nullptr);
-  }
 }
 
 } // namespace Fortran::runtime

>From 9f687f01874490c4774f30859a0c78829f9d6a06 Mon Sep 17 00:00:00 2001
From: Yi Wu <yi.wu2 at arm.com>
Date: Tue, 28 Nov 2023 12:12:05 +0000
Subject: [PATCH 16/22] Fixing error termination Linux only

Work and test on Linux, both sync and async mode.
Sync mode: termination will terminate directly
Async mode: will only terminate the child/async process, no effect on parent
Standard: If a condition occurs that would assign a nonzero value to CMDSTAT,
but the CMDSTAT variable is not present, error termination is initiated.
---
 flang/lib/Optimizer/Builder/IntrinsicCall.cpp |   2 +-
 flang/runtime/execute.cpp                     | 118 +++++++++++-------
 2 files changed, 77 insertions(+), 43 deletions(-)

diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index 9100cf0a4394b..8b262e5fda643 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -2802,7 +2802,7 @@ void IntrinsicLibrary::genExecuteCommandLine(
 
   mlir::Value waitBool = isStaticallyPresent(wait)
                              ? fir::getBase(wait)
-                             : builder.createBool(loc, false);
+                             : builder.createBool(loc, true);
   mlir::Value exitstatBox =
       isStaticallyPresent(exitstat)
           ? fir::getBase(exitstat)
diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
index d8a37dd19764d..93b5d1b0e046e 100644
--- a/flang/runtime/execute.cpp
+++ b/flang/runtime/execute.cpp
@@ -23,8 +23,25 @@
 #include <unistd.h>
 #endif
 
+
 namespace Fortran::runtime {
 
+// cmdstat specified in 16.9.73
+// −1 if the processor does not support command line execution,
+// a processor-dependent positive value if an error condition occurs
+// −2 if no error condition occurs but WAIT is present with the value false
+// and the processor does not support asynchronous execution. Otherwise it is
+// assigned the value 0
+enum CMD_STAT {
+  ASYNC_NO_SUPPORT_ERR = -2,
+  NO_SUPPORT_ERR = -1,
+  CMD_EXECUTED = 0,
+  FORK_ERR = 1,
+  EXECL_ERR = 2,
+  INVALID_CL_ERR = 3,
+  SIGNAL_ERR = 4
+};
+
 static bool IsValidCharDescriptor(const Descriptor *value) {
   return value && value->IsAllocated() &&
       value->type() == TypeCode(TypeCategory::Character, 1) &&
@@ -39,30 +56,16 @@ static bool IsValidIntDescriptor(const Descriptor *length) {
       length->type().IsInteger() && typeCode && typeCode->second != 1;
 }
 
-static void FillWithSpaces(const Descriptor &value, std::size_t offset = 0) {
-  if (offset < value.ElementBytes()) {
-    std::memset(
-        value.OffsetElement(offset), ' ', value.ElementBytes() - offset);
+void CheckAndCopyToDescriptor(const Descriptor *value, const char *rawValue,
+    std::int64_t rawValueLength, std::size_t offset = 0) {
+  if (!value) {
+    return;
   }
-}
-
-static std::int32_t CopyToDescriptor(const Descriptor &value,
-    const char *rawValue, std::int64_t rawValueLength, const Descriptor *errmsg,
-    std::size_t offset = 0) {
 
   std::int64_t toCopy{std::min(rawValueLength,
-      static_cast<std::int64_t>(value.ElementBytes() - offset))};
-  if (toCopy < 0) {
-    return ToErrmsg(errmsg, StatValueTooShort);
-  }
-
-  std::memcpy(value.OffsetElement(offset), rawValue, toCopy);
+      static_cast<std::int64_t>(value->ElementBytes() - offset))};
 
-  if (rawValueLength > toCopy) {
-    return ToErrmsg(errmsg, StatValueTooShort);
-  }
-
-  return StatOk;
+  std::memcpy(value->OffsetElement(offset), rawValue, toCopy);
 }
 
 static void StoreIntToDescriptor(
@@ -73,6 +76,13 @@ static void StoreIntToDescriptor(
       kind, terminator, *intVal, /* atIndex = */ 0, value);
 }
 
+static void CheckAndStoreIntToDescriptor(
+    const Descriptor *intVal, std::int64_t value, Terminator &terminator) {
+  if (intVal) {
+    StoreIntToDescriptor(intVal, value, terminator);
+  }
+}
+
 template <int KIND> struct FitsInIntegerKind {
   bool operator()([[maybe_unused]] std::int64_t value) {
     if constexpr (KIND >= 8) {
@@ -84,29 +94,51 @@ template <int KIND> struct FitsInIntegerKind {
   }
 };
 
+// If a condition occurs that would assign a nonzero value to CMDSTAT but
+// the CMDSTAT variable is not present, error termination is initiated.
+int TerminationCheck(int status, const Descriptor *command,
+    const Descriptor *cmdstat, const Descriptor *cmdmsg,
+    Terminator &terminator) {
+  int exitStatusVal = WEXITSTATUS(status);
+  if (exitStatusVal == 127 || exitStatusVal == 126) {
+    if (!cmdstat) {
+      terminator.Crash("\'%s\' not found with exit status code: %d",
+          command->OffsetElement(), exitStatusVal);
+    } else {
+      CheckAndStoreIntToDescriptor(cmdstat, INVALID_CL_ERR, terminator);
+      CheckAndCopyToDescriptor(cmdmsg, "Invalid command line", 20);
+    }
+  }
+
+  if (WIFSIGNALED(status)) {
+    if (!cmdstat) {
+      terminator.Crash("killed by signal: %d", WTERMSIG(status));
+    } else {
+      CheckAndStoreIntToDescriptor(cmdstat, SIGNAL_ERR, terminator);
+      CheckAndCopyToDescriptor(cmdmsg, "killed by signal", 18);
+    }
+  }
+
+  if (WIFSTOPPED(status)) {
+    if (!cmdstat) {
+      terminator.Crash("stopped by signal: %d", WSTOPSIG(status));
+    } else {
+      CheckAndStoreIntToDescriptor(cmdstat, SIGNAL_ERR, terminator);
+      CheckAndCopyToDescriptor(cmdmsg, "stopped by signal", 17);
+    }
+  }
+  return exitStatusVal;
+}
+
 void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     const Descriptor *exitstat, const Descriptor *cmdstat,
     const Descriptor *cmdmsg, const char *sourceFile, int line) {
   Terminator terminator{sourceFile, line};
 
-  // cmdstat specified in 16.9.73
-  // −1 if the processor does not support command line execution,
-  // a processor-dependent positive value if an error condition occurs
-  // −2 if no error condition occurs but WAIT is present with the value false
-  // and the processor does not support asynchronous execution. Otherwise it is
-  // assigned the value 0
-  enum CMD_STAT {
-    ASYNC_NO_SUPPORT_ERR = -2,
-    NO_SUPPORT_ERR = -1,
-    CMD_EXECUTED = 0,
-    FORK_ERR = 1,
-    EXECL_ERR = 2,
-    SIGNAL_ERR = 3
-  };
-
   if (command) {
     RUNTIME_CHECK(terminator, IsValidCharDescriptor(command));
   }
+
   if (exitstat) {
     RUNTIME_CHECK(terminator, IsValidIntDescriptor(exitstat));
     // If sync, assigned processor-dependent exit status. Otherwise unchanged
@@ -114,8 +146,6 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
 
   if (cmdstat) {
     RUNTIME_CHECK(terminator, IsValidIntDescriptor(cmdstat));
-    // If a condition occurs that would assign a nonzero value to CMDSTAT but
-    // the CMDSTAT variable is not present, error termination is initiated.
     // Assigned 0 as specifed in standard, if error then overwrite
     StoreIntToDescriptor(cmdstat, CMD_EXECUTED, terminator);
   }
@@ -126,8 +156,10 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
 
   if (wait) {
     // either wait is not specified or wait is true: synchronous mode
-    int exitstatVal = std::system(command->OffsetElement());
-    StoreIntToDescriptor(exitstat, exitstatVal, terminator);
+    int status{std::system(command->OffsetElement())};
+    int exitStatusVal =
+        TerminationCheck(status, command, cmdstat, cmdmsg, terminator);
+    CheckAndStoreIntToDescriptor(exitstat, exitStatusVal, terminator);
   } else {
 // Asynchronous mode
 #ifdef _WIN32
@@ -173,13 +205,15 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     pid_t pid = fork();
     if (pid < 0) {
       if (!cmdstat) {
-        terminator.Crash("Fork failed with error code: %d.", FORK_ERR);
+        terminator.Crash("Fork failed with pid: %d.", pid);
       } else {
         StoreIntToDescriptor(cmdstat, FORK_ERR, terminator);
-        CopyToDescriptor(*cmdmsg, "Fork failed", 11, nullptr);
+        CheckAndCopyToDescriptor(cmdmsg, "Fork failed", 11);
       }
     } else if (pid == 0) {
-      execl("/bin/sh", "sh", "-c", command->OffsetElement(), (char *)NULL);
+      int status = std::system(command->OffsetElement());
+      TerminationCheck(status, command, cmdstat, cmdmsg, terminator);
+      exit(status);
     }
 #endif
   }

>From 7ef735f5b679561d168ebdcf1795b82ad126d9fa Mon Sep 17 00:00:00 2001
From: Yi Wu <yiwu02 at wdev-yiwu02.arm.com>
Date: Tue, 28 Nov 2023 17:06:41 +0000
Subject: [PATCH 17/22] Added EXECL_ERR if exit==-1, update docs

---
 flang/docs/Intrinsics.md                      | 43 ++++++++++++++
 flang/lib/Optimizer/Builder/IntrinsicCall.cpp |  2 +-
 flang/runtime/execute.cpp                     | 57 +++++++++++++------
 3 files changed, 84 insertions(+), 18 deletions(-)

diff --git a/flang/docs/Intrinsics.md b/flang/docs/Intrinsics.md
index fef2b4ea4dd8c..ffbbed7119692 100644
--- a/flang/docs/Intrinsics.md
+++ b/flang/docs/Intrinsics.md
@@ -835,3 +835,46 @@ TRIM, UBOUND, UNPACK, VERIFY.
 
 Coarray, non standard, IEEE and ISO_C_BINDINGS intrinsic functions that can be
 used in constant expressions have currently no folding support at all.
+
+### Standard Intrinsics: EXECUTE_COMMAND_LINE
+
+#### Usage and Info
+
+- **Standard:** Fortran 2008 and later, specified in 16.9.73
+- **Class:** Subroutine
+- **Syntax:** `CALL EXECUTE_COMMAND_LINE(COMMAND [, WAIT, EXITSTAT, CMDSTAT, CMDMSG ])`
+- **Arguments:**
+
+  | Argument  | Description                                                  |
+  |-----------|--------------------------------------------------------------|
+  | `COMMAND` | Shall be a default CHARACTER scalar.                         |
+  | `WAIT`    | (Optional) Shall be a default LOGICAL scalar.                |
+  | `EXITSTAT`| (Optional) Shall be an INTEGER of the default kind.          |
+  | `CMDSTAT` | (Optional) Shall be an INTEGER of the default kind.          |
+  | `CMDMSG`  | (Optional) Shall be a CHARACTER scalar of the default kind.  |
+
+#### Implementation Specifics
+
+- **`COMMAND`:**
+  - Must be preset.
+
+- **`WAIT`:**
+  - If set to `false`, the command is executed asynchronously. If not preset or set to `false`, it is executed synchronously.
+
+- **`CMDSTAT`:**
+  - -2: No error condition occurs, but `WAIT` is present with the value `false`, and the processor does not support asynchronous execution.
+  - -1: The processor does not support command line execution.
+  - \+ (positive value): An error condition occurs.
+    - 1: Fork Error, where `pid_t < 0`, would only occur on POSIX-compatible systems.
+    - 2: Execution Error, a command exits with status -1.
+    - 3: Invalid Command Error, determined by the exit code depending on the system.
+      - On Windows, if the exit code is 1.
+      - On POSIX-compatible systems, if the exit code is 127 or 126.
+    - 4: Signal error, either it is stopped or killed by signal, would only occur on POSIX-compatible systems.
+  - 0: Otherwise.
+
+- **`CMDMSG`:**
+  - If an error condition occurs, it is assigned an explanatory message. Otherwise, it remains unchanged.
+  - If a condition occurs that would assign a nonzero value to `CMDSTAT` but the `CMDSTAT` variable is not present, error termination is initiated.
+    - On POSIX-compatible systems, this applies to both synchronous and asynchronous error termination. When the execution mode is set to async with error termination, the child process (async process) will be terminated with no effect on the parent process (continues).
+    - On Windows, this only applies to synchronous error termination.
diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index 8b262e5fda643..9017ef2377871 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -2816,7 +2816,7 @@ void IntrinsicLibrary::genExecuteCommandLine(
           ? fir::getBase(cmdmsg)
           : builder.create<fir::AbsentOp>(loc, boxNoneTy).getResult();
   fir::runtime::genExecuteCommandLine(builder, loc, command, waitBool,
-                                      cmdstatBox, exitstatBox, cmdmsgBox);
+                                      exitstatBox, cmdstatBox, cmdmsgBox);
 }
 
 // EXIT
diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
index 93b5d1b0e046e..67a61939c34c9 100644
--- a/flang/runtime/execute.cpp
+++ b/flang/runtime/execute.cpp
@@ -18,12 +18,12 @@
 #ifdef _WIN32
 #define LEAN_AND_MEAN
 #define NOMINMAX
+#include <stdio.h>
 #include <windows.h>
 #else
 #include <unistd.h>
 #endif
 
-
 namespace Fortran::runtime {
 
 // cmdstat specified in 16.9.73
@@ -56,16 +56,19 @@ static bool IsValidIntDescriptor(const Descriptor *length) {
       length->type().IsInteger() && typeCode && typeCode->second != 1;
 }
 
-void CheckAndCopyToDescriptor(const Descriptor *value, const char *rawValue,
+void CopyToDescriptor(const Descriptor &value, const char *rawValue,
     std::int64_t rawValueLength, std::size_t offset = 0) {
-  if (!value) {
-    return;
-  }
-
   std::int64_t toCopy{std::min(rawValueLength,
-      static_cast<std::int64_t>(value->ElementBytes() - offset))};
+      static_cast<std::int64_t>(value.ElementBytes() - offset))};
 
-  std::memcpy(value->OffsetElement(offset), rawValue, toCopy);
+  std::memcpy(value.OffsetElement(offset), rawValue, toCopy);
+}
+
+void CheckAndCopyToDescriptor(const Descriptor *value, const char *rawValue,
+    std::int64_t rawValueLength, std::size_t offset = 0) {
+  if (value) {
+    CopyToDescriptor(*value, rawValue, rawValueLength, offset);
+  }
 }
 
 static void StoreIntToDescriptor(
@@ -99,34 +102,51 @@ template <int KIND> struct FitsInIntegerKind {
 int TerminationCheck(int status, const Descriptor *command,
     const Descriptor *cmdstat, const Descriptor *cmdmsg,
     Terminator &terminator) {
+  if (status == -1) {
+    if (!cmdstat) {
+      terminator.Crash("Execution error with system status code: %d",
+          command->OffsetElement(), status);
+    } else {
+      CheckAndStoreIntToDescriptor(cmdstat, EXECL_ERR, terminator);
+      CopyToDescriptor(*cmdmsg, "Execution error", 15);
+    }
+  }
+#ifdef _WIN32
+  // On WIN32 API std::system directly returns exit status
+  int exitStatusVal = status;
+  if (exitStatusVal == 1) {
+#else
   int exitStatusVal = WEXITSTATUS(status);
   if (exitStatusVal == 127 || exitStatusVal == 126) {
+#endif
     if (!cmdstat) {
       terminator.Crash("\'%s\' not found with exit status code: %d",
           command->OffsetElement(), exitStatusVal);
     } else {
       CheckAndStoreIntToDescriptor(cmdstat, INVALID_CL_ERR, terminator);
-      CheckAndCopyToDescriptor(cmdmsg, "Invalid command line", 20);
+      CopyToDescriptor(*cmdmsg, "Invalid command line", 20);
     }
   }
-
+#if defined(_WIFSIGNALED) && defined(_WTERMSIG)
   if (WIFSIGNALED(status)) {
     if (!cmdstat) {
       terminator.Crash("killed by signal: %d", WTERMSIG(status));
     } else {
       CheckAndStoreIntToDescriptor(cmdstat, SIGNAL_ERR, terminator);
-      CheckAndCopyToDescriptor(cmdmsg, "killed by signal", 18);
+      CopyToDescriptor(*cmdmsg, "killed by signal", 18);
     }
   }
-
+#endif
+#if defined(_WIFSTOPPED) && defined(_WSTOPSIG)
   if (WIFSTOPPED(status)) {
     if (!cmdstat) {
       terminator.Crash("stopped by signal: %d", WSTOPSIG(status));
     } else {
       CheckAndStoreIntToDescriptor(cmdstat, SIGNAL_ERR, terminator);
-      CheckAndCopyToDescriptor(cmdmsg, "stopped by signal", 17);
+      CopyToDescriptor(*cmdmsg, "stopped by signal", 17);
     }
   }
+#endif
   return exitStatusVal;
 }
 
@@ -169,7 +189,7 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     si.cb = sizeof(si);
     ZeroMemory(&pi, sizeof(pi));
 
-    // append "cmd.exe /c " to the begining of command
+    // append "cmd.exe /c " to the beginning of command
     const char *cmd = command->OffsetElement();
     const char *prefix = "cmd.exe /c ";
     char *newCmd = (char *)malloc(strlen(prefix) + strlen(cmd) + 1);
@@ -183,21 +203,24 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     // Convert the narrow string to a wide string
     int size_needed = MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, NULL, 0);
     wchar_t *wcmd = new wchar_t[size_needed];
-    if (MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, wcmd, size_needed) != 0) {
+    if (MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, wcmd, size_needed) == 0) {
       terminator.Crash(
           "Char to wider char conversion failed with error code: %lu.",
           GetLastError());
     }
     free(newCmd);
 
-    if (!CreateProcess(nullptr, wcmd, nullptr, nullptr, FALSE, 0, nullptr,
+    if (CreateProcess(nullptr, wcmd, nullptr, nullptr, FALSE, 0, nullptr,
             nullptr, &si, &pi)) {
+      CloseHandle(pi.hProcess);
+      CloseHandle(pi.hThread);
+    } else {
       if (!cmdstat) {
         terminator.Crash(
             "CreateProcess failed with error code: %lu.", GetLastError());
       } else {
         StoreIntToDescriptor(cmdstat, (uint32_t)GetLastError(), terminator);
-        CopyToDescriptor(*cmdmsg, "CreateProcess failed.", 21, nullptr);
+        CopyToDescriptor(*cmdmsg, "CreateProcess failed.", 21);
       }
     }
     delete[] wcmd;

>From 1b17b28be64dee6dca5a2a7a072d0a4f242937be Mon Sep 17 00:00:00 2001
From: Yi Wu <yi.wu2 at arm.com>
Date: Thu, 30 Nov 2023 13:49:38 +0000
Subject: [PATCH 18/22] Add runtime tests

---
 flang/runtime/execute.cpp               |   6 +-
 flang/unittests/Runtime/CommandTest.cpp | 101 ++++++++++++++++++++++++
 2 files changed, 104 insertions(+), 3 deletions(-)

diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
index 67a61939c34c9..77b7ae2a7e4c2 100644
--- a/flang/runtime/execute.cpp
+++ b/flang/runtime/execute.cpp
@@ -127,7 +127,7 @@ int TerminationCheck(int status, const Descriptor *command,
       CopyToDescriptor(*cmdmsg, "Invalid command line", 20);
     }
   }
-#if defined(_WIFSIGNALED) && defined(_WTERMSIG)
+#if defined(WIFSIGNALED) && defined(WTERMSIG)
   if (WIFSIGNALED(status)) {
     if (!cmdstat) {
       terminator.Crash("killed by signal: %d", WTERMSIG(status));
@@ -137,7 +137,7 @@ int TerminationCheck(int status, const Descriptor *command,
     }
   }
 #endif
-#if defined(_WIFSTOPPED) && defined(_WSTOPSIG)
+#if defined(WIFSTOPPED) && defined(WSTOPSIG)
   if (WIFSTOPPED(status)) {
     if (!cmdstat) {
       terminator.Crash("stopped by signal: %d", WSTOPSIG(status));
@@ -220,7 +220,7 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
             "CreateProcess failed with error code: %lu.", GetLastError());
       } else {
         StoreIntToDescriptor(cmdstat, (uint32_t)GetLastError(), terminator);
-        CopyToDescriptor(*cmdmsg, "CreateProcess failed.", 21);
+        CheckAndCopyToDescriptor(*cmdmsg, "CreateProcess failed.", 21);
       }
     }
     delete[] wcmd;
diff --git a/flang/unittests/Runtime/CommandTest.cpp b/flang/unittests/Runtime/CommandTest.cpp
index 9f66c7924c86e..c3bf9ae5a53ec 100644
--- a/flang/unittests/Runtime/CommandTest.cpp
+++ b/flang/unittests/Runtime/CommandTest.cpp
@@ -10,6 +10,7 @@
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include "flang/Runtime/descriptor.h"
+#include "flang/Runtime/execute.h"
 #include "flang/Runtime/main.h"
 #include <cstdlib>
 
@@ -46,6 +47,18 @@ static OwningPtr<Descriptor> EmptyIntDescriptor() {
   return descriptor;
 }
 
+template <int kind = sizeof(std::int64_t)>
+static OwningPtr<Descriptor> IntDescriptor(const int &value) {
+  Terminator terminator{__FILE__, __LINE__};
+  OwningPtr<Descriptor> descriptor{Descriptor::Create(TypeCategory::Integer,
+      kind, nullptr, 0, nullptr, CFI_attribute_allocatable)};
+  if (descriptor->Allocate() != 0) {
+    return nullptr;
+  }
+  std::memcpy(descriptor->OffsetElement<int>(), &value, sizeof(int));
+  return descriptor;
+}
+
 class CommandFixture : public ::testing::Test {
 protected:
   CommandFixture(int argc, const char *argv[]) {
@@ -227,6 +240,94 @@ TEST_F(ZeroArguments, GetCommandArgument) {
 
 TEST_F(ZeroArguments, GetCommand) { CheckCommandValue(commandOnlyArgv, 1); }
 
+TEST_F(ZeroArguments, ECLValidCommandAndPadSync) {
+  OwningPtr<Descriptor> command{CharDescriptor("echo hi")};
+  bool wait{true};
+  OwningPtr<Descriptor> exitStat{EmptyIntDescriptor()};
+  OwningPtr<Descriptor> cmdStat{EmptyIntDescriptor()};
+  OwningPtr<Descriptor> cmdMsg{CharDescriptor("No change")};
+
+  RTNAME(ExecuteCommandLine)
+  (command.get(), wait, exitStat.get(), cmdStat.get(), cmdMsg.get());
+
+  std::string spaces(cmdMsg->ElementBytes(), ' ');
+  CheckDescriptorEqInt(exitStat.get(), 0);
+  CheckDescriptorEqInt(cmdStat.get(), 0);
+  CheckDescriptorEqStr(cmdMsg.get(), "No change");
+}
+
+TEST_F(ZeroArguments, ECLValidCommandStatusSetSync) {
+  OwningPtr<Descriptor> command{CharDescriptor("echo hi")};
+  bool wait{true};
+  OwningPtr<Descriptor> exitStat{IntDescriptor(404)};
+  OwningPtr<Descriptor> cmdStat{IntDescriptor(202)};
+  OwningPtr<Descriptor> cmdMsg{CharDescriptor("No change")};
+
+  RTNAME(ExecuteCommandLine)
+  (command.get(), wait, exitStat.get(), cmdStat.get(), cmdMsg.get());
+
+  CheckDescriptorEqInt(exitStat.get(), 0);
+  CheckDescriptorEqInt(cmdStat.get(), 0);
+  CheckDescriptorEqStr(cmdMsg.get(), "No change");
+}
+
+TEST_F(ZeroArguments, ECLInvalidCommandErrorSync) {
+  OwningPtr<Descriptor> command{CharDescriptor("InvalidCommand")};
+  bool wait{true};
+  OwningPtr<Descriptor> exitStat{IntDescriptor(404)};
+  OwningPtr<Descriptor> cmdStat{IntDescriptor(202)};
+  OwningPtr<Descriptor> cmdMsg{CharDescriptor("Message ChangedXXXXXXXXX")};
+
+  RTNAME(ExecuteCommandLine)
+  (command.get(), wait, exitStat.get(), cmdStat.get(), cmdMsg.get());
+
+  CheckDescriptorEqInt(exitStat.get(), 127);
+  CheckDescriptorEqInt(cmdStat.get(), 3);
+  CheckDescriptorEqStr(cmdMsg.get(), "Invalid command lineXXXX");
+}
+
+TEST_F(ZeroArguments, ECLInvalidCommandTerminatedSync) {
+  OwningPtr<Descriptor> command{CharDescriptor("InvalidCommand")};
+  bool wait{true};
+  OwningPtr<Descriptor> exitStat{EmptyIntDescriptor()};
+  OwningPtr<Descriptor> cmdMsg{CharDescriptor("No Change")};
+
+  EXPECT_DEATH(RTNAME(ExecuteCommandLine)(
+                   command.get(), wait, exitStat.get(), nullptr, cmdMsg.get()),
+      "'InvalidCommand' not found with exit status code: 127");
+
+  CheckDescriptorEqInt(exitStat.get(), 0);
+  CheckDescriptorEqStr(cmdMsg.get(), "No Change");
+}
+
+TEST_F(ZeroArguments, ECLValidCommandAndExitStatNoChangeAndCMDStatusSetAsync) {
+  OwningPtr<Descriptor> command{CharDescriptor("echo hi")};
+  bool wait{false};
+  OwningPtr<Descriptor> exitStat{IntDescriptor(404)};
+  OwningPtr<Descriptor> cmdStat{IntDescriptor(202)};
+  OwningPtr<Descriptor> cmdMsg{CharDescriptor("No change")};
+
+  RTNAME(ExecuteCommandLine)
+  (command.get(), wait, exitStat.get(), cmdStat.get(), cmdMsg.get());
+
+  CheckDescriptorEqInt(exitStat.get(), 404);
+  CheckDescriptorEqInt(cmdStat.get(), 0);
+  CheckDescriptorEqStr(cmdMsg.get(), "No change");
+}
+
+TEST_F(ZeroArguments, ECLInvalidCommandParentNotTerminatedAsync) {
+  OwningPtr<Descriptor> command{CharDescriptor("InvalidCommand")};
+  bool wait{false};
+  OwningPtr<Descriptor> exitStat{IntDescriptor(404)};
+  OwningPtr<Descriptor> cmdMsg{CharDescriptor("No change")};
+
+  EXPECT_NO_FATAL_FAILURE(RTNAME(ExecuteCommandLine)(
+      command.get(), wait, exitStat.get(), nullptr, cmdMsg.get()));
+
+  CheckDescriptorEqInt(exitStat.get(), 404);
+  CheckDescriptorEqStr(cmdMsg.get(), "No change");
+}
+
 static const char *oneArgArgv[]{"aProgram", "anArgumentOfLength20"};
 class OneArgument : public CommandFixture {
 protected:

>From 521228c5b55039f3e593522e5e8cec4e32075b18 Mon Sep 17 00:00:00 2001
From: Yi Wu <yi.wu2 at arm.com>
Date: Thu, 30 Nov 2023 21:30:59 +0000
Subject: [PATCH 19/22] Add lowering intrinsic tests

---
 .../execute_command_line-optional.f90         | 102 +++++-----
 .../Lower/Intrinsics/execute_command_line.f90 | 192 +++++-------------
 flang/unittests/Runtime/CommandTest.cpp       |   1 -
 3 files changed, 102 insertions(+), 193 deletions(-)

diff --git a/flang/test/Lower/Intrinsics/execute_command_line-optional.f90 b/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
index be63bc75f2ebf..706f544d063f4 100644
--- a/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
+++ b/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
@@ -1,55 +1,53 @@
-! Test execute_command_line with dynamically optional arguments.
 ! RUN: bbc -emit-fir %s -o - | FileCheck %s
 
-
-! CHECK-LABEL: func @_QPtest(
-! CHECK-SAME:  %[[ARG_0:.*]]: !fir.boxchar<1> {fir.bindc_command = "command", fir.optional},
-! CHECK-SAME:  %[[ARG_1:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_command = "wait", fir.optional},
-! CHECK-SAME:  %[[ARG_2:.*]]: !fir.ref<i32> {fir.bindc_command = "length", fir.optional},
-! CHECK-SAME:  %[[ARG_3:.*]]: !fir.ref<i32> {fir.bindc_command = "cmdstat", fir.optional},
-! CHECK-SAME:  %[[ARG_4:.*]]: !fir.boxchar<1> {fir.bindc_command = "cmdmsg", fir.optional}) {
-subroutine test(command, wait, length, cmdstat, cmdmsg)
-  integer, optional :: cmdstat, length
-  logical :: wait
-  character(*), optional :: command, cmdmsg
+! CHECK-LABEL: func.func @_QPall_args_optional(
+! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_name = "command", fir.optional},
+! CHECK-SAME: %[[waitArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_name = "iswait", fir.optional},
+! CHECK-SAME: %[[exitstatArg:.*]]: !fir.ref<i32> {fir.bindc_name = "exitval", fir.optional},
+! CHECK-SAME: %[[cmdstatArg:.*]]: !fir.ref<i32> {fir.bindc_name = "cmdval", fir.optional},
+! CHECK-SAME: %[[cmdmsgArg:.*]]: !fir.boxchar<1> {fir.bindc_name = "msg", fir.optional}) {
+subroutine all_args_optional(command, isWait, exitVal, cmdVal, msg)
+  CHARACTER(*), OPTIONAL :: command, msg
+  INTEGER, OPTIONAL :: exitVal, cmdVal
+  LOGICAL, OPTIONAL :: isWait
   ! Note: command is not optional in execute_command_line and must be present
-  call execute_command_line(command, wait, length, cmdstat, cmdmsg)
-! CHECK:  %[[VAL_0:.*]]:2 = fir.unboxchar %[[ARG_5]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK:  %[[VAL_1:.*]]:2 = fir.unboxchar %[[ARG_0]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK:  %[[VAL_2:.*]]:2 = fir.unboxchar %[[ARG_1]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK:  %[[VAL_3:.*]] = fir.embox %[[VAL_1]]#0 typeparams %[[VAL_1]]#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.box<!fir.char<1,?>>
-! CHECK:  %[[VAL_4:.*]] = fir.is_present %[[VAL_2]]#0 : (!fir.ref<!fir.char<1,?>>) -> i1
-! CHECK:  %[[VAL_5:.*]] = fir.embox %[[VAL_2]]#0 typeparams %[[VAL_2]]#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.box<!fir.char<1,?>>
-! CHECK:  %[[VAL_6:.*]] = fir.absent !fir.box<!fir.char<1,?>>
-! CHECK:  %[[VAL_7:.*]] = arith.select %[[VAL_4]], %[[VAL_5]], %[[VAL_6]] : !fir.box<!fir.char<1,?>>
-! CHECK:  %[[VAL_8:.*]] = fir.is_present %[[ARG_2]] : (!fir.ref<i32>) -> i1
-! CHECK:  %[[VAL_9:.*]] = fir.embox %[[ARG_2]] : (!fir.ref<i32>) -> !fir.box<i32>
-! CHECK:  %[[VAL_10:.*]] = fir.absent !fir.box<i32>
-! CHECK:  %[[VAL_11:.*]] = arith.select %[[VAL_8]], %[[VAL_9]], %[[VAL_10]] : !fir.box<i32>
-! CHECK:  %[[VAL_12:.*]] = fir.is_present %[[VAL_0]]#0 : (!fir.ref<!fir.char<1,?>>) -> i1
-! CHECK:  %[[VAL_13:.*]] = fir.embox %[[VAL_0]]#0 typeparams %[[VAL_0]]#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.box<!fir.char<1,?>>
-! CHECK:  %[[VAL_14:.*]] = fir.absent !fir.box<!fir.char<1,?>>
-! CHECK:  %[[VAL_15:.*]] = arith.select %[[VAL_12]], %[[VAL_13]], %[[VAL_14]] : !fir.box<!fir.char<1,?>>
-! CHECK:  %[[VAL_16:.*]] = fir.convert %[[ARG_4]] : (!fir.ref<!fir.logical<4>>) -> i64
-! CHECK:  %[[CONST_0:.*]] = arith.constant 0 : i64
-! CHECK:  %[[VAL_17:.*]] = arith.cmpi ne, %[[VAL_16]], %[[CONST_0]] : i64
-! CHECK:  %[[VAL_18:.*]] = fir.if %[[VAL_17]] -> (i1) {
-! CHECK:    %[[VAL_28:.*]] = fir.load %[[ARG_4]] : !fir.ref<!fir.logical<4>>
-! CHECK:    %[[VAL_29:.*]] = fir.convert %[[VAL_28]] : (!fir.logical<4>) -> i1
-! CHECK:    fir.result %[[VAL_29]] : i1
-! CHECK:  } else {
-! CHECK:    %[[CONST_1:.*]] = arith.constant true
-! CHECK:    fir.result %[[CONST_1]] : i1
-! CHECK:  }
-! CHECK:  %[[VAL_20:.*]] = fir.convert %[[VAL_3]] : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
-! CHECK:  %[[VAL_21:.*]] = fir.convert %[[VAL_7]] : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
-! CHECK:  %[[VAL_22:.*]] = fir.convert %[[VAL_11]] : (!fir.box<i32>) -> !fir.box<none>
-! CHECK:  %[[VAL_23:.*]] = fir.convert %[[VAL_15]] : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
-! CHECK:  %[[VAL_25:.*]] = fir.call @_FortranAExecuteCommandLine(%[[VAL_20]], %[[VAL_21]], %[[VAL_22]], %[[VAL_18]], %[[VAL_23]], %{{.*}}, %{{.*}}) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
-! CHECK:  %[[VAL_26:.*]] = fir.convert %[[ARG_3]] : (!fir.ref<i32>) -> i64
-! CHECK:  %[[CONST_2:.*]] = arith.constant 0 : i64
-! CHECK:  %[[VAL_27:.*]] = arith.cmpi ne, %[[VAL_26]], %[[CONST_2]] : i64
-! CHECK:  fir.if %[[VAL_27]] {
-! CHECK:    fir.store %[[VAL_25]] to %[[ARG_3]] : !fir.ref<i32>
-! CHECK:  }
-end subroutine
+  call execute_command_line(command, isWait, exitVal, cmdVal, msg)
+! CHECK:         %0 = fir.declare %[[cmdstatArg]] {fortran_attrs = #fir.var_attrs<optional>, uniq_name = "_QFall_args_optionalEcmdval"} : (!fir.ref<i32>) -> !fir.ref<i32>
+! CHECK-NEXT:    %1:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT:    %2 = fir.declare %1#0 typeparams %1#1 {fortran_attrs = #fir.var_attrs<optional>, uniq_name = "_QFall_args_optionalEcommand"} : (!fir.ref<!fir.char<1,?>>, index) -> !fir.ref<!fir.char<1,?>>
+! CHECK-NEXT:    %3 = fir.emboxchar %2, %1#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.boxchar<1>
+! CHECK-NEXT:    %4 = fir.declare %[[exitstatArg]] {fortran_attrs = #fir.var_attrs<optional>, uniq_name = "_QFall_args_optionalEexitval"} : (!fir.ref<i32>) -> !fir.ref<i32>
+! CHECK-NEXT:    %5 = fir.declare %[[waitArg]] {fortran_attrs = #fir.var_attrs<optional>, uniq_name = "_QFall_args_optionalEiswait"} : (!fir.ref<!fir.logical<4>>) -> !fir.ref<!fir.logical<4>>
+! CHECK-NEXT:    %6:2 = fir.unboxchar %[[cmdmsgArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT:    %7 = fir.declare %6#0 typeparams %6#1 {fortran_attrs = #fir.var_attrs<optional>, uniq_name = "_QFall_args_optionalEmsg"} : (!fir.ref<!fir.char<1,?>>, index) -> !fir.ref<!fir.char<1,?>>
+! CHECK-NEXT:    %8 = fir.emboxchar %7, %6#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.boxchar<1>
+! CHECK-NEXT:    %9 = fir.is_present %5 : (!fir.ref<!fir.logical<4>>) -> i1
+! CHECK-NEXT:    %10 = fir.is_present %4 : (!fir.ref<i32>) -> i1
+! CHECK-NEXT:    %11 = fir.is_present %0 : (!fir.ref<i32>) -> i1
+! CHECK-NEXT:    %12 = fir.is_present %8 : (!fir.boxchar<1>) -> i1
+! CHECK-NEXT:    %13 = fir.embox %2 typeparams %1#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.box<!fir.char<1,?>>
+! CHECK-NEXT:    %14 = fir.if %9 -> (!fir.logical<4>) {
+! CHECK-NEXT:      %31 = fir.load %5 : !fir.ref<!fir.logical<4>>
+! CHECK-NEXT:      fir.result %31 : !fir.logical<4>
+! CHECK-NEXT:    } else {
+! CHECK-NEXT:      %31 = fir.convert %false : (i1) -> !fir.logical<4>
+! CHECK-NEXT:      fir.result %31 : !fir.logical<4>
+! CHECK-NEXT:    }
+! CHECK-NEXT:    %15 = fir.embox %4 : (!fir.ref<i32>) -> !fir.box<i32>
+! CHECK-NEXT:    %16 = fir.absent !fir.box<i32>
+! CHECK-NEXT:    %17 = arith.select %10, %15, %16 : !fir.box<i32>
+! CHECK-NEXT:    %18 = fir.embox %0 : (!fir.ref<i32>) -> !fir.box<i32>
+! CHECK-NEXT:    %19 = arith.select %11, %18, %16 : !fir.box<i32>
+! CHECK-NEXT:    %20 = fir.embox %7 typeparams %6#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.box<!fir.char<1,?>>
+! CHECK-NEXT:    %21 = fir.absent !fir.box<!fir.char<1,?>> 
+! CHECK-NEXT:    %22 = arith.select %12, %20, %21 : !fir.box<!fir.char<1,?>>
+! CHECK-NEXT:    %23 = fir.address_of(@_QQclX76c8fd75e0e20222cfcde5fe9055bcbe) : !fir.ref<!fir.char<1,96>>
+! CHECK-NEXT:    %24 = fir.convert %13 : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
+! CHECK-NEXT:    %25 = fir.convert %14 : (!fir.logical<4>) -> i1
+! CHECK-NEXT:    %26 = fir.convert %17 : (!fir.box<i32>) -> !fir.box<none>
+! CHECK-NEXT:    %27 = fir.convert %19 : (!fir.box<i32>) -> !fir.box<none>
+! CHECK-NEXT:    %28 = fir.convert %22 : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
+! CHECK-NEXT:    %29 = fir.convert %23 : (!fir.ref<!fir.char<1,96>>) -> !fir.ref<i8>
+! CHECK-NEXT:    %30 = fir.call @_FortranAExecuteCommandLine(%24, %25, %26, %27, %28, %29, %c14_i32) fastmath<contract> : (!fir.box<none>, i1, !fir.box<none>, !fir.box<none>, !fir.box<none>, !fir.ref<i8>, i32) -> none
+! CHECK-NEXT:    return
+end subroutine all_args_optional
diff --git a/flang/test/Lower/Intrinsics/execute_command_line.f90 b/flang/test/Lower/Intrinsics/execute_command_line.f90
index 8ceae841440bc..68befdb850861 100644
--- a/flang/test/Lower/Intrinsics/execute_command_line.f90
+++ b/flang/test/Lower/Intrinsics/execute_command_line.f90
@@ -1,142 +1,54 @@
-! RUN: bbc -emit-fir %s -o - | FileCheck --check-prefixes=CHECK,CHECK-32 -DDEFAULT_INTEGER_SIZE=32 %s
-! RUN: flang-new -fc1 -fdefault-integer-8 -emit-fir %s -o - | FileCheck --check-prefixes=CHECK,CHECK-64 -DDEFAULT_INTEGER_SIZE=64 %s
+! RUN: bbc -emit-fir %s -o - | FileCheck %s
 
-! CHECK-LABEL: func @_QPcommand_only(
-! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"}) {
-subroutine command_only(command)
-    character(len=32) :: command
-    call execute_command_line(command)
-! CHECK-Next: fir.call @_FortranAExecuteCommandLine
-! CHECK-NEXT: return
-end subroutine command_only
+! CHECK-LABEL: func.func @_QPall_args(
+! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_name = "command"},
+! CHECK-SAME: %[[waitArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_name = "iswait"},
+! CHECK-SAME: %[[exitstatArg:.*]]: !fir.ref<i32> {fir.bindc_name = "exitval"},
+! CHECK-SAME: %[[cmdstatArg:.*]]: !fir.ref<i32> {fir.bindc_name = "cmdval"},
+! CHECK-SAME: %[[cmdmsgArg:.*]]: !fir.boxchar<1> {fir.bindc_name = "msg"}) {
+subroutine all_args(command, isWait, exitVal, cmdVal, msg)
+CHARACTER(30) :: command, msg
+INTEGER :: exitVal, cmdVal
+LOGICAL :: isWait
+call execute_command_line(command, isWait, exitVal, cmdVal, msg)
+! CHECK:             %0 = fir.declare %[[cmdstatArg]] {uniq_name = "_QFall_argsEcmdval"} : (!fir.ref<i32>) -> !fir.ref<i32>
+! CHECK-NEXT:        %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT:        %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,30>>
+! CHECK-NEXT:        %3 = fir.declare %[[commandCast]] typeparams %c30 {uniq_name = "_QFall_argsEcommand"} : (!fir.ref<!fir.char<1,30>>, index) -> !fir.ref<!fir.char<1,30>>
+! CHECK-NEXT:        %4 = fir.declare %[[exitstatArg]] {uniq_name = "_QFall_argsEexitval"} : (!fir.ref<i32>) -> !fir.ref<i32>
+! CHECK-NEXT:        %5 = fir.declare %[[waitArg]] {uniq_name = "_QFall_argsEiswait"} : (!fir.ref<!fir.logical<4>>) -> !fir.ref<!fir.logical<4>>
+! CHECK-NEXT:        %[[cmdmsgUnbox:.*]]:2 = fir.unboxchar %[[cmdmsgArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT:        %[[cmdmsgCast:.*]] = fir.convert %[[cmdmsgUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,30>>
+! CHECK-NEXT:        %8 = fir.declare %[[cmdmsgCast]] typeparams %c30 {uniq_name = "_QFall_argsEmsg"} : (!fir.ref<!fir.char<1,30>>, index) -> !fir.ref<!fir.char<1,30>>
+! CHECK-NEXT:        %[[commandBox:.*]] = fir.embox %3 : (!fir.ref<!fir.char<1,30>>) -> !fir.box<!fir.char<1,30>>
+! CHECK-NEXT:        %[[waitLoaded:.*]] = fir.load %5 : !fir.ref<!fir.logical<4>>
+! CHECK-NEXT:        %[[exitstatBox:.*]] = fir.embox %4 : (!fir.ref<i32>) -> !fir.box<i32>
+! CHECK-NEXT:        %[[cmdstatBox:.*]] = fir.embox %0 : (!fir.ref<i32>) -> !fir.box<i32>
+! CHECK-NEXT:        %[[cmdmsgBox:.*]] = fir.embox %8 : (!fir.ref<!fir.char<1,30>>) -> !fir.box<!fir.char<1,30>>
+! CHECK-NEXT:        %14 = fir.address_of(@_QQclX05b779b120ed6fd4f4d4144c6c9136d6) : !fir.ref<!fir.char<1,87>>
+! CHECK-NEXT:        %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,30>>) -> !fir.box<none>
+! CHECK-NEXT:        %[[wait:.*]] = fir.convert %[[waitLoaded]] : (!fir.logical<4>) -> i1
+! CHECK-NEXT:        %[[exitstat:.*]] = fir.convert %[[exitstatBox]] : (!fir.box<i32>) -> !fir.box<none>
+! CHECK-NEXT:        %[[cmdstat:.*]] = fir.convert %[[cmdstatBox]] : (!fir.box<i32>) -> !fir.box<none>
+! CHECK-NEXT:        %[[cmdmsg:.*]] = fir.convert %[[cmdmsgBox]] : (!fir.box<!fir.char<1,30>>) -> !fir.box<none>
+! CHECK-NEXT:        %20 = fir.convert %14 : (!fir.ref<!fir.char<1,87>>) -> !fir.ref<i8>
+! CHECK-NEXT:        %21 = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %[[cmdstat]], %[[cmdmsg]], %20, %c13_i32) fastmath<contract> : (!fir.box<none>, i1, !fir.box<none>, !fir.box<none>, !fir.box<none>, !fir.ref<i8>, i32) -> none
+! CHECK-NEXT:        return
+end subroutine all_args
 
-! CHECK-LABEL: func @_QPcommand_and_wait_only(
-! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
-! CHECK-SAME: %[[waitArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_command = "wait", fir.optional},
-subroutine command_and_wait_only(command, wait)
-    character(len=32) :: command
-    logical::wait
-    wait = .false.
-    call execute_command_line(command, wait)
-! CHECK: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
-! CHECK-NEXT: %[[waitUnbox:.*]]:2 = fir.unboxchar %[[waitArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK-NEXT: %[[waitCast:.*]] = fir.convert %[[waitUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
-! CHECK-NEXT: %[[commandBox:.*]] = fir.embox %[[commandCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
-! CHECK-NEXT: %[[waitBox:.*]] = fir.embox %[[waitCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
-! CHECK-NEXT: %true = arith.constant true
-! CHECK-NEXT: %[[exitstat:.*]] = fir.absent !fir.box<none>
-! CHECK-NEXT: %[[cmdmsg:.*]] = fir.absent !fir.box<none>
-! CHECK-NEXT: %[[sourceFileString:.*]] = fir.address_of(@_QQcl{{.*}}) : !fir.ref<!fir.char<1,[[sourceFileexitstat:.*]]>>
-! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 11]] : i32
-! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
-! CHECK-NEXT: %[[wait:.*]] = fir.convert %[[waitBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
-! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
-! CHECK-NEXT: %{{[0-9]+}} = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
-! CHECK-NEXT: return
-end subroutine command_and_wait_only
-
-! CHECK-LABEL: func @_QPcommand_and_exitstat_only(
-! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
-! CHECK-SAME: %[[exitstatArg:.*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_command = "exitstat"}) {
-subroutine command_and_exitstat_only(command, exitstat)
-    character(len=32) :: command
-    integer :: exitstat
-    call execute_command_line(command, EXITSTAT=exitstat)
-! CHECK: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
-! CHECK-NEXT: %[[commandBox:.*]] = fir.embox %[[commandCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
-! CHECK-NEXT: %[[exitstatBox:.*]] = fir.embox %arg1 : (!fir.ref<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<i[[DEFAULT_INTEGER_SIZE]]>
-! CHECK-NEXT: %true = arith.constant true
-! CHECK-NEXT: %[[wait:.*]] = fir.absent !fir.box<none>
-! CHECK-NEXT: %[[cmdmsg:.*]] = fir.absent !fir.box<none>
-! CHECK: %[[sourceFileString:.*]] = fir.address_of(@_QQcl.{{.*}}) : !fir.ref<!fir.char<1,[[sourceFileexitstat:.*]]>>
-! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 9]] : i32
-! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
-! CHECK-NEXT: %[[exitstat:.*]] = fir.convert %[[exitstatBox]] : (!fir.box<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<none>
-! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
-! CHECK-NEXT: %{{.*}} = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
-end subroutine command_and_exitstat_only
-
-! CHECK-LABEL: func @_QPcommand_and_cmdstat_only(
-! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
-! CHECK-SAME: %[[cmdstatArg:.*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_command = "cmdstat"}) {
-subroutine command_and_cmdstat_only(command, cmdstat)
-    character(len=32) :: command
-    integer :: cmdstat
-    call execute_command_line(command, CMDSTAT=cmdstat)
-! CHECK: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
-! CHECK-NEXT: %[[commandBox:.*]] = fir.embox %[[commandCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
-! CHECK-NEXT: %true = arith.constant true
-! CHECK-NEXT: %[[wait:.*]] = fir.absent !fir.box<none>
-! CHECK-NEXT: %[[exitstat:.*]] = fir.absent !fir.box<none>
-! CHECK-NEXT: %[[cmdmsg:.*]] = fir.absent !fir.box<none>
-! CHECK-NEXT: %[[sourceFileString:.*]] = fir.address_of(@_QQcl.{{.*}}) : !fir.ref<!fir.char<1,[[sourceFileexitstat:.*]]>>
-! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 9]] : i32
-! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
-! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
-! CHECK-32-NEXT: %[[cmdstat:.*]] = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
-! CHECK-64-NEXT: %[[cmdstat32:.*]] = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
-! CHECK-64: %[[cmdstat:.*]] = fir.convert %[[cmdstat32]] : (i32) -> i64
-! CHECK: fir.store %[[cmdstat]] to %[[cmdstatArg]] : !fir.ref<i[[DEFAULT_INTEGER_SIZE]]>
-end subroutine command_and_cmdstat_only
-
-! CHECK-LABEL: func @_QPcommand_and_cmdmsg_only(
-! CHECK-SAME: %[[commandArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
-! CHECK-SAME: %[[cmdmsgArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "cmdmsg"}) {
-subroutine command_and_cmdmsg_only(command, cmdmsg)
-    character(len=32) :: command, cmdmsg
-    call execute_command_line(command, CMDMSG=cmdmsg)
-! CHECK: %[[cmdmsgUnbox:.*]]:2 = fir.unboxchar %[[cmdmsgArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK-NEXT: %[[cmdmsgCast:.*]] = fir.convert %[[cmdmsgUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
-! CHECK-NEXT: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
-! CHECK-NEXT: %[[commandBox:.*]] = fir.embox %[[commandCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
-! CHECK-NEXT: %[[cmdmsgBox:.*]] = fir.embox %[[cmdmsgCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
-! CHECK-NEXT: %true = arith.constant true
-! CHECK-NEXT: %[[wait:.*]] = fir.absent !fir.box<none>
-! CHECK-NEXT: %[[exitstat:.*]] = fir.absent !fir.box<none>
-! CHECK-NEXT: %[[sourceFileString:.*]] = fir.address_of(@_QQcl.{{.*}}) : !fir.ref<!fir.char<1,[[sourceFileexitstat:.*]]>>
-! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 11]] : i32
-! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
-! CHECK-NEXT: %[[cmdmsg:.*]] = fir.convert %[[cmdmsgBox]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
-! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[sourceFileexitstat]]>>) -> !fir.ref<i8>
-! CHECK-NEXT: %{{[0-9]+}} = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %true, %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
-! CHECK-NEXT: return
-end subroutine command_and_cmdmsg_only
-
-! CHECK-LABEL: func @_QPall_arguments(
-! CHECK-SAME: %[[commandArg:[^:]*]]: !fir.boxchar<1> {fir.bindc_command = "command"},
-! CHECK-SAME: %[[waitArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_command = "wait", fir.optional},
-! CHECK-SAME: %[[exitstatArg:[^:]*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_command = "exitstat"},
-! CHECK-SAME: %[[cmdstatArg:.*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_command = "cmdstat"},
-! CHECK-SAME: %[[cmdmsgArg:.*]]: !fir.boxchar<1> {fir.bindc_command = "cmdmsg"}) {
-subroutine all_arguments(command, wait, exitstat, cmdstat, cmdmsg)
-    character(len=32) :: command, cmdmsg
-    logical :: wait
-    integer :: exitstat, cmdstat
-    wait=.false.
-    call execute_command_line(command, wait, exitstat, cmdstat, cmdmsg)
-! CHECK: %[[cmdmsgUnbox:.*]]:2 = fir.unboxchar %[[cmdmsgArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK-NEXT: %[[cmdmsgCast:.*]] = fir.convert %[[cmdmsgUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
-! CHECK-NEXT: %[[commandUnbox:.*]]:2 = fir.unboxchar %[[commandArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK-NEXT: %[[commandCast:.*]] = fir.convert %[[commandUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
-! CHECK-NEXT: %[[waitUnbox:.*]]:2 = fir.unboxchar %[[waitArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
-! CHECK-NEXT: %[[waitCast:.*]] = fir.convert %[[waitUnbox]]#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,32>>
-! CHECK-NEXT: %[[commandBoxed:.*]] = fir.embox %[[commandCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
-! CHECK-NEXT: %[[waitBoxed:.*]] = fir.embox %[[waitCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
-! CHECK-NEXT: %[[exitstatBoxed:.*]] = fir.embox %[[exitstatArg]] : (!fir.ref<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<i[[DEFAULT_INTEGER_SIZE]]>
-! CHECK-NEXT: %[[cmdmsgBoxed:.*]] = fir.embox %[[cmdmsgCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
-! CHECK: %[[sourceFileString:.*]] = fir.address_of(@_QQcl.[[fileString:.*]]) : !fir.ref<!fir.char<1,[[fileStringexitstat:.*]]>>
-! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 22]] : i32
-! CHECK-NEXT: %[[command:.*]] = fir.convert %[[commandBoxed]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
-! CHECK-NEXT: %[[wait:.*]] = fir.convert %[[waitBoxed]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
-! CHECK-NEXT: %[[exitstat:.*]] = fir.convert %[[exitstatBoxed]] : (!fir.box<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<none>
-! CHECK-NEXT: %[[cmdmsg:.*]] = fir.convert %[[cmdmsgBoxed]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
-! CHECK-NEXT: %[[sourceFile:.*]] = fir.convert %[[sourceFileString]] : (!fir.ref<!fir.char<1,[[fileStringexitstat]]>>) -> !fir.ref<i8>
-! CHECK-32-NEXT: %[[cmdstat:.*]] = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
-! CHECK-64-NEXT: %[[cmdstat32:.*]] = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %[[cmdmsg]], %[[sourceFile]], %[[sourceLine]]) {{.*}}: (!fir.box<none>, !fir.box<none>, !fir.box<none>, i1, !fir.box<none>, !fir.ref<i8>, i32) -> i32
-! CHECK-64: %[[cmdstat:.*]] = fir.convert %[[cmdstat32]] : (i32) -> i64
-! CHECK: fir.store %[[cmdstat]] to %[[cmdstatArg]] : !fir.ref<i[[DEFAULT_INTEGER_SIZE]]>
-end subroutine all_arguments
+! CHECK-LABEL: func.func @_QPonly_command_default_wait_true(
+! CHECK-SAME: %[[cmdArg:.*]]: !fir.boxchar<1> {fir.bindc_name = "command"}) {
+subroutine only_command_default_wait_true(command)
+CHARACTER(30) :: command
+call execute_command_line(command)
+! CHECK:          %0:2 = fir.unboxchar %[[cmdArg]] : (!fir.boxchar<1>) -> (!fir.ref<!fir.char<1,?>>, index)
+! CHECK-NEXT:     %1 = fir.convert %0#0 : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.char<1,30>>
+! CHECK-NEXT:     %2 = fir.declare %1 typeparams %c30 {uniq_name = "_QFonly_command_default_wait_trueEcommand"} : (!fir.ref<!fir.char<1,30>>, index) -> !fir.ref<!fir.char<1,30>>
+! CHECK-NEXT:     %3 = fir.embox %2 : (!fir.ref<!fir.char<1,30>>) -> !fir.box<!fir.char<1,30>>
+! CHECK-NEXT:     %4 = fir.absent !fir.box<none>
+! CHECK-NEXT:     %5 = fir.address_of(@_QQclX05b779b120ed6fd4f4d4144c6c9136d6) : !fir.ref<!fir.char<1,87>>
+! CHECK-NEXT:     %6 = fir.convert %3 : (!fir.box<!fir.char<1,30>>) -> !fir.box<none> 
+! CHECK-NEXT:     %7 = fir.convert %5 : (!fir.ref<!fir.char<1,87>>) -> !fir.ref<i8>
+! CHECK-NEXT:     %8 = fir.call @_FortranAExecuteCommandLine(%6, %true, %4, %4, %4, %7, %c43_i32) fastmath<contract> : (!fir.box<none>, i1, !fir.box<none>, !fir.box<none>, !fir.box<none>, !fir.ref<i8>, i32) -> none 
+! CHECK-NEXT:     return
+end subroutine only_command_default_wait_true
diff --git a/flang/unittests/Runtime/CommandTest.cpp b/flang/unittests/Runtime/CommandTest.cpp
index c3bf9ae5a53ec..66b5d3970ba76 100644
--- a/flang/unittests/Runtime/CommandTest.cpp
+++ b/flang/unittests/Runtime/CommandTest.cpp
@@ -49,7 +49,6 @@ static OwningPtr<Descriptor> EmptyIntDescriptor() {
 
 template <int kind = sizeof(std::int64_t)>
 static OwningPtr<Descriptor> IntDescriptor(const int &value) {
-  Terminator terminator{__FILE__, __LINE__};
   OwningPtr<Descriptor> descriptor{Descriptor::Create(TypeCategory::Integer,
       kind, nullptr, 0, nullptr, CFI_attribute_allocatable)};
   if (descriptor->Allocate() != 0) {

>From f7133e441209ed4d39c14f1426ea47005ceecc4d Mon Sep 17 00:00:00 2001
From: Yi Wu <yi.wu2 at arm.com>
Date: Fri, 1 Dec 2023 10:09:59 +0000
Subject: [PATCH 20/22] add more docs, format, and brace initialization

---
 flang/docs/Intrinsics.md  |  2 ++
 flang/runtime/execute.cpp | 28 ++++++++++++++--------------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/flang/docs/Intrinsics.md b/flang/docs/Intrinsics.md
index ffbbed7119692..40445526314b0 100644
--- a/flang/docs/Intrinsics.md
+++ b/flang/docs/Intrinsics.md
@@ -860,6 +860,8 @@ used in constant expressions have currently no folding support at all.
 
 - **`WAIT`:**
   - If set to `false`, the command is executed asynchronously. If not preset or set to `false`, it is executed synchronously.
+  - Sync: achieved by passing command into `std::system` on all systems.
+  - Async: achieved by calling a `fork()` on POSIX-compatible systems, or `CreateProcess()` on Windows.
 
 - **`CMDSTAT`:**
   - -2: No error condition occurs, but `WAIT` is present with the value `false`, and the processor does not support asynchronous execution.
diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
index 77b7ae2a7e4c2..7ae64f7ee86a0 100644
--- a/flang/runtime/execute.cpp
+++ b/flang/runtime/execute.cpp
@@ -112,11 +112,11 @@ int TerminationCheck(int status, const Descriptor *command,
     }
   }
 #ifdef _WIN32
-  // On WIN32 API std::system directly returns exit status
-  int exitStatusVal = status;
+  // On WIN32 API std::system returns exit status directly
+  int exitStatusVal{status};
   if (exitStatusVal == 1) {
 #else
-  int exitStatusVal = WEXITSTATUS(status);
+  int exitStatusVal{WEXITSTATUS(status)};
   if (exitStatusVal == 127 || exitStatusVal == 126) {
 #endif
     if (!cmdstat) {
@@ -177,8 +177,8 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
   if (wait) {
     // either wait is not specified or wait is true: synchronous mode
     int status{std::system(command->OffsetElement())};
-    int exitStatusVal =
-        TerminationCheck(status, command, cmdstat, cmdmsg, terminator);
+    int exitStatusVal{
+        TerminationCheck(status, command, cmdstat, cmdmsg, terminator)};
     CheckAndStoreIntToDescriptor(exitstat, exitStatusVal, terminator);
   } else {
 // Asynchronous mode
@@ -186,13 +186,13 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     STARTUPINFO si;
     PROCESS_INFORMATION pi;
     ZeroMemory(&si, sizeof(si));
-    si.cb = sizeof(si);
+    si.cb{sizeof(si)};
     ZeroMemory(&pi, sizeof(pi));
 
     // append "cmd.exe /c " to the beginning of command
-    const char *cmd = command->OffsetElement();
-    const char *prefix = "cmd.exe /c ";
-    char *newCmd = (char *)malloc(strlen(prefix) + strlen(cmd) + 1);
+    const char *cmd{command->OffsetElement()};
+    const char *prefix{"cmd.exe /c "};
+    char *newCmd{(char *)malloc(strlen(prefix) + strlen(cmd) + 1)};
     if (newCmd != NULL) {
       std::strcpy(newCmd, prefix);
       std::strcat(newCmd, cmd);
@@ -201,9 +201,9 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     }
 
     // Convert the narrow string to a wide string
-    int size_needed = MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, NULL, 0);
-    wchar_t *wcmd = new wchar_t[size_needed];
-    if (MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, wcmd, size_needed) == 0) {
+    int sizeNeede{MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, NULL, 0)};
+    wchar_t *wcmd{new wchar_t[sizeNeeded]};
+    if (MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, wcmd, sizeNeeded) == 0) {
       terminator.Crash(
           "Char to wider char conversion failed with error code: %lu.",
           GetLastError());
@@ -225,7 +225,7 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     }
     delete[] wcmd;
 #else
-    pid_t pid = fork();
+    pid_t pid{fork()};
     if (pid < 0) {
       if (!cmdstat) {
         terminator.Crash("Fork failed with pid: %d.", pid);
@@ -234,7 +234,7 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
         CheckAndCopyToDescriptor(cmdmsg, "Fork failed", 11);
       }
     } else if (pid == 0) {
-      int status = std::system(command->OffsetElement());
+      int status{std::system(command->OffsetElement())};
       TerminationCheck(status, command, cmdstat, cmdmsg, terminator);
       exit(status);
     }

>From c8e2e00c5a331096c20e582673a6c6ccf8bd5e39 Mon Sep 17 00:00:00 2001
From: Yi Wu <yiwu02 at wdev-yiwu02.arm.com>
Date: Fri, 1 Dec 2023 10:55:58 +0000
Subject: [PATCH 21/22] add test fixes on Windows and remove `address_of` in
 testing

---
 flang/runtime/execute.cpp                     | 20 +++++++++----------
 .../execute_command_line-optional.f90         |  6 ++----
 .../Lower/Intrinsics/execute_command_line.f90 | 12 ++++-------
 flang/unittests/Runtime/CommandTest.cpp       | 18 ++++++++++++-----
 4 files changed, 28 insertions(+), 28 deletions(-)

diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
index 7ae64f7ee86a0..13a103333c1c8 100644
--- a/flang/runtime/execute.cpp
+++ b/flang/runtime/execute.cpp
@@ -120,8 +120,8 @@ int TerminationCheck(int status, const Descriptor *command,
   if (exitStatusVal == 127 || exitStatusVal == 126) {
 #endif
     if (!cmdstat) {
-      terminator.Crash("\'%s\' not found with exit status code: %d",
-          command->OffsetElement(), exitStatusVal);
+      terminator.Crash(
+          "Invalid command quit with exit status code: %d", exitStatusVal);
     } else {
       CheckAndStoreIntToDescriptor(cmdstat, INVALID_CL_ERR, terminator);
       CopyToDescriptor(*cmdmsg, "Invalid command line", 20);
@@ -186,13 +186,13 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     STARTUPINFO si;
     PROCESS_INFORMATION pi;
     ZeroMemory(&si, sizeof(si));
-    si.cb{sizeof(si)};
+    si.cb = sizeof(si);
     ZeroMemory(&pi, sizeof(pi));
 
     // append "cmd.exe /c " to the beginning of command
     const char *cmd{command->OffsetElement()};
     const char *prefix{"cmd.exe /c "};
-    char *newCmd{(char *)malloc(strlen(prefix) + strlen(cmd) + 1)};
+    char *newCmd{(char *)malloc(std::strlen(prefix) + std::strlen(cmd) + 1)};
     if (newCmd != NULL) {
       std::strcpy(newCmd, prefix);
       std::strcat(newCmd, cmd);
@@ -200,13 +200,11 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
       terminator.Crash("Memory allocation failed for newCmd");
     }
 
-    // Convert the narrow string to a wide string
-    int sizeNeede{MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, NULL, 0)};
+    // Convert the char to wide char
+    const size_t sizeNeeded{mbstowcs(NULL, newCmd, 0) + 1};
     wchar_t *wcmd{new wchar_t[sizeNeeded]};
-    if (MultiByteToWideChar(CP_UTF8, 0, newCmd, -1, wcmd, sizeNeeded) == 0) {
-      terminator.Crash(
-          "Char to wider char conversion failed with error code: %lu.",
-          GetLastError());
+    if (std::mbstowcs(wcmd, newCmd, sizeNeeded) == static_cast<size_t>(-1)) {
+      terminator.Crash("Char to wide char failed for newCmd");
     }
     free(newCmd);
 
@@ -220,7 +218,7 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
             "CreateProcess failed with error code: %lu.", GetLastError());
       } else {
         StoreIntToDescriptor(cmdstat, (uint32_t)GetLastError(), terminator);
-        CheckAndCopyToDescriptor(*cmdmsg, "CreateProcess failed.", 21);
+        CheckAndCopyToDescriptor(cmdmsg, "CreateProcess failed.", 21);
       }
     }
     delete[] wcmd;
diff --git a/flang/test/Lower/Intrinsics/execute_command_line-optional.f90 b/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
index 706f544d063f4..eef3b0ccabc09 100644
--- a/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
+++ b/flang/test/Lower/Intrinsics/execute_command_line-optional.f90
@@ -41,13 +41,11 @@ subroutine all_args_optional(command, isWait, exitVal, cmdVal, msg)
 ! CHECK-NEXT:    %20 = fir.embox %7 typeparams %6#1 : (!fir.ref<!fir.char<1,?>>, index) -> !fir.box<!fir.char<1,?>>
 ! CHECK-NEXT:    %21 = fir.absent !fir.box<!fir.char<1,?>> 
 ! CHECK-NEXT:    %22 = arith.select %12, %20, %21 : !fir.box<!fir.char<1,?>>
-! CHECK-NEXT:    %23 = fir.address_of(@_QQclX76c8fd75e0e20222cfcde5fe9055bcbe) : !fir.ref<!fir.char<1,96>>
-! CHECK-NEXT:    %24 = fir.convert %13 : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
+! CHECK:         %24 = fir.convert %13 : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
 ! CHECK-NEXT:    %25 = fir.convert %14 : (!fir.logical<4>) -> i1
 ! CHECK-NEXT:    %26 = fir.convert %17 : (!fir.box<i32>) -> !fir.box<none>
 ! CHECK-NEXT:    %27 = fir.convert %19 : (!fir.box<i32>) -> !fir.box<none>
 ! CHECK-NEXT:    %28 = fir.convert %22 : (!fir.box<!fir.char<1,?>>) -> !fir.box<none>
-! CHECK-NEXT:    %29 = fir.convert %23 : (!fir.ref<!fir.char<1,96>>) -> !fir.ref<i8>
-! CHECK-NEXT:    %30 = fir.call @_FortranAExecuteCommandLine(%24, %25, %26, %27, %28, %29, %c14_i32) fastmath<contract> : (!fir.box<none>, i1, !fir.box<none>, !fir.box<none>, !fir.box<none>, !fir.ref<i8>, i32) -> none
+! CHECK:         %30 = fir.call @_FortranAExecuteCommandLine(%24, %25, %26, %27, %28, %29, %c14_i32) fastmath<contract> : (!fir.box<none>, i1, !fir.box<none>, !fir.box<none>, !fir.box<none>, !fir.ref<i8>, i32) -> none
 ! CHECK-NEXT:    return
 end subroutine all_args_optional
diff --git a/flang/test/Lower/Intrinsics/execute_command_line.f90 b/flang/test/Lower/Intrinsics/execute_command_line.f90
index 68befdb850861..3d6d4c1ed8fe2 100644
--- a/flang/test/Lower/Intrinsics/execute_command_line.f90
+++ b/flang/test/Lower/Intrinsics/execute_command_line.f90
@@ -25,14 +25,12 @@ subroutine all_args(command, isWait, exitVal, cmdVal, msg)
 ! CHECK-NEXT:        %[[exitstatBox:.*]] = fir.embox %4 : (!fir.ref<i32>) -> !fir.box<i32>
 ! CHECK-NEXT:        %[[cmdstatBox:.*]] = fir.embox %0 : (!fir.ref<i32>) -> !fir.box<i32>
 ! CHECK-NEXT:        %[[cmdmsgBox:.*]] = fir.embox %8 : (!fir.ref<!fir.char<1,30>>) -> !fir.box<!fir.char<1,30>>
-! CHECK-NEXT:        %14 = fir.address_of(@_QQclX05b779b120ed6fd4f4d4144c6c9136d6) : !fir.ref<!fir.char<1,87>>
-! CHECK-NEXT:        %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,30>>) -> !fir.box<none>
+! CHECK:             %[[command:.*]] = fir.convert %[[commandBox]] : (!fir.box<!fir.char<1,30>>) -> !fir.box<none>
 ! CHECK-NEXT:        %[[wait:.*]] = fir.convert %[[waitLoaded]] : (!fir.logical<4>) -> i1
 ! CHECK-NEXT:        %[[exitstat:.*]] = fir.convert %[[exitstatBox]] : (!fir.box<i32>) -> !fir.box<none>
 ! CHECK-NEXT:        %[[cmdstat:.*]] = fir.convert %[[cmdstatBox]] : (!fir.box<i32>) -> !fir.box<none>
 ! CHECK-NEXT:        %[[cmdmsg:.*]] = fir.convert %[[cmdmsgBox]] : (!fir.box<!fir.char<1,30>>) -> !fir.box<none>
-! CHECK-NEXT:        %20 = fir.convert %14 : (!fir.ref<!fir.char<1,87>>) -> !fir.ref<i8>
-! CHECK-NEXT:        %21 = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %[[cmdstat]], %[[cmdmsg]], %20, %c13_i32) fastmath<contract> : (!fir.box<none>, i1, !fir.box<none>, !fir.box<none>, !fir.box<none>, !fir.ref<i8>, i32) -> none
+! CHECK:             %21 = fir.call @_FortranAExecuteCommandLine(%[[command]], %[[wait]], %[[exitstat]], %[[cmdstat]], %[[cmdmsg]], %20, %c13_i32) fastmath<contract> : (!fir.box<none>, i1, !fir.box<none>, !fir.box<none>, !fir.box<none>, !fir.ref<i8>, i32) -> none
 ! CHECK-NEXT:        return
 end subroutine all_args
 
@@ -46,9 +44,7 @@ subroutine only_command_default_wait_true(command)
 ! CHECK-NEXT:     %2 = fir.declare %1 typeparams %c30 {uniq_name = "_QFonly_command_default_wait_trueEcommand"} : (!fir.ref<!fir.char<1,30>>, index) -> !fir.ref<!fir.char<1,30>>
 ! CHECK-NEXT:     %3 = fir.embox %2 : (!fir.ref<!fir.char<1,30>>) -> !fir.box<!fir.char<1,30>>
 ! CHECK-NEXT:     %4 = fir.absent !fir.box<none>
-! CHECK-NEXT:     %5 = fir.address_of(@_QQclX05b779b120ed6fd4f4d4144c6c9136d6) : !fir.ref<!fir.char<1,87>>
-! CHECK-NEXT:     %6 = fir.convert %3 : (!fir.box<!fir.char<1,30>>) -> !fir.box<none> 
-! CHECK-NEXT:     %7 = fir.convert %5 : (!fir.ref<!fir.char<1,87>>) -> !fir.ref<i8>
-! CHECK-NEXT:     %8 = fir.call @_FortranAExecuteCommandLine(%6, %true, %4, %4, %4, %7, %c43_i32) fastmath<contract> : (!fir.box<none>, i1, !fir.box<none>, !fir.box<none>, !fir.box<none>, !fir.ref<i8>, i32) -> none 
+! CHECK:          %6 = fir.convert %3 : (!fir.box<!fir.char<1,30>>) -> !fir.box<none> 
+! CHECK:          %8 = fir.call @_FortranAExecuteCommandLine(%6, %true, %4, %4, %4, %7, %c41_i32) fastmath<contract> : (!fir.box<none>, i1, !fir.box<none>, !fir.box<none>, !fir.box<none>, !fir.ref<i8>, i32) -> none
 ! CHECK-NEXT:     return
 end subroutine only_command_default_wait_true
diff --git a/flang/unittests/Runtime/CommandTest.cpp b/flang/unittests/Runtime/CommandTest.cpp
index 66b5d3970ba76..ee82a5b3a4672 100644
--- a/flang/unittests/Runtime/CommandTest.cpp
+++ b/flang/unittests/Runtime/CommandTest.cpp
@@ -279,8 +279,11 @@ TEST_F(ZeroArguments, ECLInvalidCommandErrorSync) {
 
   RTNAME(ExecuteCommandLine)
   (command.get(), wait, exitStat.get(), cmdStat.get(), cmdMsg.get());
-
+#ifdef _WIN32
+  CheckDescriptorEqInt(exitStat.get(), 1);
+#else
   CheckDescriptorEqInt(exitStat.get(), 127);
+#endif
   CheckDescriptorEqInt(cmdStat.get(), 3);
   CheckDescriptorEqStr(cmdMsg.get(), "Invalid command lineXXXX");
 }
@@ -288,14 +291,19 @@ TEST_F(ZeroArguments, ECLInvalidCommandErrorSync) {
 TEST_F(ZeroArguments, ECLInvalidCommandTerminatedSync) {
   OwningPtr<Descriptor> command{CharDescriptor("InvalidCommand")};
   bool wait{true};
-  OwningPtr<Descriptor> exitStat{EmptyIntDescriptor()};
+  OwningPtr<Descriptor> exitStat{IntDescriptor(404)};
   OwningPtr<Descriptor> cmdMsg{CharDescriptor("No Change")};
 
+#ifdef _WIN32
   EXPECT_DEATH(RTNAME(ExecuteCommandLine)(
                    command.get(), wait, exitStat.get(), nullptr, cmdMsg.get()),
-      "'InvalidCommand' not found with exit status code: 127");
-
-  CheckDescriptorEqInt(exitStat.get(), 0);
+      "Invalid command quit with exit status code: 1");
+#else
+  EXPECT_DEATH(RTNAME(ExecuteCommandLine)(
+                   command.get(), wait, exitStat.get(), nullptr, cmdMsg.get()),
+      "Invalid command quit with exit status code: 127");
+#endif
+  CheckDescriptorEqInt(exitStat.get(), 404);
   CheckDescriptorEqStr(cmdMsg.get(), "No Change");
 }
 

>From af9294c5e2c15936d9869c3d253f55acedd0f34c Mon Sep 17 00:00:00 2001
From: Yi Wu <yi.wu2 at arm.com>
Date: Mon, 4 Dec 2023 16:38:59 +0000
Subject: [PATCH 22/22] terminated children do not become zombies on Linux

signal(SIGCHLD, SIG_IGN);
https://man7.org/linux/man-pages/man2/sigaction.2.html

POSIX.1-1990 disallowed setting the action for SIGCHLD to
SIG_IGN.  POSIX.1-2001 and later allow this possibility, so that
ignoring SIGCHLD can be used to prevent the creation of zombies
(see wait(2)).  Nevertheless, the historical BSD and System V
behaviors for ignoring SIGCHLD differ, so that the only
completely portable method of ensuring that terminated children
do not become zombies is to catch the SIGCHLD signal and perform
a wait(2) or similar.
---
 flang/runtime/execute.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/flang/runtime/execute.cpp b/flang/runtime/execute.cpp
index 13a103333c1c8..3a57194644a14 100644
--- a/flang/runtime/execute.cpp
+++ b/flang/runtime/execute.cpp
@@ -21,6 +21,7 @@
 #include <stdio.h>
 #include <windows.h>
 #else
+#include <signal.h>
 #include <unistd.h>
 #endif
 
@@ -223,6 +224,8 @@ void RTNAME(ExecuteCommandLine)(const Descriptor *command, bool wait,
     }
     delete[] wcmd;
 #else
+    // terminated children do not become zombies
+    signal(SIGCHLD, SIG_IGN);
     pid_t pid{fork()};
     if (pid < 0) {
       if (!cmdstat) {