[flang-commits] [flang] [flang][parser] handle semicolons uniformly in program unit constructs (PR #181180)
Andre Kuhlenschmidt via flang-commits
flang-commits at lists.llvm.org
Thu Mar 5 09:28:44 PST 2026
https://github.com/akuhlens updated https://github.com/llvm/llvm-project/pull/181180
>From 026101b50f5d52d956474c323918d442f728235a Mon Sep 17 00:00:00 2001
From: Andre Kuhlenschmidt <akuhlenschmi at nvidia.com>
Date: Mon, 9 Feb 2026 15:20:51 -0800
Subject: [PATCH 1/5] initial commit
---
flang/lib/Parser/program-parsers.cpp | 11 ++++++-----
flang/test/Parser/bug176914.f90 | 16 ++++++++++++++++
2 files changed, 22 insertions(+), 5 deletions(-)
create mode 100644 flang/test/Parser/bug176914.f90
diff --git a/flang/lib/Parser/program-parsers.cpp b/flang/lib/Parser/program-parsers.cpp
index dac377c29d9db..7aea0ad59ae96 100644
--- a/flang/lib/Parser/program-parsers.cpp
+++ b/flang/lib/Parser/program-parsers.cpp
@@ -68,9 +68,9 @@ static constexpr auto programUnit{
construct<ProgramUnit>(indirect(functionSubprogram)) ||
construct<ProgramUnit>(indirect(Parser<MainProgram>{}))};
-static constexpr auto normalProgramUnit{
- !consumedAllInput >> StartNewSubprogram{} >> programUnit /
- skipMany(";"_tok) / space / recovery(endOfLine, skipToNextLineIfAny)};
+static constexpr auto normalProgramUnit{!consumedAllInput >>
+ StartNewSubprogram{} >>
+ programUnit / recovery(endOfStmt, skipToNextLineIfAny)};
static constexpr auto globalCompilerDirective{
construct<ProgramUnit>(indirect(compilerDirective))};
@@ -91,8 +91,9 @@ TYPE_PARSER(
"nonstandard usage: empty source file"_port_en_US,
skipStuffBeforeStatement >> consumedAllInput >>
pure<std::list<ProgramUnit>>()) ||
- some(globalCompilerDirective || globalOpenACCCompilerDirective ||
- normalProgramUnit) /
+ some(skipStuffBeforeStatement >> (globalCompilerDirective ||
+ globalOpenACCCompilerDirective ||
+ normalProgramUnit)) /
skipStuffBeforeStatement))
// R507 declaration-construct ->
diff --git a/flang/test/Parser/bug176914.f90 b/flang/test/Parser/bug176914.f90
new file mode 100644
index 0000000000000..ee31a1d295ec8
--- /dev/null
+++ b/flang/test/Parser/bug176914.f90
@@ -0,0 +1,16 @@
+!RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema %s 2>&1 | FileCheck %s
+! CHECK: Program -> ProgramUnit -> MainProgram
+! CHECK-NEXT: | ProgramStmt -> Name = 'semicolon'
+; program semicolon
+use semi;
+IMPLICIT NONE ;
+testvar2 = testvar
+;; ; intvar = testvar + testvar2;intvar2=intvar;
+print *,testvar , testvar2, intvar, intvar2
+! CHECK: | EndProgramStmt
+! CHECK: ProgramUnit -> SubroutineSubprogram
+! CHECK-NEXT: | SubroutineStmt
+! CHECK-NEXT: | | Name = 'test'
+end ; ; subroutine test( arg1, arg2 );real arg1, arg2;;;; arg1=arg2; ; ; end;;;
+;;
+! CHECK: | EndSubroutineStmt
\ No newline at end of file
>From c94a659e7f813bd0860ab24d0a488e72224a24a8 Mon Sep 17 00:00:00 2001
From: Andre Kuhlenschmidt <akuhlenschmi at nvidia.com>
Date: Mon, 23 Feb 2026 14:51:47 -0800
Subject: [PATCH 2/5] refactor program parser
---
flang/lib/Parser/program-parsers.cpp | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/flang/lib/Parser/program-parsers.cpp b/flang/lib/Parser/program-parsers.cpp
index 7aea0ad59ae96..1dd932ec79aca 100644
--- a/flang/lib/Parser/program-parsers.cpp
+++ b/flang/lib/Parser/program-parsers.cpp
@@ -86,15 +86,14 @@ static constexpr auto globalOpenACCCompilerDirective{
// Consequently, a program unit END statement should be the last statement
// on its line. We parse those END statements via unterminatedStatement()
// and then skip over the end of the line here.
-TYPE_PARSER(
- construct<Program>(extension<LanguageFeature::EmptySourceFile>(
- "nonstandard usage: empty source file"_port_en_US,
- skipStuffBeforeStatement >> consumedAllInput >>
- pure<std::list<ProgramUnit>>()) ||
+TYPE_PARSER(construct<Program>(skipStuffBeforeStatement >>
+ (extension<LanguageFeature::EmptySourceFile>(
+ "nonstandard usage: empty source file"_port_en_US,
+ consumedAllInput >> pure<std::list<ProgramUnit>>()) ||
some(skipStuffBeforeStatement >> (globalCompilerDirective ||
globalOpenACCCompilerDirective ||
normalProgramUnit)) /
- skipStuffBeforeStatement))
+ skipStuffBeforeStatement)))
// R507 declaration-construct ->
// specification-construct | data-stmt | format-stmt |
>From 4cdaac36c54653adb291a72db283eb2988fc4551 Mon Sep 17 00:00:00 2001
From: Andre Kuhlenschmidt <akuhlenschmi at nvidia.com>
Date: Wed, 4 Mar 2026 15:00:00 -0800
Subject: [PATCH 3/5] add tests
---
flang/test/Parser/bug176914.did-work.0.f90 | 2 ++
flang/test/Parser/bug176914.did-work.1.f90 | 11 +++++++++++
flang/test/Parser/bug176914.did-work.2.f90 | 9 +++++++++
flang/test/Parser/bug176914.did-work.3.f90 | 3 +++
flang/test/Parser/bug176914.was-broken.0.f90 | 4 ++++
flang/test/Parser/bug176914.was-broken.1.f90 | 5 +++++
flang/test/Parser/bug176914.was-broken.2.f90 | 6 ++++++
7 files changed, 40 insertions(+)
create mode 100644 flang/test/Parser/bug176914.did-work.0.f90
create mode 100644 flang/test/Parser/bug176914.did-work.1.f90
create mode 100644 flang/test/Parser/bug176914.did-work.2.f90
create mode 100644 flang/test/Parser/bug176914.did-work.3.f90
create mode 100644 flang/test/Parser/bug176914.was-broken.0.f90
create mode 100644 flang/test/Parser/bug176914.was-broken.1.f90
create mode 100644 flang/test/Parser/bug176914.was-broken.2.f90
diff --git a/flang/test/Parser/bug176914.did-work.0.f90 b/flang/test/Parser/bug176914.did-work.0.f90
new file mode 100644
index 0000000000000..4435300fc7bf5
--- /dev/null
+++ b/flang/test/Parser/bug176914.did-work.0.f90
@@ -0,0 +1,2 @@
+!RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema %s 2>&1 | FileCheck %s
+! CHECK: Program
\ No newline at end of file
diff --git a/flang/test/Parser/bug176914.did-work.1.f90 b/flang/test/Parser/bug176914.did-work.1.f90
new file mode 100644
index 0000000000000..05f55ac37032b
--- /dev/null
+++ b/flang/test/Parser/bug176914.did-work.1.f90
@@ -0,0 +1,11 @@
+!RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema %s 2>&1 | FileCheck %s
+;
+! CHECK: Program -> ProgramUnit -> CompilerDirective
+!DIR$ unknown_directive empty statement
+;
+! CHECK: ProgramUnit -> MainProgram
+program semicolon; end;
+! CHECK: ProgramUnit -> CompilerDirective
+ !DIR$ unknown_directive leading space
+! CHECK: ProgramUnit -> CompilerDirective
+; !DIR$ unknown_directive leading empty statement
\ No newline at end of file
diff --git a/flang/test/Parser/bug176914.did-work.2.f90 b/flang/test/Parser/bug176914.did-work.2.f90
new file mode 100644
index 0000000000000..0215794bd1599
--- /dev/null
+++ b/flang/test/Parser/bug176914.did-work.2.f90
@@ -0,0 +1,9 @@
+!RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema %s 2>&1 | FileCheck %s
+! CHECK: Program -> ProgramUnit -> MainProgram
+! CHECK-NEXT: | ProgramStmt -> Name = 'semicolon'
+program semicolon; end
+;
+subroutine sub; end;
+function fn(); end;;
+; ;
+module mod; end;
\ No newline at end of file
diff --git a/flang/test/Parser/bug176914.did-work.3.f90 b/flang/test/Parser/bug176914.did-work.3.f90
new file mode 100644
index 0000000000000..cd38283a5e118
--- /dev/null
+++ b/flang/test/Parser/bug176914.did-work.3.f90
@@ -0,0 +1,3 @@
+!RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema %s 2>&1 | FileCheck %s
+! CHECK: Program
+;;
diff --git a/flang/test/Parser/bug176914.was-broken.0.f90 b/flang/test/Parser/bug176914.was-broken.0.f90
new file mode 100644
index 0000000000000..6cc6eff981cde
--- /dev/null
+++ b/flang/test/Parser/bug176914.was-broken.0.f90
@@ -0,0 +1,4 @@
+!RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema %s 2>&1 | FileCheck %s
+! CHECK: Program -> ProgramUnit -> MainProgram
+program semicolon; end
+;
diff --git a/flang/test/Parser/bug176914.was-broken.1.f90 b/flang/test/Parser/bug176914.was-broken.1.f90
new file mode 100644
index 0000000000000..a7ce66b88d98c
--- /dev/null
+++ b/flang/test/Parser/bug176914.was-broken.1.f90
@@ -0,0 +1,5 @@
+!RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema %s 2>&1 | FileCheck %s
+! CHECK: Program -> ProgramUnit -> MainProgram
+! CHECK: ProgramUnit -> SubroutineSubprogram
+program semicolon; end; subroutine sub; end;
+
diff --git a/flang/test/Parser/bug176914.was-broken.2.f90 b/flang/test/Parser/bug176914.was-broken.2.f90
new file mode 100644
index 0000000000000..6cb832d5f926b
--- /dev/null
+++ b/flang/test/Parser/bug176914.was-broken.2.f90
@@ -0,0 +1,6 @@
+!RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema %s 2>&1 | FileCheck %s
+! CHECK: Program -> ProgramUnit -> SubroutineSubprogram
+subroutine sub; end
+;
+! CHECK: ProgramUnit -> FunctionSubprogram
+function fn(); end
>From bfae0835bb59f416f4d867d0572863a00d2ab36f Mon Sep 17 00:00:00 2001
From: Andre Kuhlenschmidt <akuhlenschmi at nvidia.com>
Date: Wed, 4 Mar 2026 15:09:52 -0800
Subject: [PATCH 4/5] add newline at the end of tests
---
flang/test/Parser/bug176914.did-work.0.f90 | 2 +-
flang/test/Parser/bug176914.did-work.1.f90 | 2 +-
flang/test/Parser/bug176914.f90 | 2 +-
flang/test/Parser/bug176914.was-broken.1.f90 | 1 -
4 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/flang/test/Parser/bug176914.did-work.0.f90 b/flang/test/Parser/bug176914.did-work.0.f90
index 4435300fc7bf5..0df1a2e527e1b 100644
--- a/flang/test/Parser/bug176914.did-work.0.f90
+++ b/flang/test/Parser/bug176914.did-work.0.f90
@@ -1,2 +1,2 @@
!RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema %s 2>&1 | FileCheck %s
-! CHECK: Program
\ No newline at end of file
+! CHECK: Program
diff --git a/flang/test/Parser/bug176914.did-work.1.f90 b/flang/test/Parser/bug176914.did-work.1.f90
index 05f55ac37032b..d28cd35a59e1a 100644
--- a/flang/test/Parser/bug176914.did-work.1.f90
+++ b/flang/test/Parser/bug176914.did-work.1.f90
@@ -8,4 +8,4 @@ program semicolon; end;
! CHECK: ProgramUnit -> CompilerDirective
!DIR$ unknown_directive leading space
! CHECK: ProgramUnit -> CompilerDirective
-; !DIR$ unknown_directive leading empty statement
\ No newline at end of file
+; !DIR$ unknown_directive leading empty statement
diff --git a/flang/test/Parser/bug176914.f90 b/flang/test/Parser/bug176914.f90
index ee31a1d295ec8..d7d960e9fcee4 100644
--- a/flang/test/Parser/bug176914.f90
+++ b/flang/test/Parser/bug176914.f90
@@ -13,4 +13,4 @@
! CHECK-NEXT: | | Name = 'test'
end ; ; subroutine test( arg1, arg2 );real arg1, arg2;;;; arg1=arg2; ; ; end;;;
;;
-! CHECK: | EndSubroutineStmt
\ No newline at end of file
+! CHECK: | EndSubroutineStmt
diff --git a/flang/test/Parser/bug176914.was-broken.1.f90 b/flang/test/Parser/bug176914.was-broken.1.f90
index a7ce66b88d98c..fef95323a1807 100644
--- a/flang/test/Parser/bug176914.was-broken.1.f90
+++ b/flang/test/Parser/bug176914.was-broken.1.f90
@@ -2,4 +2,3 @@
! CHECK: Program -> ProgramUnit -> MainProgram
! CHECK: ProgramUnit -> SubroutineSubprogram
program semicolon; end; subroutine sub; end;
-
>From 9072355dc2f9bdfa390ffd7ac61cce423cc1bd95 Mon Sep 17 00:00:00 2001
From: Andre Kuhlenschmidt <akuhlenschmi at nvidia.com>
Date: Thu, 5 Mar 2026 09:28:10 -0800
Subject: [PATCH 5/5] remove comment
---
flang/lib/Parser/program-parsers.cpp | 5 -----
1 file changed, 5 deletions(-)
diff --git a/flang/lib/Parser/program-parsers.cpp b/flang/lib/Parser/program-parsers.cpp
index 1dd932ec79aca..775810f8c3c0f 100644
--- a/flang/lib/Parser/program-parsers.cpp
+++ b/flang/lib/Parser/program-parsers.cpp
@@ -81,11 +81,6 @@ static constexpr auto globalOpenACCCompilerDirective{
// R501 program -> program-unit [program-unit]...
// This is the top-level production for the Fortran language.
-// F'2018 6.3.1 defines a program unit as a sequence of one or more lines,
-// implying that a line can't be part of two distinct program units.
-// Consequently, a program unit END statement should be the last statement
-// on its line. We parse those END statements via unterminatedStatement()
-// and then skip over the end of the line here.
TYPE_PARSER(construct<Program>(skipStuffBeforeStatement >>
(extension<LanguageFeature::EmptySourceFile>(
"nonstandard usage: empty source file"_port_en_US,
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