[flang-commits] [flang] e5d98c1 - Revert "[flang][driver] Allow main program to be in an archive"
Andrzej Warzynski via flang-commits
flang-commits at lists.llvm.org
Fri Apr 28 01:42:01 PDT 2023
Author: Andrzej Warzynski
Date: 2023-04-28T09:39:27+01:00
New Revision: e5d98c15cb7ba467c5f93b5ef08ac9b18d390133
URL: https://github.com/llvm/llvm-project/commit/e5d98c15cb7ba467c5f93b5ef08ac9b18d390133
DIFF: https://github.com/llvm/llvm-project/commit/e5d98c15cb7ba467c5f93b5ef08ac9b18d390133.diff
LOG: Revert "[flang][driver] Allow main program to be in an archive"
This reverts commit 876df74dd47196a9ca3b4fff21ffb5441491a0a0.
My understanding (based on https://reviews.llvm.org/D149429) is that
this patch has caused all of Flang's buildbots to fail. I'm not really
able to verify 100% as the buildbot UI is incredibly slow ATM. I am
reverting either way so that we can discuss the right solution offline.
Added:
Modified:
clang/lib/Driver/ToolChains/Gnu.cpp
flang/docs/FlangDriver.md
flang/test/CMakeLists.txt
flang/test/Driver/linker-flags.f90
Removed:
flang/test/Driver/link-c-main.c
flang/test/Driver/link-f90-main.f90
################################################################################
diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index c4a276126b653..b0716322bc141 100644
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -598,14 +598,6 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// these dependencies need to be listed before the C runtime below (i.e.
// AddRuntTimeLibs).
if (D.IsFlangMode()) {
- // A Fortran main program will be lowered to a function named _QQmain. Make
- // _QQmain an undefined symbol, so that it's correctly resolved even when
- // creating executable from archives. This is a workaround for how and where
- // Flang's `main` is defined. For more context, see:
- // * https://github.com/llvm/llvm-project/issues/54787
- if (!Args.hasArg(options::OPT_shared))
- CmdArgs.push_back("--undefined=_QQmain");
-
addFortranRuntimeLibraryPath(ToolChain, Args, CmdArgs);
addFortranRuntimeLibs(ToolChain, CmdArgs);
CmdArgs.push_back("-lm");
diff --git a/flang/docs/FlangDriver.md b/flang/docs/FlangDriver.md
index 9522e223b17b5..6c2a473820634 100644
--- a/flang/docs/FlangDriver.md
+++ b/flang/docs/FlangDriver.md
@@ -149,6 +149,13 @@ flang-new -ccc-print-phases -c file.f
+- 3: backend, {2}, assembler
4: assembler, {3}, object
```
+Note that currently Flang does not support code-generation and `flang-new` will
+fail during the second step above with the following error:
+```bash
+error: code-generation is not available yet
+```
+The other phases are printed nonetheless when using `-ccc-print-phases`, as
+that reflects what `clangDriver`, the library, will try to create and run.
For actions specific to the frontend (e.g. preprocessing or code generation), a
command to call the frontend driver is generated (more specifically, an
@@ -198,41 +205,6 @@ is `ParseSyntaxOnlyAction`, which corresponds to `-fsyntax-only`. In other
words, `flang-new -fc1 <input-file>` is equivalent to `flang-new -fc1 -fsyntax-only
<input-file>`.
-## Linker invocation
-> **_NOTE:_** Linker invocation through the `flang-new` driver is so far
-> experimental. This section describes the currently intended design, and not
-> necessarily what is implemented.
-
-Calling
-```bash
-flang-new -flang-experimental-exec prog.f90
-```
-will, on a high level, do two things:
-* call the frontend driver, `flang-new -fc1`, to build the object file `prog.o`
-* call the system linker to build the executable `a.out`.
-
-In both invocations, `flang-new` will add default options to the frontend driver
-and the linker invocations. To see the exact invocations on your system, you can
-call
-```bash
-flang-new -### prog.f90
-```
-The link line will contain a fair number of options, which will depend on your
-system. Compared to when linking a C program with `clang`, the main additions
-are (on GNU/linux),
-* `--undefined=_QQmain`: A Fortran main program will appear in the corresponding
- object file as a function called `_QQmain`. This flag makes sure that an
- object file containing a Fortran main program (i.e., a symbol `_QQmain`) be
- included in the linking also when it is bundled in an archive.
-* `-lFortran_main`: The Fortran_main archive is part of Flang's runtime. It
- exports the symbol `main`, i.e., a c main function, which will make some
- initial configuration before calling `_QQmain`, and clean up before returning.
-* `-lFortranRuntime`: Flang's Fortran runtime, containing, for example,
- implementations of intrinsic functions.
-* `-lFortranDecimal`: Part of Flang's runtime, containing routines for parsing
- and formatting decimal numbers.
-* `-lm`: Link with the math library, on which Flang's runtime depends.
-
## The `flang-to-external-fc` script
The `flang-to-external-fc` wrapper script for `flang-new` was introduced as a
development tool and to facilitate testing. The `flang-to-external-fc` wrapper
diff --git a/flang/test/CMakeLists.txt b/flang/test/CMakeLists.txt
index dbb02574ec183..7d96a72e5f36d 100644
--- a/flang/test/CMakeLists.txt
+++ b/flang/test/CMakeLists.txt
@@ -57,7 +57,6 @@ set(FLANG_TEST_DEPENDS
fir-opt
tco
bbc
- llvm-ar
llvm-dis
llvm-objdump
llvm-readobj
diff --git a/flang/test/Driver/link-c-main.c b/flang/test/Driver/link-c-main.c
deleted file mode 100644
index e6814259a33d2..0000000000000
--- a/flang/test/Driver/link-c-main.c
+++ /dev/null
@@ -1,28 +0,0 @@
-/*
-Test that an object file with a C main function can be linked to an executable
-by Flang.
-
-For now, this test only covers the Gnu toolchain on Linux.
-
-REQUIRES: x86-registered-target || aarch64-registered-target || riscv64-registered-target
-REQUIRES: system-linux, c-compiler
-
-RUN: %cc -c %s -o %t.o
-RUN: %flang -target x86_64-unknown-linux-gnu %t.o -o %t.out -flang-experimental-exec
-RUN: llvm-objdump --syms %t.out | FileCheck %s --implicit-check-not Fortran
-
-Test that it also works if the c-main is bundled in an archive.
-
-RUN: llvm-ar -r %t.a %t.o
-RUN: %flang -target x86_64-unknown-linux-gnu %t.a -o %ta.out -flang-experimental-exec
-RUN: llvm-objdump --syms %ta.out | FileCheck %s --implicit-check-not Fortran
-*/
-
-int main(void) {
- return 0;
-}
-
-/*
-CHECK-DAG: F .text {{[a-f0-9]+}} main
-CHECK-DAG: *UND* {{[a-f0-9]+}} _QQmain
-*/
diff --git a/flang/test/Driver/link-f90-main.f90 b/flang/test/Driver/link-f90-main.f90
deleted file mode 100644
index 01f77f40d0300..0000000000000
--- a/flang/test/Driver/link-f90-main.f90
+++ /dev/null
@@ -1,23 +0,0 @@
-! Test that a fortran main program can be linked to an executable
-! by flang.
-!
-! For now, this test only covers the Gnu toolchain on linux.
-
-!REQUIRES: x86-registered-target || aarch64-registered-target || riscv64-registered-target
-!REQUIRES: system-linux
-
-! RUN: %flang_fc1 -emit-obj %s -o %t.o
-! RUN: %flang -target x86_64-unknown-linux-gnu %t.o -o %t.out -flang-experimental-exec
-! RUN: llvm-objdump --syms %t.out | FileCheck %s
-
-! Test that it also works if the program is bundled in an archive.
-
-! RUN: llvm-ar -r %t.a %t.o
-! RUN: %flang -target x86_64-unknown-linux-gnu %t.a -o %ta.out -flang-experimental-exec
-! RUN: llvm-objdump --syms %ta.out | FileCheck %s
-
-end program
-
-! CHECK-DAG: F .text {{[a-f0-9]+}} main
-! CHECK-DAG: F .text {{[a-f0-9]+}} _QQmain
-! CHECK-DAG: _FortranAProgramStart
diff --git a/flang/test/Driver/linker-flags.f90 b/flang/test/Driver/linker-flags.f90
index f776d76129698..e1350b74ae30a 100644
--- a/flang/test/Driver/linker-flags.f90
+++ b/flang/test/Driver/linker-flags.f90
@@ -12,14 +12,6 @@
! Make sure they're not added.
! RUN: %flang -### -flang-experimental-exec -target aarch64-windows-msvc %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,MSVC --implicit-check-not libcmt --implicit-check-not oldnames
-! Check linker invocation to generate shared object (only GNU toolchain for now)
-! Output should not contain any undefined reference to _QQmain since it is not
-! considered a valid entry point for shared objects, which are usually specified
-! using the bind attribute.
-! RUN: %flang -### -flang-experimental-exec -shared -target x86_64-linux-gnu %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,GNU-SHARED --implicit-check-not _QQmain
-! RUN: %flang -### -flang-experimental-exec -shared -target aarch64-linux-gnu %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,GNU-SHARED --implicit-check-not _QQmain
-! RUN: %flang -### -flang-experimental-exec -shared -target riscv64-linux-gnu %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,GNU-SHARED --implicit-check-not _QQmain
-
! Compiler invocation to generate the object file
! CHECK-LABEL: {{.*}} "-emit-obj"
! CHECK-SAME: "-o" "[[object_file:.*\.o]]" {{.*}}Inputs/hello.f90
@@ -31,7 +23,6 @@
! executable and may find the GNU linker from MinGW or Cygwin.
! GNU-LABEL: "{{.*}}ld{{(\.exe)?}}"
! GNU-SAME: "[[object_file]]"
-! GNU-SAME: --undefined=_QQmain
! GNU-SAME: -lFortran_main
! GNU-SAME: -lFortranRuntime
! GNU-SAME: -lFortranDecimal
@@ -59,9 +50,3 @@
! MSVC-SAME: FortranDecimal.lib
! MSVC-SAME: /subsystem:console
! MSVC-SAME: "[[object_file]]"
-
-! Linker invocation to generate a shared object
-! GNU-SHARED-LABEL: "{{.*}}ld"
-! GNU-SHARED-SAME: "[[object_file]]"
-! GNU-SHARED-SAME: -lFortranRuntime
-! GNU-SHARED-SAME: -lFortranDecimal
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