[clang] 17feb33 - [flang][Driver] Let the linker fail on multiple definitions of main() (#73124)
via cfe-commits
cfe-commits at lists.llvm.org
Tue Nov 28 12:20:35 PST 2023
Author: Michael Klemm
Date: 2023-11-28T14:20:30-06:00
New Revision: 17feb330aab39c6c0c21ee9b02efb484dfb2261e
URL: https://github.com/llvm/llvm-project/commit/17feb330aab39c6c0c21ee9b02efb484dfb2261e
DIFF: https://github.com/llvm/llvm-project/commit/17feb330aab39c6c0c21ee9b02efb484dfb2261e.diff
LOG: [flang][Driver] Let the linker fail on multiple definitions of main() (#73124)
The flang driver was silently ignoring the `main()` function in
`Fortran_main.a` for entry into the Fortran program unit if an external
`main()` as supplied (e.g., via cross-language linkage with Fortran and
C/C++). This PR fixes this by making sure that the linker always pulls
in the `main()` definition from `Fortran_main.a` and consequently fails
due to multiple definitions of the same symbol if another object file
also has a definition of `main()`.
Added:
flang/test/Driver/Inputs/no_duplicate_main.ll
flang/test/Driver/no_duplicate_main.f90
Modified:
clang/lib/Driver/ToolChains/CommonArgs.cpp
clang/lib/Driver/ToolChains/CommonArgs.h
clang/lib/Driver/ToolChains/Darwin.cpp
clang/lib/Driver/ToolChains/DragonFly.cpp
clang/lib/Driver/ToolChains/FreeBSD.cpp
clang/lib/Driver/ToolChains/Gnu.cpp
clang/lib/Driver/ToolChains/Haiku.cpp
clang/lib/Driver/ToolChains/MSVC.cpp
clang/lib/Driver/ToolChains/MinGW.cpp
clang/lib/Driver/ToolChains/NetBSD.cpp
clang/lib/Driver/ToolChains/OpenBSD.cpp
clang/lib/Driver/ToolChains/Solaris.cpp
flang/test/Driver/linker-flags.f90
Removed:
################################################################################
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index 1f31c6395206ee8..efb8b71f24a932c 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -977,14 +977,60 @@ bool tools::addOpenMPRuntime(ArgStringList &CmdArgs, const ToolChain &TC,
return true;
}
-void tools::addFortranRuntimeLibs(const ToolChain &TC,
+void tools::addFortranRuntimeLibs(const ToolChain &TC, const ArgList &Args,
llvm::opt::ArgStringList &CmdArgs) {
// These are handled earlier on Windows by telling the frontend driver to add
// the correct libraries to link against as dependents in the object file.
if (!TC.getTriple().isKnownWindowsMSVCEnvironment()) {
+ // The --whole-archive option needs to be part of the link line to
+ // make sure that the main() function from Fortran_main.a is pulled
+ // in by the linker. Determine if --whole-archive is active when
+ // flang will try to link Fortran_main.a. If it is, don't add the
+ // --whole-archive flag to the link line. If it's not, add a proper
+ // --whole-archive/--no-whole-archive bracket to the link line.
+ bool WholeArchiveActive = false;
+ for (auto *Arg : Args.filtered(options::OPT_Wl_COMMA))
+ if (Arg)
+ for (StringRef ArgValue : Arg->getValues()) {
+ if (ArgValue == "--whole-archive")
+ WholeArchiveActive = true;
+ if (ArgValue == "--no-whole-archive")
+ WholeArchiveActive = false;
+ }
+
+ if (!WholeArchiveActive)
+ CmdArgs.push_back("--whole-archive");
CmdArgs.push_back("-lFortran_main");
+ if (!WholeArchiveActive)
+ CmdArgs.push_back("--no-whole-archive");
+
+ // Perform regular linkage of the remaining runtime libraries.
CmdArgs.push_back("-lFortranRuntime");
CmdArgs.push_back("-lFortranDecimal");
+ } else {
+ unsigned RTOptionID = options::OPT__SLASH_MT;
+ if (auto *rtl = Args.getLastArg(options::OPT_fms_runtime_lib_EQ)) {
+ RTOptionID = llvm::StringSwitch<unsigned>(rtl->getValue())
+ .Case("static", options::OPT__SLASH_MT)
+ .Case("static_dbg", options::OPT__SLASH_MTd)
+ .Case("dll", options::OPT__SLASH_MD)
+ .Case("dll_dbg", options::OPT__SLASH_MDd)
+ .Default(options::OPT__SLASH_MT);
+ }
+ switch (RTOptionID) {
+ case options::OPT__SLASH_MT:
+ CmdArgs.push_back("/WHOLEARCHIVE:Fortran_main.static.lib");
+ break;
+ case options::OPT__SLASH_MTd:
+ CmdArgs.push_back("/WHOLEARCHIVE:Fortran_main.static_dbg.lib");
+ break;
+ case options::OPT__SLASH_MD:
+ CmdArgs.push_back("/WHOLEARCHIVE:Fortran_main.dynamic.lib");
+ break;
+ case options::OPT__SLASH_MDd:
+ CmdArgs.push_back("/WHOLEARCHIVE:Fortran_main.dynamic_dbg.lib");
+ break;
+ }
}
}
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.h b/clang/lib/Driver/ToolChains/CommonArgs.h
index f364c9793c9be62..0a0951c5386e601 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.h
+++ b/clang/lib/Driver/ToolChains/CommonArgs.h
@@ -116,7 +116,7 @@ bool addOpenMPRuntime(llvm::opt::ArgStringList &CmdArgs, const ToolChain &TC,
bool IsOffloadingHost = false, bool GompNeedsRT = false);
/// Adds Fortran runtime libraries to \p CmdArgs.
-void addFortranRuntimeLibs(const ToolChain &TC,
+void addFortranRuntimeLibs(const ToolChain &TC, const llvm::opt::ArgList &Args,
llvm::opt::ArgStringList &CmdArgs);
/// Adds the path for the Fortran runtime libraries to \p CmdArgs.
diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index 1f61bb02c6ae226..7c3d4982d8f6a8c 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -678,7 +678,7 @@ void darwin::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// to generate executables.
if (getToolChain().getDriver().IsFlangMode()) {
addFortranRuntimeLibraryPath(getToolChain(), Args, CmdArgs);
- addFortranRuntimeLibs(getToolChain(), CmdArgs);
+ addFortranRuntimeLibs(getToolChain(), Args, CmdArgs);
}
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs))
diff --git a/clang/lib/Driver/ToolChains/DragonFly.cpp b/clang/lib/Driver/ToolChains/DragonFly.cpp
index 181d0ad0d834b2b..9942fc632e0a917 100644
--- a/clang/lib/Driver/ToolChains/DragonFly.cpp
+++ b/clang/lib/Driver/ToolChains/DragonFly.cpp
@@ -153,7 +153,7 @@ void dragonfly::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// AddRunTimeLibs).
if (D.IsFlangMode()) {
addFortranRuntimeLibraryPath(ToolChain, Args, CmdArgs);
- addFortranRuntimeLibs(ToolChain, CmdArgs);
+ addFortranRuntimeLibs(ToolChain, Args, CmdArgs);
CmdArgs.push_back("-lm");
}
diff --git a/clang/lib/Driver/ToolChains/FreeBSD.cpp b/clang/lib/Driver/ToolChains/FreeBSD.cpp
index d08764aeef77539..d46feb3459a6344 100644
--- a/clang/lib/Driver/ToolChains/FreeBSD.cpp
+++ b/clang/lib/Driver/ToolChains/FreeBSD.cpp
@@ -310,7 +310,7 @@ void freebsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// AddRunTimeLibs).
if (D.IsFlangMode()) {
addFortranRuntimeLibraryPath(ToolChain, Args, CmdArgs);
- addFortranRuntimeLibs(ToolChain, CmdArgs);
+ addFortranRuntimeLibs(ToolChain, Args, CmdArgs);
if (Profiling)
CmdArgs.push_back("-lm_p");
else
diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index 16cf5707227264d..b875991844ffff5 100644
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -564,7 +564,7 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// AddRunTimeLibs).
if (D.IsFlangMode()) {
addFortranRuntimeLibraryPath(ToolChain, Args, CmdArgs);
- addFortranRuntimeLibs(ToolChain, CmdArgs);
+ addFortranRuntimeLibs(ToolChain, Args, CmdArgs);
CmdArgs.push_back("-lm");
}
diff --git a/clang/lib/Driver/ToolChains/Haiku.cpp b/clang/lib/Driver/ToolChains/Haiku.cpp
index 3fe92054ac53e15..e0d94035823fd37 100644
--- a/clang/lib/Driver/ToolChains/Haiku.cpp
+++ b/clang/lib/Driver/ToolChains/Haiku.cpp
@@ -118,7 +118,7 @@ void haiku::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// AddRunTimeLibs).
if (D.IsFlangMode()) {
addFortranRuntimeLibraryPath(ToolChain, Args, CmdArgs);
- addFortranRuntimeLibs(ToolChain, CmdArgs);
+ addFortranRuntimeLibs(ToolChain, Args, CmdArgs);
}
CmdArgs.push_back("-lgcc");
diff --git a/clang/lib/Driver/ToolChains/MSVC.cpp b/clang/lib/Driver/ToolChains/MSVC.cpp
index 4966d102c51f1ac..8a4a174c90ea855 100644
--- a/clang/lib/Driver/ToolChains/MSVC.cpp
+++ b/clang/lib/Driver/ToolChains/MSVC.cpp
@@ -131,7 +131,7 @@ void visualstudio::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (C.getDriver().IsFlangMode()) {
addFortranRuntimeLibraryPath(TC, Args, CmdArgs);
- addFortranRuntimeLibs(TC, CmdArgs);
+ addFortranRuntimeLibs(TC, Args, CmdArgs);
// Inform the MSVC linker that we're generating a console application, i.e.
// one with `main` as the "user-defined" entry point. The `main` function is
diff --git a/clang/lib/Driver/ToolChains/MinGW.cpp b/clang/lib/Driver/ToolChains/MinGW.cpp
index 39d767795445dbe..5d7f8675daf8d28 100644
--- a/clang/lib/Driver/ToolChains/MinGW.cpp
+++ b/clang/lib/Driver/ToolChains/MinGW.cpp
@@ -249,7 +249,7 @@ void tools::MinGW::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (C.getDriver().IsFlangMode()) {
addFortranRuntimeLibraryPath(TC, Args, CmdArgs);
- addFortranRuntimeLibs(TC, CmdArgs);
+ addFortranRuntimeLibs(TC, Args, CmdArgs);
}
// TODO: Add profile stuff here
diff --git a/clang/lib/Driver/ToolChains/NetBSD.cpp b/clang/lib/Driver/ToolChains/NetBSD.cpp
index 90b195a007caa78..240bf5764b9cce2 100644
--- a/clang/lib/Driver/ToolChains/NetBSD.cpp
+++ b/clang/lib/Driver/ToolChains/NetBSD.cpp
@@ -325,7 +325,7 @@ void netbsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// AddRunTimeLibs).
if (D.IsFlangMode()) {
addFortranRuntimeLibraryPath(ToolChain, Args, CmdArgs);
- addFortranRuntimeLibs(ToolChain, CmdArgs);
+ addFortranRuntimeLibs(ToolChain, Args, CmdArgs);
CmdArgs.push_back("-lm");
}
diff --git a/clang/lib/Driver/ToolChains/OpenBSD.cpp b/clang/lib/Driver/ToolChains/OpenBSD.cpp
index 133b5ff13a4c7e2..21b9004ef2d52d1 100644
--- a/clang/lib/Driver/ToolChains/OpenBSD.cpp
+++ b/clang/lib/Driver/ToolChains/OpenBSD.cpp
@@ -237,7 +237,7 @@ void openbsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// AddRunTimeLibs).
if (D.IsFlangMode()) {
addFortranRuntimeLibraryPath(ToolChain, Args, CmdArgs);
- addFortranRuntimeLibs(ToolChain, CmdArgs);
+ addFortranRuntimeLibs(ToolChain, Args, CmdArgs);
if (Profiling)
CmdArgs.push_back("-lm_p");
else
diff --git a/clang/lib/Driver/ToolChains/Solaris.cpp b/clang/lib/Driver/ToolChains/Solaris.cpp
index 32b6cbe647da6ad..485730da7df1f8c 100644
--- a/clang/lib/Driver/ToolChains/Solaris.cpp
+++ b/clang/lib/Driver/ToolChains/Solaris.cpp
@@ -226,7 +226,7 @@ void solaris::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// these dependencies need to be listed before the C runtime below.
if (D.IsFlangMode()) {
addFortranRuntimeLibraryPath(getToolChain(), Args, CmdArgs);
- addFortranRuntimeLibs(getToolChain(), CmdArgs);
+ addFortranRuntimeLibs(getToolChain(), Args, CmdArgs);
CmdArgs.push_back("-lm");
}
if (Args.hasArg(options::OPT_fstack_protector) ||
diff --git a/flang/test/Driver/Inputs/no_duplicate_main.ll b/flang/test/Driver/Inputs/no_duplicate_main.ll
new file mode 100644
index 000000000000000..ff2b19dfe9e288b
--- /dev/null
+++ b/flang/test/Driver/Inputs/no_duplicate_main.ll
@@ -0,0 +1,7 @@
+; Create the symbol 'main'; does not have to be the correct
+; signature for 'main', we just need the symbol for the linker
+; to fail during the test.
+
+define i32 @main() {
+ ret i32 0
+}
diff --git a/flang/test/Driver/linker-flags.f90 b/flang/test/Driver/linker-flags.f90
index 85c4d60b3f09862..ea91946316cfaa6 100644
--- a/flang/test/Driver/linker-flags.f90
+++ b/flang/test/Driver/linker-flags.f90
@@ -28,7 +28,7 @@
! executable and may find the GNU linker from MinGW or Cygwin.
! UNIX-LABEL: "{{.*}}ld{{(\.exe)?}}"
! UNIX-SAME: "[[object_file]]"
-! UNIX-SAME: "-lFortran_main" "-lFortranRuntime" "-lFortranDecimal" "-lm"
+! UNIX-SAME: "--whole-archive" "-lFortran_main" "--no-whole-archive" "-lFortranRuntime" "-lFortranDecimal" "-lm"
! DARWIN-LABEL: "{{.*}}ld{{(\.exe)?}}"
! DARWIN-SAME: "[[object_file]]"
@@ -38,7 +38,7 @@
! HAIKU-LABEL: "{{.*}}ld{{(\.exe)?}}"
! HAIKU-SAME: "[[object_file]]"
-! HAIKU-SAME: "-lFortran_main" "-lFortranRuntime" "-lFortranDecimal"
+! HAIKU-SAME: "--whole-archive" "-lFortran_main" "--no-whole-archive" "-lFortranRuntime" "-lFortranDecimal"
! MINGW-LABEL: "{{.*}}ld{{(\.exe)?}}"
! MINGW-SAME: "[[object_file]]"
diff --git a/flang/test/Driver/no_duplicate_main.f90 b/flang/test/Driver/no_duplicate_main.f90
new file mode 100644
index 000000000000000..4e33f4f2aeba3f7
--- /dev/null
+++ b/flang/test/Driver/no_duplicate_main.f90
@@ -0,0 +1,14 @@
+! UNSUPPORTED: system-windows
+
+! RUN: %flang -x ir -o %t.c-object -c %S/Inputs/no_duplicate_main.ll
+! RUN: %flang -o %t -c %s
+! RUN: not %flang -o %t.exe %t %t.c-object 2>&1
+
+! TODO: potentially add further checks to ensure that proper
+! linker error messages are detected and checked via
+! FileCheck.
+
+program main_dupes
+ ! Irrelevant what to do in here.
+ ! Test is supposed to fail at link time.
+end program main_dupes
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