https://github.com/parabola94 created
https://github.com/llvm/llvm-project/pull/149786
The default linker could be changed by a CMake variable CLANG_DEFAULT_LINKER
before. However, it also changes the default linker invoked by clang. This
patch distincts the default linkers of clang and flang.
Note that FLANG_DEFAULT_LINKER will be the same as CLANG_DEFAULT_LINKER unless
it is defined explicitly. That means this patch does not affect the current
behavior.
Fixes #73153
>From c6d3516b04946c9529083b293ce640f14c1879fe Mon Sep 17 00:00:00 2001
From: parabola94 <heavybaby5...@toki.waseda.jp>
Date: Mon, 21 Jul 2025 18:00:05 +0900
Subject: [PATCH 1/2] [clang][Driver] Add a new member for CLANG_DEFAULT_LINKER
to clang::driver::Driver (NFC)
The default linker can be changed by a CMake variable CLANG_DEFAULT_LINKER,
but it is shared in all toolchains. This patch intends to resolve this.
---
clang/include/clang/Driver/Driver.h | 9 +++++++++
clang/lib/Driver/Driver.cpp | 4 ++--
clang/lib/Driver/ToolChain.cpp | 2 +-
clang/lib/Driver/ToolChains/MSVC.cpp | 4 ++--
clang/lib/Driver/ToolChains/MinGW.cpp | 2 +-
clang/lib/Driver/ToolChains/Solaris.cpp | 6 +++---
clang/lib/Driver/ToolChains/UEFI.cpp | 4 ++--
7 files changed, 20 insertions(+), 11 deletions(-)
diff --git a/clang/include/clang/Driver/Driver.h
b/clang/include/clang/Driver/Driver.h
index d9e328fe918bc..107b3d95dde42 100644
--- a/clang/include/clang/Driver/Driver.h
+++ b/clang/include/clang/Driver/Driver.h
@@ -337,6 +337,10 @@ class Driver {
/// "clang" as it's first argument.
const char *PrependArg;
+ /// The default value of -fuse-ld= option. An empty string means the default
+ /// system linker.
+ std::string PreferredLinker;
+
/// Whether to check that input files exist when constructing compilation
/// jobs.
LLVM_PREFERRED_TYPE(bool)
@@ -450,6 +454,11 @@ class Driver {
return ClangExecutable.c_str();
}
+ StringRef getPreferredLinker() const { return PreferredLinker; }
+ void setPreferredLinker(std::string Value) {
+ PreferredLinker = std::move(Value);
+ }
+
bool isSaveTempsEnabled() const { return SaveTemps != SaveTempsNone; }
bool isSaveTempsObj() const { return SaveTemps == SaveTempsObj; }
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index ec1135eecd401..46c8ffbc493d2 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -266,8 +266,8 @@ Driver::Driver(StringRef ClangExecutable, StringRef
TargetTriple,
CCLogDiagnostics(false), CCGenDiagnostics(false),
CCPrintProcessStats(false), CCPrintInternalStats(false),
TargetTriple(TargetTriple), Saver(Alloc), PrependArg(nullptr),
- CheckInputsExist(true), ProbePrecompiled(true),
- SuppressMissingInputWarning(false) {
+ PreferredLinker(CLANG_DEFAULT_LINKER), CheckInputsExist(true),
+ ProbePrecompiled(true), SuppressMissingInputWarning(false) {
// Provide a sane fallback if no VFS is specified.
if (!this->VFS)
this->VFS = llvm::vfs::getRealFileSystem();
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 481f575518b93..38616a3f97183 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -1100,7 +1100,7 @@ std::string ToolChain::GetLinkerPath(bool *LinkerIsLLD)
const {
// Get -fuse-ld= first to prevent -Wunused-command-line-argument. -fuse-ld=
is
// considered as the linker flavor, e.g. "bfd", "gold", or "lld".
const Arg* A = Args.getLastArg(options::OPT_fuse_ld_EQ);
- StringRef UseLinker = A ? A->getValue() : CLANG_DEFAULT_LINKER;
+ StringRef UseLinker = A ? A->getValue() : getDriver().getPreferredLinker();
// --ld-path= takes precedence over -fuse-ld= and specifies the executable
// name. -B, COMPILER_PATH and PATH and consulted if the value does not
diff --git a/clang/lib/Driver/ToolChains/MSVC.cpp
b/clang/lib/Driver/ToolChains/MSVC.cpp
index 7d31eea603087..bb469ff095cd4 100644
--- a/clang/lib/Driver/ToolChains/MSVC.cpp
+++ b/clang/lib/Driver/ToolChains/MSVC.cpp
@@ -279,8 +279,8 @@ void visualstudio::Linker::ConstructJob(Compilation &C,
const JobAction &JA,
AddRunTimeLibs(TC, TC.getDriver(), CmdArgs, Args);
}
- StringRef Linker =
- Args.getLastArgValue(options::OPT_fuse_ld_EQ, CLANG_DEFAULT_LINKER);
+ StringRef Linker = Args.getLastArgValue(options::OPT_fuse_ld_EQ,
+ TC.getDriver().getPreferredLinker());
if (Linker.empty())
Linker = "link";
// We need to translate 'lld' into 'lld-link'.
diff --git a/clang/lib/Driver/ToolChains/MinGW.cpp
b/clang/lib/Driver/ToolChains/MinGW.cpp
index b2e36ae6f97c3..6abd0c04ecc0e 100644
--- a/clang/lib/Driver/ToolChains/MinGW.cpp
+++ b/clang/lib/Driver/ToolChains/MinGW.cpp
@@ -548,7 +548,7 @@ toolchains::MinGW::MinGW(const Driver &D, const
llvm::Triple &Triple,
getFilePaths().push_back(Base + "lib");
NativeLLVMSupport =
- Args.getLastArgValue(options::OPT_fuse_ld_EQ, CLANG_DEFAULT_LINKER)
+ Args.getLastArgValue(options::OPT_fuse_ld_EQ, D.getPreferredLinker())
.equals_insensitive("lld");
}
diff --git a/clang/lib/Driver/ToolChains/Solaris.cpp
b/clang/lib/Driver/ToolChains/Solaris.cpp
index a3574e1b701e8..02aa59817449d 100644
--- a/clang/lib/Driver/ToolChains/Solaris.cpp
+++ b/clang/lib/Driver/ToolChains/Solaris.cpp
@@ -39,7 +39,7 @@ void solaris::Assembler::ConstructJob(Compilation &C, const
JobAction &JA,
bool solaris::isLinkerGnuLd(const ToolChain &TC, const ArgList &Args) {
// Only used if targetting Solaris.
const Arg *A = Args.getLastArg(options::OPT_fuse_ld_EQ);
- StringRef UseLinker = A ? A->getValue() : CLANG_DEFAULT_LINKER;
+ StringRef UseLinker = A ? A->getValue() :
TC.getDriver().getPreferredLinker();
return UseLinker == "bfd" || UseLinker == "gld";
}
@@ -52,7 +52,7 @@ static bool getPIE(const ArgList &Args, const ToolChain &TC) {
TC.isPIEDefault(Args));
}
-// FIXME: Need to handle CLANG_DEFAULT_LINKER here?
+// FIXME: Need to handle PreferredLinker here?
std::string solaris::Linker::getLinkerPath(const ArgList &Args) const {
const ToolChain &ToolChain = getToolChain();
if (const Arg *A = Args.getLastArg(options::OPT_fuse_ld_EQ)) {
@@ -345,7 +345,7 @@ SanitizerMask Solaris::getSupportedSanitizers() const {
const char *Solaris::getDefaultLinker() const {
// FIXME: Only handle Solaris ld and GNU ld here.
- return llvm::StringSwitch<const char *>(CLANG_DEFAULT_LINKER)
+ return llvm::StringSwitch<const char *>(getDriver().getPreferredLinker())
.Cases("bfd", "gld", "/usr/gnu/bin/ld")
.Default("/usr/bin/ld");
}
diff --git a/clang/lib/Driver/ToolChains/UEFI.cpp
b/clang/lib/Driver/ToolChains/UEFI.cpp
index ac6668e6bdd5f..2b41173543477 100644
--- a/clang/lib/Driver/ToolChains/UEFI.cpp
+++ b/clang/lib/Driver/ToolChains/UEFI.cpp
@@ -83,8 +83,8 @@ void tools::uefi::Linker::ConstructJob(Compilation &C, const
JobAction &JA,
// This should ideally be handled by ToolChain::GetLinkerPath but we need
// to special case some linker paths. In the case of lld, we need to
// translate 'lld' into 'lld-link'.
- StringRef Linker =
- Args.getLastArgValue(options::OPT_fuse_ld_EQ, CLANG_DEFAULT_LINKER);
+ StringRef Linker = Args.getLastArgValue(options::OPT_fuse_ld_EQ,
+ TC.getDriver().getPreferredLinker());
if (Linker.empty() || Linker == "lld")
Linker = "lld-link";
>From 7a97f531134060f7b0480cdb2d980373834d7ea2 Mon Sep 17 00:00:00 2001
From: parabola94 <heavybaby5...@toki.waseda.jp>
Date: Mon, 21 Jul 2025 18:29:59 +0900
Subject: [PATCH 2/2] [flang][Driver] Enable FLANG_DEFAULT_LINKER
The default linker could be changed by a CMake variable CLANG_DEFAULT_LINKER
before.
However, it also changes the default linker invoked by clang.
This patch distincts the default linkers of clang and flang.
Note that FLANG_DEFAULT_LINKER will be the same as CLANG_DEFAULT_LINKER
unless it is defined explicitly.
That means this patch does not affect the current behavior.
Fixes #73153
---
flang/CMakeLists.txt | 2 +-
flang/include/flang/Config/config.h.cmake | 16 +++++++++-------
flang/tools/flang-driver/driver.cpp | 2 ++
3 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/flang/CMakeLists.txt b/flang/CMakeLists.txt
index 0bfada476348a..6cbe6d4ed6a3e 100644
--- a/flang/CMakeLists.txt
+++ b/flang/CMakeLists.txt
@@ -317,7 +317,7 @@ if (NOT ENABLE_LINKER_BUILD_ID)
set(ENABLE_LINKER_BUILD_ID OFF CACHE BOOL "pass --build-id to ld")
endif()
-set(FLANG_DEFAULT_LINKER "" CACHE STRING
+set(FLANG_DEFAULT_LINKER ${CLANG_DEFAULT_LINKER} CACHE STRING
"Default linker to use (linker name or absolute path, empty for platform
default)")
set(FLANG_DEFAULT_RTLIB "" CACHE STRING
diff --git a/flang/include/flang/Config/config.h.cmake
b/flang/include/flang/Config/config.h.cmake
index fd34d3f403631..f7ff495880fa1 100644
--- a/flang/include/flang/Config/config.h.cmake
+++ b/flang/include/flang/Config/config.h.cmake
@@ -1,10 +1,10 @@
-#===-- include/flang/Config/config.h.cmake
---------------------------------===#
-#
-# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-# See https://llvm.org/LICENSE.txt for license information.
-# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-#
-#===------------------------------------------------------------------------===#
+//===-- include/flang/Config/config.h.cmake
---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM
Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===------------------------------------------------------------------------===//
/* This generated file is for internal use. Do not include it from headers. */
@@ -16,6 +16,8 @@
#define FLANG_VERSION "${FLANG_VERSION}"
+#define FLANG_DEFAULT_LINKER "${FLANG_DEFAULT_LINKER}"
+
#endif
diff --git a/flang/tools/flang-driver/driver.cpp
b/flang/tools/flang-driver/driver.cpp
index 3a2dffc66428f..b1e02383cd33d 100644
--- a/flang/tools/flang-driver/driver.cpp
+++ b/flang/tools/flang-driver/driver.cpp
@@ -16,6 +16,7 @@
//===----------------------------------------------------------------------===//
#include "clang/Driver/Driver.h"
+#include "flang/Config/config.h"
#include "flang/Frontend/CompilerInvocation.h"
#include "flang/Frontend/TextDiagnosticPrinter.h"
#include "clang/Basic/Diagnostic.h"
@@ -138,6 +139,7 @@ int main(int argc, const char **argv) {
llvm::sys::getDefaultTargetTriple(), diags,
"flang LLVM compiler");
theDriver.setTargetAndMode(targetandMode);
+ theDriver.setPreferredLinker(FLANG_DEFAULT_LINKER);
#ifdef FLANG_RUNTIME_F128_MATH_LIB
theDriver.setFlangF128MathLibrary(FLANG_RUNTIME_F128_MATH_LIB);
#endif
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