[clang] [Driver][Gnu] Auto-link libstdc++fs for GCC < 9.2 (PR #154826)
Yaxun Liu via cfe-commits
cfe-commits at lists.llvm.org
Thu Aug 21 13:15:38 PDT 2025
https://github.com/yxsamliu updated https://github.com/llvm/llvm-project/pull/154826
>From 7e93842c711d077e187a54bdc6ca7565fc1eaff9 Mon Sep 17 00:00:00 2001
From: "Yaxun (Sam) Liu" <yaxun.liu at amd.com>
Date: Thu, 21 Aug 2025 15:12:43 -0400
Subject: [PATCH] [Driver][Gnu] Auto-link libstdc++fs for GCC versions in [5.3,
9.2)
Teach Generic_GCC to append -lstdc++fs when using libstdc++ from a valid GCC installation whose version is >= 5.3.0 and < 9.2.0. This covers older libstdc++ where std::filesystem resides in a separate library, improving out-of-the-box linking without affecting libc++ or newer libstdc++ where filesystem is integrated.
Update bare-metal driver tests (aarch64, arm, riscv32, riscv64) to expect "-lstdc++fs" alongside "-lstdc++". Behavior triggers only for libstdc++ with detected GCC in the specified version range.
Fixes: SWDEV-549946
---
clang/lib/Driver/ToolChains/Gnu.cpp | 21 +++++++++++++++++++++
clang/lib/Driver/ToolChains/Gnu.h | 2 ++
clang/test/Driver/aarch64-toolchain.c | 4 ++--
clang/test/Driver/arm-toolchain.c | 4 ++--
clang/test/Driver/riscv32-toolchain.c | 4 ++--
clang/test/Driver/riscv64-toolchain.c | 4 ++--
6 files changed, 31 insertions(+), 8 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index 01b146db24f3e..8a2969d636a28 100644
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -268,6 +268,27 @@ void tools::gnutools::StaticLibTool::ConstructJob(
Exec, CmdArgs, Inputs, Output));
}
+void Generic_GCC::AddCXXStdlibLibArgs(const ArgList &Args,
+ ArgStringList &CmdArgs) const {
+ ToolChain::AddCXXStdlibLibArgs(Args, CmdArgs);
+ CXXStdlibType Type = GetCXXStdlibType(Args);
+
+ switch (Type) {
+ case ToolChain::CST_Libcxx:
+ // Do nothing.
+ break;
+
+ case ToolChain::CST_Libstdcxx:
+ if (GCCInstallation.isValid()) {
+ const GCCVersion V = GCCInstallation.getVersion();
+ // Add -lstdc++fs only for GCC >= 5.3.0 and < 9.2.0.
+ if (!V.isOlderThan(5, 3, 0) && V.isOlderThan(9, 2, 0))
+ CmdArgs.push_back("-lstdc++fs");
+ }
+ break;
+ }
+}
+
void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
const InputInfo &Output,
const InputInfoList &Inputs,
diff --git a/clang/lib/Driver/ToolChains/Gnu.h b/clang/lib/Driver/ToolChains/Gnu.h
index ad817452e5933..2b088d962f0a2 100644
--- a/clang/lib/Driver/ToolChains/Gnu.h
+++ b/clang/lib/Driver/ToolChains/Gnu.h
@@ -306,6 +306,8 @@ class LLVM_LIBRARY_VISIBILITY Generic_GCC : public ToolChain {
llvm::opt::DerivedArgList *
TranslateArgs(const llvm::opt::DerivedArgList &Args, StringRef BoundArch,
Action::OffloadKind DeviceOffloadKind) const override;
+ void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
+ llvm::opt::ArgStringList &CmdArgs) const override;
protected:
Tool *getTool(Action::ActionClass AC) const override;
diff --git a/clang/test/Driver/aarch64-toolchain.c b/clang/test/Driver/aarch64-toolchain.c
index 4fddcce240c13..213c24c81eb49 100644
--- a/clang/test/Driver/aarch64-toolchain.c
+++ b/clang/test/Driver/aarch64-toolchain.c
@@ -72,7 +72,7 @@
// CXX-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
// CXX-AARCH64-BAREMETAL: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
// CXX-AARCH64-BAREMETAL: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib"
-// CXX-AARCH64-BAREMETAL: "{{.*}}.o" "-lstdc++" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-AARCH64-BAREMETAL: "{{.*}}.o" "-lstdc++" "-lstdc++fs" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
// CXX-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
// RUN: %clangxx -### %s -fuse-ld= \
@@ -91,7 +91,7 @@
// CXX-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
// CXX-AARCH64-BAREMETAL-NOSYSROOT: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
// CXX-AARCH64-BAREMETAL-NOSYSROOT: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib"
-// CXX-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}.o" "-lstdc++" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}.o" "-lstdc++" "-lstdc++fs" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
// CXX-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
// RUN: %clangxx -### %s -fuse-ld= \
diff --git a/clang/test/Driver/arm-toolchain.c b/clang/test/Driver/arm-toolchain.c
index 7ee65a4782e21..b5783ae987ead 100644
--- a/clang/test/Driver/arm-toolchain.c
+++ b/clang/test/Driver/arm-toolchain.c
@@ -72,7 +72,7 @@
// CXX-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtbegin.o"
// CXX-ARM-BAREMETAL: "-L{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1"
// CXX-ARM-BAREMETAL: "-L{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib"
-// CXX-ARM-BAREMETAL: "{{.*}}.o" "-lstdc++" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-ARM-BAREMETAL: "{{.*}}.o" "-lstdc++" "-lstdc++fs" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
// CXX-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtend.o"
@@ -92,7 +92,7 @@
// CXX-ARM-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtbegin.o"
// CXX-ARM-BAREMETAL-NOSYSROOT: "-L{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1"
// CXX-ARM-BAREMETAL-NOSYSROOT: "-L{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../armv6m-none-eabi/lib"
-// CXX-ARM-BAREMETAL-NOSYSROOT: "{{.*}}.o" "-lstdc++" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-ARM-BAREMETAL-NOSYSROOT: "{{.*}}.o" "-lstdc++" "-lstdc++fs" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
// CXX-ARM-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtend.o"
// RUN: %clangxx -### %s -fuse-ld= \
diff --git a/clang/test/Driver/riscv32-toolchain.c b/clang/test/Driver/riscv32-toolchain.c
index 04acf1e7edbe0..2ca33ad8efcd0 100644
--- a/clang/test/Driver/riscv32-toolchain.c
+++ b/clang/test/Driver/riscv32-toolchain.c
@@ -58,7 +58,7 @@
// CXX-RV32-BAREMETAL-ILP32: "{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1/crtbegin.o"
// CXX-RV32-BAREMETAL-ILP32: "-L{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1"
// CXX-RV32-BAREMETAL-ILP32: "-L{{.*}}/Inputs/basic_riscv32_tree/riscv32-unknown-elf/lib"
-// CXX-RV32-BAREMETAL-ILP32: "-lstdc++" "-lm" "--start-group" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-RV32-BAREMETAL-ILP32: "-lstdc++" "-lstdc++fs" "-lm" "--start-group" "-lgcc" "-lc" "-lgloss" "--end-group"
// CXX-RV32-BAREMETAL-ILP32: "{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1/crtend.o"
// RUN: %clangxx -### %s -fuse-ld= \
@@ -73,7 +73,7 @@
// CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1/crtbegin.o"
// CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "-L{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1"
// CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "-L{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1/../../../../riscv32-unknown-elf/lib"
-// CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "-lstdc++" "-lm" "--start-group" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "-lstdc++" "-lstdc++fs" "-lm" "--start-group" "-lgcc" "-lc" "-lgloss" "--end-group"
// CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1/crtend.o"
// RUN: env "PATH=" %clang -### %s -fuse-ld=ld -no-pie \
diff --git a/clang/test/Driver/riscv64-toolchain.c b/clang/test/Driver/riscv64-toolchain.c
index 378f3d9db7bad..c749035f92b9e 100644
--- a/clang/test/Driver/riscv64-toolchain.c
+++ b/clang/test/Driver/riscv64-toolchain.c
@@ -58,7 +58,7 @@
// CXX-RV64-BAREMETAL-LP64: "{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1/crtbegin.o"
// CXX-RV64-BAREMETAL-LP64: "-L{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1"
// CXX-RV64-BAREMETAL-LP64: "-L{{.*}}/Inputs/basic_riscv64_tree/riscv64-unknown-elf/lib"
-// CXX-RV64-BAREMETAL-LP64: "-lstdc++" "-lm" "--start-group" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-RV64-BAREMETAL-LP64: "-lstdc++" "-lstdc++fs" "-lm" "--start-group" "-lgcc" "-lc" "-lgloss" "--end-group"
// CXX-RV64-BAREMETAL-LP64: "{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1/crtend.o"
// RUN: env "PATH=" %clangxx -### %s -fuse-ld= \
@@ -73,7 +73,7 @@
// CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1/crtbegin.o"
// CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "-L{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1"
// CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "-L{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1/../../../../riscv64-unknown-elf/lib"
-// CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "-lstdc++" "-lm" "--start-group" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "-lstdc++" "-lstdc++fs" "-lm" "--start-group" "-lgcc" "-lc" "-lgloss" "--end-group"
// CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1/crtend.o"
// RUN: env "PATH=" %clang -### %s -fuse-ld= -no-pie \
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