[Driver] Normalize the baremetal handling of libc++ and runtimes #101259
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The handling of libc++ and other runtime libraries in the baremetal driver is different from other targets for no particular reason. This change removes the custom in the baremetal driver logic and replaces it with the generic logic to improve consistency and reduce maintenance overhead while also handling additional flags the current logic doesn't.
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@llvm/pr-subscribers-clang-driver @llvm/pr-subscribers-clang Author: Petr Hosek (petrhosek) ChangesThe handling of libc++ and other runtime libraries in the baremetal driver is different from other targets for no particular reason. This change removes the custom in the baremetal driver logic and replaces it with the generic logic to improve consistency and reduce maintenance overhead while also handling additional flags the current logic doesn't. Full diff: https://github.com/llvm/llvm-project/pull/101259.diff 5 Files Affected:
diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index 852e0442f50a2..6dd2d7419bd85 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -382,38 +382,6 @@ void BareMetal::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
}
}
-void BareMetal::AddCXXStdlibLibArgs(const ArgList &Args,
- ArgStringList &CmdArgs) const {
- switch (GetCXXStdlibType(Args)) {
- case ToolChain::CST_Libcxx:
- CmdArgs.push_back("-lc++");
- if (Args.hasArg(options::OPT_fexperimental_library))
- CmdArgs.push_back("-lc++experimental");
- CmdArgs.push_back("-lc++abi");
- break;
- case ToolChain::CST_Libstdcxx:
- CmdArgs.push_back("-lstdc++");
- CmdArgs.push_back("-lsupc++");
- break;
- }
- CmdArgs.push_back("-lunwind");
-}
-
-void BareMetal::AddLinkRuntimeLib(const ArgList &Args,
- ArgStringList &CmdArgs) const {
- ToolChain::RuntimeLibType RLT = GetRuntimeLibType(Args);
- switch (RLT) {
- case ToolChain::RLT_CompilerRT: {
- CmdArgs.push_back(getCompilerRTArgString(Args, "builtins"));
- return;
- }
- case ToolChain::RLT_Libgcc:
- CmdArgs.push_back("-lgcc");
- return;
- }
- llvm_unreachable("Unhandled RuntimeLibType.");
-}
-
void baremetal::StaticLibTool::ConstructJob(Compilation &C, const JobAction &JA,
const InputInfo &Output,
const InputInfoList &Inputs,
@@ -495,14 +463,21 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
for (const auto &LibPath : TC.getLibraryPaths())
CmdArgs.push_back(Args.MakeArgString(llvm::Twine("-L", LibPath)));
- if (TC.ShouldLinkCXXStdlib(Args))
+ if (TC.ShouldLinkCXXStdlib(Args)) {
+ bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
+ !Args.hasArg(options::OPT_static);
+ if (OnlyLibstdcxxStatic)
+ CmdArgs.push_back("-Bstatic");
TC.AddCXXStdlibLibArgs(Args, CmdArgs);
+ if (OnlyLibstdcxxStatic)
+ CmdArgs.push_back("-Bdynamic");
+ CmdArgs.push_back("-lm");
+ }
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
- CmdArgs.push_back("-lc");
- CmdArgs.push_back("-lm");
+ AddRunTimeLibs(TC, D, CmdArgs, Args);
- TC.AddLinkRuntimeLib(Args, CmdArgs);
+ CmdArgs.push_back("-lc");
}
if (D.isUsingLTO()) {
diff --git a/clang/lib/Driver/ToolChains/BareMetal.h b/clang/lib/Driver/ToolChains/BareMetal.h
index 67b5aa5998fc3..3e3861687caba 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.h
+++ b/clang/lib/Driver/ToolChains/BareMetal.h
@@ -67,10 +67,6 @@ class LLVM_LIBRARY_VISIBILITY BareMetal : public ToolChain {
void AddClangCXXStdlibIncludeArgs(
const llvm::opt::ArgList &DriverArgs,
llvm::opt::ArgStringList &CC1Args) const override;
- void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
- llvm::opt::ArgStringList &CmdArgs) const override;
- void AddLinkRuntimeLib(const llvm::opt::ArgList &Args,
- llvm::opt::ArgStringList &CmdArgs) const;
std::string computeSysRoot() const override;
SanitizerMask getSupportedSanitizers() const override;
diff --git a/clang/test/Driver/baremetal-multilib.yaml b/clang/test/Driver/baremetal-multilib.yaml
index 9ed83e4aec839..69696291525be 100644
--- a/clang/test/Driver/baremetal-multilib.yaml
+++ b/clang/test/Driver/baremetal-multilib.yaml
@@ -17,7 +17,8 @@
# CHECK-SAME: "-x" "c++" "{{.*}}baremetal-multilib.yaml"
# CHECK-NEXT: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
# CHECK-SAME: "-L[[SYSROOT]]/bin/../lib/clang-runtimes/arm-none-eabi/thumb/v8-m.main/fp/lib"
-# CHECK-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a"
+# CHECK-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+# CHECK-SAME: "-lc"
# CHECK-SAME: "-o" "{{.*}}.tmp.out"
# RUN: %T/baremetal_multilib/bin/clang -no-canonical-prefixes -x c++ %s -### -o %t.out 2>&1 \
diff --git a/clang/test/Driver/baremetal-sysroot.cpp b/clang/test/Driver/baremetal-sysroot.cpp
index 18654be33b87c..5cbb7ac69a7ac 100644
--- a/clang/test/Driver/baremetal-sysroot.cpp
+++ b/clang/test/Driver/baremetal-sysroot.cpp
@@ -18,5 +18,6 @@
// CHECK-V6M-C-SAME: "-x" "c++" "{{.*}}baremetal-sysroot.cpp"
// CHECK-V6M-C-NEXT: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-V6M-C-SAME: "-L{{.*}}/baremetal_default_sysroot{{[/\\]+}}bin{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+}}armv6m-none-eabi{{[/\\]+}}lib"
-// CHECK-V6M-C-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-V6M-C-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-V6M-C-SAME: "-lc"
// CHECK-V6M-C-SAME: "-o" "{{.*}}.o"
diff --git a/clang/test/Driver/baremetal.cpp b/clang/test/Driver/baremetal.cpp
index de4e93434e203..86fcf5cf680a0 100644
--- a/clang/test/Driver/baremetal.cpp
+++ b/clang/test/Driver/baremetal.cpp
@@ -18,7 +18,9 @@
// CHECK-V6M-C-NEXT: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic" "-EL"
// CHECK-V6M-C-SAME: "-T" "semihosted.lds" "-Lsome{{[/\\]+}}directory{{[/\\]+}}user{{[/\\]+}}asked{{[/\\]+}}for"
// CHECK-V6M-C-SAME: "-L[[SYSROOT:[^"]+]]{{[/\\]+}}lib"
-// CHECK-V6M-C-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "--target2=rel" "-o" "{{.*}}.tmp.out"
+// CHECK-V6M-C-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-V6M-C-SAME: "-lc"
+// CHECK-V6M-C-SAME: "--target2=rel" "-o" "{{.*}}.tmp.out"
// RUN: %clang %s -### --target=armv6m-none-eabi -nostdlibinc -nobuiltininc 2>&1 \
// RUN: --sysroot=%S/Inputs/baremetal_arm | FileCheck --check-prefix=CHECK-V6M-LIBINC %s
@@ -38,7 +40,9 @@
// CHECK-V6M-TREE-SAME: "-x" "c++" "{{.*}}baremetal.cpp"
// CHECK-V6M-TREE-NEXT: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic" "-EL"
// CHECK-V6M-TREE-SAME: "-L[[INSTALLED_DIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}armv6m-unknown-none-eabi"
-// CHECK-V6M-TREE-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "--target2=rel" "-o" "{{.*}}.tmp.out"
+// CHECK-V6M-TREE-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-V6M-TREE-SAME: "-lc"
+// CHECK-V6M-TREE-SAME: "--target2=rel" "-o" "{{.*}}.tmp.out"
// RUN: %clang %s -### --target=armv7m-vendor-none-eabi -rtlib=compiler-rt 2>&1 \
// RUN: --sysroot=%S/Inputs/baremetal_arm \
@@ -50,15 +54,19 @@
// CHECK-ARMV7M-PER-TARGET: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic" "-EL"
// CHECK-ARMV7M-PER-TARGET: "-L[[SYSROOT:[^"]+]]{{[/\\]+}}lib"
// CHECK-ARMV7M-PER-TARGET: "-L[[RESOURCE_DIR:[^"]+]]{{[/\\]+}}lib{{[/\\]+}}armv7m-vendor-none-eabi
-// CHECK-ARMV7M-PER-TARGET: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-ARMV7M-PER-TARGET: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-ARMV7M-PER-TARGET: "-lc"
// RUN: %clangxx %s -### --target=armv6m-none-eabi 2>&1 \
// RUN: --sysroot=%S/Inputs/baremetal_arm | FileCheck --check-prefix=CHECK-V6M-DEFAULTCXX %s
// CHECK-V6M-DEFAULTCXX: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
// CHECK-V6M-DEFAULTCXX: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic" "-EL"
// CHECK-V6M-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}baremetal_arm{{[/\\]+}}lib"
-// CHECK-V6M-DEFAULTCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
-// CHECK-V6M-DEFAULTCXX-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "--target2=rel" "-o" "a.out"
+// CHECK-V6M-DEFAULTCXX-SAME: "-lc++"
+// CHECK-V6M-DEFAULTCXX-SAME: "-lm"
+// CHECK-V6M-DEFAULTCXX-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-V6M-DEFAULTCXX-SAME: "-lc"
+// CHECK-V6M-DEFAULTCXX-SAME: "--target2=rel" "-o" "a.out"
// RUN: %clangxx %s -### --target=armv6m-none-eabi -stdlib=libc++ 2>&1 \
// RUN: --sysroot=%S/Inputs/baremetal_arm | FileCheck --check-prefix=CHECK-V6M-LIBCXX %s
@@ -67,8 +75,11 @@
// CHECK-V6M-LIBCXX-SAME: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
// CHECK-V6M-LIBCXX: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic" "-EL"
// CHECK-V6M-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}baremetal_arm{{[/\\]+}}lib"
-// CHECK-V6M-LIBCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
-// CHECK-V6M-LIBCXX-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "--target2=rel" "-o" "a.out"
+// CHECK-V6M-LIBCXX-SAME: "-lc++"
+// CHECK-V6M-LIBCXX-SAME: "-lm"
+// CHECK-V6M-LIBCXX-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-V6M-LIBCXX-SAME: "-lc"
+// CHECK-V6M-LIBCXX-SAME: "--target2=rel" "-o" "a.out"
// RUN: %clangxx %s -### --target=armv6m-none-eabi 2>&1 \
// RUN: --sysroot=%S/Inputs/baremetal_arm \
@@ -79,8 +90,10 @@
// CHECK-V6M-LIBSTDCXX-SAME: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}6.0.0"
// CHECK-V6M-LIBSTDCXX: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic" "-EL"
// CHECK-V6M-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}baremetal_arm{{[/\\]+}}lib"
-// CHECK-V6M-LIBSTDCXX-SAME: "-lstdc++" "-lsupc++" "-lunwind"
-// CHECK-V6M-LIBSTDCXX-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "--target2=rel" "-o" "a.out"
+// CHECK-V6M-LIBSTDCXX-SAME: "-lstdc++" "-lm"
+// CHECK-V6M-LIBSTDCXX-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-V6M-LIBSTDCXX-SAME: "-lc"
+// CHECK-V6M-LIBSTDCXX-SAME: "--target2=rel" "-o" "a.out"
// RUN: %clangxx %s -### --target=armv6m-none-eabi 2>&1 \
// RUN: --sysroot=%S/Inputs/baremetal_arm \
@@ -102,8 +115,9 @@
// CHECK-V6M-LIBCXX-USR-SAME: "-internal-isystem" "{{[^"]+}}baremetal_cxx_sysroot{{[/\\]+}}usr{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
// CHECK-V6M-LIBCXX-USR: "{{[^"]*}}-Bstatic"
// CHECK-V6M-LIBCXX-USR-SAME: "-L{{[^"]*}}{{[/\\]+}}baremetal_cxx_sysroot{{[/\\]+}}lib"
-// CHECK-V6M-LIBCXX-USR-SAME: "-lc++" "-lc++abi" "-lunwind"
-// CHECK-V6M-LIBCXX-USR-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-V6M-LIBCXX-USR-SAME: "-lc++" "-lm"
+// CHECK-V6M-LIBCXX-USR-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-V6M-LIBCXX-USR-SAME: "-lc"
// RUN: %clangxx --target=arm-none-eabi -v 2>&1 \
// RUN: | FileCheck %s --check-prefix=CHECK-THREAD-MODEL
@@ -117,7 +131,7 @@
// RUN: | FileCheck %s --check-prefix=CHECK-THREAD-MODEL-POSIX
// CHECK-THREAD-MODEL-POSIX: Thread model: posix
-// RUN: %clang -### --target=arm-none-eabi -rtlib=libgcc -v %s 2>&1 \
+// RUN: %clang -### --target=arm-none-eabi -rtlib=libgcc --unwindlib=libgcc -v %s 2>&1 \
// RUN: | FileCheck %s --check-prefix=CHECK-RTLIB-GCC
// CHECK-RTLIB-GCC: -lgcc
@@ -186,7 +200,9 @@
// CHECK-RV64-NEXT: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-RV64-SAME: "-Lsome{{[/\\]+}}directory{{[/\\]+}}user{{[/\\]+}}asked{{[/\\]+}}for"
// CHECK-RV64-SAME: "-L[[SYSROOT:[^"]+]]{{[/\\]+}}lib"
-// CHECK-RV64-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-X" "-o" "{{.*}}.tmp.out"
+// CHECK-RV64-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-RV64-SAME: "-lc"
+// CHECK-RV64-SAME: "-X" "-o" "{{.*}}.tmp.out"
// RUN: %clangxx %s -### --target=riscv64-unknown-elf 2>&1 \
// RUN: --sysroot=%S/Inputs/basic_riscv64_tree/riscv64-unknown-elf \
@@ -194,8 +210,10 @@
// CHECK-RV64-DEFAULTCXX: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
// CHECK-RV64-DEFAULTCXX: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-RV64-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv64_tree{{[/\\]+}}riscv64-unknown-elf{{[/\\]+}}lib"
-// CHECK-RV64-DEFAULTCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
-// CHECK-RV64-DEFAULTCXX-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-X" "-o" "a.out"
+// CHECK-RV64-DEFAULTCXX-SAME: "-lc++" "-lm"
+// CHECK-RV64-DEFAULTCXX-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-RV64-DEFAULTCXX-SAME: "-lc"
+// CHECK-RV64-DEFAULTCXX-SAME: "-X" "-o" "a.out"
// RUN: %clangxx %s -### --target=riscv64-unknown-elf 2>&1 \
// RUN: --sysroot=%S/Inputs/basic_riscv64_tree/riscv64-unknown-elf \
@@ -206,8 +224,10 @@
// CHECK-RV64-LIBCXX-SAME: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
// CHECK-RV64-LIBCXX: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-RV64-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv64_tree{{[/\\]+}}riscv64-unknown-elf{{[/\\]+}}lib"
-// CHECK-RV64-LIBCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
-// CHECK-RV64-LIBCXX-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-X" "-o" "a.out"
+// CHECK-RV64-LIBCXX-SAME: "-lc++" "-lm"
+// CHECK-RV64-LIBCXX-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-RV64-LIBCXX-SAME: "-lc"
+// CHECK-RV64-LIBCXX-SAME: "-X" "-o" "a.out"
// RUN: %clangxx %s -### 2>&1 --target=riscv64-unknown-elf \
// RUN: --sysroot=%S/Inputs/basic_riscv64_tree/riscv64-unknown-elf \
@@ -218,8 +238,10 @@
// CHECK-RV64-LIBSTDCXX-SAME: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}8.0.1"
// CHECK-RV64-LIBSTDCXX: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-RV64-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv64_tree{{[/\\]+}}riscv64-unknown-elf{{[/\\]+}}lib"
-// CHECK-RV64-LIBSTDCXX-SAME: "-lstdc++" "-lsupc++" "-lunwind"
-// CHECK-RV64-LIBSTDCXX-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-X" "-o" "a.out"
+// CHECK-RV64-LIBSTDCXX-SAME: "-lstdc++" "-lm"
+// CHECK-RV64-LIBSTDCXX-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-RV64-LIBSTDCXX-SAME: "-lc"
+// CHECK-RV64-LIBSTDCXX-SAME: "-X" "-o" "a.out"
// RUN: %clang %s -### 2>&1 --target=riscv32-unknown-elf \
// RUN: -L some/directory/user/asked/for \
@@ -234,7 +256,9 @@
// CHECK-RV32-NEXT: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-RV32-SAME: "-Lsome{{[/\\]+}}directory{{[/\\]+}}user{{[/\\]+}}asked{{[/\\]+}}for"
// CHECK-RV32-SAME: "-L[[SYSROOT:[^"]+]]{{[/\\]+}}lib"
-// CHECK-RV32-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-X" "-o" "a.out"
+// CHECK-RV32-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-RV32-SAME: "-lc"
+// CHECK-RV32-SAME: "-X" "-o" "a.out"
// RUN: %clangxx %s -### 2>&1 --target=riscv32-unknown-elf \
// RUN: --sysroot=%S/Inputs/basic_riscv32_tree/riscv32-unknown-elf \
@@ -242,8 +266,10 @@
// CHECK-RV32-DEFAULTCXX: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
// CHECK-RV32-DEFAULTCXX: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-RV32-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv32_tree{{[/\\]+}}riscv32-unknown-elf{{[/\\]+}}lib"
-// CHECK-RV32-DEFAULTCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
-// CHECK-RV32-DEFAULTCXX-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-X" "-o" "a.out"
+// CHECK-RV32-DEFAULTCXX-SAME: "-lc++" "-lm"
+// CHECK-RV32-DEFAULTCXX-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-RV32-DEFAULTCXX-SAME: "-lc"
+// CHECK-RV32-DEFAULTCXX-SAME: "-X" "-o" "a.out"
// RUN: %clangxx %s -### 2>&1 --target=riscv32-unknown-elf \
// RUN: --sysroot=%S/Inputs/basic_riscv32_tree/riscv32-unknown-elf \
@@ -254,8 +280,9 @@
// CHECK-RV32-LIBCXX-SAME: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
// CHECK-RV32-LIBCXX: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-RV32-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv32_tree{{[/\\]+}}riscv32-unknown-elf{{[/\\]+}}lib"
-// CHECK-RV32-LIBCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
-// CHECK-RV32-LIBCXX-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-X" "-o" "a.out"
+// CHECK-RV32-LIBCXX-SAME: "-lc++" "-lm"
+// CHECK-RV32-LIBCXX-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-RV32-LIBCXX-SAME: "-X" "-o" "a.out"
// RUN: %clangxx %s -### 2>&1 --target=riscv32-unknown-elf \
// RUN: --sysroot=%S/Inputs/basic_riscv32_tree/riscv32-unknown-elf \
@@ -266,8 +293,9 @@
// CHECK-RV32-LIBSTDCXX-SAME: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}8.0.1"
// CHECK-RV32-LIBSTDCXX: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-RV32-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv32_tree{{[/\\]+}}riscv32-unknown-elf{{[/\\]+}}lib"
-// CHECK-RV32-LIBSTDCXX-SAME: "-lstdc++" "-lsupc++" "-lunwind"
-// CHECK-RV32-LIBSTDCXX-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-X" "-o" "a.out"
+// CHECK-RV32-LIBSTDCXX-SAME: "-lstdc++" "-lm"
+// CHECK-RV32-LIBSTDCXX-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-RV32-LIBSTDCXX-SAME: "-lc" "-X" "-o" "a.out"
// RUN: %clang %s -### 2>&1 --target=riscv64-unknown-elf \
// RUN: -nostdlibinc -nobuiltininc \
@@ -389,7 +417,9 @@
// CHECK-PPCEABI-SAME: "-internal-isystem" "[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}include"
// CHECK-PPCEABI-NEXT: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-PPCEABI-SAME: "-L[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}lib"
-// CHECK-PPCEABI-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-o" "a.out"
+// CHECK-PPCEABI-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-PPCEABI-SAME: "-lc"
+// CHECK-PPCEABI-SAME: "-o" "a.out"
// RUN: %clang -no-canonical-prefixes %s -### --target=powerpc64-unknown-eabi 2>&1 \
// RUN: | FileCheck --check-prefix=CHECK-PPC64EABI %s
@@ -401,7 +431,9 @@
// CHECK-PPC64EABI-SAME: "-internal-isystem" "[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}include"
// CHECK-PPC64EABI-NEXT: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-PPC64EABI-SAME: "-L[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}lib"
-// CHECK-PPC64EABI-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-o" "a.out"
+// CHECK-PPC64EABI-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-PPC64EABI-SAME: "-lc"
+// CHECK-PPC64EABI-SAME: "-o" "a.out"
// RUN: %clang -no-canonical-prefixes %s -### --target=powerpcle-unknown-eabi 2>&1 \
// RUN: | FileCheck --check-prefix=CHECK-PPCLEEABI %s
@@ -413,7 +445,9 @@
// CHECK-PPCLEEABI-SAME: "-internal-isystem" "[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}include"
// CHECK-PPCLEEABI-NEXT: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-PPCLEEABI-SAME: "-L[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}lib"
-// CHECK-PPCLEEABI-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-o" "a.out"
+// CHECK-PPCLEEABI-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-PPCLEEABI-SAME: "-lc"
+// CHECK-PPCLEEABI-SAME: "-o" "a.out"
// RUN: %clang -no-canonical-prefixes %s -### --target=powerpc64le-unknown-eabi 2>&1 \
// RUN: | FileCheck --check-prefix=CHECK-PPC64LEEABI %s
@@ -425,7 +459,9 @@
// CHECK-PPC64LEEABI-SAME: "-internal-isystem" "[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}include"
// CHECK-PPC64LEEABI-NEXT: ld{{(.exe)?}}" "{{.*}}.o" "-Bstatic"
// CHECK-PPC64LEEABI-SAME: "-L[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}lib"
-// CHECK-PPC64LEEABI-SAME: "-lc" "-lm" "{{[^"]*}}libclang_rt.builtins.a" "-o" "a.out"
+// CHECK-PPC64LEEABI-SAME: "{{[^"]*}}libclang_rt.builtins.a"
+// CHECK-PPC64LEEABI-SAME: "-lc"
+// CHECK-PPC64LEEABI-SAME: "-o" "a.out"
// Check that compiler-rt library without the arch filename suffix will
// be used if present.
|
mysterymath
reviewed
Jul 30, 2024
| CmdArgs.push_back("-lc++"); | ||
| if (Args.hasArg(options::OPT_fexperimental_library)) | ||
| CmdArgs.push_back("-lc++experimental"); | ||
| CmdArgs.push_back("-lc++abi"); |
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It looks like the generic version of this doesn't include -lc++abi, while this one does. Similarly for -lsupc++. Is that an important difference? It seems like most of the derived toolchains include this in their overrides.
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This could be a static/dynamic linking thing. If libc++ is a shared library it would have a DT_NEEDED libc++abi (or the GCC equivalent).
For static links I think we'd need the explicit -lc++abi or the GNU equivalent.
If I can find some time I'll see if we can try this patch out on our exceptions/rtti library variant as that would need objects from libc++abi.
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Yes I can confirm that leaving out -lc++abi does cause build failures with our C++ samples with undefined symbols from libc++abi.
The lld command (paths shortened for brevity) coming out of clang++ --target=armv6m-none-eabi -march=armv6m -mfpu=none -mfloat-abi=soft -lcrt0-semihost -lsemihost -g -T ../../ldscripts/microbit.ld -o hello-exn.elf hello-exn.cpp
"bin/ld.lld" -lcrt0-semihost -lsemihost /tmp/hello-exn-5244ae.o -Bstatic -EL -T ../../ldscripts/microbit.ld -Lbin/../lib/clang-runtimes/arm-none-eabi/armv6m_soft_nofp_exn_rtti/lib -Llib/clang/20/lib/armv6m-unknown-none-eabi -Lbin/../lib/clang-runtimes/arm-none-eabi/armv6m_soft_nofp_exn_rtti/lib -lc++ -lm b\
in/../lib/clang-runtimes/arm-none-eabi/armv6m_soft_nofp_exn_rtti/lib/libclang_rt.builtins.a -lc --target2=rel -o hello-exn.elf
ld.lld: error: undefined symbol: operator new(unsigned int)
...
ld.lld: error: undefined symbol: __cxa_allocate_exception
...
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The problem with the current implementation is that it assumes that libc++abi is used as the C++ ABI library, but libc++ supports a number of different C++ ABI library implementations, including none which may be desirable for some of the baremetal use cases. The fact that baremetal driver explicitly passes -lc++abi is a problem for us because there is no libc++abi.a in our toolchain and that's intentional but it leads to a link error.
There are two solutions for pulling in the right C++ ABI library without needing to explicitly pass -lc++abi to the linker that are already used by other platforms:
- Replace
libc++.soandlibc++.awith an input linker script that pulls in the right C++ ABI library; libc++ build can generate one forlibc++.so, this could be extended to supportlibc++.aif needed. - You can merge
libc++abi.aintolibc++.aso you don't need a separate-lc++abi, this is already supported by libc++ build.
The advantage of either of these solutions is that Clang driver can remain agnostic to which C++ ABI library the vendor built libc++ against.
@smithp35 Would it be feasible to migrate your toolchain to use either of these solutions?
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libc++abi is intended to be an implementation detail of libc++. I don't have authority over the Clang Driver, but it makes sense to me that the Driver would only link against libc++ and assume that this provides the necessary symbols. If that means libc++ needs to merge libc++abi into itself or something like that, that's IMO the right thing to do.
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@smithp35 Would it be feasible to migrate your toolchain to use either of these solutions?
It would definitely be feasible. I'm hoping that we can make a solution drop out of the existing runtimes build perhaps with an additional CMake flag. For example if we provide an extra option to the runtimes build then it either spits out a libc++ linker script fragment (my preference) or merge libc++ and libc++abi libraries (this should work as long as libc++abi's objects are inserted after libc++).
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spits out a libc++ linker script fragment (my preference)
We already have this and it's used on platforms like Darwin, Fuchsia or Linux:
llvm-project/libcxx/CMakeLists.txt
Lines 269 to 271 in 3d08ade
merge libc++ and libc++abi libraries (this should work as long as libc++abi's objects are inserted after libc++)
We already have this and it's what we've been using in our baremetal build for example:
llvm-project/libcxx/CMakeLists.txt
Lines 247 to 253 in 3d08ade
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Thanks for pointing those out, I was under the impression that they had to be developed first. Although I'm not the Driver owner either I can try those out and get back to you tomorrow (apologies its a bit late in the day) with a second approval.
ldionne
reviewed
Aug 1, 2024
|
Gentle ping @petrhosek |
I'd like to go ahead and merge this PR but I still need someone to approve this change. |
Sorry, somehow I thought this was waiting on a reply from you. |
ldionne
approved these changes
Aug 29, 2024
smithp35
approved these changes
Aug 30, 2024
ostannard
added a commit
to ostannard/LLVM-embedded-toolchain-for-Arm
that referenced
this pull request
Sep 3, 2024
This will prevent C++ links from breaking when llvm/llvm-project#101259 lands, as that removes -lc++abi and -lunwind from the linker command-line.
ostannard
added a commit
to ARM-software/LLVM-embedded-toolchain-for-Arm
that referenced
this pull request
Sep 3, 2024
This will prevent C++ links from breaking when llvm/llvm-project#101259 lands, as that removes -lc++abi and -lunwind from the linker command-line.
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The handling of libc++ and other runtime libraries in the baremetal driver is different from other targets for no particular reason. This change removes the custom in the baremetal driver logic and replaces it with the generic logic to improve consistency and reduce maintenance overhead while also handling additional flags the current logic doesn't.