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Reland [Driver] Add support for crtbegin.o, crtend.o and libgloss lib to BareMetal toolchain object #144649

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Merged
merged 1 commit into from
Jun 29, 2025
Merged

Reland [Driver] Add support for crtbegin.o, crtend.o and libgloss lib to BareMetal toolchain object #144649

merged 1 commit into from
Jun 29, 2025
+246 −13

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quic-garvgupt
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This patch conditionalise the addition of crt{begin,end}.o object files
along with addition of -lgloss lib based on whether libc selected is newlib or
llvm libc. Since there is no way a user can specify which libc it wants to
link against, currently passing valid GCCInstallation to driver will select
newlib otherwise it will default to llvm libc.

Moreover, this patch makes gnuld the default linker for baremetal
toolchain object. User need to pass -fuse-ld=lld explicitly to driver to select
lld

This is the 2nd patch in the series of patches of merging RISCVToolchain
into BareMetal toolchain object.

RFC:
https://discourse.llvm.org/t/merging-riscvtoolchain-and-baremetal-toolchains/75524

@llvmbot llvmbot added clang Clang issues not falling into any other category clang:driver 'clang' and 'clang++' user-facing binaries. Not 'clang-cl' labels Jun 18, 2025
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llvmbot commented Jun 18, 2025

@llvm/pr-subscribers-clang-driver

Author: Garvit Gupta (quic-garvgupt)

Changes

This patch conditionalise the addition of crt{begin,end}.o object files
along with addition of -lgloss lib based on whether libc selected is newlib or
llvm libc. Since there is no way a user can specify which libc it wants to
link against, currently passing valid GCCInstallation to driver will select
newlib otherwise it will default to llvm libc.

Moreover, this patch makes gnuld the default linker for baremetal
toolchain object. User need to pass -fuse-ld=lld explicitly to driver to select
lld

This is the 2nd patch in the series of patches of merging RISCVToolchain
into BareMetal toolchain object.

RFC:
https://discourse.llvm.org/t/merging-riscvtoolchain-and-baremetal-toolchains/75524

Patch is 30.23 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/144649.diff

8 Files Affected:

  • (modified) clang/lib/Driver/ToolChains/BareMetal.cpp (+33-4)
  • (modified) clang/lib/Driver/ToolChains/BareMetal.h (+1-2)
  • (modified) clang/test/Driver/aarch64-toolchain-extra.c (+10-3)
  • (modified) clang/test/Driver/aarch64-toolchain.c (+95)
  • (modified) clang/test/Driver/arm-toolchain-extra.c (+7)
  • (modified) clang/test/Driver/arm-toolchain.c (+97-2)
  • (modified) clang/test/Driver/baremetal.cpp (+2-1)
  • (modified) clang/test/Driver/sanitizer-ld.c (+1-1)
diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index 0fbfe6c77f342..a08bb588dd764 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -584,9 +584,31 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back(Arch == llvm::Triple::aarch64_be ? "-EB" : "-EL");
   }
 
-  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles,
-                   options::OPT_r)) {
-    CmdArgs.push_back(Args.MakeArgString(TC.GetFilePath("crt0.o")));
+  bool NeedCRTs =
+      !Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles);
+
+  const char *CRTBegin, *CRTEnd;
+  if (NeedCRTs) {
+    if (!Args.hasArg(options::OPT_r))
+      CmdArgs.push_back(Args.MakeArgString(TC.GetFilePath("crt0.o")));
+    if (TC.hasValidGCCInstallation() || detectGCCToolchainAdjacent(D)) {
+      auto RuntimeLib = TC.GetRuntimeLibType(Args);
+      switch (RuntimeLib) {
+      case (ToolChain::RLT_Libgcc): {
+        CRTBegin = "crtbegin.o";
+        CRTEnd = "crtend.o";
+        break;
+      }
+      case (ToolChain::RLT_CompilerRT): {
+        CRTBegin =
+            TC.getCompilerRTArgString(Args, "crtbegin", ToolChain::FT_Object);
+        CRTEnd =
+            TC.getCompilerRTArgString(Args, "crtend", ToolChain::FT_Object);
+        break;
+      }
+      }
+      CmdArgs.push_back(Args.MakeArgString(TC.GetFilePath(CRTBegin)));
+    }
   }
 
   Args.addAllArgs(CmdArgs, {options::OPT_L, options::OPT_T_Group,
@@ -609,15 +631,22 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   }
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
+    CmdArgs.push_back("--start-group");
     AddRunTimeLibs(TC, D, CmdArgs, Args);
-
     CmdArgs.push_back("-lc");
+    if (TC.hasValidGCCInstallation() || detectGCCToolchainAdjacent(D))
+      CmdArgs.push_back("-lgloss");
+    CmdArgs.push_back("--end-group");
   }
 
   if (D.isUsingLTO())
     addLTOOptions(TC, Args, CmdArgs, Output, Inputs,
                   D.getLTOMode() == LTOK_Thin);
 
+  if ((TC.hasValidGCCInstallation() || detectGCCToolchainAdjacent(D)) &&
+      NeedCRTs)
+    CmdArgs.push_back(Args.MakeArgString(TC.GetFilePath(CRTEnd)));
+
   if (TC.getTriple().isRISCV())
     CmdArgs.push_back("-X");
 
diff --git a/clang/lib/Driver/ToolChains/BareMetal.h b/clang/lib/Driver/ToolChains/BareMetal.h
index 930f8584e6435..54805530bae82 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.h
+++ b/clang/lib/Driver/ToolChains/BareMetal.h
@@ -38,6 +38,7 @@ class LLVM_LIBRARY_VISIBILITY BareMetal : public Generic_ELF {
 public:
   bool initGCCInstallation(const llvm::Triple &Triple,
                            const llvm::opt::ArgList &Args);
+  bool hasValidGCCInstallation() const { return IsGCCInstallationValid; }
   bool isBareMetal() const override { return true; }
   bool isCrossCompiling() const override { return true; }
   bool HasNativeLLVMSupport() const override { return true; }
@@ -63,8 +64,6 @@ class LLVM_LIBRARY_VISIBILITY BareMetal : public Generic_ELF {
     return ToolChain::CST_Libcxx;
   }
 
-  const char *getDefaultLinker() const override { return "ld.lld"; }
-
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;
diff --git a/clang/test/Driver/aarch64-toolchain-extra.c b/clang/test/Driver/aarch64-toolchain-extra.c
index 2610e962bd690..2a930e35acd45 100644
--- a/clang/test/Driver/aarch64-toolchain-extra.c
+++ b/clang/test/Driver/aarch64-toolchain-extra.c
@@ -15,14 +15,21 @@
 // RUN: mkdir -p %t/aarch64-nogcc/bin
 // RUN: ln -s %clang %t/aarch64-nogcc/bin/clang
 // RUN: ln -s %S/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf %t/aarch64-nogcc/aarch64-none-elf
+// RUN: ln -s %S/Inputs/basic_aarch64_nogcc_tree/bin/aarch64-none-elf-ld %t/aarch64-nogcc/bin/aarch64-none-elf-ld
 // RUN: %t/aarch64-nogcc/bin/clang %s -### -no-canonical-prefixes \
 // RUN:    --gcc-toolchain=%t/aarch64-nogcc/invalid \
 // RUN:    --target=aarch64-none-elf --rtlib=libgcc -fuse-ld=ld 2>&1 \
-// RUN:    | FileCheck -check-prefix=C-ARM-BAREMETAL-NOGCC %s
+// RUN:    | FileCheck -check-prefix=C-AARCH64-BAREMETAL-NOGCC %s
 
 // RUN: %t/aarch64-nogcc/bin/clang %s -### -no-canonical-prefixes \
 // RUN:    --sysroot=%t/aarch64-nogcc/bin/../aarch64-none-elf \
 // RUN:    --target=aarch64-none-elf --rtlib=libgcc -fuse-ld=ld 2>&1 \
-// RUN:    | FileCheck -check-prefix=C-ARM-BAREMETAL-NOGCC %s
+// RUN:    | FileCheck -check-prefix=C-AARCH64-BAREMETAL-NOGCC %s
 
-// C-ARM-BAREMETAL-NOGCC: "-internal-isystem" "{{.*}}/aarch64-nogcc/bin/../aarch64-none-elf/include"
+// C-AARCH64-BAREMETAL-NOGCC: "-internal-isystem" "{{.*}}/aarch64-nogcc/bin/../aarch64-none-elf/include"
+// C-AARCH64-BAREMETAL-NOGCC: "{{.*}}/aarch64-nogcc/bin/aarch64-none-elf-ld"
+// C-AARCH64-BAREMETAL-NOGCC: "{{.*}}/aarch64-nogcc/bin/../aarch64-none-elf/lib/crt0.o"
+// C-AARCH64-BAREMETAL-NOGCC: "{{.*}}/aarch64-nogcc/{{.*}}/aarch64-none-elf/lib/crtbegin.o"
+// C-AARCH64-BAREMETAL-NOGCC: "{{.*}}/aarch64-nogcc/bin/../aarch64-none-elf/lib"
+// C-AARCH64-BAREMETAL-NOGCC: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// C-AARCH64-BAREMETAL-NOGCC: "{{.*}}/aarch64-nogcc/{{.*}}/aarch64-none-elf/lib/crtend.o"
diff --git a/clang/test/Driver/aarch64-toolchain.c b/clang/test/Driver/aarch64-toolchain.c
index 7f2c01d928e43..83cd95136b158 100644
--- a/clang/test/Driver/aarch64-toolchain.c
+++ b/clang/test/Driver/aarch64-toolchain.c
@@ -1,5 +1,24 @@
 // UNSUPPORTED: system-windows
 
+// Test interaction with -fuse-ld=lld
+// RUN: %clang -### %s -fuse-ld=lld -B%S/Inputs/lld \
+// RUN:   --target=aarch64-none-elf --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=LLD-AARCH64-BAREMETAL %s
+
+// LLD-AARCH64-BAREMETAL: "-cc1" "-triple" "aarch64-unknown-none-elf"
+// LLD-AARCH64-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
+// LLD-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+// LLD-AARCH64-BAREMETAL: "{{.*}}/Inputs/lld/ld.lld"
+// LLD-AARCH64-BAREMETAL: "{{.*}}.o" "-Bstatic" "-EL"
+// LLD-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/crt0.o"
+// LLD-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
+// LLD-AARCH64-BAREMETAL: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
+// LLD-AARCH64-BAREMETAL: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib"
+// LLD-AARCH64-BAREMETAL: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// LLD-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
+
 // RUN: %clang -### %s -fuse-ld= \
 // RUN:   --target=aarch64-none-elf --rtlib=libgcc \
 // RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
@@ -9,6 +28,14 @@
 // C-AARCH64-BAREMETAL: "-cc1" "-triple" "aarch64-unknown-none-elf"
 // C-AARCH64-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
 // C-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+// C-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// C-AARCH64-BAREMETAL: "{{.*}}.o" "-Bstatic" "-EL"
+// C-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/crt0.o"
+// C-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
+// C-AARCH64-BAREMETAL: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
+// C-AARCH64-BAREMETAL: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib"
+// C-AARCH64-BAREMETAL: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// C-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
 
 // RUN: %clang -### %s -fuse-ld= \
 // RUN:   --target=aarch64-none-elf --rtlib=libgcc \
@@ -18,6 +45,14 @@
 
 // C-AARCH64-BAREMETAL-NOSYSROOT: "-cc1" "-triple" "aarch64-unknown-none-elf"
 // C-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}.o" "-Bstatic" "-EL"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib/crt0.o"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
 
 // RUN: %clangxx -### %s -fuse-ld= \
 // RUN:   --target=aarch64-none-elf -stdlib=libstdc++ --rtlib=libgcc \
@@ -29,6 +64,14 @@
 // CXX-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/8.2.1/backward"
 // CXX-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/8.2.1"
 // CXX-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+// CXX-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// CXX-AARCH64-BAREMETAL: "{{.*}}.o" "-Bstatic" "-EL"
+// CXX-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/crt0.o"
+// 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: "-lstdc++" "-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= \
 // RUN:   --target=aarch64-none-elf -stdlib=libstdc++ --rtlib=libgcc \
@@ -40,6 +83,14 @@
 // CXX-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include/c++/8.2.1/backward"
 // CXX-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include/c++/8.2.1"
 // CXX-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}.o" "-Bstatic" "-EL"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib/crt0.o"
+// 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: "-lstdc++" "-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= \
 // RUN:   --target=aarch64-none-elf -stdlib=libc++ --rtlib=libgcc \
@@ -50,6 +101,14 @@
 // CXX-AARCH64-BAREMETAL-LIBCXX: "-isysroot" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
 // CXX-AARCH64-BAREMETAL-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/v1"
 // CXX-AARCH64-BAREMETAL-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld
+// CXX-AARCH64-BAREMETAL-LIBCXX: "{{.*}}.o" "-Bstatic" "-EL"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/crt0.o"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "-lc++" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
 
 // RUN: %clangxx -### %s -fuse-ld= \
 // RUN:   --target=aarch64-none-elf -stdlib=libc++ --rtlib=libgcc \
@@ -59,3 +118,39 @@
 
 // CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include/c++/v1"
 // CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "{{.*}}.o" "-Bstatic" "-EL"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib/crt0.o"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-lc++" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
+
+// RUN: %clang -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf --rtlib=compiler-rt \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=AARCH64-BAREMETAL-COMPILER-RT %s
+
+// AARCH64-BAREMETAL-COMPILER-RT: "{{.*}}crt0.o"
+// AARCH64-BAREMETAL-COMPILER-RT: "{{.*}}clang_rt.crtbegin.o"
+// AARCH64-BAREMETAL-COMPILER-RT: "--start-group" "{{.*}}libclang_rt.builtins.a" "-lc" "-lgloss" "--end-group"
+// AARCH64-BAREMETAL-COMPILER-RT: "{{.*}}clang_rt.crtend.o"
+
+// RUN: %clang -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf --unwindlib=libunwind \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=AARCH64-BAREMETAL-UNWINDLIB %s
+
+// RUN: %clang -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf --rtlib=compiler-rt --unwindlib=libunwind \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=AARCH64-BAREMETAL-UNWINDLIB %s
+
+// AARCH64-BAREMETAL-UNWINDLIB: "{{.*}}crt0.o"
+// AARCH64-BAREMETAL-UNWINDLIB: "{{.*}}clang_rt.crtbegin.o"
+// AARCH64-BAREMETAL-UNWINDLIB: "--start-group" "{{.*}}libclang_rt.builtins.a" "--as-needed" "-lunwind" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// AARCH64-BAREMETAL-UNWINDLIB: "{{.*}}clang_rt.crtend.o"
diff --git a/clang/test/Driver/arm-toolchain-extra.c b/clang/test/Driver/arm-toolchain-extra.c
index 114de0a8154ab..2adf4ab698ba0 100644
--- a/clang/test/Driver/arm-toolchain-extra.c
+++ b/clang/test/Driver/arm-toolchain-extra.c
@@ -15,6 +15,7 @@
 // RUN: mkdir -p %t/arm-nogcc/bin
 // RUN: ln -s %clang %t/arm-nogcc/bin/clang
 // RUN: ln -s %S/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi %t/arm-nogcc/armv6m-none-eabi
+// RUN: ln -s %S/Inputs/basic_arm_nogcc_tree/bin/armv6m-none-eabi-ld %t/arm-nogcc/bin/armv6m-none-eabi-ld
 // RUN: %t/arm-nogcc/bin/clang %s -### -no-canonical-prefixes \
 // RUN:    --gcc-toolchain=%t/arm-nogcc/invalid \
 // RUN:    --target=armv6m-none-eabi --rtlib=libgcc -fuse-ld=ld 2>&1 \
@@ -26,4 +27,10 @@
 // RUN:    | FileCheck -check-prefix=C-ARM-BAREMETAL-NOGCC %s
 
 // C-ARM-BAREMETAL-NOGCC: "-internal-isystem" "{{.*}}/arm-nogcc/bin/../armv6m-none-eabi/include"
+// C-ARM-BAREMETAL-NOGCC: "{{.*}}/arm-nogcc/bin/armv6m-none-eabi-ld"
+// C-ARM-BAREMETAL-NOGCC: "{{.*}}/arm-nogcc/bin/../armv6m-none-eabi/lib/crt0.o"
+// C-ARM-BAREMETAL-NOGCC: "{{.*}}/arm-nogcc/{{.*}}/armv6m-none-eabi/lib/crtbegin.o"
+// C-ARM-BAREMETAL-NOGCC: "{{.*}}/arm-nogcc/bin/../armv6m-none-eabi/lib"
+// C-ARM-BAREMETAL-NOGCC: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// C-ARM-BAREMETAL-NOGCC: "{{.*}}/arm-nogcc/{{.*}}/armv6m-none-eabi/lib/crtend.o"
 
diff --git a/clang/test/Driver/arm-toolchain.c b/clang/test/Driver/arm-toolchain.c
index 2e38461fb7a3e..66bed1b0c4d87 100644
--- a/clang/test/Driver/arm-toolchain.c
+++ b/clang/test/Driver/arm-toolchain.c
@@ -1,5 +1,23 @@
 // UNSUPPORTED: system-windows
 
+// RUN: %clang -### %s -fuse-ld=lld -B%S/Inputs/lld \
+// RUN:   --target=armv6m-none-eabi --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_arm_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_arm_gcc_tree/armv6m-none-eabi 2>&1 \
+// RUN:   | FileCheck -check-prefix=LLD-ARM-BAREMETAL %s
+
+// LLD-ARM-BAREMETAL: "-cc1" "-triple" "thumbv6m-unknown-none-eabi"
+// LLD-ARM-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi"
+// LLD-ARM-BAREMETAL: "-internal-isystem" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include"
+// LLD-ARM-BAREMETAL: "{{.*}}/Inputs/lld/ld.lld"
+// LLD-ARM-BAREMETAL: "{{.*}}.o" "-Bstatic" "-EL"
+// LLD-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/crt0.o"
+// LLD-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtbegin.o"
+// LLD-ARM-BAREMETAL: "-L{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1"
+// LLD-ARM-BAREMETAL: "-L{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib"
+// LLD-ARM-BAREMETAL: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// LLD-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtend.o"
+
 // RUN: %clang -### %s -fuse-ld= \
 // RUN:   --target=armv6m-none-eabi --rtlib=libgcc \
 // RUN:   --gcc-toolchain=%S/Inputs/basic_arm_gcc_tree \
@@ -9,6 +27,14 @@
 // C-ARM-BAREMETAL: "-cc1" "-triple" "thumbv6m-unknown-none-eabi"
 // C-ARM-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi"
 // C-ARM-BAREMETAL: "-internal-isystem" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include"
+// C-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../bin/armv6m-none-eabi-ld"
+// C-ARM-BAREMETAL: "{{.*}}.o" "-Bstatic" "-EL"
+// C-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/crt0.o"
+// C-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8...
[truncated]

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llvmbot commented Jun 18, 2025

@llvm/pr-subscribers-clang

Author: Garvit Gupta (quic-garvgupt)

Changes

This patch conditionalise the addition of crt{begin,end}.o object files
along with addition of -lgloss lib based on whether libc selected is newlib or
llvm libc. Since there is no way a user can specify which libc it wants to
link against, currently passing valid GCCInstallation to driver will select
newlib otherwise it will default to llvm libc.

Moreover, this patch makes gnuld the default linker for baremetal
toolchain object. User need to pass -fuse-ld=lld explicitly to driver to select
lld

This is the 2nd patch in the series of patches of merging RISCVToolchain
into BareMetal toolchain object.

RFC:
https://discourse.llvm.org/t/merging-riscvtoolchain-and-baremetal-toolchains/75524

Patch is 30.23 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/144649.diff

8 Files Affected:

  • (modified) clang/lib/Driver/ToolChains/BareMetal.cpp (+33-4)
  • (modified) clang/lib/Driver/ToolChains/BareMetal.h (+1-2)
  • (modified) clang/test/Driver/aarch64-toolchain-extra.c (+10-3)
  • (modified) clang/test/Driver/aarch64-toolchain.c (+95)
  • (modified) clang/test/Driver/arm-toolchain-extra.c (+7)
  • (modified) clang/test/Driver/arm-toolchain.c (+97-2)
  • (modified) clang/test/Driver/baremetal.cpp (+2-1)
  • (modified) clang/test/Driver/sanitizer-ld.c (+1-1)
diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index 0fbfe6c77f342..a08bb588dd764 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -584,9 +584,31 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back(Arch == llvm::Triple::aarch64_be ? "-EB" : "-EL");
   }
 
-  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles,
-                   options::OPT_r)) {
-    CmdArgs.push_back(Args.MakeArgString(TC.GetFilePath("crt0.o")));
+  bool NeedCRTs =
+      !Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles);
+
+  const char *CRTBegin, *CRTEnd;
+  if (NeedCRTs) {
+    if (!Args.hasArg(options::OPT_r))
+      CmdArgs.push_back(Args.MakeArgString(TC.GetFilePath("crt0.o")));
+    if (TC.hasValidGCCInstallation() || detectGCCToolchainAdjacent(D)) {
+      auto RuntimeLib = TC.GetRuntimeLibType(Args);
+      switch (RuntimeLib) {
+      case (ToolChain::RLT_Libgcc): {
+        CRTBegin = "crtbegin.o";
+        CRTEnd = "crtend.o";
+        break;
+      }
+      case (ToolChain::RLT_CompilerRT): {
+        CRTBegin =
+            TC.getCompilerRTArgString(Args, "crtbegin", ToolChain::FT_Object);
+        CRTEnd =
+            TC.getCompilerRTArgString(Args, "crtend", ToolChain::FT_Object);
+        break;
+      }
+      }
+      CmdArgs.push_back(Args.MakeArgString(TC.GetFilePath(CRTBegin)));
+    }
   }
 
   Args.addAllArgs(CmdArgs, {options::OPT_L, options::OPT_T_Group,
@@ -609,15 +631,22 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   }
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
+    CmdArgs.push_back("--start-group");
     AddRunTimeLibs(TC, D, CmdArgs, Args);
-
     CmdArgs.push_back("-lc");
+    if (TC.hasValidGCCInstallation() || detectGCCToolchainAdjacent(D))
+      CmdArgs.push_back("-lgloss");
+    CmdArgs.push_back("--end-group");
   }
 
   if (D.isUsingLTO())
     addLTOOptions(TC, Args, CmdArgs, Output, Inputs,
                   D.getLTOMode() == LTOK_Thin);
 
+  if ((TC.hasValidGCCInstallation() || detectGCCToolchainAdjacent(D)) &&
+      NeedCRTs)
+    CmdArgs.push_back(Args.MakeArgString(TC.GetFilePath(CRTEnd)));
+
   if (TC.getTriple().isRISCV())
     CmdArgs.push_back("-X");
 
diff --git a/clang/lib/Driver/ToolChains/BareMetal.h b/clang/lib/Driver/ToolChains/BareMetal.h
index 930f8584e6435..54805530bae82 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.h
+++ b/clang/lib/Driver/ToolChains/BareMetal.h
@@ -38,6 +38,7 @@ class LLVM_LIBRARY_VISIBILITY BareMetal : public Generic_ELF {
 public:
   bool initGCCInstallation(const llvm::Triple &Triple,
                            const llvm::opt::ArgList &Args);
+  bool hasValidGCCInstallation() const { return IsGCCInstallationValid; }
   bool isBareMetal() const override { return true; }
   bool isCrossCompiling() const override { return true; }
   bool HasNativeLLVMSupport() const override { return true; }
@@ -63,8 +64,6 @@ class LLVM_LIBRARY_VISIBILITY BareMetal : public Generic_ELF {
     return ToolChain::CST_Libcxx;
   }
 
-  const char *getDefaultLinker() const override { return "ld.lld"; }
-
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;
diff --git a/clang/test/Driver/aarch64-toolchain-extra.c b/clang/test/Driver/aarch64-toolchain-extra.c
index 2610e962bd690..2a930e35acd45 100644
--- a/clang/test/Driver/aarch64-toolchain-extra.c
+++ b/clang/test/Driver/aarch64-toolchain-extra.c
@@ -15,14 +15,21 @@
 // RUN: mkdir -p %t/aarch64-nogcc/bin
 // RUN: ln -s %clang %t/aarch64-nogcc/bin/clang
 // RUN: ln -s %S/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf %t/aarch64-nogcc/aarch64-none-elf
+// RUN: ln -s %S/Inputs/basic_aarch64_nogcc_tree/bin/aarch64-none-elf-ld %t/aarch64-nogcc/bin/aarch64-none-elf-ld
 // RUN: %t/aarch64-nogcc/bin/clang %s -### -no-canonical-prefixes \
 // RUN:    --gcc-toolchain=%t/aarch64-nogcc/invalid \
 // RUN:    --target=aarch64-none-elf --rtlib=libgcc -fuse-ld=ld 2>&1 \
-// RUN:    | FileCheck -check-prefix=C-ARM-BAREMETAL-NOGCC %s
+// RUN:    | FileCheck -check-prefix=C-AARCH64-BAREMETAL-NOGCC %s
 
 // RUN: %t/aarch64-nogcc/bin/clang %s -### -no-canonical-prefixes \
 // RUN:    --sysroot=%t/aarch64-nogcc/bin/../aarch64-none-elf \
 // RUN:    --target=aarch64-none-elf --rtlib=libgcc -fuse-ld=ld 2>&1 \
-// RUN:    | FileCheck -check-prefix=C-ARM-BAREMETAL-NOGCC %s
+// RUN:    | FileCheck -check-prefix=C-AARCH64-BAREMETAL-NOGCC %s
 
-// C-ARM-BAREMETAL-NOGCC: "-internal-isystem" "{{.*}}/aarch64-nogcc/bin/../aarch64-none-elf/include"
+// C-AARCH64-BAREMETAL-NOGCC: "-internal-isystem" "{{.*}}/aarch64-nogcc/bin/../aarch64-none-elf/include"
+// C-AARCH64-BAREMETAL-NOGCC: "{{.*}}/aarch64-nogcc/bin/aarch64-none-elf-ld"
+// C-AARCH64-BAREMETAL-NOGCC: "{{.*}}/aarch64-nogcc/bin/../aarch64-none-elf/lib/crt0.o"
+// C-AARCH64-BAREMETAL-NOGCC: "{{.*}}/aarch64-nogcc/{{.*}}/aarch64-none-elf/lib/crtbegin.o"
+// C-AARCH64-BAREMETAL-NOGCC: "{{.*}}/aarch64-nogcc/bin/../aarch64-none-elf/lib"
+// C-AARCH64-BAREMETAL-NOGCC: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// C-AARCH64-BAREMETAL-NOGCC: "{{.*}}/aarch64-nogcc/{{.*}}/aarch64-none-elf/lib/crtend.o"
diff --git a/clang/test/Driver/aarch64-toolchain.c b/clang/test/Driver/aarch64-toolchain.c
index 7f2c01d928e43..83cd95136b158 100644
--- a/clang/test/Driver/aarch64-toolchain.c
+++ b/clang/test/Driver/aarch64-toolchain.c
@@ -1,5 +1,24 @@
 // UNSUPPORTED: system-windows
 
+// Test interaction with -fuse-ld=lld
+// RUN: %clang -### %s -fuse-ld=lld -B%S/Inputs/lld \
+// RUN:   --target=aarch64-none-elf --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=LLD-AARCH64-BAREMETAL %s
+
+// LLD-AARCH64-BAREMETAL: "-cc1" "-triple" "aarch64-unknown-none-elf"
+// LLD-AARCH64-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
+// LLD-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+// LLD-AARCH64-BAREMETAL: "{{.*}}/Inputs/lld/ld.lld"
+// LLD-AARCH64-BAREMETAL: "{{.*}}.o" "-Bstatic" "-EL"
+// LLD-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/crt0.o"
+// LLD-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
+// LLD-AARCH64-BAREMETAL: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
+// LLD-AARCH64-BAREMETAL: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib"
+// LLD-AARCH64-BAREMETAL: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// LLD-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
+
 // RUN: %clang -### %s -fuse-ld= \
 // RUN:   --target=aarch64-none-elf --rtlib=libgcc \
 // RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
@@ -9,6 +28,14 @@
 // C-AARCH64-BAREMETAL: "-cc1" "-triple" "aarch64-unknown-none-elf"
 // C-AARCH64-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
 // C-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+// C-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// C-AARCH64-BAREMETAL: "{{.*}}.o" "-Bstatic" "-EL"
+// C-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/crt0.o"
+// C-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
+// C-AARCH64-BAREMETAL: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
+// C-AARCH64-BAREMETAL: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib"
+// C-AARCH64-BAREMETAL: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// C-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
 
 // RUN: %clang -### %s -fuse-ld= \
 // RUN:   --target=aarch64-none-elf --rtlib=libgcc \
@@ -18,6 +45,14 @@
 
 // C-AARCH64-BAREMETAL-NOSYSROOT: "-cc1" "-triple" "aarch64-unknown-none-elf"
 // C-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}.o" "-Bstatic" "-EL"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib/crt0.o"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
 
 // RUN: %clangxx -### %s -fuse-ld= \
 // RUN:   --target=aarch64-none-elf -stdlib=libstdc++ --rtlib=libgcc \
@@ -29,6 +64,14 @@
 // CXX-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/8.2.1/backward"
 // CXX-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/8.2.1"
 // CXX-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+// CXX-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// CXX-AARCH64-BAREMETAL: "{{.*}}.o" "-Bstatic" "-EL"
+// CXX-AARCH64-BAREMETAL: "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/crt0.o"
+// 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: "-lstdc++" "-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= \
 // RUN:   --target=aarch64-none-elf -stdlib=libstdc++ --rtlib=libgcc \
@@ -40,6 +83,14 @@
 // CXX-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include/c++/8.2.1/backward"
 // CXX-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include/c++/8.2.1"
 // CXX-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}.o" "-Bstatic" "-EL"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib/crt0.o"
+// 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: "-lstdc++" "-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= \
 // RUN:   --target=aarch64-none-elf -stdlib=libc++ --rtlib=libgcc \
@@ -50,6 +101,14 @@
 // CXX-AARCH64-BAREMETAL-LIBCXX: "-isysroot" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
 // CXX-AARCH64-BAREMETAL-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/v1"
 // CXX-AARCH64-BAREMETAL-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld
+// CXX-AARCH64-BAREMETAL-LIBCXX: "{{.*}}.o" "-Bstatic" "-EL"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/crt0.o"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "-lc++" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
 
 // RUN: %clangxx -### %s -fuse-ld= \
 // RUN:   --target=aarch64-none-elf -stdlib=libc++ --rtlib=libgcc \
@@ -59,3 +118,39 @@
 
 // CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include/c++/v1"
 // CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "{{.*}}.o" "-Bstatic" "-EL"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib/crt0.o"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-L{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/lib"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-lc++" "-lm" "--start-group" "-lgcc_s" "-lgcc" "-lc" "-lgloss" "--end-group"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o"
+
+// RUN: %clang -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf --rtlib=compiler-rt \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=AARCH64-BAREMETAL-COMPILER-RT %s
+
+// AARCH64-BAREMETAL-COMPILER-RT: "{{.*}}crt0.o"
+// AARCH64-BAREMETAL-COMPILER-RT: "{{.*}}clang_rt.crtbegin.o"
+// AARCH64-BAREMETAL-COMPILER-RT: "--start-group" "{{.*}}libclang_rt.builtins.a" "-lc" "-lgloss" "--end-group"
+// AARCH64-BAREMETAL-COMPILER-RT: "{{.*}}clang_rt.crtend.o"
+
+// RUN: %clang -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf --unwindlib=libunwind \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=AARCH64-BAREMETAL-UNWINDLIB %s
+
+// RUN: %clang -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf --rtlib=compiler-rt --unwindlib=libunwind \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=AARCH64-BAREMETAL-UNWINDLIB %s
+
+// AARCH64-BAREMETAL-UNWINDLIB: "{{.*}}crt0.o"
+// AARCH64-BAREMETAL-UNWINDLIB: "{{.*}}clang_rt.crtbegin.o"
+// AARCH64-BAREMETAL-UNWINDLIB: "--start-group" "{{.*}}libclang_rt.builtins.a" "--as-needed" "-lunwind" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// AARCH64-BAREMETAL-UNWINDLIB: "{{.*}}clang_rt.crtend.o"
diff --git a/clang/test/Driver/arm-toolchain-extra.c b/clang/test/Driver/arm-toolchain-extra.c
index 114de0a8154ab..2adf4ab698ba0 100644
--- a/clang/test/Driver/arm-toolchain-extra.c
+++ b/clang/test/Driver/arm-toolchain-extra.c
@@ -15,6 +15,7 @@
 // RUN: mkdir -p %t/arm-nogcc/bin
 // RUN: ln -s %clang %t/arm-nogcc/bin/clang
 // RUN: ln -s %S/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi %t/arm-nogcc/armv6m-none-eabi
+// RUN: ln -s %S/Inputs/basic_arm_nogcc_tree/bin/armv6m-none-eabi-ld %t/arm-nogcc/bin/armv6m-none-eabi-ld
 // RUN: %t/arm-nogcc/bin/clang %s -### -no-canonical-prefixes \
 // RUN:    --gcc-toolchain=%t/arm-nogcc/invalid \
 // RUN:    --target=armv6m-none-eabi --rtlib=libgcc -fuse-ld=ld 2>&1 \
@@ -26,4 +27,10 @@
 // RUN:    | FileCheck -check-prefix=C-ARM-BAREMETAL-NOGCC %s
 
 // C-ARM-BAREMETAL-NOGCC: "-internal-isystem" "{{.*}}/arm-nogcc/bin/../armv6m-none-eabi/include"
+// C-ARM-BAREMETAL-NOGCC: "{{.*}}/arm-nogcc/bin/armv6m-none-eabi-ld"
+// C-ARM-BAREMETAL-NOGCC: "{{.*}}/arm-nogcc/bin/../armv6m-none-eabi/lib/crt0.o"
+// C-ARM-BAREMETAL-NOGCC: "{{.*}}/arm-nogcc/{{.*}}/armv6m-none-eabi/lib/crtbegin.o"
+// C-ARM-BAREMETAL-NOGCC: "{{.*}}/arm-nogcc/bin/../armv6m-none-eabi/lib"
+// C-ARM-BAREMETAL-NOGCC: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// C-ARM-BAREMETAL-NOGCC: "{{.*}}/arm-nogcc/{{.*}}/armv6m-none-eabi/lib/crtend.o"
 
diff --git a/clang/test/Driver/arm-toolchain.c b/clang/test/Driver/arm-toolchain.c
index 2e38461fb7a3e..66bed1b0c4d87 100644
--- a/clang/test/Driver/arm-toolchain.c
+++ b/clang/test/Driver/arm-toolchain.c
@@ -1,5 +1,23 @@
 // UNSUPPORTED: system-windows
 
+// RUN: %clang -### %s -fuse-ld=lld -B%S/Inputs/lld \
+// RUN:   --target=armv6m-none-eabi --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_arm_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_arm_gcc_tree/armv6m-none-eabi 2>&1 \
+// RUN:   | FileCheck -check-prefix=LLD-ARM-BAREMETAL %s
+
+// LLD-ARM-BAREMETAL: "-cc1" "-triple" "thumbv6m-unknown-none-eabi"
+// LLD-ARM-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi"
+// LLD-ARM-BAREMETAL: "-internal-isystem" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include"
+// LLD-ARM-BAREMETAL: "{{.*}}/Inputs/lld/ld.lld"
+// LLD-ARM-BAREMETAL: "{{.*}}.o" "-Bstatic" "-EL"
+// LLD-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/crt0.o"
+// LLD-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtbegin.o"
+// LLD-ARM-BAREMETAL: "-L{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1"
+// LLD-ARM-BAREMETAL: "-L{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib"
+// LLD-ARM-BAREMETAL: "--start-group" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgloss" "--end-group"
+// LLD-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtend.o"
+
 // RUN: %clang -### %s -fuse-ld= \
 // RUN:   --target=armv6m-none-eabi --rtlib=libgcc \
 // RUN:   --gcc-toolchain=%S/Inputs/basic_arm_gcc_tree \
@@ -9,6 +27,14 @@
 // C-ARM-BAREMETAL: "-cc1" "-triple" "thumbv6m-unknown-none-eabi"
 // C-ARM-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi"
 // C-ARM-BAREMETAL: "-internal-isystem" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include"
+// C-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../bin/armv6m-none-eabi-ld"
+// C-ARM-BAREMETAL: "{{.*}}.o" "-Bstatic" "-EL"
+// C-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/crt0.o"
+// C-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8...
[truncated]

@quic-garvgupt quic-garvgupt mentioned this pull request Jun 23, 2025
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@quic-garvgupt quic-garvgupt requested review from petrhosek and removed request for petrhosek June 23, 2025 20:17
@quic-garvgupt quic-garvgupt force-pushed the unifi2 branch 3 times, most recently from 36f8e16 to 624e295 Compare June 26, 2025 20:37
@llvmbot llvmbot added the clang:frontend Language frontend issues, e.g. anything involving "Sema" label Jun 26, 2025
@quic-garvgupt quic-garvgupt force-pushed the unifi2 branch 3 times, most recently from d5cd71e to 9c28666 Compare June 26, 2025 21:04
@quic-garvgupt
[Driver] Add support for crtbegin.o, crtend.o and libgloss lib to Bar…
14a2bb5 
…eMetal toolchain object (llvm#121830)

This patch conditionalise the addition of crt{begin,end}.o object files
along
with addition of -lgloss lib based on whether libc selected is newlib or
llvm
libc. Since there is no way a user can specify which libc it wants to
link
against, currently passing valid GCCInstallation to driver will select
newlib
otherwise it will default to llvm libc.

Moreover, this patch makes gnuld the default linker for baremetal
toolchain
object. User need to pass `-fuse-ld=lld` explicitly to driver to select
lld

This is the 2nd patch in the series of patches of merging RISCVToolchain
into
BareMetal toolchain object.

RFC:

https: //discourse.llvm.org/t/merging-riscvtoolchain-and-baremetal-toolchains/75524
Change-Id: Ie8eca262b53550d70c40c02f3395b2958ef19351
@quic-garvgupt quic-garvgupt merged commit ed25d47 into llvm:main Jun 29, 2025
7 checks passed
nico
nico reviewed Jun 30, 2025
View reviewed changes
clang/test/Driver/aarch64-toolchain.c

// AARCH64-BAREMETAL-COMPILER-RT: "{{.*}}crt0.o"
// AARCH64-BAREMETAL-COMPILER-RT: "{{.*}}clang_rt.crtbegin.o"
// AARCH64-BAREMETAL-COMPILER-RT: "--start-group" "{{.*}}libclang_rt.builtins.a" "-lc" "-lgloss" "--end-group"
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This line was failing on my bots like so: http://45.33.8.238/macm1/109605/step_6.txt

The other files touched in this commit are fine.

My bots use the GN build, which uses the old runtimes layout (what you get in the cmake build with --DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=OFF). However, this does not reproduce for me locally, so maybe it's dependent on some incremental build state.

It looks like the problem is that clang prints libclang_rt.builtins-aarch64.a (with the -aarch64 suffix).

5220e4f fixed it.

Does that make sense to you?

Would this fail with -DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=OFF in CMake too? Is this the right fix? Is it needed in other tests too?

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However, this does not reproduce for me locally, so maybe it's dependent on some incremental build state.

Can you confirm if you are still seeing the error on your buildbots?

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No, as I said:

5220e4f fixed it.

I'm just looking for answers to the questions in the last two paragraphs :)

nico referenced this pull request Jun 30, 2025
@nico
Speculative test tweak after ed25d47
5220e4f
@hvdijk
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hvdijk commented Jun 30, 2025

Moreover, this patch makes gnuld the default linker for baremetal
toolchain object. User need to pass -fuse-ld=lld explicitly to driver to select
lld

This seems like an unrelated change, it was not mentioned in the RFC, and it breaks things: baremetal toolchains generally should not be presumed to be for the same architecture as host. On an x86_64 host, this results in /usr/bin/ld being used for clang --target=riscv64, but /usr/bin/ld is (generally) a linker that does not understand RISC-V targets or object files. This seems like a bad idea, can this please be reverted?

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quic-garvgupt commented Jun 30, 2025 •
edited
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Moreover, this patch makes gnuld the default linker for baremetal
toolchain object. User need to pass -fuse-ld=lld explicitly to driver to select
lld

This seems like an unrelated change, it was not mentioned in the RFC, and it breaks things: baremetal toolchains generally should not be presumed to be for the same architecture as host. On an x86_64 host, this results in /usr/bin/ld being used for clang --target=riscv64, but /usr/bin/ld is (generally) a linker that does not understand RISC-V targets or object files. This seems like a bad idea, can this please be reverted?

This patch does not make assumption that it is for the same architecture as host. Rather, it is inline with other toolchain objects that supports GCCInstallation which have ld as the default linker. And this change is done only after reaching a consensus with lld and clang driver maintainer which can be found here. The conclusion of that discussion was that if a user wants to use a different linker, they should do so by specifying it explicitly via -fuse-ld or CLANG_DEFAULT_LINKER.

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hvdijk commented Jun 30, 2025

This patch does not make assumption that it is for the same architecture as host. Rather, it is inline with other toolchain objects that supports GCCInstallation which have ld as the default linker.

Thus breaking the case where it is not for the same architecture as host.

Thanks for the reference to where this was requested. Was it considered there that this would break things for users? I'm not seeing any mention of that.

I do appreciate that this is easy enough to work around, but having defaults that don't work still seems like a bad idea to me.

rlavaee pushed a commit to rlavaee/llvm-project that referenced this pull request Jul 1, 2025
@quic-garvgupt @rlavaee
Reland [Driver] Add support for crtbegin.o, crtend.o and libgloss lib…
97f5ba3 
… to BareMetal toolchain object (llvm#144649)

This patch conditionalise the addition of crt{begin,end}.o object files
along with addition of -lgloss lib based on whether libc selected is
newlib or
llvm libc. Since there is no way a user can specify which libc it wants
to
link against, currently passing valid GCCInstallation to driver will
select
newlib otherwise it will default to llvm libc.

Moreover, this patch makes gnuld the default linker for baremetal
toolchain object. User need to pass `-fuse-ld=lld` explicitly to driver
to select
lld

This is the 2nd patch in the series of patches of merging RISCVToolchain
into BareMetal toolchain object.

RFC:
https://discourse.llvm.org/t/merging-riscvtoolchain-and-baremetal-toolchains/75524
rlavaee pushed a commit to rlavaee/llvm-project that referenced this pull request Jul 1, 2025
@quic-garvgupt @rlavaee
Reland [Driver] Add support for crtbegin.o, crtend.o and libgloss lib…
13ff21b 
… to BareMetal toolchain object (llvm#144649)

This patch conditionalise the addition of crt{begin,end}.o object files
along with addition of -lgloss lib based on whether libc selected is
newlib or
llvm libc. Since there is no way a user can specify which libc it wants
to
link against, currently passing valid GCCInstallation to driver will
select
newlib otherwise it will default to llvm libc.

Moreover, this patch makes gnuld the default linker for baremetal
toolchain object. User need to pass `-fuse-ld=lld` explicitly to driver
to select
lld

This is the 2nd patch in the series of patches of merging RISCVToolchain
into BareMetal toolchain object.

RFC:
https://discourse.llvm.org/t/merging-riscvtoolchain-and-baremetal-toolchains/75524
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