[Driver] Forward sysroot from Driver to linker in BareMetal ToolChain Object (#132808)

RISCVToolChain object passes `--sysroot` option from clang to gnuld.
Adding
the supprt for the same in BareMetal toolchain object.

This is done as a part of the effort to merge RISCVToolchain object into
BareMetal toolchain object.

This is the 5th patch in the series of patches for merging
RISCVToolchain object
into BareMetal toolchain object.

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

Author: Garvit Gupta

clang/lib/Driver/ToolChains/BareMetal.cpp

@@ -568,6 +568,9 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   const llvm::Triple::ArchType Arch = TC.getArch();
   const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
 
+  if (!D.SysRoot.empty())
+    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+
   CmdArgs.push_back("-Bstatic");
 
   if (TC.getTriple().isRISCV() && Args.hasArg(options::OPT_mno_relax))

clang/test/Driver/aarch64-toolchain.c

@@ -29,6 +29,7 @@
 // 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: "--sysroot={{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
 // C-AARCH64-BAREMETAL: "-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"
@@ -65,6 +66,7 @@
 // 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: "--sysroot={{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
 // CXX-AARCH64-BAREMETAL: "-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"
@@ -101,7 +103,8 @@
 // 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: "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../bin/aarch64-none-elf-ld"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "--sysroot={{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
 // CXX-AARCH64-BAREMETAL-LIBCXX: "-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"

clang/test/Driver/arm-toolchain.c

@@ -28,6 +28,7 @@
 // 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: "--sysroot={{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi"
 // C-ARM-BAREMETAL: "-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/8.2.1/crtbegin.o"
@@ -65,6 +66,7 @@
 // CXX-ARM-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include/c++/8.2.1"
 // CXX-ARM-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include"
 // CXX-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../bin/armv6m-none-eabi-ld"
+// CXX-ARM-BAREMETAL: "--sysroot={{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi"
 // CXX-ARM-BAREMETAL: "-Bstatic" "-EL"
 // CXX-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/crt0.o"
 // CXX-ARM-BAREMETAL: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtbegin.o"
@@ -103,6 +105,7 @@
 // CXX-ARM-BAREMETAL-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include/c++/v1"
 // CXX-ARM-BAREMETAL-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include"
 // CXX-ARM-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../bin/armv6m-none-eabi-ld"
+// CXX-ARM-BAREMETAL-LIBCXX: "--sysroot={{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi"
 // CXX-ARM-BAREMETAL-LIBCXX: "-Bstatic" "-EL"
 // CXX-ARM-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/crt0.o"
 // CXX-ARM-BAREMETAL-LIBCXX: "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtbegin.o"