Reland[Driver] Add option to force undefined symbols during linking in BareMetal toolchain object.

[quic-garvgupt]

Add support for -u option to force defined symbols. This option is supported by both lld and gnuld.

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

This is the 4th 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

[llvmbot]

@llvm/pr-subscribers-backend-risc-v

@llvm/pr-subscribers-clang

Author: Garvit Gupta (quic-garvgupt)

Changes

Add support for -u option to force defined symbols. This option is supported by both lld and gnuld.

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

This is the 4th 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

---

Full diff: https://github.com/llvm/llvm-project/pull/146304.diff

3 Files Affected:

• (modified) clang/lib/Driver/ToolChains/BareMetal.cpp (+3-2)
• (added) clang/test/Driver/baremetal-undefined-symbols.c (+14)
• (removed) clang/test/Driver/riscv-args.c (-6)

diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index a665040662a3f..d4e4e6d04b417 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -609,8 +609,9 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
-  Args.addAllArgs(CmdArgs, {options::OPT_L, options::OPT_T_Group,
-                            options::OPT_s, options::OPT_t, options::OPT_r});
+  Args.addAllArgs(CmdArgs,
+                  {options::OPT_L, options::OPT_u, options::OPT_T_Group,
+                   options::OPT_s, options::OPT_t, options::OPT_r});
 
   TC.AddFilePathLibArgs(Args, CmdArgs);
 
diff --git a/clang/test/Driver/baremetal-undefined-symbols.c b/clang/test/Driver/baremetal-undefined-symbols.c
new file mode 100644
index 0000000000000..bff58c7c54c33
--- /dev/null
+++ b/clang/test/Driver/baremetal-undefined-symbols.c
@@ -0,0 +1,14 @@
+// Check the arguments are correctly passed
+
+// Make sure -T is the last with gcc-toolchain option
+// RUN: %clang -### --target=riscv32 --gcc-toolchain= -Xlinker --defsym=FOO=10 -T a.lds -u foo %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-LD %s
+// CHECK-LD: {{.*}} "--defsym=FOO=10" {{.*}} "-u" "foo" {{.*}} "-T" "a.lds"
+
+// TODO: Merge this test with the above in the last patch when finally integrating riscv
+// Make sure -T is the last with gcc-toolchain option
+// RUN: %clang -### --target=aarch64-none-elf --gcc-toolchain= -Xlinker --defsym=FOO=10 -T a.lds -u foo %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARM-LD %s
+// RUN: %clang -### --target=armv6m-none-eabi --gcc-toolchain= -Xlinker --defsym=FOO=10 -T a.lds -u foo %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARM-LD %s
+// CHECK-ARM-LD: {{.*}} "-T" "a.lds" "-u" "foo" {{.*}} "--defsym=FOO=10"
diff --git a/clang/test/Driver/riscv-args.c b/clang/test/Driver/riscv-args.c
deleted file mode 100644
index cab08e5b0f811..0000000000000
--- a/clang/test/Driver/riscv-args.c
+++ /dev/null
@@ -1,6 +0,0 @@
-// Check the arguments are correctly passed
-
-// Make sure -T is the last with gcc-toolchain option
-// RUN: %clang -### --target=riscv32 --gcc-toolchain= -Xlinker --defsym=FOO=10 -T a.lds -u foo %s 2>&1 \
-// RUN:   | FileCheck -check-prefix=CHECK-LD %s
-// CHECK-LD: {{.*}} "--defsym=FOO=10" {{.*}} "-u" "foo" {{.*}} "-T" "a.lds"