[clang] [Driver] Add option to force undefined symbols during linking in BareMetal toolchain object. (PR #132807)

[Garvit Gupta via cfe-commits]

https://github.com/quic-garvgupt updated https://github.com/llvm/llvm-project/pull/132807

>From 7f26ac995e18f71ec8bccdb5b39be95bf629da19 Mon Sep 17 00:00:00 2001
From: Garvit Gupta <quic_garvgupt at quicinc.com>
Date: Mon, 24 Mar 2025 06:49:09 -0700
Subject: [PATCH] [Driver] Add option to force udnefined symbols during linking
 in BareMetal toolchain object.

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

Change-Id: Ia6597c756923a77fd9c7cb9a6ae8e52a56f5457d
---
 clang/lib/Driver/ToolChains/BareMetal.cpp       |  5 +++--
 clang/test/Driver/baremetal-undefined-symbols.c | 14 ++++++++++++++
 clang/test/Driver/riscv-args.c                  |  6 ------
 3 files changed, 17 insertions(+), 8 deletions(-)
 create mode 100644 clang/test/Driver/baremetal-undefined-symbols.c
 delete mode 100644 clang/test/Driver/riscv-args.c

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"