[clang] b16f765 - [LinkerWrapper] Accept some needed lld-link linker arguments for COFF targets (#72889)

[via cfe-commits]

Author: Joseph Huber
Date: 2023-11-22T20:23:23-06:00
New Revision: b16f765d6fec56a07aecd2056bb1760a9e72d64f

URL: https://github.com/llvm/llvm-project/commit/b16f765d6fec56a07aecd2056bb1760a9e72d64f
DIFF: https://github.com/llvm/llvm-project/commit/b16f765d6fec56a07aecd2056bb1760a9e72d64f.diff

LOG: [LinkerWrapper] Accept some needed lld-link linker arguments for COFF targets (#72889)

Summary:
The linker wrapper is a utility used to create offloading programs from
single-source offloading languages such as OpenMP or CUDA. This is done
by embedding device code into the host object, then feeding it into the
linker wrapper which extracts the accelerator object files, links them,
then wraps them in registration code for the target  runtime. This
previously has only worked in Linux / ELF platforms.

This patch attempts to hand Windows / COFF inputs by also accepting COFF
forms of certain linker arguments we use internally. The important
arguments are library search paths, so we can identify libraries which
may contain device code, libraries themselves, and the output name used
for intermediate output.

I am not intimately familiar with the semantics here for the semantics
in how a `lib` file is earched. I am simply treating `foo.lib` as the
GNU equivalent `-l:foo.lib` in the search logic. Similarly, I am
assuming that static libraries will be llvm-ar style libraries. I will
need to investigate the actual deficiencies later, but this should be a
good starting point along with
https://github.com/llvm/llvm-project/pull/72697

Added: 
    

Modified: 
    clang/test/Driver/linker-wrapper.c
    clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
    clang/tools/clang-linker-wrapper/LinkerWrapperOpts.td

Removed: 
    


################################################################################
diff  --git a/clang/test/Driver/linker-wrapper.c b/clang/test/Driver/linker-wrapper.c
index da7bdc22153ceae..e82febd61823102 100644
--- a/clang/test/Driver/linker-wrapper.c
+++ b/clang/test/Driver/linker-wrapper.c
@@ -140,3 +140,11 @@
 // RUN:   --linker-path=/usr/bin/ld -- %t.o -o a.out 2>&1 | FileCheck %s --check-prefix=CLANG-BACKEND
 
 // CLANG-BACKEND: clang{{.*}} -o {{.*}}.img --target=amdgcn-amd-amdhsa -mcpu=gfx908 -O2 -Wl,--no-undefined {{.*}}.bc
+
+// RUN: clang-offload-packager -o %t.out \
+// RUN:   --image=file=%t.elf.o,kind=openmp,triple=nvptx64-nvidia-cuda,arch=sm_70
+// RUN: %clang -cc1 %s -triple x86_64-unknown-windows-msvc -emit-obj -o %t.o -fembed-offload-object=%t.out
+// RUN: clang-linker-wrapper --host-triple=x86_64-unknown-windows-msvc --dry-run \
+// RUN:   --linker-path=/usr/bin/lld-link -- %t.o -libpath:./ -out:a.exe 2>&1 | FileCheck %s --check-prefix=COFF
+
+// COFF: "/usr/bin/lld-link" {{.*}}.o -libpath:./ -out:a.exe {{.*}}openmp.image.wrapper{{.*}}

diff  --git a/clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp b/clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
index bafe8ace60d1cea..db0ce3e2a190192 100644
--- a/clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
+++ b/clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
@@ -254,7 +254,7 @@ Error runLinker(ArrayRef<StringRef> Files, const ArgList &Args) {
       continue;
 
     Arg->render(Args, NewLinkerArgs);
-    if (Arg->getOption().matches(OPT_o))
+    if (Arg->getOption().matches(OPT_o) || Arg->getOption().matches(OPT_out))
       llvm::transform(Files, std::back_inserter(NewLinkerArgs),
                       [&](StringRef Arg) { return Args.MakeArgString(Arg); });
   }
@@ -1188,7 +1188,7 @@ searchLibraryBaseName(StringRef Name, StringRef Root,
 /// `-lfoo` or `-l:libfoo.a`.
 std::optional<std::string> searchLibrary(StringRef Input, StringRef Root,
                                          ArrayRef<StringRef> SearchPaths) {
-  if (Input.startswith(":"))
+  if (Input.startswith(":") || Input.ends_with(".lib"))
     return findFromSearchPaths(Input.drop_front(), Root, SearchPaths);
   return searchLibraryBaseName(Input, Root, SearchPaths);
 }
@@ -1339,7 +1339,7 @@ Expected<SmallVector<OffloadFile>> getDeviceInput(const ArgList &Args) {
 
   StringRef Root = Args.getLastArgValue(OPT_sysroot_EQ);
   SmallVector<StringRef> LibraryPaths;
-  for (const opt::Arg *Arg : Args.filtered(OPT_library_path))
+  for (const opt::Arg *Arg : Args.filtered(OPT_library_path, OPT_libpath))
     LibraryPaths.push_back(Arg->getValue());
 
   BumpPtrAllocator Alloc;
@@ -1348,7 +1348,7 @@ Expected<SmallVector<OffloadFile>> getDeviceInput(const ArgList &Args) {
   // Try to extract device code from the linker input files.
   SmallVector<OffloadFile> InputFiles;
   DenseMap<OffloadFile::TargetID, DenseMap<StringRef, Symbol>> Syms;
-  bool WholeArchive = false;
+  bool WholeArchive = Args.hasArg(OPT_wholearchive_flag) ? true : false;
   for (const opt::Arg *Arg : Args.filtered(
            OPT_INPUT, OPT_library, OPT_whole_archive, OPT_no_whole_archive)) {
     if (Arg->getOption().matches(OPT_whole_archive) ||
@@ -1474,9 +1474,17 @@ int main(int Argc, char **Argv) {
   Verbose = Args.hasArg(OPT_verbose);
   DryRun = Args.hasArg(OPT_dry_run);
   SaveTemps = Args.hasArg(OPT_save_temps);
-  ExecutableName = Args.getLastArgValue(OPT_o, "a.out");
   CudaBinaryPath = Args.getLastArgValue(OPT_cuda_path_EQ).str();
 
+  llvm::Triple Triple(
+      Args.getLastArgValue(OPT_host_triple_EQ, sys::getDefaultTargetTriple()));
+  if (Args.hasArg(OPT_o))
+    ExecutableName = Args.getLastArgValue(OPT_o, "a.out");
+  else if (Args.hasArg(OPT_out))
+    ExecutableName = Args.getLastArgValue(OPT_out, "a.exe");
+  else
+    ExecutableName = Triple.isOSWindows() ? "a.exe" : "a.out";
+
   parallel::strategy = hardware_concurrency(1);
   if (auto *Arg = Args.getLastArg(OPT_wrapper_jobs)) {
     unsigned Threads = 0;

diff  --git a/clang/tools/clang-linker-wrapper/LinkerWrapperOpts.td b/clang/tools/clang-linker-wrapper/LinkerWrapperOpts.td
index 2ce6ee0d21d1d6e..b6d3297987fffe5 100644
--- a/clang/tools/clang-linker-wrapper/LinkerWrapperOpts.td
+++ b/clang/tools/clang-linker-wrapper/LinkerWrapperOpts.td
@@ -126,3 +126,8 @@ def version : Flag<["--", "-"], "version">, Flags<[HelpHidden]>, Alias<v>;
 
 def whole_archive : Flag<["--", "-"], "whole-archive">, Flags<[HelpHidden]>;
 def no_whole_archive : Flag<["--", "-"], "no-whole-archive">, Flags<[HelpHidden]>;
+
+// link.exe-style linker options.
+def out : Joined<["/", "-", "/?", "-?"], "out:">, Flags<[HelpHidden]>;
+def libpath : Joined<["/", "-", "/?", "-?"], "libpath:">, Flags<[HelpHidden]>;
+def wholearchive_flag : Joined<["/", "-", "/?", "-?"], "wholearchive">, Flags<[HelpHidden]>;