caio/clang-p2996
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[Clang] Suppress missing architecture error when doing LTO (#100652)

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Summary:
The `nvlink-wrapper` can do LTO now, which means we can still create
some LLVM-IR without needing an architecture. In the case that we try to
invoke `nvlink` internally, that will still fail. This patch simply
defers the error until later so we can use `--lto-emit-llvm` to get the
IR without specifying an architecture.
This commit is contained in:
Joseph Huber
2024-07-31 14:41:55 -05:00
committed by GitHub
parent 6740d701bd
commit 2bf58f5d27
5 changed files with 21 additions and 5 deletions
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8
clang/lib/Driver/ToolChains/Cuda.cpp
View File

@@ -596,14 +596,16 @@ void NVPTX::Linker::ConstructJob(Compilation &C, const JobAction &JA,
CmdArgs.push_back("-v");
StringRef GPUArch = Args.getLastArgValue(options::OPT_march_EQ);
if (GPUArch.empty()) {
if (GPUArch.empty() && !C.getDriver().isUsingLTO()) {
C.getDriver().Diag(diag::err_drv_offload_missing_gpu_arch)
<< getToolChain().getArchName() << getShortName();
return;
}
CmdArgs.push_back("-arch");
CmdArgs.push_back(Args.MakeArgString(GPUArch));
if (!GPUArch.empty()) {
CmdArgs.push_back("-arch");
CmdArgs.push_back(Args.MakeArgString(GPUArch));
}
if (Args.hasArg(options::OPT_ptxas_path_EQ))
CmdArgs.push_back(Args.MakeArgString(

7
clang/test/Driver/cuda-cross-compiling.c
View File

@@ -84,6 +84,13 @@
// MISSING: error: must pass in an explicit nvptx64 gpu architecture to 'ptxas'
// MISSING: error: must pass in an explicit nvptx64 gpu architecture to 'nvlink'
// Do not error when performing LTO.
//
// RUN: %clang -target nvptx64-nvidia-cuda -flto %s -### 2>&1 \
// RUN: | FileCheck -check-prefix=MISSING-LTO %s
// MISSING-LTO-NOT: error: must pass in an explicit nvptx64 gpu architecture to 'nvlink'
// RUN: %clang -target nvptx64-nvidia-cuda -flto -c %s -### 2>&1 \
// RUN: | FileCheck -check-prefix=GENERIC %s
// RUN: %clang -target nvptx64-nvidia-cuda -march=sm_52 -march=generic -flto -c %s -### 2>&1 \

7
clang/tools/clang-nvlink-wrapper/ClangNVLinkWrapper.cpp
View File

@@ -302,6 +302,9 @@ Expected<StringRef> runPTXAs(StringRef File, const ArgList &Args) {
findProgram(Args, "ptxas", {CudaPath + "/bin", GivenPath});
if (!PTXAsPath)
return PTXAsPath.takeError();
if (!Args.hasArg(OPT_arch))
return createStringError(
"must pass in an explicit nvptx64 gpu architecture to 'ptxas'");
auto TempFileOrErr = createTempFile(
Args, sys::path::stem(Args.getLastArgValue(OPT_o, "a.out")), "cubin");
@@ -694,6 +697,10 @@ Error runNVLink(ArrayRef<StringRef> Files, const ArgList &Args) {
if (!NVLinkPath)
return NVLinkPath.takeError();
if (!Args.hasArg(OPT_arch))
return createStringError(
"must pass in an explicit nvptx64 gpu architecture to 'nvlink'");
ArgStringList NewLinkerArgs;
for (const opt::Arg *Arg : Args) {
// Do not forward arguments only intended for the linker wrapper.

2
libc/cmake/modules/LLVMLibCLibraryRules.cmake
View File

@@ -113,7 +113,7 @@ function(add_bitcode_entrypoint_library target_name base_target_name)
add_executable(${target_name} ${objects})
target_link_options(${target_name} PRIVATE
"-r" "-nostdlib" "-flto" "-Wl,--lto-emit-llvm" "-march= ")
"-r" "-nostdlib" "-flto" "-Wl,--lto-emit-llvm")
endfunction(add_bitcode_entrypoint_library)
# A rule to build a library from a collection of entrypoint objects.

2
libc/startup/gpu/CMakeLists.txt
View File

@@ -34,7 +34,7 @@ function(add_startup_object name)
RUNTIME_OUTPUT_DIRECTORY ${LIBC_LIBRARY_DIR}
RUNTIME_OUTPUT_NAME ${name}.o)
target_link_options(${fq_target_name}.exe PRIVATE
"-nostdlib" "-flto" "-Wl,--lto-emit-llvm" "-march= ")
"-nostdlib" "-flto" "-Wl,--lto-emit-llvm")
endif()
endfunction()