[LinkerWrapper] Pass all files to the device linker #97573
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@llvm/pr-subscribers-clang-driver @llvm/pr-subscribers-clang Author: Joseph Huber (jhuber6) ChangesSummary: Now since I wrote #96561 we The JIT support is a notable departure, however there is an option This patch does not fully delete the LTO handling, primarily because I Depends on #96561. Patch is 62.40 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/97573.diff 14 Files Affected:
diff --git a/clang/docs/ClangNVLinkWrapper.rst b/clang/docs/ClangNVLinkWrapper.rst
new file mode 100644
index 0000000000000..0a312bdbf3066
--- /dev/null
+++ b/clang/docs/ClangNVLinkWrapper.rst
@@ -0,0 +1,64 @@
+====================
+Clang nvlink Wrapper
+====================
+
+.. contents::
+ :local:
+
+.. _clang-nvlink-wrapper:
+
+Introduction
+============
+
+This tools works as a wrapper around the NVIDIA ``nvlink`` linker. The purpose
+of this wrapper is to provide an interface similar to the ``ld.lld`` linker
+while still relying on NVIDIA's proprietary linker to produce the final output.
+Features include, static archive (.a) linking, LTO, and accepting files ending
+in ``.o`` without error.
+
+Usage
+=====
+
+This tool can be used with the following options. Any arguments not intended
+only for the linker wrapper will be forwarded to ``nvlink``.
+
+.. code-block:: console
+
+ OVERVIEW: A utility that wraps around the NVIDIA 'nvlink' linker.
+ This enables static linking and LTO handling for NVPTX targets.
+
+ USAGE: clang-nvlink-wrapper [options] <options to passed to nvlink>
+
+ OPTIONS:
+ --arch <value> Specify the 'sm_' name of the target architecture.
+ --cuda-path=<dir> Set the system CUDA path
+ --dry-run Print generated commands without running.
+ --feature <value> Specify the '+ptx' freature to use for LTO.
+ -g Specify that this was a debug compile.
+ -help-hidden Display all available options
+ -help Display available options (--help-hidden for more)
+ -L <dir> Add <dir> to the library search path
+ -l <libname> Search for library <libname>
+ -mllvm <arg> Arguments passed to LLVM, including Clang invocations, for which the '-mllvm' prefix is preserved. Use '-mllvm --help' for a list of options.
+ -o <path> Path to file to write output
+ --plugin-opt=jobs=<value>
+ Number of LTO codegen partitions
+ --plugin-opt=lto-partitions=<value>
+ Number of LTO codegen partitions
+ --plugin-opt=O<O0, O1, O2, or O3>
+ Optimization level for LTO
+ --plugin-opt=thinlto<value>
+ Enable the thin-lto backend
+ --plugin-opt=<value> Options passed to LLVM, not including the Clang invocation. Use '--plugin-opt=--help' for a list of options.
+ --save-temps Save intermediate results
+ --version Display the version number and exit
+ -v Print verbose information
+
+Example
+=======
+
+This tool is intended to be invoked when targeting the NVPTX toolchain directly.
+
+.. code-block:: console
+
+ clang --target=nvptx64-nvidia-cuda -march=native -flto=full input.c
diff --git a/clang/docs/index.rst b/clang/docs/index.rst
index a35a867b96bd7..9bae0bd83243b 100644
--- a/clang/docs/index.rst
+++ b/clang/docs/index.rst
@@ -92,6 +92,7 @@ Using Clang Tools
ClangFormatStyleOptions
ClangFormattedStatus
ClangLinkerWrapper
+ ClangNVLinkWrapper
ClangOffloadBundler
ClangOffloadPackager
ClangRepl
diff --git a/clang/lib/Driver/ToolChains/Cuda.cpp b/clang/lib/Driver/ToolChains/Cuda.cpp
index 08a4633902654..a8dd91e61f96c 100644
--- a/clang/lib/Driver/ToolChains/Cuda.cpp
+++ b/clang/lib/Driver/ToolChains/Cuda.cpp
@@ -461,13 +461,6 @@ void NVPTX::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
CmdArgs.push_back("--output-file");
std::string OutputFileName = TC.getInputFilename(Output);
- // If we are invoking `nvlink` internally we need to output a `.cubin` file.
- // FIXME: This should hopefully be removed if NVIDIA updates their tooling.
- if (!C.getInputArgs().getLastArg(options::OPT_c)) {
- SmallString<256> Filename(Output.getFilename());
- llvm::sys::path::replace_extension(Filename, "cubin");
- OutputFileName = Filename.str();
- }
if (Output.isFilename() && OutputFileName != Output.getFilename())
C.addTempFile(Args.MakeArgString(OutputFileName));
@@ -618,6 +611,11 @@ void NVPTX::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// Add standard library search paths passed on the command line.
Args.AddAllArgs(CmdArgs, options::OPT_L);
getToolChain().AddFilePathLibArgs(Args, CmdArgs);
+ AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
+
+ if (C.getDriver().isUsingLTO())
+ addLTOOptions(getToolChain(), Args, CmdArgs, Output, Inputs[0],
+ C.getDriver().getLTOMode() == LTOK_Thin);
// Add paths for the default clang library path.
SmallString<256> DefaultLibPath =
@@ -625,51 +623,12 @@ void NVPTX::Linker::ConstructJob(Compilation &C, const JobAction &JA,
llvm::sys::path::append(DefaultLibPath, CLANG_INSTALL_LIBDIR_BASENAME);
CmdArgs.push_back(Args.MakeArgString(Twine("-L") + DefaultLibPath));
- for (const auto &II : Inputs) {
- if (II.getType() == types::TY_LLVM_IR || II.getType() == types::TY_LTO_IR ||
- II.getType() == types::TY_LTO_BC || II.getType() == types::TY_LLVM_BC) {
- C.getDriver().Diag(diag::err_drv_no_linker_llvm_support)
- << getToolChain().getTripleString();
- continue;
- }
-
- // The 'nvlink' application performs RDC-mode linking when given a '.o'
- // file and device linking when given a '.cubin' file. We always want to
- // perform device linking, so just rename any '.o' files.
- // FIXME: This should hopefully be removed if NVIDIA updates their tooling.
- if (II.isFilename()) {
- auto InputFile = getToolChain().getInputFilename(II);
- if (llvm::sys::path::extension(InputFile) != ".cubin") {
- // If there are no actions above this one then this is direct input and
- // we can copy it. Otherwise the input is internal so a `.cubin` file
- // should exist.
- if (II.getAction() && II.getAction()->getInputs().size() == 0) {
- const char *CubinF =
- Args.MakeArgString(getToolChain().getDriver().GetTemporaryPath(
- llvm::sys::path::stem(InputFile), "cubin"));
- if (llvm::sys::fs::copy_file(InputFile, C.addTempFile(CubinF)))
- continue;
-
- CmdArgs.push_back(CubinF);
- } else {
- SmallString<256> Filename(InputFile);
- llvm::sys::path::replace_extension(Filename, "cubin");
- CmdArgs.push_back(Args.MakeArgString(Filename));
- }
- } else {
- CmdArgs.push_back(Args.MakeArgString(InputFile));
- }
- } else if (!II.isNothing()) {
- II.getInputArg().renderAsInput(Args, CmdArgs);
- }
- }
-
C.addCommand(std::make_unique<Command>(
JA, *this,
ResponseFileSupport{ResponseFileSupport::RF_Full, llvm::sys::WEM_UTF8,
"--options-file"},
- Args.MakeArgString(getToolChain().GetProgramPath("nvlink")), CmdArgs,
- Inputs, Output));
+ Args.MakeArgString(getToolChain().GetProgramPath("clang-nvlink-wrapper")),
+ CmdArgs, Inputs, Output));
}
void NVPTX::getNVPTXTargetFeatures(const Driver &D, const llvm::Triple &Triple,
@@ -949,11 +908,7 @@ std::string CudaToolChain::getInputFilename(const InputInfo &Input) const {
if (Input.getType() != types::TY_Object || getDriver().offloadDeviceOnly())
return ToolChain::getInputFilename(Input);
- // Replace extension for object files with cubin because nvlink relies on
- // these particular file names.
- SmallString<256> Filename(ToolChain::getInputFilename(Input));
- llvm::sys::path::replace_extension(Filename, "cubin");
- return std::string(Filename);
+ return ToolChain::getInputFilename(Input);
}
llvm::opt::DerivedArgList *
diff --git a/clang/lib/Driver/ToolChains/Cuda.h b/clang/lib/Driver/ToolChains/Cuda.h
index 7464d88cb350b..7a6a6fb209012 100644
--- a/clang/lib/Driver/ToolChains/Cuda.h
+++ b/clang/lib/Driver/ToolChains/Cuda.h
@@ -155,6 +155,7 @@ class LLVM_LIBRARY_VISIBILITY NVPTXToolChain : public ToolChain {
bool isPIEDefault(const llvm::opt::ArgList &Args) const override {
return false;
}
+ bool HasNativeLLVMSupport() const override { return true; }
bool isPICDefaultForced() const override { return false; }
bool SupportsProfiling() const override { return false; }
@@ -192,6 +193,8 @@ class LLVM_LIBRARY_VISIBILITY CudaToolChain : public NVPTXToolChain {
return &HostTC.getTriple();
}
+ bool HasNativeLLVMSupport() const override { return false; }
+
std::string getInputFilename(const InputInfo &Input) const override;
llvm::opt::DerivedArgList *
diff --git a/clang/test/Driver/cuda-cross-compiling.c b/clang/test/Driver/cuda-cross-compiling.c
index 1dc4520f485db..42d56cbfcc321 100644
--- a/clang/test/Driver/cuda-cross-compiling.c
+++ b/clang/test/Driver/cuda-cross-compiling.c
@@ -32,8 +32,8 @@
// RUN: | FileCheck -check-prefix=ARGS %s
// ARGS: -cc1" "-triple" "nvptx64-nvidia-cuda" "-S" {{.*}} "-target-cpu" "sm_61" "-target-feature" "+ptx{{[0-9]+}}" {{.*}} "-o" "[[PTX:.+]].s"
-// ARGS-NEXT: ptxas{{.*}}"-m64" "-O0" "--gpu-name" "sm_61" "--output-file" "[[CUBIN:.+]].cubin" "[[PTX]].s" "-c"
-// ARGS-NEXT: nvlink{{.*}}"-o" "a.out" "-arch" "sm_61" {{.*}} "[[CUBIN]].cubin"
+// ARGS-NEXT: ptxas{{.*}}"-m64" "-O0" "--gpu-name" "sm_61" "--output-file" "[[CUBIN:.+]].o" "[[PTX]].s" "-c"
+// ARGS-NEXT: clang-nvlink-wrapper{{.*}}"-o" "a.out" "-arch" "sm_61"{{.*}}"[[CUBIN]].o"
//
// Test the generated arguments to the CUDA binary utils when targeting NVPTX.
@@ -55,7 +55,7 @@
// RUN: %clang -target nvptx64-nvidia-cuda -march=sm_61 -### %t.o 2>&1 \
// RUN: | FileCheck -check-prefix=LINK %s
-// LINK: nvlink{{.*}}"-o" "a.out" "-arch" "sm_61" {{.*}} "{{.*}}.cubin"
+// LINK: clang-nvlink-wrapper{{.*}}"-o" "a.out" "-arch" "sm_61"{{.*}}[[CUBIN:.+]].o
//
// Test to ensure that we enable handling global constructors in a freestanding
@@ -72,7 +72,7 @@
// RUN: %clang -target nvptx64-nvidia-cuda -Wl,-v -Wl,a,b -march=sm_52 -### %s 2>&1 \
// RUN: | FileCheck -check-prefix=LINKER-ARGS %s
-// LINKER-ARGS: nvlink{{.*}}"-v"{{.*}}"a" "b"
+// LINKER-ARGS: clang-nvlink-wrapper{{.*}}"-v"{{.*}}"a" "b"
// Tests for handling a missing architecture.
//
diff --git a/clang/test/Driver/linker-wrapper-libs.c b/clang/test/Driver/linker-wrapper-libs.c
index 22cc24f2e258a..cb5c7c137a0ba 100644
--- a/clang/test/Driver/linker-wrapper-libs.c
+++ b/clang/test/Driver/linker-wrapper-libs.c
@@ -48,7 +48,7 @@ int bar() { return weak; }
// RUN: --linker-path=/usr/bin/ld %t.a %t.o -o a.out 2>&1 \
// RUN: | FileCheck %s --check-prefix=LIBRARY-RESOLVES
-// LIBRARY-RESOLVES: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_70 {{.*}}.s {{.*}}.o
+// LIBRARY-RESOLVES: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_70 {{.*}}.o {{.*}}.o
// LIBRARY-RESOLVES: clang{{.*}} -o {{.*}}.img --target=amdgcn-amd-amdhsa -mcpu=gfx1030 {{.*}}.o {{.*}}.o
//
@@ -72,7 +72,7 @@ int bar() { return weak; }
// RUN: --linker-path=/usr/bin/ld %t.a %t.o -o a.out 2>&1 \
// RUN: | FileCheck %s --check-prefix=LIBRARY-GLOBAL
-// LIBRARY-GLOBAL: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_70 {{.*}}.s {{.*}}.o
+// LIBRARY-GLOBAL: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_70 {{.*}}.o {{.*}}.o
// LIBRARY-GLOBAL: clang{{.*}} -o {{.*}}.img --target=amdgcn-amd-amdhsa -mcpu=gfx1030 {{.*}}.o {{.*}}.o
//
@@ -96,7 +96,7 @@ int bar() { return weak; }
// RUN: | FileCheck %s --check-prefix=LIBRARY-GLOBAL-NONE
// LIBRARY-GLOBAL-NONE-NOT: clang{{.*}} -o {{.*}}.img --target=amdgcn-amd-amdhsa -mcpu=gfx1030 {{.*}}.o {{.*}}.o
-// LIBRARY-GLOBAL-NONE-NOT: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_70 {{.*}}.s {{.*}}.o
+// LIBRARY-GLOBAL-NONE-NOT: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_70 {{.*}}.o {{.*}}.o
//
// Check that we do not extract an external weak symbol.
@@ -161,7 +161,7 @@ int bar() { return weak; }
// RUN: --linker-path=/usr/bin/ld %t.o %t.a %t.a -o a.out 2>&1 \
// RUN: | FileCheck %s --check-prefix=LIBRARY-GLOBAL-DEFINED
-// LIBRARY-GLOBAL-DEFINED: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_70 {{.*}}.s {{.*}}.o
+// LIBRARY-GLOBAL-DEFINED: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_70 {{.*}}.o {{.*}}.o
// LIBRARY-GLOBAL-DEFINED-NOT: {{.*}}gfx1030{{.*}}.o
// LIBRARY-GLOBAL-DEFINED: clang{{.*}} -o {{.*}}.img --target=amdgcn-amd-amdhsa -mcpu=gfx1030 {{.*}}.o {{.*}}.o
@@ -185,7 +185,7 @@ int bar() { return weak; }
// RUN: --linker-path=/usr/bin/ld %t.o --whole-archive %t.a -o a.out 2>&1 \
// RUN: | FileCheck %s --check-prefix=LIBRARY-WHOLE-ARCHIVE
-// LIBRARY-WHOLE-ARCHIVE: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_70 {{.*}}.s {{.*}}.o
+// LIBRARY-WHOLE-ARCHIVE: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_70 {{.*}}.o {{.*}}.o
// LIBRARY-WHOLE-ARCHIVE: clang{{.*}} -o {{.*}}.img --target=amdgcn-amd-amdhsa -mcpu=gfx1030 {{.*}}.o {{.*}}.o
-// LIBRARY-WHOLE-ARCHIVE: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_52 {{.*}}.s
+// LIBRARY-WHOLE-ARCHIVE: clang{{.*}} -o {{.*}}.img --target=nvptx64-nvidia-cuda -march=sm_52 {{.*}}.o
// LIBRARY-WHOLE-ARCHIVE: clang{{.*}} -o {{.*}}.img --target=amdgcn-amd-amdhsa -mcpu=gfx90a {{.*}}.o
diff --git a/clang/test/Driver/linker-wrapper.c b/clang/test/Driver/linker-wrapper.c
index b9fa08ace0ff7..63d43921be9ac 100644
--- a/clang/test/Driver/linker-wrapper.c
+++ b/clang/test/Driver/linker-wrapper.c
@@ -48,7 +48,7 @@ __attribute__((visibility("protected"), used)) int x;
// RUN: clang-linker-wrapper --host-triple=x86_64-unknown-linux-gnu --dry-run --save-temps -O2 \
// RUN: --linker-path=/usr/bin/ld %t.o -o a.out 2>&1 | FileCheck %s --check-prefix=AMDGPU-LTO-TEMPS
-// AMDGPU-LTO-TEMPS: clang{{.*}} -o {{.*}}.img --target=amdgcn-amd-amdhsa -mcpu=gfx1030 -O2 -Wl,--no-undefined {{.*}}.s -save-temps
+// AMDGPU-LTO-TEMPS: clang{{.*}} -o {{.*}}.img --target=amdgcn-amd-amdhsa -mcpu=gfx1030 -O2 -Wl,--no-undefined {{.*}}.o -save-temps
// RUN: clang-offload-packager -o %t.out \
// RUN: --image=file=%t.elf.o,kind=openmp,triple=x86_64-unknown-linux-gnu \
@@ -147,7 +147,7 @@ __attribute__((visibility("protected"), used)) int x;
// RUN: clang-linker-wrapper --host-triple=x86_64-unknown-linux-gnu --dry-run --clang-backend \
// 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
+// CLANG-BACKEND: clang{{.*}} -o {{.*}}.img --target=amdgcn-amd-amdhsa -mcpu=gfx908 -O2 -Wl,--no-undefined {{.*}}.o
// RUN: clang-offload-packager -o %t.out \
// RUN: --image=file=%t.elf.o,kind=openmp,triple=nvptx64-nvidia-cuda,arch=sm_70
diff --git a/clang/test/Driver/nvlink-wrapper.c b/clang/test/Driver/nvlink-wrapper.c
new file mode 100644
index 0000000000000..fdda93f1f9cdc
--- /dev/null
+++ b/clang/test/Driver/nvlink-wrapper.c
@@ -0,0 +1,65 @@
+// REQUIRES: x86-registered-target
+// REQUIRES: nvptx-registered-target
+
+#if defined(X)
+extern int y;
+int foo() { return y; }
+
+int x = 0;
+#elif defined(Y)
+int y = 42;
+#elif defined(Z)
+int z = 42;
+#elif defined(W)
+int w = 42;
+#elif defined(U)
+extern int x;
+extern int __attribute__((weak)) w;
+
+int bar() {
+ return x + w;
+}
+#else
+extern int y;
+int __attribute__((visibility("hidden"))) x = 999;
+int baz() { return y + x; }
+#endif
+
+// Create various inputs to test basic linking and LTO capabilities. Creating a
+// CUDA binary requires access to the `ptxas` executable, so we just use x64.
+// RUN: %clang -cc1 %s -triple x86_64-unknown-linux-gnu -emit-obj -DX -o %t-x.o
+// RUN: %clang -cc1 %s -triple x86_64-unknown-linux-gnu -emit-obj -DY -o %t-y.o
+// RUN: %clang -cc1 %s -triple x86_64-unknown-linux-gnu -emit-obj -DZ -o %t-z.o
+// RUN: %clang -cc1 %s -triple x86_64-unknown-linux-gnu -emit-obj -DW -o %t-w.o
+// RUN: %clang -cc1 %s -triple x86_64-unknown-linux-gnu -emit-obj -DU -o %t-u.o
+// RUN: llvm-ar rcs %t-x.a %t-x.o
+// RUN: llvm-ar rcs %t-y.a %t-y.o
+// RUN: llvm-ar rcs %t-z.a %t-z.o
+// RUN: llvm-ar rcs %t-w.a %t-w.o
+
+//
+// Check that we forward any unrecognized argument to 'nvlink'.
+//
+// RUN: clang-nvlink-wrapper --dry-run -arch sm_52 %t-u.o -foo -o a.out 2>&1 \
+// RUN: | FileCheck %s --check-prefix=ARGS
+// ARGS: nvlink{{.*}} -arch sm_52 -foo -o a.out [[INPUT:.+]].cubin
+
+//
+// Check the symbol resolution for static archives. We expect to only link
+// `libx.a` and `liby.a` because extern weak symbols do not extract and `libz.a`
+// is not used at all.
+//
+// RUN: clang-nvlink-wrapper --dry-run %t-x.a %t-u.o %t-y.a %t-z.a %t-w.a \
+// RUN: -arch sm_52 -o a.out 2>&1 | FileCheck %s --check-prefix=LINK
+// LINK: nvlink{{.*}} -arch sm_52 -o a.out [[INPUT:.+]].cubin {{.*}}-x-{{.*}}.cubin{{.*}}-y-{{.*}}.cubin
+
+// RUN: %clang -cc1 %s -triple nvptx64-nvidia-cuda -emit-llvm-bc -o %t.o
+
+//
+// Check that the LTO interface works and properly preserves symbols used in a
+// regular object file.
+//
+// RUN: clang-nvlink-wrapper --dry-run %t.o %t-u.o %t-y.a \
+// RUN: -arch sm_52 -o a.out 2>&1 | FileCheck %s --check-prefix=LTO
+// LTO: ptxas{{.*}} -m64 -c [[PTX:.+]].s -O3 -arch sm_52 -o [[CUBIN:.+]].cubin
+// LTO: nvlink{{.*}} -arch sm_52 -o a.out [[CUBIN]].cubin {{.*}}-u-{{.*}}.cubin {{.*}}-y-{{.*}}.cubin
diff --git a/clang/test/lit.cfg.py b/clang/test/lit.cfg.py
index e5630a07424c7..92a3361ce672e 100644
--- a/clang/test/lit.cfg.py
+++ b/clang/test/lit.cfg.py
@@ -95,6 +95,7 @@
"llvm-ifs",
"yaml2obj",
"clang-linker-wrapper",
+ "clang-nvlink-wrapper",
"llvm-lto",
"llvm-lto2",
"llvm-profdata",
diff --git a/clang/tools/CMakeLists.txt b/clang/tools/CMakeLists.txt
index bdd8004be3e02..4885afc1584d0 100644
--- a/clang/tools/CMakeLists.txt
+++ b/clang/tools/CMakeLists.txt
@@ -9,6 +9,7 @@ add_clang_subdirectory(clang-format-vs)
add_clang_subdirectory(clang-fuzzer)
add_clang_subdirectory(clang-import-test)
add_clang_subdirectory(clang-linker-wrapper)
+add_clang_subdirectory(clang-nvlink-wrapper)
add_clang_subdirectory(clang-offload-packager)
add_clang_subdirectory(clang-offload-bundler)
add_clang_subdirectory(clang-scan-deps)
diff --git a/clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp b/clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
index 9027076119cf9..15b215bf078f8 100644
--- a/clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
+++ b/clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
@@ -242,6 +242,13 @@ Expected<std::string> findProgram(StringRef Name, ArrayRef<StringRef> Paths) {
return *Path;
}
+/// We will defer LTO to the target's linker if we are not doing JIT and it is
+/// supported by the toolchain.
+bool linkerSupportsLTO(const ArgList &Args) {
+ llvm::Triple Triple(Args.getLastArgValue(OPT_triple_EQ));
+ return Triple.isNVPTX() || Triple.isAMDGPU();
+}
+
/// Returns the hashed value for a constant string.
std::string getHash(StringRef Str) {
llvm::MD5 Hasher;
@@ -504,11 +511,10 @@ Expected<StringRef> clang(ArrayRef<StringRef> InputFiles, const ArgList &Args) {
llvm::copy(LinkerArgs, std::back_inserter(CmdArgs));
}
- // Pass on -mllvm options to the clang invocation.
- for (const opt::Arg *Arg : Args.filtered(OPT_mllvm)) {
- CmdArgs.push_back("-mllvm");
- CmdArgs.push_back(Arg->getValue());
- }
+ // Pass on -mllvm options to the linker invocation.
+ for (const opt::Arg *Arg : Args.filtered(OPT_mllvm))
+ CmdArgs.push_back(
+ Args.MakeArgString("-Wl,-mllvm=" + StringRef(Arg->getValue())));
if (Args.hasArg(OPT_debug))
CmdArgs.push_back("-g");
@@ -516,6 +522,12 @@ Expected<StringRef> clang(ArrayRef<StringRef> InputFiles, const ArgList &Args) {
if (SaveTemps)
CmdArgs.push_back("-save-temps");
+ if (SaveTemps && linkerSupportsLTO(Args))
+ CmdArgs.push_back("-Wl,--save-temps");
+
+ if (Args.hasArg(OPT_embed_bitcode))
+ CmdArgs.push_back("-Wl,--lto-emit-llvm");
+
if (Verbose)
CmdArgs.push_back("-v");
@@ -536,8 +548,8 @@ Expected<StringRef> clang(ArrayRef<StringRef> InputFiles, const ArgList &Args) {
Args.MakeArgString(Arg.split('=').second)});
}
- // The OpenMPOpt pass can introduce new calls and is expensive, we do not want
- // this when running CodeGen through clang.
+ // The OpenMPOpt pass ca...
[truncated]
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saiislam
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The second commit to "Pass all files to the device linker" looks good to me.
Overall, I am fine with the first commit of re-introducing clang-nvlinker-wrapper as well. Last time, we added it to wrap static device archives only (https://reviews.llvm.org/D108291).
But, let's wait for @Artem-B to finish the review of #96561
Artem-B
reviewed
Jul 22, 2024
clang/docs/ClangNVLinkWrapper.rst
Outdated
| -help Display available options (--help-hidden for more) | ||
| -L <dir> Add <dir> to the library search path | ||
| -l <libname> Search for library <libname> | ||
| -mllvm <arg> Arguments passed to LLVM, including Clang invocations, for which the '-mllvm' prefix is preserved. Use '-mllvm --help' for a list of options. |
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Nit: Should we wrap long lines here it for readability? I think code blocks in restructured markup will try to scroll along the line w/o wrapping it.
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| if (Args.hasArg(OPT_debug)) | ||
| CmdArgs.push_back("-g"); | ||
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| if (SaveTemps) | ||
| CmdArgs.push_back("-save-temps"); | ||
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| if (SaveTemps && linkerSupportsLTO(Args)) |
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Is -save-temps propagated from the top-level compilation?
If so, how do we handle --save-temps=obj -o /some/other/dir/foo.o ?
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In this logic we only have the link job remaining, so we pass -Wl,--save-temps to it.
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My question is the origin of that option. E.g. is the user uses --save-temps=obj -o /some/other/dir/foo.o at the top-level clang invocation, what do we get if the offloading w/ the new driver and this patch are in effect?
Will the intermediate files end up in the current directory? In the object file directory? Both? E.g clang's files end up in the object file directory, but linker's intermediate files end up in the current dir? Or, perhaps not even created, if clangs--save-temps are not propagated to the linker-wrapper.
Summary: The linker wrapper's job is to extract embedded device code from fat binaries and create linked images that can then be embedded and executed. In order to support LTO, we originally reinvented all of the LTO handling that `ld.lld` normally does. Primarily, this was because `nvlink` didn't support this at all, and we have special hacks required for offloading languages interacting with archive libraries. Now since I wrote llvm#96561 we should be able to pass all the inputs to the device linker transparently. This has the advantage of allowing the `clang` Driver to do its own handling. Primarily, this will be used to implicitly pass libraries to the device link job to make it more consistent with other toolchains. The JIT support is a notable departure, however there is an option called `--lto-emit-llvm` that performs the exact function where we want the final link job to output LLVM-IR that we can then embed instead. This patch does not fully delete the LTO handling, primarily because I think the SPIR-V people might want it. To see only the relevant patches, ignore the first commit of the nvlink-wrapper. Depends on llvm#96561.
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/59/builds/2083 Here is the relevant piece of the build log for the reference: |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/73/builds/2459 Here is the relevant piece of the build log for the reference: |
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Summary: The linker wrapper's job is to extract embedded device code from fat binaries and create linked images that can then be embedded and executed. In order to support LTO, we originally reinvented all of the LTO handling that `ld.lld` normally does. Primarily, this was because `nvlink` didn't support this at all, and we have special hacks required for offloading languages interacting with archive libraries. Now since I wrote #96561 we should be able to pass all the inputs to the device linker transparently. This has the advantage of allowing the `clang` Driver to do its own handling. Primarily, this will be used to implicitly pass libraries to the device link job to make it more consistent with other toolchains. The JIT support is a notable departure, however there is an option called `--lto-emit-llvm` that performs the exact function where we want the final link job to output LLVM-IR that we can then embed instead. This patch does not fully delete the LTO handling, primarily because I think the SPIR-V people might want it. To see only the relevant patches, ignore the first commit of the nvlink-wrapper. Depends on #96561.
This was referenced Mar 21, 2025
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Summary:
The linker wrapper's job is to extract embedded device code from fat
binaries and create linked images that can then be embedded and
executed. In order to support LTO, we originally reinvented all of the
LTO handling that
ld.lldnormally does. Primarily, this was becausenvlinkdidn't support this at all, and we have special hacks requiredfor offloading languages interacting with archive libraries.
Now since I wrote #96561 we
should be able to pass all the inputs to the device linker
transparently. This has the advantage of allowing the
clangDriver todo its own handling. Primarily, this will be used to implicitly pass
libraries to the device link job to make it more consistent with other
toolchains.
The JIT support is a notable departure, however there is an option
called
--lto-emit-llvmthat performs the exact function where we wantthe final link job to output LLVM-IR that we can then embed instead.
This patch does not fully delete the LTO handling, primarily because I
think the SPIR-V people might want it. To see only the relevant patches,
ignore the first commit of the nvlink-wrapper.
Depends on #96561.