[libc] [llvm] [LLVM] Make the GPU loader utilities an LLVM tool (PR #132096)
Joseph Huber via llvm-commits
llvm-commits at lists.llvm.org
Wed Mar 19 13:49:20 PDT 2025
https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/132096
Summary:
These tools `amdhsa-loader` and `nvptx-loader` are used to execute unit
tests directly on the GPU. We use this for `libc` and `libcxx` unit
tests as well as general GPU experimentation. It looks like this.
```console
> clang++ main.cpp --target=amdgcn-amd-amdhsa -mcpu=native -flto -lc ./lib/amdgcn-amd-amdhsa/crt1.o
> llvm-gpu-loader a.out
Hello World!
```
Currently these are a part of the `libc` project, but this creates
issues as `libc` itself depends on them to run tests. Right now we get
around this by force-including the `libc` project prior to running the
runtimes build so that this dependency can be built first. We should
instead just make this a simple LLVM tool so it's always available.
This has the effect of installing these by default now instead of just
when `libc` was enabled, but they should be relatively small. Right now
this only supports a 'static' configuration. That is, we locate the CUDA
and HSA dependencies at LLVM compile time. In the future we should be
able to provide this by default using `dlopen` and some API.
I don't know if it's required to reformat all of these names since they
used the `libc` naming convention so I just left it for now.
>From 0a16c3256025927b80a56c418761962af5d85f7a Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Wed, 19 Mar 2025 15:42:47 -0500
Subject: [PATCH] [LLVM] Make the GPU loader utilities an LLVM tool
Summary:
These tools `amdhsa-loader` and `nvptx-loader` are used to execute unit
tests directly on the GPU. We use this for `libc` and `libcxx` unit
tests as well as general GPU experimentation. It looks like this.
```console
> clang++ main.cpp --target=amdgcn-amd-amdhsa -mcpu=native -flto -lc ./lib/amdgcn-amd-amdhsa/crt1.o
> llvm-gpu-loader a.out
Hello World!
```
Currently these are a part of the `libc` project, but this creates
issues as `libc` itself depends on them to run tests. Right now we get
around this by force-including the `libc` project prior to running the
runtimes build so that this dependency can be built first. We should
instead just make this a simple LLVM tool so it's always available.
This has the effect of installing these by default now instead of just
when `libc` was enabled, but they should be relatively small. Right now
this only supports a 'static' configuration. That is, we locate the CUDA
and HSA dependencies at LLVM compile time. In the future we should be
able to provide this by default using `dlopen` and some API.
I don't know if it's required to reformat all of these names since they
used the `libc` naming convention so I just left it for now.
---
libc/CMakeLists.txt | 7 ---
libc/utils/gpu/CMakeLists.txt | 1 -
libc/utils/gpu/loader/CMakeLists.txt | 54 -------------------
libc/utils/gpu/loader/amdgpu/CMakeLists.txt | 10 ----
libc/utils/gpu/loader/nvptx/CMakeLists.txt | 9 ----
llvm/CMakeLists.txt | 4 --
llvm/runtimes/CMakeLists.txt | 14 -----
llvm/tools/llvm-gpu-loader/CMakeLists.txt | 45 ++++++++++++++++
.../tools/llvm-gpu-loader/amdhsa.cpp | 8 +--
.../tools/llvm-gpu-loader/llvm-gpu-loader.cpp | 46 +++++++++++++---
.../tools/llvm-gpu-loader/llvm-gpu-loader.h | 13 +++--
.../tools/llvm-gpu-loader/nvptx.cpp | 8 +--
12 files changed, 102 insertions(+), 117 deletions(-)
delete mode 100644 libc/utils/gpu/CMakeLists.txt
delete mode 100644 libc/utils/gpu/loader/CMakeLists.txt
delete mode 100644 libc/utils/gpu/loader/amdgpu/CMakeLists.txt
delete mode 100644 libc/utils/gpu/loader/nvptx/CMakeLists.txt
create mode 100644 llvm/tools/llvm-gpu-loader/CMakeLists.txt
rename libc/utils/gpu/loader/amdgpu/amdhsa-loader.cpp => llvm/tools/llvm-gpu-loader/amdhsa.cpp (99%)
rename libc/utils/gpu/loader/Main.cpp => llvm/tools/llvm-gpu-loader/llvm-gpu-loader.cpp (76%)
rename libc/utils/gpu/loader/Loader.h => llvm/tools/llvm-gpu-loader/llvm-gpu-loader.h (93%)
rename libc/utils/gpu/loader/nvptx/nvptx-loader.cpp => llvm/tools/llvm-gpu-loader/nvptx.cpp (98%)
diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index ad39ff6fbcb1e..b264dcb4974c7 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -59,13 +59,6 @@ set(LIBC_NAMESPACE ${default_namespace}
CACHE STRING "The namespace to use to enclose internal implementations. Must start with '__llvm_libc'."
)
-# We will build the GPU utilities if we are not doing a runtimes build.
-option(LIBC_BUILD_GPU_LOADER "Always build the GPU loader utilities" OFF)
-if(LIBC_BUILD_GPU_LOADER OR ((NOT LLVM_RUNTIMES_BUILD) AND LLVM_LIBC_GPU_BUILD))
- add_subdirectory(utils/gpu)
- return()
-endif()
-
option(LIBC_CMAKE_VERBOSE_LOGGING
"Log details warnings and notifications during CMake configuration." OFF)
diff --git a/libc/utils/gpu/CMakeLists.txt b/libc/utils/gpu/CMakeLists.txt
deleted file mode 100644
index e529646a1206e..0000000000000
--- a/libc/utils/gpu/CMakeLists.txt
+++ /dev/null
@@ -1 +0,0 @@
-add_subdirectory(loader)
diff --git a/libc/utils/gpu/loader/CMakeLists.txt b/libc/utils/gpu/loader/CMakeLists.txt
deleted file mode 100644
index 9b3bd009dc0f1..0000000000000
--- a/libc/utils/gpu/loader/CMakeLists.txt
+++ /dev/null
@@ -1,54 +0,0 @@
-add_library(gpu_loader OBJECT Main.cpp)
-
-include(FindLibcCommonUtils)
-target_link_libraries(gpu_loader PUBLIC llvm-libc-common-utilities)
-
-target_include_directories(gpu_loader PUBLIC
- ${CMAKE_CURRENT_SOURCE_DIR}
- ${LIBC_SOURCE_DIR}/include
- ${LIBC_SOURCE_DIR}
- ${LLVM_MAIN_INCLUDE_DIR}
- ${LLVM_BINARY_DIR}/include
-)
-if(NOT LLVM_ENABLE_RTTI)
- target_compile_options(gpu_loader PUBLIC -fno-rtti)
-endif()
-
-find_package(hsa-runtime64 QUIET 1.2.0 HINTS ${CMAKE_INSTALL_PREFIX} PATHS /opt/rocm)
-if(hsa-runtime64_FOUND)
- add_subdirectory(amdgpu)
-endif()
-
-# The CUDA loader requires LLVM to traverse the ELF image for symbols.
-find_package(CUDAToolkit 11.2 QUIET)
-if(CUDAToolkit_FOUND)
- add_subdirectory(nvptx)
-endif()
-
-if(TARGET amdhsa-loader AND LIBC_TARGET_ARCHITECTURE_IS_AMDGPU)
- add_custom_target(libc.utils.gpu.loader)
- add_dependencies(libc.utils.gpu.loader amdhsa-loader)
- set_target_properties(
- libc.utils.gpu.loader
- PROPERTIES
- TARGET amdhsa-loader
- EXECUTABLE "$<TARGET_FILE:amdhsa-loader>"
- )
-elseif(TARGET nvptx-loader AND LIBC_TARGET_ARCHITECTURE_IS_NVPTX)
- add_custom_target(libc.utils.gpu.loader)
- add_dependencies(libc.utils.gpu.loader nvptx-loader)
- set_target_properties(
- libc.utils.gpu.loader
- PROPERTIES
- TARGET nvptx-loader
- EXECUTABLE "$<TARGET_FILE:nvptx-loader>"
- )
-endif()
-
-foreach(gpu_loader_tgt amdhsa-loader nvptx-loader)
- if(TARGET ${gpu_loader_tgt})
- install(TARGETS ${gpu_loader_tgt}
- DESTINATION ${CMAKE_INSTALL_BINDIR}
- COMPONENT libc)
- endif()
-endforeach()
diff --git a/libc/utils/gpu/loader/amdgpu/CMakeLists.txt b/libc/utils/gpu/loader/amdgpu/CMakeLists.txt
deleted file mode 100644
index 17878daf0b6fe..0000000000000
--- a/libc/utils/gpu/loader/amdgpu/CMakeLists.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-set(LLVM_LINK_COMPONENTS
- BinaryFormat
- Object
- Option
- Support
- FrontendOffloading
- )
-
-add_llvm_executable(amdhsa-loader amdhsa-loader.cpp)
-target_link_libraries(amdhsa-loader PRIVATE hsa-runtime64::hsa-runtime64 gpu_loader)
diff --git a/libc/utils/gpu/loader/nvptx/CMakeLists.txt b/libc/utils/gpu/loader/nvptx/CMakeLists.txt
deleted file mode 100644
index 42510ac31dad4..0000000000000
--- a/libc/utils/gpu/loader/nvptx/CMakeLists.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-set(LLVM_LINK_COMPONENTS
- BinaryFormat
- Object
- Option
- Support
- )
-
-add_llvm_executable(nvptx-loader nvptx-loader.cpp)
-target_link_libraries(nvptx-loader PRIVATE gpu_loader CUDA::cuda_driver)
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index 18b6ee85fae8d..f9ace9f078e2b 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -210,10 +210,6 @@ if("${LIBC_TARGET_TRIPLE}" STREQUAL "amdgcn-amd-amdhsa" OR
"${LIBC_TARGET_TRIPLE}" STREQUAL "nvptx64-nvidia-cuda")
set(LLVM_LIBC_GPU_BUILD ON)
endif()
-if (NOT "libc" IN_LIST LLVM_ENABLE_PROJECTS AND LLVM_LIBC_GPU_BUILD)
- message(STATUS "Enabling libc project to build libc testing tools")
- list(APPEND LLVM_ENABLE_PROJECTS "libc")
-endif()
# LLVM_ENABLE_PROJECTS_USED is `ON` if the user has ever used the
# `LLVM_ENABLE_PROJECTS` CMake cache variable. This exists for
diff --git a/llvm/runtimes/CMakeLists.txt b/llvm/runtimes/CMakeLists.txt
index 136099dc48ab8..51433d1ec9831 100644
--- a/llvm/runtimes/CMakeLists.txt
+++ b/llvm/runtimes/CMakeLists.txt
@@ -534,20 +534,6 @@ if(build_runtimes)
endif()
if(LLVM_LIBC_GPU_BUILD)
list(APPEND extra_cmake_args "-DLLVM_LIBC_GPU_BUILD=ON")
- if("libc" IN_LIST RUNTIMES_amdgcn-amd-amdhsa_LLVM_ENABLE_RUNTIMES)
- if(TARGET amdhsa-loader)
- list(APPEND extra_cmake_args
- "-DRUNTIMES_amdgcn-amd-amdhsa_LIBC_GPU_LOADER_EXECUTABLE=$<TARGET_FILE:amdhsa-loader>")
- list(APPEND extra_deps amdhsa-loader)
- endif()
- endif()
- if("libc" IN_LIST RUNTIMES_nvptx64-nvidia-cuda_LLVM_ENABLE_RUNTIMES)
- if(TARGET nvptx-loader)
- list(APPEND extra_cmake_args
- "-DRUNTIMES_nvptx64-nvidia-cuda_LIBC_GPU_LOADER_EXECUTABLE=$<TARGET_FILE:nvptx-loader>")
- list(APPEND extra_deps nvptx-loader)
- endif()
- endif()
if(TARGET clang-offload-packager)
list(APPEND extra_deps clang-offload-packager)
endif()
diff --git a/llvm/tools/llvm-gpu-loader/CMakeLists.txt b/llvm/tools/llvm-gpu-loader/CMakeLists.txt
new file mode 100644
index 0000000000000..4b4a6e72e47ae
--- /dev/null
+++ b/llvm/tools/llvm-gpu-loader/CMakeLists.txt
@@ -0,0 +1,45 @@
+set(LLVM_LINK_COMPONENTS
+ BinaryFormat
+ Object
+ Option
+ Support
+ FrontendOffloading
+)
+
+add_llvm_tool(llvm-gpu-loader
+ llvm-gpu-loader.cpp
+
+ # TODO: We intentionally split this currently due to statically linking the
+ # GPU runtimes. Dynamically load the dependencies, possibly using the
+ # LLVM offloading API when it is complete.
+ PARTIAL_SOURCES_INTENDED
+
+ DEPENDS
+ intrinsics_gen
+)
+
+# Locate the RPC server handling interface.
+include(FindLibcCommonUtils)
+target_link_libraries(llvm-gpu-loader PUBLIC llvm-libc-common-utilities)
+
+# Check for HSA support for targeting AMD GPUs.
+find_package(hsa-runtime64 QUIET 1.2.0 HINTS ${CMAKE_INSTALL_PREFIX} PATHS /opt/rocm)
+if(hsa-runtime64_FOUND)
+ target_sources(llvm-gpu-loader PRIVATE amdhsa.cpp)
+ target_compile_definitions(llvm-gpu-loader PRIVATE AMDHSA_SUPPORT)
+ target_link_libraries(llvm-gpu-loader PRIVATE hsa-runtime64::hsa-runtime64)
+
+ # Compatibility with the old amdhsa-loader name.
+ add_llvm_tool_symlink(amdhsa-loader llvm-gpu-loader)
+endif()
+
+# Check for CUDA support for targeting NVIDIA GPUs.
+find_package(CUDAToolkit 11.2 QUIET)
+if(CUDAToolkit_FOUND)
+ target_sources(llvm-gpu-loader PRIVATE nvptx.cpp)
+ target_compile_definitions(llvm-gpu-loader PRIVATE NVPTX_SUPPORT)
+ target_link_libraries(llvm-gpu-loader PRIVATE CUDA::cuda_driver)
+
+ # Compatibility with the old nvptx-loader name.
+ add_llvm_tool_symlink(nvptx-loader llvm-gpu-loader)
+endif()
diff --git a/libc/utils/gpu/loader/amdgpu/amdhsa-loader.cpp b/llvm/tools/llvm-gpu-loader/amdhsa.cpp
similarity index 99%
rename from libc/utils/gpu/loader/amdgpu/amdhsa-loader.cpp
rename to llvm/tools/llvm-gpu-loader/amdhsa.cpp
index 00fde147b0abd..f3c8f646b6421 100644
--- a/libc/utils/gpu/loader/amdgpu/amdhsa-loader.cpp
+++ b/llvm/tools/llvm-gpu-loader/amdhsa.cpp
@@ -13,7 +13,7 @@
//
//===----------------------------------------------------------------------===//
-#include "Loader.h"
+#include "llvm-gpu-loader.h"
#include "hsa/hsa.h"
#include "hsa/hsa_ext_amd.h"
@@ -330,9 +330,9 @@ static hsa_status_t hsa_memcpy(void *dst, hsa_agent_t dst_agent,
return HSA_STATUS_SUCCESS;
}
-int load(int argc, const char **argv, const char **envp, void *image,
- size_t size, const LaunchParameters ¶ms,
- bool print_resource_usage) {
+int load_amdhsa(int argc, const char **argv, const char **envp, void *image,
+ size_t size, const LaunchParameters ¶ms,
+ bool print_resource_usage) {
// Initialize the HSA runtime used to communicate with the device.
if (hsa_status_t err = hsa_init())
handle_error(err);
diff --git a/libc/utils/gpu/loader/Main.cpp b/llvm/tools/llvm-gpu-loader/llvm-gpu-loader.cpp
similarity index 76%
rename from libc/utils/gpu/loader/Main.cpp
rename to llvm/tools/llvm-gpu-loader/llvm-gpu-loader.cpp
index c3aeeffd56368..9b157e3f9dcb1 100644
--- a/libc/utils/gpu/loader/Main.cpp
+++ b/llvm/tools/llvm-gpu-loader/llvm-gpu-loader.cpp
@@ -6,14 +6,17 @@
//
//===----------------------------------------------------------------------===//
//
-// This file opens a device image passed on the command line and passes it to
-// one of the loader implementations for launch.
+// This utility is used to launch standard programs onto the GPU in conjunction
+// with the LLVM 'libc' project. It is designed to mimic a standard emulator
+// workflow, allowing for unit tests to be run on the GPU directly.
//
//===----------------------------------------------------------------------===//
-#include "Loader.h"
+#include "llvm-gpu-loader.h"
#include "llvm/BinaryFormat/Magic.h"
+#include "llvm/Object/ELF.h"
+#include "llvm/Object/ELFObjectFile.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FileSystem.h"
@@ -21,6 +24,7 @@
#include "llvm/Support/Path.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/WithColor.h"
+#include "llvm/TargetParser/Triple.h"
#include <cerrno>
#include <cstdio>
@@ -125,12 +129,40 @@ int main(int argc, const char **argv, const char **envp) {
strerror(errno)));
}
- // Drop the loader from the program arguments.
LaunchParameters params{threads_x, threads_y, threads_z,
blocks_x, blocks_y, blocks_z};
- int ret = load(new_argv.size(), new_argv.data(), envp,
- const_cast<char *>(image.getBufferStart()),
- image.getBufferSize(), params, print_resource_usage);
+
+ Expected<llvm::object::ELF64LEObjectFile> elf_or_err =
+ llvm::object::ELF64LEObjectFile::create(image);
+ if (!elf_or_err)
+ report_error(std::move(elf_or_err.takeError()));
+
+ int ret = 1;
+ if (elf_or_err->getArch() == Triple::amdgcn) {
+#ifdef AMDHSA_SUPPORT
+ ret = load_amdhsa(new_argv.size(), new_argv.data(), envp,
+ const_cast<char *>(image.getBufferStart()),
+ image.getBufferSize(), params, print_resource_usage);
+#else
+ report_error(createStringError(
+ "Unsupported architecture; %s",
+ Triple::getArchTypeName(elf_or_err->getArch()).bytes_begin()));
+#endif
+ } else if (elf_or_err->getArch() == Triple::nvptx64) {
+#ifdef NVPTX_SUPPORT
+ ret = load_nvptx(new_argv.size(), new_argv.data(), envp,
+ const_cast<char *>(image.getBufferStart()),
+ image.getBufferSize(), params, print_resource_usage);
+#else
+ report_error(createStringError(
+ "Unsupported architecture; %s",
+ Triple::getArchTypeName(elf_or_err->getArch()).bytes_begin()));
+#endif
+ } else {
+ report_error(createStringError(
+ "Unsupported architecture; %s",
+ Triple::getArchTypeName(elf_or_err->getArch()).bytes_begin()));
+ }
if (no_parallelism) {
if (flock(fd, LOCK_UN) == -1)
diff --git a/libc/utils/gpu/loader/Loader.h b/llvm/tools/llvm-gpu-loader/llvm-gpu-loader.h
similarity index 93%
rename from libc/utils/gpu/loader/Loader.h
rename to llvm/tools/llvm-gpu-loader/llvm-gpu-loader.h
index ec05117a041ab..29da395e3bc20 100644
--- a/libc/utils/gpu/loader/Loader.h
+++ b/llvm/tools/llvm-gpu-loader/llvm-gpu-loader.h
@@ -54,9 +54,16 @@ struct end_args_t {
/// Generic interface to load the \p image and launch execution of the _start
/// kernel on the target device. Copies \p argc and \p argv to the device.
/// Returns the final value of the `main` function on the device.
-int load(int argc, const char **argv, const char **evnp, void *image,
- size_t size, const LaunchParameters ¶ms,
- bool print_resource_usage);
+#ifdef AMDHSA_SUPPORT
+int load_amdhsa(int argc, const char **argv, const char **evnp, void *image,
+ size_t size, const LaunchParameters ¶ms,
+ bool print_resource_usage);
+#endif
+#ifdef NVPTX_SUPPORT
+int load_nvptx(int argc, const char **argv, const char **evnp, void *image,
+ size_t size, const LaunchParameters ¶ms,
+ bool print_resource_usage);
+#endif
/// Return \p V aligned "upwards" according to \p Align.
template <typename V, typename A> inline V align_up(V val, A align) {
diff --git a/libc/utils/gpu/loader/nvptx/nvptx-loader.cpp b/llvm/tools/llvm-gpu-loader/nvptx.cpp
similarity index 98%
rename from libc/utils/gpu/loader/nvptx/nvptx-loader.cpp
rename to llvm/tools/llvm-gpu-loader/nvptx.cpp
index 7d6c176c6f360..f7495605ecc68 100644
--- a/libc/utils/gpu/loader/nvptx/nvptx-loader.cpp
+++ b/llvm/tools/llvm-gpu-loader/nvptx.cpp
@@ -13,7 +13,7 @@
//
//===----------------------------------------------------------------------===//
-#include "Loader.h"
+#include "llvm-gpu-loader.h"
#include "cuda.h"
@@ -236,9 +236,9 @@ CUresult launch_kernel(CUmodule binary, CUstream stream, rpc::Server &server,
return CUDA_SUCCESS;
}
-int load(int argc, const char **argv, const char **envp, void *image,
- size_t size, const LaunchParameters ¶ms,
- bool print_resource_usage) {
+int load_nvptx(int argc, const char **argv, const char **envp, void *image,
+ size_t size, const LaunchParameters ¶ms,
+ bool print_resource_usage) {
if (CUresult err = cuInit(0))
handle_error(err);
// Obtain the first device found on the system.
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