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[OpenMP] Use new offloading binary when embedding offloading images 

The previous patch introduced the offloading binary format so we can
store some metada along with the binary image. This patch introduces
using this inside the linker wrapper and Clang instead of the previous
method that embedded the metadata in the section name.

Differential Revision: https://reviews.llvm.org/D122683
This commit is contained in:
Joseph Huber 2022-03-25 11:03:02 -04:00
parent cac81161ed
commit 984a0dc386
10 changed files with 122 additions and 104 deletions
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9
clang/include/clang/Basic/CodeGenOptions.h
View File

@ -276,9 +276,12 @@ public:
/// CUDA runtime back-end for incorporating them into host-side object file.
std::string CudaGpuBinaryFileName;
/// List of filenames and section name pairs passed in using the
/// -fembed-offload-object option to embed device-side offloading objects into
/// the host as a named section. Input passed in as '<filename>,<section>'
/// List of filenames and metadata passed in using the -fembed-offload-object
/// option to embed device-side offloading objects into the host as a named
/// section. Input passed in as 'filename,kind,triple,arch'.
///
/// NOTE: This will need to be expanded whenever we want to pass in more
/// metadata, at some point this should be its own clang tool.
std::vector<std::string> OffloadObjects;
/// The name of the file to which the backend should save YAML optimization

40
clang/lib/CodeGen/BackendUtil.cpp
View File

@ -39,6 +39,7 @@
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Object/OffloadBinary.h"
#include "llvm/Passes/PassBuilder.h"
#include "llvm/Passes/PassPlugin.h"
#include "llvm/Passes/StandardInstrumentations.h"
@ -1206,22 +1207,33 @@ void clang::EmbedObject(llvm::Module *M, const CodeGenOptions &CGOpts,
return;
for (StringRef OffloadObject : CGOpts.OffloadObjects) {
if (OffloadObject.count(',') != 1)
Diags.Report(Diags.getCustomDiagID(
DiagnosticsEngine::Error, "Invalid string pair for embedding '%0'"))
<< OffloadObject;
auto FilenameAndSection = OffloadObject.split(',');
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> ObjectOrErr =
llvm::MemoryBuffer::getFileOrSTDIN(FilenameAndSection.first);
if (std::error_code EC = ObjectOrErr.getError()) {
auto DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
"could not open '%0' for embedding");
Diags.Report(DiagID) << FilenameAndSection.first;
SmallVector<StringRef, 4> ObjectFields;
OffloadObject.split(ObjectFields, ',');
if (ObjectFields.size() != 4) {
auto DiagID = Diags.getCustomDiagID(
DiagnosticsEngine::Error, "Expected at least four arguments '%0'");
Diags.Report(DiagID) << OffloadObject;
return;
}
SmallString<128> SectionName(
{".llvm.offloading.", FilenameAndSection.second});
llvm::embedBufferInModule(*M, **ObjectOrErr, SectionName);
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> ObjectOrErr =
llvm::MemoryBuffer::getFileOrSTDIN(ObjectFields[0]);
if (std::error_code EC = ObjectOrErr.getError()) {
auto DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
"could not open '%0' for embedding");
Diags.Report(DiagID) << ObjectFields[0];
return;
}
OffloadBinary::OffloadingImage Image{};
Image.TheImageKind = getImageKind(ObjectFields[0].rsplit(".").second);
Image.TheOffloadKind = getOffloadKind(ObjectFields[1]);
Image.StringData = {{"triple", ObjectFields[2]}, {"arch", ObjectFields[3]}};
Image.Image = **ObjectOrErr;
std::unique_ptr<MemoryBuffer> OffloadBuffer = OffloadBinary::write(Image);
llvm::embedBufferInModule(*M, *OffloadBuffer, ".llvm.offloading",
Align(OffloadBinary::getAlignment()));
}
}

11
clang/lib/Driver/ToolChains/Clang.cpp
View File

@ -6940,13 +6940,12 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
const ArgList &TCArgs = C.getArgsForToolChain(TC, "", Action::OFK_OpenMP);
StringRef File =
C.getArgs().MakeArgString(TC->getInputFilename(*InputFile));
StringRef InputName = Clang::getBaseInputStem(Args, Inputs);
CmdArgs.push_back(Args.MakeArgString(
"-fembed-offload-object=" + File + "," +
Action::GetOffloadKindName(Action::OFK_OpenMP) + "." +
TC->getTripleString() + "." +
TCArgs.getLastArgValue(options::OPT_march_EQ) + "." + InputName));
CmdArgs.push_back(
Args.MakeArgString("-fembed-offload-object=" + File + "," +
Action::GetOffloadKindName(Action::OFK_OpenMP) +
"," + TC->getTripleString() + "," +
TCArgs.getLastArgValue(options::OPT_march_EQ)));
}
}

2
clang/test/Driver/openmp-offload-gpu.c
View File

@ -344,4 +344,4 @@
// RUN: -fopenmp-new-driver -no-canonical-prefixes -nogpulib %s -o openmp-offload-gpu 2>&1 \
// RUN: | FileCheck -check-prefix=NEW_DRIVER_EMBEDDING %s
// NEW_DRIVER_EMBEDDING: -fembed-offload-object=[[CUBIN:.*\.cubin]],openmp.nvptx64-nvidia-cuda.sm_70
// NEW_DRIVER_EMBEDDING: -fembed-offload-object=[[CUBIN:.*\.cubin]],openmp,nvptx64-nvidia-cuda,sm_70

7
clang/test/Frontend/embed-object.c
View File

@ -1,6 +1,7 @@
// RUN: %clang_cc1 -x c -triple x86_64-unknown-linux-gnu -emit-llvm -fembed-offload-object=%S/Inputs/empty.h,section
// RUN: %clang_cc1 -x c -triple x86_64-unknown-linux-gnu -emit-llvm -fembed-offload-object=%S/Inputs/empty.h,,, -o - %s | FileCheck %s
// CHECK: @[[OBJECT:.+]] = private constant [120 x i8] c"\10\FF\10\AD{{.*}}", section ".llvm.offloading", align 8
// CHECK: @llvm.compiler.used = appending global [1 x ptr] [ptr @[[OBJECT]]], section "llvm.metadata"
// CHECK: @[[OBJECT:.+]] = private constant [0 x i8] zeroinitializer, section ".llvm.offloading.section"
// CHECK: @llvm.compiler.used = appending global [3 x i8*] [i8* getelementptr inbounds ([0 x i8], [0 x i8]* @[[OBJECT1]]], section "llvm.metadata"
void foo(void) {}

12
clang/test/Frontend/embed-object.ll
View File

@ -1,14 +1,14 @@
; RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm \
; RUN: -fembed-offload-object=%S/Inputs/empty.h,section1 \
; RUN: -fembed-offload-object=%S/Inputs/empty.h,section2 -x ir %s -o - \
; RUN: -fembed-offload-object=%S/Inputs/empty.h,,, \
; RUN: -fembed-offload-object=%S/Inputs/empty.h,,, -x ir %s -o - \
; RUN: | FileCheck %s -check-prefix=CHECK
; CHECK: @[[OBJECT1:.+]] = hidden constant [0 x i8] zeroinitializer, section ".llvm.offloading.section1"
; CHECK: @[[OBJECT2:.+]] = hidden constant [0 x i8] zeroinitializer, section ".llvm.offloading.section2"
; CHECK: @llvm.compiler.used = appending global [3 x i8*] [i8* @x, i8* getelementptr inbounds ([0 x i8], [0 x i8]* @[[OBJECT1]], i32 0, i32 0), i8* getelementptr inbounds ([0 x i8], [0 x i8]* @[[OBJECT2]], i32 0, i32 0)], section "llvm.metadata"
; CHECK: @[[OBJECT_1:.+]] = private constant [120 x i8] c"\10\FF\10\AD{{.*}}\00", section ".llvm.offloading", align 8
; CHECK: @[[OBJECT_2:.+]] = private constant [120 x i8] c"\10\FF\10\AD{{.*}}\00", section ".llvm.offloading", align 8
; CHECK: @llvm.compiler.used = appending global [3 x ptr] [ptr @x, ptr @[[OBJECT_1]], ptr @[[OBJECT_2]]], section "llvm.metadata"
@x = private constant i8 1
@llvm.compiler.used = appending global [1 x i8*] [i8* @x], section "llvm.metadata"
@llvm.compiler.used = appending global [1 x ptr] [ptr @x], section "llvm.metadata"
define i32 @foo() {
ret i32 0

126
clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
View File

@ -29,6 +29,7 @@
#include "llvm/Object/ArchiveWriter.h"
#include "llvm/Object/Binary.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Object/OffloadBinary.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/FileOutputBuffer.h"
@ -146,8 +147,8 @@ static SmallVector<std::string, 16> TempFiles;
static codegen::RegisterCodeGenFlags CodeGenFlags;
/// Magic section string that marks the existence of offloading data. The
/// section string will be formatted as `.llvm.offloading.<triple>.<arch>`.
#define OFFLOAD_SECTION_MAGIC_STR ".llvm.offloading."
/// section will contain one or more offloading binaries stored contiguously.
#define OFFLOAD_SECTION_MAGIC_STR ".llvm.offloading"
/// Information for a device offloading file extracted from the host.
struct DeviceFile {
@ -201,16 +202,6 @@ void printCommands(ArrayRef<StringRef> CmdArgs) {
llvm::errs() << *IC << (std::next(IC) != IE ? " " : "\n");
}
static StringRef getDeviceFileExtension(StringRef DeviceTriple,
bool IsBitcode = false) {
Triple TheTriple(DeviceTriple);
if (TheTriple.isAMDGPU() || IsBitcode)
return "bc";
if (TheTriple.isNVPTX())
return "cubin";
return "o";
}
std::string getMainExecutable(const char *Name) {
void *Ptr = (void *)(intptr_t)&getMainExecutable;
auto COWPath = sys::fs::getMainExecutable(Name, Ptr);
@ -289,6 +280,55 @@ void removeFromCompilerUsed(Module &M, GlobalValue &Value) {
GV->setSection("llvm.metadata");
}
/// Attempts to extract all the embedded device images contained inside the
/// buffer \p Contents. The buffer is expected to contain a valid offloading
/// binary format.
Error extractOffloadFiles(StringRef Contents, StringRef Prefix,
SmallVectorImpl<DeviceFile> &DeviceFiles) {
uint64_t Offset = 0;
// There could be multiple offloading binaries stored at this section.
while (Offset < Contents.size()) {
std::unique_ptr<MemoryBuffer> Buffer =
MemoryBuffer::getMemBuffer(Contents.drop_front(Offset), "",
/*RequiresNullTerminator*/ false);
auto BinaryOrErr = OffloadBinary::create(*Buffer);
if (!BinaryOrErr)
return BinaryOrErr.takeError();
OffloadBinary &Binary = **BinaryOrErr;
if (Binary.getVersion() != 1)
return createStringError(inconvertibleErrorCode(),
"Incompatible device image version");
StringRef Kind = getOffloadKindName(Binary.getOffloadKind());
StringRef Suffix = getImageKindName(Binary.getImageKind());
SmallString<128> TempFile;
if (Error Err =
createOutputFile(Prefix + "-" + Kind + "-" + Binary.getTriple() +
"-" + Binary.getArch(),
Suffix, TempFile))
return std::move(Err);
Expected<std::unique_ptr<FileOutputBuffer>> OutputOrErr =
FileOutputBuffer::create(TempFile, Binary.getImage().size());
if (!OutputOrErr)
return OutputOrErr.takeError();
std::unique_ptr<FileOutputBuffer> Output = std::move(*OutputOrErr);
std::copy(Binary.getImage().bytes_begin(), Binary.getImage().bytes_end(),
Output->getBufferStart());
if (Error E = Output->commit())
return std::move(E);
DeviceFiles.emplace_back(Kind, Binary.getTriple(), Binary.getArch(),
TempFile);
Offset += Binary.getSize();
}
return Error::success();
}
Expected<Optional<std::string>>
extractFromBinary(const ObjectFile &Obj,
SmallVectorImpl<DeviceFile> &DeviceFiles) {
@ -296,40 +336,21 @@ extractFromBinary(const ObjectFile &Obj,
StringRef Prefix = sys::path::stem(Obj.getFileName());
SmallVector<StringRef, 4> ToBeStripped;
// Extract data from sections of the form `.llvm.offloading.<triple>.<arch>`.
// Extract offloading binaries from sections with the name `.llvm.offloading`.
for (const SectionRef &Sec : Obj.sections()) {
Expected<StringRef> Name = Sec.getName();
if (!Name || !Name->startswith(OFFLOAD_SECTION_MAGIC_STR))
if (!Name || !Name->equals(OFFLOAD_SECTION_MAGIC_STR))
continue;
SmallVector<StringRef, 4> SectionFields;
Name->split(SectionFields, '.');
StringRef Kind = SectionFields[3];
StringRef DeviceTriple = SectionFields[4];
StringRef Arch = SectionFields[5];
Expected<StringRef> Contents = Sec.getContents();
if (!Contents)
return Contents.takeError();
if (Expected<StringRef> Contents = Sec.getContents()) {
SmallString<128> TempFile;
StringRef DeviceExtension = getDeviceFileExtension(
DeviceTriple, identify_magic(*Contents) == file_magic::bitcode);
if (Error Err = createOutputFile(Prefix + "-" + Kind + "-" +
DeviceTriple + "-" + Arch,
DeviceExtension, TempFile))
if (Error Err = extractOffloadFiles(*Contents, Prefix, DeviceFiles))
return std::move(Err);
Expected<std::unique_ptr<FileOutputBuffer>> OutputOrErr =
FileOutputBuffer::create(TempFile, Sec.getSize());
if (!OutputOrErr)
return OutputOrErr.takeError();
std::unique_ptr<FileOutputBuffer> Output = std::move(*OutputOrErr);
std::copy(Contents->begin(), Contents->end(), Output->getBufferStart());
if (Error E = Output->commit())
return std::move(E);
DeviceFiles.emplace_back(Kind, DeviceTriple, Arch, TempFile);
ToBeStripped.push_back(*Name);
}
}
if (ToBeStripped.empty() || !StripSections)
return None;
@ -405,42 +426,21 @@ extractFromBitcode(std::unique_ptr<MemoryBuffer> Buffer,
SmallVector<GlobalVariable *, 4> ToBeDeleted;
// Extract data from the global string containing a section of the form
// `.llvm.offloading.<triple>.<arch>`.
// Extract offloading data from globals with the `.llvm.offloading` section
// name.
for (GlobalVariable &GV : M->globals()) {
if (!GV.hasSection() ||
!GV.getSection().startswith(OFFLOAD_SECTION_MAGIC_STR))
if (!GV.hasSection() || !GV.getSection().equals(OFFLOAD_SECTION_MAGIC_STR))
continue;
auto *CDS = dyn_cast<ConstantDataSequential>(GV.getInitializer());
if (!CDS)
continue;
SmallVector<StringRef, 4> SectionFields;
GV.getSection().split(SectionFields, '.');
StringRef Kind = SectionFields[3];
StringRef DeviceTriple = SectionFields[4];
StringRef Arch = SectionFields[5];
StringRef Contents = CDS->getAsString();
SmallString<128> TempFile;
StringRef DeviceExtension = getDeviceFileExtension(
DeviceTriple, identify_magic(Contents) == file_magic::bitcode);
if (Error Err = createOutputFile(Prefix + "-" + Kind + "-" + DeviceTriple +
"-" + Arch,
DeviceExtension, TempFile))
if (Error Err = extractOffloadFiles(Contents, Prefix, DeviceFiles))
return std::move(Err);
Expected<std::unique_ptr<FileOutputBuffer>> OutputOrErr =
FileOutputBuffer::create(TempFile, Contents.size());
if (!OutputOrErr)
return OutputOrErr.takeError();
std::unique_ptr<FileOutputBuffer> Output = std::move(*OutputOrErr);
std::copy(Contents.begin(), Contents.end(), Output->getBufferStart());
if (Error E = Output->commit())
return std::move(E);
DeviceFiles.emplace_back(Kind, DeviceTriple, Arch, TempFile);
ToBeDeleted.push_back(&GV);
}

1
llvm/include/llvm/Object/OffloadBinary.h
View File

@ -73,6 +73,7 @@ public:
ImageKind getImageKind() const { return TheEntry->TheImageKind; }
OffloadKind getOffloadKind() const { return TheEntry->TheOffloadKind; }
uint32_t getVersion() const { return TheHeader->Version; }
uint32_t getFlags() const { return TheEntry->Flags; }
uint64_t getSize() const { return TheHeader->Size; }

4
llvm/include/llvm/Transforms/Utils/ModuleUtils.h
View File

@ -14,6 +14,7 @@
#define LLVM_TRANSFORMS_UTILS_MODULEUTILS_H
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Alignment.h"
#include "llvm/Support/MemoryBufferRef.h"
#include <utility> // for std::pair
@ -109,7 +110,8 @@ std::string getUniqueModuleId(Module *M);
/// Embed the memory buffer \p Buf into the module \p M as a global using the
/// specified section name.
void embedBufferInModule(Module &M, MemoryBufferRef Buf, StringRef SectionName);
void embedBufferInModule(Module &M, MemoryBufferRef Buf, StringRef SectionName,
Align Alignment = Align(1));
class CallInst;
namespace VFABI {

10
llvm/lib/Transforms/Utils/ModuleUtils.cpp
View File

@ -265,15 +265,15 @@ void VFABI::setVectorVariantNames(CallInst *CI,
}
void llvm::embedBufferInModule(Module &M, MemoryBufferRef Buf,
StringRef SectionName) {
// Embed the buffer into the module.
StringRef SectionName, Align Alignment) {
// Embed the memory buffer into the module.
Constant *ModuleConstant = ConstantDataArray::get(
M.getContext(), makeArrayRef(Buf.getBufferStart(), Buf.getBufferSize()));
GlobalVariable *GV = new GlobalVariable(
M, ModuleConstant->getType(), true, GlobalValue::ExternalLinkage,
ModuleConstant, SectionName.drop_front());
M, ModuleConstant->getType(), true, GlobalValue::PrivateLinkage,
ModuleConstant, "llvm.embedded.object");
GV->setSection(SectionName);
GV->setVisibility(GlobalValue::HiddenVisibility);
GV->setAlignment(Alignment);
appendToCompilerUsed(M, GV);
}