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[OpenMP] Change __tgt_device_image to point to the image #77003

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Merged
merged 1 commit into from
Jan 5, 2024
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[OpenMP] Change __tgt_device_image to point to the image #77003

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4 changes: 2 additions & 2 deletions clang/test/Driver/linker-wrapper-image.c
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Original file line number Diff line number Diff line change
Expand Up @@ -19,8 +19,8 @@
// OPENMP-COFF: @__start_omp_offloading_entries = hidden constant [0 x %struct.__tgt_offload_entry] zeroinitializer, section "omp_offloading_entries$OA"
// OPENMP-COFF-NEXT: @__stop_omp_offloading_entries = hidden constant [0 x %struct.__tgt_offload_entry] zeroinitializer, section "omp_offloading_entries$OZ"

// OPENMP: @.omp_offloading.device_image = internal unnamed_addr constant [[[SIZE:[0-9]+]] x i8] c"\10\FF\10\AD{{.*}}"
// OPENMP-NEXT: @.omp_offloading.device_images = internal unnamed_addr constant [1 x %__tgt_device_image] [%__tgt_device_image { ptr @.omp_offloading.device_image, ptr getelementptr inbounds ([[[SIZE]] x i8], ptr @.omp_offloading.device_image, i64 1, i64 0), ptr @__start_omp_offloading_entries, ptr @__stop_omp_offloading_entries }]
// OPENMP-NEXT: @.omp_offloading.device_image = internal unnamed_addr constant [[[SIZE:[0-9]+]] x i8] c"\10\FF\10\AD\01{{.*}}", section ".llvm.offloading", align 8
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This test now fails on big-endian architectures (where the \01) will not be at the start.

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Whoops, that was an accident to not cut it off after the magic bytes. I'll fix it, thanks for bringing this to my attention.

// OPENMP-NEXT: @.omp_offloading.device_images = internal unnamed_addr constant [1 x %__tgt_device_image] [%__tgt_device_image { ptr getelementptr inbounds ([[[BEGIN:[0-9]+]] x i8], ptr @.omp_offloading.device_image, i64 1, i64 0), ptr getelementptr inbounds ([[[END:[0-9]+]] x i8], ptr @.omp_offloading.device_image, i64 1, i64 0), ptr @__start_omp_offloading_entries, ptr @__stop_omp_offloading_entries }]
// OPENMP-NEXT: @.omp_offloading.descriptor = internal constant %__tgt_bin_desc { i32 1, ptr @.omp_offloading.device_images, ptr @__start_omp_offloading_entries, ptr @__stop_omp_offloading_entries }
// OPENMP-NEXT: @llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 1, ptr @.omp_offloading.descriptor_reg, ptr null }]
// OPENMP-NEXT: @llvm.global_dtors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 1, ptr @.omp_offloading.descriptor_unreg, ptr null }]
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24 changes: 21 additions & 3 deletions clang/tools/clang-linker-wrapper/OffloadWrapper.cpp
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Expand Up @@ -8,6 +8,7 @@

#include "OffloadWrapper.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/BinaryFormat/Magic.h"
#include "llvm/Frontend/Offloading/Utility.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/GlobalVariable.h"
Expand Down Expand Up @@ -121,19 +122,36 @@ GlobalVariable *createBinDesc(Module &M, ArrayRef<ArrayRef<char>> Bufs) {
SmallVector<Constant *, 4u> ImagesInits;
ImagesInits.reserve(Bufs.size());
for (ArrayRef<char> Buf : Bufs) {
// We embed the full offloading entry so the binary utilities can parse it.
auto *Data = ConstantDataArray::get(C, Buf);
auto *Image = new GlobalVariable(M, Data->getType(), /*isConstant*/ true,
auto *Image = new GlobalVariable(M, Data->getType(), /*isConstant=*/true,
GlobalVariable::InternalLinkage, Data,
".omp_offloading.device_image");
Image->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
Image->setSection(".llvm.offloading");
Image->setAlignment(Align(object::OffloadBinary::getAlignment()));

auto *Size = ConstantInt::get(getSizeTTy(M), Buf.size());
StringRef Binary(Buf.data(), Buf.size());
assert(identify_magic(Binary) == file_magic::offload_binary &&
"Invalid binary format");

// The device image struct contains the pointer to the beginning and end of
// the image stored inside of the offload binary. There should only be one
// of these for each buffer so we parse it out manually.
const auto *Header =
reinterpret_cast<const object::OffloadBinary::Header *>(
Binary.bytes_begin());
const auto *Entry = reinterpret_cast<const object::OffloadBinary::Entry *>(
Binary.bytes_begin() + Header->EntryOffset);

auto *Begin = ConstantInt::get(getSizeTTy(M), Entry->ImageOffset);
auto *Size =
ConstantInt::get(getSizeTTy(M), Entry->ImageOffset + Entry->ImageSize);
Constant *ZeroBegin[] = {Zero, Begin};
Constant *ZeroSize[] = {Zero, Size};

auto *ImageB =
ConstantExpr::getGetElementPtr(Image->getValueType(), Image, ZeroZero);
ConstantExpr::getGetElementPtr(Image->getValueType(), Image, ZeroBegin);
auto *ImageE =
ConstantExpr::getGetElementPtr(Image->getValueType(), Image, ZeroSize);

Expand Down