Skip to content

[mlir][spirv] Truncate Literal String size at max number words #142916

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 4 commits into from
Jun 11, 2025
Merged

[mlir][spirv] Truncate Literal String size at max number words #142916

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
54172aa
[mlir][spirv] Truncate Literal String size at max number words
davidegrohmann Jan 29, 2025
89989ba
Fix review comments
davidegrohmann Jun 6, 2025
fefa194
Add missing full stop marks
davidegrohmann Jun 10, 2025
9402ece
resolve clang-format problem
davidegrohmann Jun 11, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 7 additions & 0 deletions mlir/include/mlir/Target/SPIRV/SPIRVBinaryUtils.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,13 @@ constexpr uint32_t kMagicNumber = 0x07230203;
/// The serializer tool ID registered to the Khronos Group
constexpr uint32_t kGeneratorNumber = 22;

/// Max number of words
/// https://registry.khronos.org/SPIR-V/specs/unified1/SPIRV.html#_universal_limits
constexpr uint32_t kMaxWordCount = 65535;

/// Max number of words for literal
constexpr uint32_t kMaxLiteralWordCount = kMaxWordCount - 3;

/// Appends a SPRI-V module header to `header` with the given `version` and
/// `idBound`.
void appendModuleHeader(SmallVectorImpl<uint32_t> &header,
Expand Down
20 changes: 17 additions & 3 deletions mlir/lib/Target/SPIRV/SPIRVBinaryUtils.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,9 @@
#include "mlir/Target/SPIRV/SPIRVBinaryUtils.h"
#include "mlir/Dialect/SPIRV/IR/SPIRVTypes.h"
#include "llvm/Config/llvm-config.h" // for LLVM_VERSION_MAJOR
#include "llvm/Support/Debug.h"

#define DEBUG_TYPE "spirv-binary-utils"

using namespace mlir;

Expand Down Expand Up @@ -67,8 +70,19 @@ uint32_t spirv::getPrefixedOpcode(uint32_t wordCount, spirv::Opcode opcode) {
void spirv::encodeStringLiteralInto(SmallVectorImpl<uint32_t> &binary,
StringRef literal) {
// We need to encode the literal and the null termination.
auto encodingSize = literal.size() / 4 + 1;
auto bufferStartSize = binary.size();
size_t encodingSize = literal.size() / 4 + 1;
size_t sizeOfDataToCopy = literal.size();
if (encodingSize >= kMaxLiteralWordCount) {
// Reserve one word for the null termination.
encodingSize = kMaxLiteralWordCount - 1;
// Do not override the last word (null termination) when copying.
sizeOfDataToCopy = (encodingSize - 1) * 4;
LLVM_DEBUG(llvm::dbgs()
<< "Truncating string literal to max size ("
<< (kMaxLiteralWordCount - 1) << "): " << literal << "\n");
}
size_t bufferStartSize = binary.size();
binary.resize(bufferStartSize + encodingSize, 0);
std::memcpy(binary.data() + bufferStartSize, literal.data(), literal.size());
std::memcpy(binary.data() + bufferStartSize, literal.data(),
sizeOfDataToCopy);
}