https://github.com/skc7 created https://github.com/llvm/llvm-project/pull/188200
Upstreaming clangIR PR: https://github.com/llvm/clangir/pull/422 This PR implement support for `__attribute__((section("name")))` on global variables in ClangIR, matching OGCG behavior. >From 901f19fde677f684a9b1d40528c5260f1d801d8f Mon Sep 17 00:00:00 2001 From: skc7 <[email protected]> Date: Tue, 24 Mar 2026 15:00:31 +0530 Subject: [PATCH] [CIR][CIRGen] Support for section atttribute --- clang/include/clang/CIR/Dialect/IR/CIROps.td | 8 +++- clang/include/clang/CIR/MissingFeatures.h | 1 - clang/lib/CIR/CodeGen/CIRGenModule.cpp | 24 ++++++++++-- .../CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp | 39 ++++++++++++------- clang/test/CIR/CodeGen/global-section.c | 14 +++++++ 5 files changed, 67 insertions(+), 19 deletions(-) create mode 100644 clang/test/CIR/CodeGen/global-section.c diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td index 41858a61480a8..15f98d1d7b9a9 100644 --- a/clang/include/clang/CIR/Dialect/IR/CIROps.td +++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td @@ -2842,7 +2842,9 @@ def CIR_GlobalOp : CIR_Op<"global", [ UnitAttr:$dso_local, OptionalAttr<CIR_StaticLocalGuardAttr>:$static_local_guard, OptionalAttr<I64Attr>:$alignment, - OptionalAttr<ASTVarDeclInterface>:$ast); + OptionalAttr<ASTVarDeclInterface>:$ast, + OptionalAttr<StrAttr>:$section + ); let regions = (region MaxSizedRegion<1>:$ctorRegion, MaxSizedRegion<1>:$dtorRegion); @@ -2901,6 +2903,10 @@ def CIR_GlobalOp : CIR_Op<"global", [ void setupRegionInitializedLLVMGlobalOp( cir::GlobalOp op, mlir::ConversionPatternRewriter &rewriter) const; + llvm::SmallVector<mlir::NamedAttribute> lowerGlobalAttributes( + cir::GlobalOp op, + mlir::ConversionPatternRewriter &rewriter) const; + mutable mlir::LLVM::ComdatOp comdatOp = nullptr; mlir::SymbolRefAttr getComdatAttr(cir::GlobalOp &op, mlir::OpBuilder &builder) const; diff --git a/clang/include/clang/CIR/MissingFeatures.h b/clang/include/clang/CIR/MissingFeatures.h index 68db08a5580ca..740816efc9dc4 100644 --- a/clang/include/clang/CIR/MissingFeatures.h +++ b/clang/include/clang/CIR/MissingFeatures.h @@ -31,7 +31,6 @@ struct MissingFeatures { static bool opGlobalThreadLocal() { return false; } static bool opGlobalWeakRef() { return false; } static bool opGlobalUnnamedAddr() { return false; } - static bool opGlobalSection() { return false; } static bool opGlobalVisibility() { return false; } static bool opGlobalDLLImportExport() { return false; } static bool opGlobalPartition() { return false; } diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.cpp b/clang/lib/CIR/CodeGen/CIRGenModule.cpp index f3ab733bf4c6a..ffa8b35014b79 100644 --- a/clang/lib/CIR/CodeGen/CIRGenModule.cpp +++ b/clang/lib/CIR/CodeGen/CIRGenModule.cpp @@ -664,11 +664,17 @@ void CIRGenModule::setCommonAttributes(GlobalDecl gd, mlir::Operation *gv) { void CIRGenModule::setNonAliasAttributes(GlobalDecl gd, mlir::Operation *op) { setCommonAttributes(gd, op); + const Decl *d = gd.getDecl(); + if (d) { + if (auto globalOp = mlir::dyn_cast<cir::GlobalOp>(op)) { + if (const auto *sa = d->getAttr<SectionAttr>()) + globalOp.setSectionAttr(builder.getStringAttr(sa->getName())); + } + } + assert(!cir::MissingFeatures::opGlobalUsedOrCompilerUsed()); - assert(!cir::MissingFeatures::opGlobalSection()); assert(!cir::MissingFeatures::opFuncCPUAndFeaturesAttributes()); assert(!cir::MissingFeatures::opFuncSection()); - assert(!cir::MissingFeatures::setTargetAttributes()); } @@ -991,7 +997,11 @@ CIRGenModule::getOrCreateCIRGlobal(StringRef mangledName, mlir::Type ty, errorNYI(d->getSourceRange(), "getOrCreateCIRGlobal: MS static data member inline definition"); - assert(!cir::MissingFeatures::opGlobalSection()); + // Emit section information for extern variables. + if (d->hasExternalStorage()) { + if (const SectionAttr *sa = d->getAttr<SectionAttr>()) + gv.setSectionAttr(builder.getStringAttr(sa->getName())); + } gv.setGlobalVisibilityAttr(getGlobalVisibilityAttrFromDecl(d)); // Handle XCore specific ABI requirements. @@ -1243,7 +1253,13 @@ void CIRGenModule::emitGlobalVarDefinition(const clang::VarDecl *vd, vd->getType().isConstantStorage(astContext, /*ExcludeCtor=*/true, /*ExcludeDtor=*/true))); - assert(!cir::MissingFeatures::opGlobalSection()); + // If it is in a read-only section, mark it 'constant'. + if (const SectionAttr *sa = vd->getAttr<SectionAttr>()) { + gv.setSectionAttr(getBuilder().getStringAttr(sa->getName())); + const ASTContext::SectionInfo &si = astContext.SectionInfos[sa->getName()]; + if ((si.SectionFlags & ASTContext::PSF_Write) == 0) + gv.setConstant(true); + } // Set CIR linkage and DLL storage class. gv.setLinkage(linkage); diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp index 9fa0e720e1591..fd252196c25c3 100644 --- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp +++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp @@ -2557,6 +2557,26 @@ mlir::LogicalResult CIRToLLVMGetGlobalOpLowering::matchAndRewrite( return mlir::success(); } +llvm::SmallVector<mlir::NamedAttribute> +CIRToLLVMGlobalOpLowering::lowerGlobalAttributes( + cir::GlobalOp op, mlir::ConversionPatternRewriter &rewriter) const { + SmallVector<mlir::NamedAttribute> attributes; + + if (auto sectionAttr = op.getSectionAttr()) + attributes.push_back(rewriter.getNamedAttr("section", sectionAttr)); + + mlir::LLVM::VisibilityAttr visibility = mlir::LLVM::VisibilityAttr::get( + getContext(), lowerCIRVisibilityToLLVMVisibility( + op.getGlobalVisibilityAttr().getValue())); + attributes.push_back(rewriter.getNamedAttr("visibility_", visibility)); + + if (op->getAttr(CUDAExternallyInitializedAttr::getMnemonic())) + attributes.push_back(rewriter.getNamedAttr("externally_initialized", + rewriter.getUnitAttr())); + + return attributes; +} + /// Replace CIR global with a region initialized LLVM global and update /// insertion point to the end of the initializer block. void CIRToLLVMGlobalOpLowering::setupRegionInitializedLLVMGlobalOp( @@ -2580,7 +2600,9 @@ void CIRToLLVMGlobalOpLowering::setupRegionInitializedLLVMGlobalOp( const StringRef symbol = op.getSymName(); mlir::SymbolRefAttr comdatAttr = getComdatAttr(op, rewriter); - SmallVector<mlir::NamedAttribute> attributes; + SmallVector<mlir::NamedAttribute> attributes = + lowerGlobalAttributes(op, rewriter); + mlir::LLVM::GlobalOp newGlobalOp = rewriter.replaceOpWithNewOp<mlir::LLVM::GlobalOp>( op, llvmType, isConst, linkage, symbol, nullptr, alignment, addrSpace, @@ -2641,14 +2663,8 @@ mlir::LogicalResult CIRToLLVMGlobalOpLowering::matchAndRewrite( const uint64_t alignment = op.getAlignment().value_or(0); const mlir::LLVM::Linkage linkage = convertLinkage(op.getLinkage()); const StringRef symbol = op.getSymName(); - SmallVector<mlir::NamedAttribute> attributes; - - // Mark externally_initialized for __device__ and __constant__ - if (auto extInit = - op->getAttr(CUDAExternallyInitializedAttr::getMnemonic())) { - attributes.push_back(rewriter.getNamedAttr("externally_initialized", - rewriter.getUnitAttr())); - } + SmallVector<mlir::NamedAttribute> attributes = + lowerGlobalAttributes(op, rewriter); if (init.has_value()) { if (mlir::isa<cir::FPAttr, cir::IntAttr, cir::BoolAttr>(init.value())) { @@ -2679,13 +2695,10 @@ mlir::LogicalResult CIRToLLVMGlobalOpLowering::matchAndRewrite( } } - mlir::LLVM::Visibility visibility = - lowerCIRVisibilityToLLVMVisibility(op.getGlobalVisibility()); mlir::SymbolRefAttr comdatAttr = getComdatAttr(op, rewriter); - auto newOp = rewriter.replaceOpWithNewOp<mlir::LLVM::GlobalOp>( + rewriter.replaceOpWithNewOp<mlir::LLVM::GlobalOp>( op, llvmType, isConst, linkage, symbol, init.value_or(mlir::Attribute()), alignment, addrSpace, isDsoLocal, isThreadLocal, comdatAttr, attributes); - newOp.setVisibility_(visibility); return mlir::success(); } diff --git a/clang/test/CIR/CodeGen/global-section.c b/clang/test/CIR/CodeGen/global-section.c new file mode 100644 index 0000000000000..f82c085b73312 --- /dev/null +++ b/clang/test/CIR/CodeGen/global-section.c @@ -0,0 +1,14 @@ +// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o - | FileCheck %s --check-prefix=CIR +// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o - | FileCheck %s --check-prefix=LLVM +// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o - | FileCheck %s --check-prefix=LLVM + +extern int __attribute__((section(".shared"))) ext; +int getExt(void) { + return ext; +} +// CIR: cir.global "private" external @ext : !s32i {{{.*}}section = ".shared"} +// LLVM: @ext = external global i32, section ".shared" + +int __attribute__((section(".shared"))) glob = 42; +// CIR: cir.global external @glob = #cir.int<42> : !s32i {{{.*}}section = ".shared"} +// LLVM: @glob = global i32 42, section ".shared" _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
