llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Andy Kaylor (andykaylor) <details> <summary>Changes</summary> This change implements correct lowering of function aliases to the LLVM dialect. --- Full diff: https://github.com/llvm/llvm-project/pull/150520.diff 4 Files Affected: - (modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp (+70-6) - (modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h (+5) - (modified) clang/test/CIR/CodeGen/ctor-alias.cpp (+21-4) - (modified) clang/test/CIR/CodeGen/dtor-alias.cpp (+2-4) ``````````diff diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp index 3cd7de0a56bc3..baa0a5e326c4a 100644 --- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp +++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp @@ -919,13 +919,46 @@ rewriteCallOrInvoke(mlir::Operation *op, mlir::ValueRange callOperands, memoryEffects, noUnwind, willReturn); mlir::LLVM::LLVMFunctionType llvmFnTy; + + // Temporary to handle the case where we need to prepend an operand if the + // callee is an alias. + SmallVector<mlir::Value> adjustedCallOperands; + if (calleeAttr) { // direct call - mlir::FunctionOpInterface fn = - mlir::SymbolTable::lookupNearestSymbolFrom<mlir::FunctionOpInterface>( - op, calleeAttr); - assert(fn && "Did not find function for call"); - llvmFnTy = cast<mlir::LLVM::LLVMFunctionType>( - converter->convertType(fn.getFunctionType())); + mlir::Operation *callee = + mlir::SymbolTable::lookupNearestSymbolFrom(op, calleeAttr); + if (auto fn = dyn_cast<mlir::FunctionOpInterface>(callee)) { + llvmFnTy = cast<mlir::LLVM::LLVMFunctionType>( + converter->convertType(fn.getFunctionType())); + } else if (auto alias = cast<mlir::LLVM::AliasOp>(callee)) { + // If the callee wasan alias. In that case, + // we need to prepend the address of the alias to the operands. The + // way aliases work in the LLVM dialect is a little counter-intuitive. + // The AliasOp itself is a pseudo-function that returns the address of + // the global value being aliased, but when we generate the call we + // need to insert an operation that gets the address of the AliasOp. + // This all gets sorted out when the LLVM dialect is lowered to LLVM IR. + auto symAttr = cast<mlir::FlatSymbolRefAttr>(calleeAttr); + auto addrOfAlias = + rewriter + .create<mlir::LLVM::AddressOfOp>( + op->getLoc(), + mlir::LLVM::LLVMPointerType::get(rewriter.getContext()), + symAttr) + .getResult(); + adjustedCallOperands.push_back(addrOfAlias); + + // Now add the regular operands and assign this to the range value. + llvm::append_range(adjustedCallOperands, callOperands); + callOperands = adjustedCallOperands; + + // Clear the callee attribute because we're calling an alias. + calleeAttr = {}; + llvmFnTy = cast<mlir::LLVM::LLVMFunctionType>(alias.getType()); + } else { + // Was this an ifunc? + return op->emitError("Unexpected callee type!"); + } } else { // indirect call assert(!op->getOperands().empty() && "operands list must no be empty for the indirect call"); @@ -1166,6 +1199,31 @@ void CIRToLLVMFuncOpLowering::lowerFuncAttributes( } } +mlir::LogicalResult CIRToLLVMFuncOpLowering::matchAndRewriteAlias( + cir::FuncOp op, mlir::FlatSymbolRefAttr aliasee, mlir::Type ty, + OpAdaptor adaptor, mlir::ConversionPatternRewriter &rewriter) const { + SmallVector<mlir::NamedAttribute, 4> attributes; + lowerFuncAttributes(op, /*filterArgAndResAttrs=*/false, attributes); + + mlir::Location loc = op.getLoc(); + auto aliasOp = rewriter.replaceOpWithNewOp<mlir::LLVM::AliasOp>( + op, ty, convertLinkage(op.getLinkage()), op.getName(), op.getDsoLocal(), + /*threadLocal=*/false, attributes); + + // Create the alias body + mlir::OpBuilder builder(op.getContext()); + mlir::Block *block = builder.createBlock(&aliasOp.getInitializerRegion()); + builder.setInsertionPointToStart(block); + // The type of AddressOfOp is always a pointer. + assert(!cir::MissingFeatures::addressSpace()); + mlir::Type ptrTy = mlir::LLVM::LLVMPointerType::get(ty.getContext()); + auto addrOp = + builder.create<mlir::LLVM::AddressOfOp>(loc, ptrTy, aliasee.getValue()); + builder.create<mlir::LLVM::ReturnOp>(loc, addrOp); + + return mlir::success(); +} + mlir::LogicalResult CIRToLLVMFuncOpLowering::matchAndRewrite( cir::FuncOp op, OpAdaptor adaptor, mlir::ConversionPatternRewriter &rewriter) const { @@ -1190,6 +1248,12 @@ mlir::LogicalResult CIRToLLVMFuncOpLowering::matchAndRewrite( resultType ? resultType : mlir::LLVM::LLVMVoidType::get(getContext()), signatureConversion.getConvertedTypes(), /*isVarArg=*/fnType.isVarArg()); + + // If this is an alias, it needs to be lowered to llvm::AliasOp. + std::optional<mlir::FlatSymbolRefAttr> aliasee = op.getAliaseeAttr(); + if (aliasee && *aliasee) + return matchAndRewriteAlias(op, *aliasee, llvmFnTy, adaptor, rewriter); + // LLVMFuncOp expects a single FileLine Location instead of a fused // location. mlir::Location loc = op.getLoc(); diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h index 2911ced66e58e..0f003f644d2fa 100644 --- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h +++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h @@ -257,6 +257,11 @@ class CIRToLLVMFuncOpLowering : public mlir::OpConversionPattern<cir::FuncOp> { cir::FuncOp func, bool filterArgAndResAttrs, mlir::SmallVectorImpl<mlir::NamedAttribute> &result) const; + mlir::LogicalResult + matchAndRewriteAlias(cir::FuncOp op, mlir::FlatSymbolRefAttr aliasee, + mlir::Type ty, OpAdaptor adaptor, + mlir::ConversionPatternRewriter &rewriter) const; + public: using mlir::OpConversionPattern<cir::FuncOp>::OpConversionPattern; diff --git a/clang/test/CIR/CodeGen/ctor-alias.cpp b/clang/test/CIR/CodeGen/ctor-alias.cpp index a20e206c6d714..c4bf455e3a09b 100644 --- a/clang/test/CIR/CodeGen/ctor-alias.cpp +++ b/clang/test/CIR/CodeGen/ctor-alias.cpp @@ -11,6 +11,8 @@ struct B { B::B() { } +// LLVM: @_ZN1BC1Ev = alias void (ptr), ptr @_ZN1BC2Ev + // OGCG: @_ZN1BC1Ev = unnamed_addr alias void (ptr), ptr @_ZN1BC2Ev // CHECK: cir.func{{.*}} @_ZN1BC2Ev(%arg0: !cir.ptr<!rec_B> @@ -25,15 +27,30 @@ B::B() { // LLVM: store ptr %[[THIS_ARG]], ptr %[[THIS_ADDR]] // LLVM: %[[THIS:.*]] = load ptr, ptr %[[THIS_ADDR]] -// This should be an alias, like the similar OGCG alias above, but that's not -// implemented yet. -// LLVM: declare dso_local void @_ZN1BC1Ev(ptr) - // OGCG: define{{.*}} @_ZN1BC2Ev(ptr{{.*}} %[[THIS_ARG:.*]]) // OGCG: %[[THIS_ADDR:.*]] = alloca ptr // OGCG: store ptr %[[THIS_ARG]], ptr %[[THIS_ADDR]] // OGCG: %[[THIS:.*]] = load ptr, ptr %[[THIS_ADDR]] +void bar() { + B b; +} + +// CHECK: cir.func{{.*}} @_Z3barv() +// CHECK: %[[B:.*]] = cir.alloca !rec_B, !cir.ptr<!rec_B>, ["b", init] +// CHECK: cir.call @_ZN1BC1Ev(%[[B]]) : (!cir.ptr<!rec_B>) -> () +// CHECK: cir.return + +// LLVM: define{{.*}} void @_Z3barv() +// LLVM: %[[B:.*]] = alloca %struct.B, i64 1, align 1 +// LLVM: call void @_ZN1BC1Ev(ptr %[[B]]) +// LLVM: ret void + +// OGCG: define{{.*}} void @_Z3barv() +// OGCG: %[[B:.*]] = alloca %struct.B, align 1 +// OGCG: call void @_ZN1BC1Ev(ptr{{.*}} %[[B]]) +// OGCG: ret void + // The constructor in this cases is handled by RAUW rather than aliasing. struct Struk { Struk() {} diff --git a/clang/test/CIR/CodeGen/dtor-alias.cpp b/clang/test/CIR/CodeGen/dtor-alias.cpp index e37ddabb5b4fd..f4d54dfd7da26 100644 --- a/clang/test/CIR/CodeGen/dtor-alias.cpp +++ b/clang/test/CIR/CodeGen/dtor-alias.cpp @@ -11,6 +11,8 @@ struct B { B::~B() { } +// LLVM: @_ZN1BD1Ev = alias void (ptr), ptr @_ZN1BD2Ev + // OGCG: @_ZN1BD1Ev = unnamed_addr alias void (ptr), ptr @_ZN1BD2Ev // CHECK: cir.func{{.*}} @_ZN1BD2Ev(%arg0: !cir.ptr<!rec_B> @@ -25,10 +27,6 @@ B::~B() { // LLVM: store ptr %[[THIS_ARG]], ptr %[[THIS_ADDR]] // LLVM: %[[THIS:.*]] = load ptr, ptr %[[THIS_ADDR]] -// This should be an alias, like the similar OGCG alias above, but that's not -// implemented yet. -// LLVM: declare dso_local void @_ZN1BD1Ev(ptr) - // OGCG: define{{.*}} @_ZN1BD2Ev(ptr{{.*}} %[[THIS_ARG:.*]]) // OGCG: %[[THIS_ADDR:.*]] = alloca ptr // OGCG: store ptr %[[THIS_ARG]], ptr %[[THIS_ADDR]] `````````` </details> https://github.com/llvm/llvm-project/pull/150520 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
