Author: adams381 Date: 2025-12-09T15:09:25-08:00 New Revision: 84b9e444454a06ddf01f568164e3d5c8d956707d
URL: https://github.com/llvm/llvm-project/commit/84b9e444454a06ddf01f568164e3d5c8d956707d DIFF: https://github.com/llvm/llvm-project/commit/84b9e444454a06ddf01f568164e3d5c8d956707d.diff LOG: [CIR] Add Function Argument Demotion support (#170915) This PR migrates the Function Argument Demotion feature from the incubator repository to upstream. The feature handles K&R-style function parameters that are promoted (e.g., short->int, float->double) and demotes them back to their declared types. ## Changes - Add emitArgumentDemotion helper function for type demotion - Create emitFunctionProlog function to handle function prologue setup (addresses existing TODO to move parameter handling logic) - Move parameter handling logic into emitFunctionProlog - Add test case kr-func-promote.c to verify the feature Tested: All CIR tests pass (320/321, 99.69%). The one unsupported test is an expected failure. Added: clang/test/CIR/CodeGen/kr-func-promote.c Modified: clang/lib/CIR/CodeGen/CIRGenFunction.cpp clang/lib/CIR/CodeGen/CIRGenFunction.h Removed: ################################################################################ diff --git a/clang/lib/CIR/CodeGen/CIRGenFunction.cpp b/clang/lib/CIR/CodeGen/CIRGenFunction.cpp index 492cbb69fabb3..6b2e60a551198 100644 --- a/clang/lib/CIR/CodeGen/CIRGenFunction.cpp +++ b/clang/lib/CIR/CodeGen/CIRGenFunction.cpp @@ -16,6 +16,7 @@ #include "CIRGenCall.h" #include "CIRGenValue.h" #include "mlir/IR/Location.h" +#include "clang/AST/Attr.h" #include "clang/AST/ExprCXX.h" #include "clang/AST/GlobalDecl.h" #include "clang/CIR/MissingFeatures.h" @@ -422,28 +423,35 @@ cir::TryOp CIRGenFunction::LexicalScope::getClosestTryParent() { return nullptr; } -void CIRGenFunction::startFunction(GlobalDecl gd, QualType returnType, - cir::FuncOp fn, cir::FuncType funcType, - FunctionArgList args, SourceLocation loc, - SourceLocation startLoc) { - assert(!curFn && - "CIRGenFunction can only be used for one function at a time"); +/// An argument came in as a promoted argument; demote it back to its +/// declared type. +static mlir::Value emitArgumentDemotion(CIRGenFunction &cgf, const VarDecl *var, + mlir::Value value) { + mlir::Type ty = cgf.convertType(var->getType()); - curFn = fn; + // This can happen with promotions that actually don't change the + // underlying type, like the enum promotions. + if (value.getType() == ty) + return value; - const Decl *d = gd.getDecl(); + assert((mlir::isa<cir::IntType>(ty) || cir::isAnyFloatingPointType(ty)) && + "unexpected promotion type"); - didCallStackSave = false; - curCodeDecl = d; - const auto *fd = dyn_cast_or_null<FunctionDecl>(d); - curFuncDecl = d->getNonClosureContext(); + if (mlir::isa<cir::IntType>(ty)) + return cgf.getBuilder().CIRBaseBuilderTy::createIntCast(value, ty); - prologueCleanupDepth = ehStack.stable_begin(); + return cgf.getBuilder().createFloatingCast(value, ty); +} - mlir::Block *entryBB = &fn.getBlocks().front(); - builder.setInsertionPointToStart(entryBB); +void CIRGenFunction::emitFunctionProlog(const FunctionArgList &args, + mlir::Block *entryBB, + const FunctionDecl *fd, + SourceLocation bodyBeginLoc) { + // Naked functions don't have prologues. + if (fd && fd->hasAttr<NakedAttr>()) { + cgm.errorNYI(bodyBeginLoc, "naked function decl"); + } - // TODO(cir): this should live in `emitFunctionProlog // Declare all the function arguments in the symbol table. for (const auto nameValue : llvm::zip(args, entryBB->getArguments())) { const VarDecl *paramVar = std::get<0>(nameValue); @@ -466,20 +474,64 @@ void CIRGenFunction::startFunction(GlobalDecl gd, QualType returnType, cast<ParmVarDecl>(paramVar)->isKNRPromoted(); assert(!cir::MissingFeatures::constructABIArgDirectExtend()); if (isPromoted) - cgm.errorNYI(fd->getSourceRange(), "Function argument demotion"); + paramVal = emitArgumentDemotion(*this, paramVar, paramVal); // Location of the store to the param storage tracked as beginning of // the function body. - mlir::Location fnBodyBegin = getLoc(fd->getBody()->getBeginLoc()); + mlir::Location fnBodyBegin = getLoc(bodyBeginLoc); builder.CIRBaseBuilderTy::createStore(fnBodyBegin, paramVal, addrVal); } assert(builder.getInsertionBlock() && "Should be valid"); +} + +void CIRGenFunction::startFunction(GlobalDecl gd, QualType returnType, + cir::FuncOp fn, cir::FuncType funcType, + FunctionArgList args, SourceLocation loc, + SourceLocation startLoc) { + assert(!curFn && + "CIRGenFunction can only be used for one function at a time"); + + curFn = fn; + + const Decl *d = gd.getDecl(); + + didCallStackSave = false; + curCodeDecl = d; + const auto *fd = dyn_cast_or_null<FunctionDecl>(d); + curFuncDecl = d->getNonClosureContext(); + + prologueCleanupDepth = ehStack.stable_begin(); + + mlir::Block *entryBB = &fn.getBlocks().front(); + builder.setInsertionPointToStart(entryBB); + + // Determine the function body begin location for the prolog. + // If fd is null or has no body, use startLoc as fallback. + SourceLocation bodyBeginLoc = startLoc; + if (fd) { + if (Stmt *body = fd->getBody()) + bodyBeginLoc = body->getBeginLoc(); + else + bodyBeginLoc = fd->getLocation(); + } + + emitFunctionProlog(args, entryBB, fd, bodyBeginLoc); // When the current function is not void, create an address to store the // result value. - if (!returnType->isVoidType()) - emitAndUpdateRetAlloca(returnType, getLoc(fd->getBody()->getEndLoc()), + if (!returnType->isVoidType()) { + // Determine the function body end location. + // If fd is null or has no body, use loc as fallback. + SourceLocation bodyEndLoc = loc; + if (fd) { + if (Stmt *body = fd->getBody()) + bodyEndLoc = body->getEndLoc(); + else + bodyEndLoc = fd->getLocation(); + } + emitAndUpdateRetAlloca(returnType, getLoc(bodyEndLoc), getContext().getTypeAlignInChars(returnType)); + } if (isa_and_nonnull<CXXMethodDecl>(d) && cast<CXXMethodDecl>(d)->isInstance()) { diff --git a/clang/lib/CIR/CodeGen/CIRGenFunction.h b/clang/lib/CIR/CodeGen/CIRGenFunction.h index 0df812bcfb94e..15322ee72a1b0 100644 --- a/clang/lib/CIR/CodeGen/CIRGenFunction.h +++ b/clang/lib/CIR/CodeGen/CIRGenFunction.h @@ -954,6 +954,11 @@ class CIRGenFunction : public CIRGenTypeCache { clang::QualType buildFunctionArgList(clang::GlobalDecl gd, FunctionArgList &args); + /// Emit the function prologue: declare function arguments in the symbol + /// table. + void emitFunctionProlog(const FunctionArgList &args, mlir::Block *entryBB, + const FunctionDecl *fd, SourceLocation bodyBeginLoc); + /// Emit code for the start of a function. /// \param loc The location to be associated with the function. /// \param startLoc The location of the function body. diff --git a/clang/test/CIR/CodeGen/kr-func-promote.c b/clang/test/CIR/CodeGen/kr-func-promote.c new file mode 100644 index 0000000000000..5fed068a30398 --- /dev/null +++ b/clang/test/CIR/CodeGen/kr-func-promote.c @@ -0,0 +1,42 @@ +// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c89 -fclangir -emit-cir %s -o %t.cir +// RUN: FileCheck --input-file=%t.cir %s -check-prefix=CIR +// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c89 -fclangir -emit-llvm %s -o %t-cir.ll +// RUN: FileCheck --input-file=%t-cir.ll %s -check-prefix=LLVM +// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c89 -emit-llvm %s -o %t.ll +// RUN: FileCheck --input-file=%t.ll %s -check-prefix=OGCG + +// CIR: cir.func {{.*}}@foo(%arg0: !s32i +// CIR: %0 = cir.alloca !s16i, !cir.ptr<!s16i>, ["x", init] +// CIR: %1 = cir.cast integral %arg0 : !s32i -> !s16i +// CIR: cir.store %1, %0 : !s16i, !cir.ptr<!s16i> +// expected-warning@+1 {{a function definition without a prototype is deprecated}} +void foo(x) short x; {} + +// LLVM: define{{.*}} void @foo(i32 %0) +// LLVM: %[[X_PTR:.*]] = alloca i16, i64 1, align 2 +// LLVM: %[[X:.*]] = trunc i32 %0 to i16 +// LLVM: store i16 %[[X]], ptr %[[X_PTR]], align 2 + +// OGCG: define{{.*}} void @foo(i32 noundef %0) +// OGCG: entry: +// OGCG: %[[X_PTR:.*]] = alloca i16, align 2 +// OGCG: %[[X:.*]] = trunc i32 %0 to i16 +// OGCG: store i16 %[[X]], ptr %[[X_PTR]], align 2 + +// CIR: cir.func{{.*}}no_proto dso_local @bar(%arg0: !cir.double +// CIR: %0 = cir.alloca !cir.float, !cir.ptr<!cir.float>, ["f", init] +// CIR: %1 = cir.cast floating %arg0 : !cir.double -> !cir.float +// CIR: cir.store %1, %0 : !cir.float, !cir.ptr<!cir.float> +// expected-warning@+1 {{a function definition without a prototype is deprecated}} +void bar(f) float f; {} + +// LLVM: define{{.*}} void @bar(double %0) +// LLVM: %[[F_PTR:.*]] = alloca float, i64 1, align 4 +// LLVM: %[[F:.*]] = fptrunc double %0 to float +// LLVM: store float %[[F]], ptr %[[F_PTR]], align 4 + +// OGCG: define{{.*}} void @bar(double noundef %0) +// OGCG: entry: +// OGCG: %[[F_PTR:.*]] = alloca float, align 4 +// OGCG: %[[F:.*]] = fptrunc double %0 to float +// OGCG: store float %[[F]], ptr %[[F_PTR]], align 4 _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
