diff options
Diffstat (limited to 'clang/lib/CIR')
| -rw-r--r-- | clang/lib/CIR/CodeGen/CIRGenDecl.cpp | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/clang/lib/CIR/CodeGen/CIRGenDecl.cpp b/clang/lib/CIR/CodeGen/CIRGenDecl.cpp index aeea0ef..325875d 100644 --- a/clang/lib/CIR/CodeGen/CIRGenDecl.cpp +++ b/clang/lib/CIR/CodeGen/CIRGenDecl.cpp @@ -50,6 +50,41 @@ CIRGenFunction::emitAutoVarAlloca(const VarDecl &d, Address address = Address::invalid(); if (ty->isConstantSizeType()) { + // If this value is an array, struct, or vector with a statically + // determinable constant initializer, there are optimizations we can do. + // + // TODO: We should constant-evaluate the initializer of any variable, + // as long as it is initialized by a constant expression. Currently, + // isConstantInitializer produces wrong answers for structs with + // reference or bitfield members, and a few other cases, and checking + // for POD-ness protects us from some of these. + if (d.getInit() && + (ty->isArrayType() || ty->isRecordType() || ty->isVectorType()) && + (d.isConstexpr() || + ((ty.isPODType(getContext()) || + getContext().getBaseElementType(ty)->isObjCObjectPointerType()) && + d.getInit()->isConstantInitializer(getContext(), false)))) { + + // If the variable's a const type, and it's neither an NRVO + // candidate nor a __block variable and has no mutable members, + // emit it as a global instead. + // Exception is if a variable is located in non-constant address space + // in OpenCL. + // TODO(cir): perhaps we don't need this at all at CIR since this can + // be done as part of lowering down to LLVM. + bool needsDtor = + d.needsDestruction(getContext()) == QualType::DK_cxx_destructor; + if ((!getContext().getLangOpts().OpenCL || + ty.getAddressSpace() == LangAS::opencl_constant) && + (cgm.getCodeGenOpts().MergeAllConstants && !nrvo && + !d.isEscapingByref() && + ty.isConstantStorage(getContext(), true, !needsDtor))) { + cgm.errorNYI(d.getSourceRange(), "emitAutoVarAlloca: type constant"); + } + // Otherwise, tell the initialization code that we're in this case. + emission.isConstantAggregate = true; + } + // A normal fixed sized variable becomes an alloca in the entry block, // unless: // - it's an NRVO variable. @@ -131,6 +166,47 @@ bool CIRGenFunction::isTrivialInitializer(const Expr *init) { return false; } +static void emitStoresForConstant(CIRGenModule &cgm, const VarDecl &d, + Address addr, bool isVolatile, + CIRGenBuilderTy &builder, + mlir::TypedAttr constant) { + mlir::Type ty = constant.getType(); + cir::CIRDataLayout layout{cgm.getModule()}; + uint64_t constantSize = layout.getTypeAllocSize(ty); + if (!constantSize) + return; + assert(!cir::MissingFeatures::addAutoInitAnnotation()); + assert(!cir::MissingFeatures::vectorConstants()); + assert(!cir::MissingFeatures::shouldUseBZeroPlusStoresToInitialize()); + assert(!cir::MissingFeatures::shouldUseMemSetToInitialize()); + assert(!cir::MissingFeatures::shouldSplitConstantStore()); + assert(!cir::MissingFeatures::shouldCreateMemCpyFromGlobal()); + // In CIR we want to emit a store for the whole thing, later lowering + // prepare to LLVM should unwrap this into the best policy (see asserts + // above). + // + // FIXME(cir): This is closer to memcpy behavior but less optimal, instead of + // copy from a global, we just create a cir.const out of it. + + if (addr.getElementType() != ty) + addr = addr.withElementType(builder, ty); + + // If the address is an alloca, set the init attribute. + // The address is usually and alloca, but there is at least one case where + // emitAutoVarInit is called from the OpenACC codegen with an address that + // is not an alloca. + auto allocaOp = addr.getDefiningOp<cir::AllocaOp>(); + if (allocaOp) + allocaOp.setInitAttr(mlir::UnitAttr::get(&cgm.getMLIRContext())); + + // There are cases where OpenACC codegen calls emitAutoVarInit with a + // temporary decl that doesn't have a source range set. + mlir::Location loc = builder.getUnknownLoc(); + if (d.getSourceRange().isValid()) + loc = cgm.getLoc(d.getSourceRange()); + builder.createStore(loc, builder.getConstant(loc, constant), addr); +} + void CIRGenFunction::emitAutoVarInit( const CIRGenFunction::AutoVarEmission &emission) { assert(emission.variable && "emission was not valid!"); @@ -237,6 +313,9 @@ void CIRGenFunction::emitAutoVarInit( return emitStoreThroughLValue( RValue::get(builder.getConstant(initLoc, typedConstant)), lv); } + + emitStoresForConstant(cgm, d, addr, type.isVolatileQualified(), builder, + typedConstant); } void CIRGenFunction::emitAutoVarCleanups( |