403 lines
15 KiB
C++
403 lines
15 KiB
C++
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//==- CGObjCRuntime.cpp - Interface to Shared Objective-C Runtime Features ==//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This abstract class defines the interface for Objective-C runtime-specific
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// code generation. It provides some concrete helper methods for functionality
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// shared between all (or most) of the Objective-C runtimes supported by clang.
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//
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//===----------------------------------------------------------------------===//
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#include "CGObjCRuntime.h"
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#include "CGCXXABI.h"
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#include "CGCleanup.h"
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#include "CGRecordLayout.h"
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#include "CodeGenFunction.h"
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#include "CodeGenModule.h"
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#include "clang/AST/RecordLayout.h"
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#include "clang/AST/StmtObjC.h"
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#include "clang/CodeGen/CGFunctionInfo.h"
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#include "clang/CodeGen/CodeGenABITypes.h"
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#include "llvm/Support/SaveAndRestore.h"
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using namespace clang;
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using namespace CodeGen;
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uint64_t CGObjCRuntime::ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
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const ObjCInterfaceDecl *OID,
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const ObjCIvarDecl *Ivar) {
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return CGM.getContext().lookupFieldBitOffset(OID, nullptr, Ivar) /
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CGM.getContext().getCharWidth();
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}
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uint64_t CGObjCRuntime::ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
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const ObjCImplementationDecl *OID,
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const ObjCIvarDecl *Ivar) {
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return CGM.getContext().lookupFieldBitOffset(OID->getClassInterface(), OID,
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Ivar) /
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CGM.getContext().getCharWidth();
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}
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unsigned CGObjCRuntime::ComputeBitfieldBitOffset(
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CodeGen::CodeGenModule &CGM,
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const ObjCInterfaceDecl *ID,
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const ObjCIvarDecl *Ivar) {
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return CGM.getContext().lookupFieldBitOffset(ID, ID->getImplementation(),
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Ivar);
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}
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LValue CGObjCRuntime::EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
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const ObjCInterfaceDecl *OID,
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llvm::Value *BaseValue,
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const ObjCIvarDecl *Ivar,
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unsigned CVRQualifiers,
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llvm::Value *Offset) {
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// Compute (type*) ( (char *) BaseValue + Offset)
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QualType InterfaceTy{OID->getTypeForDecl(), 0};
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QualType ObjectPtrTy =
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CGF.CGM.getContext().getObjCObjectPointerType(InterfaceTy);
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QualType IvarTy =
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Ivar->getUsageType(ObjectPtrTy).withCVRQualifiers(CVRQualifiers);
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llvm::Type *LTy = CGF.CGM.getTypes().ConvertTypeForMem(IvarTy);
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llvm::Value *V = CGF.Builder.CreateBitCast(BaseValue, CGF.Int8PtrTy);
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V = CGF.Builder.CreateInBoundsGEP(V, Offset, "add.ptr");
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if (!Ivar->isBitField()) {
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V = CGF.Builder.CreateBitCast(V, llvm::PointerType::getUnqual(LTy));
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LValue LV = CGF.MakeNaturalAlignAddrLValue(V, IvarTy);
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return LV;
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}
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// We need to compute an access strategy for this bit-field. We are given the
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// offset to the first byte in the bit-field, the sub-byte offset is taken
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// from the original layout. We reuse the normal bit-field access strategy by
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// treating this as an access to a struct where the bit-field is in byte 0,
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// and adjust the containing type size as appropriate.
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//
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// FIXME: Note that currently we make a very conservative estimate of the
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// alignment of the bit-field, because (a) it is not clear what guarantees the
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// runtime makes us, and (b) we don't have a way to specify that the struct is
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// at an alignment plus offset.
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//
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// Note, there is a subtle invariant here: we can only call this routine on
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// non-synthesized ivars but we may be called for synthesized ivars. However,
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// a synthesized ivar can never be a bit-field, so this is safe.
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uint64_t FieldBitOffset =
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CGF.CGM.getContext().lookupFieldBitOffset(OID, nullptr, Ivar);
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uint64_t BitOffset = FieldBitOffset % CGF.CGM.getContext().getCharWidth();
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uint64_t AlignmentBits = CGF.CGM.getTarget().getCharAlign();
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uint64_t BitFieldSize = Ivar->getBitWidthValue(CGF.getContext());
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CharUnits StorageSize = CGF.CGM.getContext().toCharUnitsFromBits(
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llvm::alignTo(BitOffset + BitFieldSize, AlignmentBits));
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CharUnits Alignment = CGF.CGM.getContext().toCharUnitsFromBits(AlignmentBits);
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// Allocate a new CGBitFieldInfo object to describe this access.
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//
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// FIXME: This is incredibly wasteful, these should be uniqued or part of some
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// layout object. However, this is blocked on other cleanups to the
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// Objective-C code, so for now we just live with allocating a bunch of these
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// objects.
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CGBitFieldInfo *Info = new (CGF.CGM.getContext()) CGBitFieldInfo(
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CGBitFieldInfo::MakeInfo(CGF.CGM.getTypes(), Ivar, BitOffset, BitFieldSize,
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CGF.CGM.getContext().toBits(StorageSize),
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CharUnits::fromQuantity(0)));
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Address Addr(V, Alignment);
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Addr = CGF.Builder.CreateElementBitCast(Addr,
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llvm::Type::getIntNTy(CGF.getLLVMContext(),
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Info->StorageSize));
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return LValue::MakeBitfield(Addr, *Info, IvarTy,
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LValueBaseInfo(AlignmentSource::Decl),
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TBAAAccessInfo());
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}
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namespace {
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struct CatchHandler {
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const VarDecl *Variable;
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const Stmt *Body;
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llvm::BasicBlock *Block;
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llvm::Constant *TypeInfo;
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/// Flags used to differentiate cleanups and catchalls in Windows SEH
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unsigned Flags;
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};
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struct CallObjCEndCatch final : EHScopeStack::Cleanup {
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CallObjCEndCatch(bool MightThrow, llvm::FunctionCallee Fn)
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: MightThrow(MightThrow), Fn(Fn) {}
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bool MightThrow;
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llvm::FunctionCallee Fn;
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void Emit(CodeGenFunction &CGF, Flags flags) override {
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if (MightThrow)
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CGF.EmitRuntimeCallOrInvoke(Fn);
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else
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CGF.EmitNounwindRuntimeCall(Fn);
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}
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};
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}
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void CGObjCRuntime::EmitTryCatchStmt(CodeGenFunction &CGF,
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const ObjCAtTryStmt &S,
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llvm::FunctionCallee beginCatchFn,
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llvm::FunctionCallee endCatchFn,
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llvm::FunctionCallee exceptionRethrowFn) {
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// Jump destination for falling out of catch bodies.
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CodeGenFunction::JumpDest Cont;
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if (S.getNumCatchStmts())
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Cont = CGF.getJumpDestInCurrentScope("eh.cont");
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bool useFunclets = EHPersonality::get(CGF).usesFuncletPads();
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CodeGenFunction::FinallyInfo FinallyInfo;
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if (!useFunclets)
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if (const ObjCAtFinallyStmt *Finally = S.getFinallyStmt())
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FinallyInfo.enter(CGF, Finally->getFinallyBody(),
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beginCatchFn, endCatchFn, exceptionRethrowFn);
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SmallVector<CatchHandler, 8> Handlers;
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// Enter the catch, if there is one.
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if (S.getNumCatchStmts()) {
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for (unsigned I = 0, N = S.getNumCatchStmts(); I != N; ++I) {
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const ObjCAtCatchStmt *CatchStmt = S.getCatchStmt(I);
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const VarDecl *CatchDecl = CatchStmt->getCatchParamDecl();
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Handlers.push_back(CatchHandler());
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CatchHandler &Handler = Handlers.back();
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Handler.Variable = CatchDecl;
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Handler.Body = CatchStmt->getCatchBody();
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Handler.Block = CGF.createBasicBlock("catch");
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Handler.Flags = 0;
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// @catch(...) always matches.
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if (!CatchDecl) {
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auto catchAll = getCatchAllTypeInfo();
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Handler.TypeInfo = catchAll.RTTI;
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Handler.Flags = catchAll.Flags;
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// Don't consider any other catches.
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break;
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}
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Handler.TypeInfo = GetEHType(CatchDecl->getType());
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}
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EHCatchScope *Catch = CGF.EHStack.pushCatch(Handlers.size());
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for (unsigned I = 0, E = Handlers.size(); I != E; ++I)
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Catch->setHandler(I, { Handlers[I].TypeInfo, Handlers[I].Flags }, Handlers[I].Block);
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}
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if (useFunclets)
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if (const ObjCAtFinallyStmt *Finally = S.getFinallyStmt()) {
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CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
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if (!CGF.CurSEHParent)
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CGF.CurSEHParent = cast<NamedDecl>(CGF.CurFuncDecl);
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// Outline the finally block.
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const Stmt *FinallyBlock = Finally->getFinallyBody();
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HelperCGF.startOutlinedSEHHelper(CGF, /*isFilter*/false, FinallyBlock);
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// Emit the original filter expression, convert to i32, and return.
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HelperCGF.EmitStmt(FinallyBlock);
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HelperCGF.FinishFunction(FinallyBlock->getEndLoc());
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llvm::Function *FinallyFunc = HelperCGF.CurFn;
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// Push a cleanup for __finally blocks.
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CGF.pushSEHCleanup(NormalAndEHCleanup, FinallyFunc);
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}
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// Emit the try body.
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CGF.EmitStmt(S.getTryBody());
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// Leave the try.
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if (S.getNumCatchStmts())
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CGF.popCatchScope();
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// Remember where we were.
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CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
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// Emit the handlers.
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for (unsigned I = 0, E = Handlers.size(); I != E; ++I) {
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CatchHandler &Handler = Handlers[I];
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CGF.EmitBlock(Handler.Block);
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llvm::CatchPadInst *CPI = nullptr;
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SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(CGF.CurrentFuncletPad);
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if (useFunclets)
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if ((CPI = dyn_cast_or_null<llvm::CatchPadInst>(Handler.Block->getFirstNonPHI()))) {
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CGF.CurrentFuncletPad = CPI;
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CPI->setOperand(2, CGF.getExceptionSlot().getPointer());
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}
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llvm::Value *RawExn = CGF.getExceptionFromSlot();
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// Enter the catch.
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llvm::Value *Exn = RawExn;
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if (beginCatchFn)
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Exn = CGF.EmitNounwindRuntimeCall(beginCatchFn, RawExn, "exn.adjusted");
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CodeGenFunction::LexicalScope cleanups(CGF, Handler.Body->getSourceRange());
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if (endCatchFn) {
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// Add a cleanup to leave the catch.
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bool EndCatchMightThrow = (Handler.Variable == nullptr);
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CGF.EHStack.pushCleanup<CallObjCEndCatch>(NormalAndEHCleanup,
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EndCatchMightThrow,
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endCatchFn);
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}
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// Bind the catch parameter if it exists.
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if (const VarDecl *CatchParam = Handler.Variable) {
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llvm::Type *CatchType = CGF.ConvertType(CatchParam->getType());
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llvm::Value *CastExn = CGF.Builder.CreateBitCast(Exn, CatchType);
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CGF.EmitAutoVarDecl(*CatchParam);
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EmitInitOfCatchParam(CGF, CastExn, CatchParam);
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}
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if (CPI)
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CGF.EHStack.pushCleanup<CatchRetScope>(NormalCleanup, CPI);
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CGF.ObjCEHValueStack.push_back(Exn);
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CGF.EmitStmt(Handler.Body);
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CGF.ObjCEHValueStack.pop_back();
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// Leave any cleanups associated with the catch.
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cleanups.ForceCleanup();
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CGF.EmitBranchThroughCleanup(Cont);
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}
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// Go back to the try-statement fallthrough.
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CGF.Builder.restoreIP(SavedIP);
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// Pop out of the finally.
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if (!useFunclets && S.getFinallyStmt())
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FinallyInfo.exit(CGF);
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if (Cont.isValid())
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CGF.EmitBlock(Cont.getBlock());
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}
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void CGObjCRuntime::EmitInitOfCatchParam(CodeGenFunction &CGF,
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llvm::Value *exn,
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const VarDecl *paramDecl) {
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Address paramAddr = CGF.GetAddrOfLocalVar(paramDecl);
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switch (paramDecl->getType().getQualifiers().getObjCLifetime()) {
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case Qualifiers::OCL_Strong:
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exn = CGF.EmitARCRetainNonBlock(exn);
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LLVM_FALLTHROUGH;
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case Qualifiers::OCL_None:
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case Qualifiers::OCL_ExplicitNone:
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case Qualifiers::OCL_Autoreleasing:
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CGF.Builder.CreateStore(exn, paramAddr);
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return;
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case Qualifiers::OCL_Weak:
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CGF.EmitARCInitWeak(paramAddr, exn);
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return;
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}
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llvm_unreachable("invalid ownership qualifier");
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}
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namespace {
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struct CallSyncExit final : EHScopeStack::Cleanup {
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llvm::FunctionCallee SyncExitFn;
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llvm::Value *SyncArg;
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CallSyncExit(llvm::FunctionCallee SyncExitFn, llvm::Value *SyncArg)
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: SyncExitFn(SyncExitFn), SyncArg(SyncArg) {}
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void Emit(CodeGenFunction &CGF, Flags flags) override {
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CGF.EmitNounwindRuntimeCall(SyncExitFn, SyncArg);
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}
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};
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}
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void CGObjCRuntime::EmitAtSynchronizedStmt(CodeGenFunction &CGF,
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const ObjCAtSynchronizedStmt &S,
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llvm::FunctionCallee syncEnterFn,
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llvm::FunctionCallee syncExitFn) {
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CodeGenFunction::RunCleanupsScope cleanups(CGF);
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// Evaluate the lock operand. This is guaranteed to dominate the
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// ARC release and lock-release cleanups.
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const Expr *lockExpr = S.getSynchExpr();
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llvm::Value *lock;
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if (CGF.getLangOpts().ObjCAutoRefCount) {
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lock = CGF.EmitARCRetainScalarExpr(lockExpr);
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lock = CGF.EmitObjCConsumeObject(lockExpr->getType(), lock);
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} else {
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lock = CGF.EmitScalarExpr(lockExpr);
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}
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lock = CGF.Builder.CreateBitCast(lock, CGF.VoidPtrTy);
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// Acquire the lock.
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CGF.Builder.CreateCall(syncEnterFn, lock)->setDoesNotThrow();
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||
|
|
|
||
|
|
// Register an all-paths cleanup to release the lock.
|
||
|
|
CGF.EHStack.pushCleanup<CallSyncExit>(NormalAndEHCleanup, syncExitFn, lock);
|
||
|
|
|
||
|
|
// Emit the body of the statement.
|
||
|
|
CGF.EmitStmt(S.getSynchBody());
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Compute the pointer-to-function type to which a message send
|
||
|
|
/// should be casted in order to correctly call the given method
|
||
|
|
/// with the given arguments.
|
||
|
|
///
|
||
|
|
/// \param method - may be null
|
||
|
|
/// \param resultType - the result type to use if there's no method
|
||
|
|
/// \param callArgs - the actual arguments, including implicit ones
|
||
|
|
CGObjCRuntime::MessageSendInfo
|
||
|
|
CGObjCRuntime::getMessageSendInfo(const ObjCMethodDecl *method,
|
||
|
|
QualType resultType,
|
||
|
|
CallArgList &callArgs) {
|
||
|
|
// If there's a method, use information from that.
|
||
|
|
if (method) {
|
||
|
|
const CGFunctionInfo &signature =
|
||
|
|
CGM.getTypes().arrangeObjCMessageSendSignature(method, callArgs[0].Ty);
|
||
|
|
|
||
|
|
llvm::PointerType *signatureType =
|
||
|
|
CGM.getTypes().GetFunctionType(signature)->getPointerTo();
|
||
|
|
|
||
|
|
const CGFunctionInfo &signatureForCall =
|
||
|
|
CGM.getTypes().arrangeCall(signature, callArgs);
|
||
|
|
|
||
|
|
return MessageSendInfo(signatureForCall, signatureType);
|
||
|
|
}
|
||
|
|
|
||
|
|
// There's no method; just use a default CC.
|
||
|
|
const CGFunctionInfo &argsInfo =
|
||
|
|
CGM.getTypes().arrangeUnprototypedObjCMessageSend(resultType, callArgs);
|
||
|
|
|
||
|
|
// Derive the signature to call from that.
|
||
|
|
llvm::PointerType *signatureType =
|
||
|
|
CGM.getTypes().GetFunctionType(argsInfo)->getPointerTo();
|
||
|
|
return MessageSendInfo(argsInfo, signatureType);
|
||
|
|
}
|
||
|
|
|
||
|
|
llvm::Constant *
|
||
|
|
clang::CodeGen::emitObjCProtocolObject(CodeGenModule &CGM,
|
||
|
|
const ObjCProtocolDecl *protocol) {
|
||
|
|
return CGM.getObjCRuntime().GetOrEmitProtocol(protocol);
|
||
|
|
}
|
||
|
|
|
||
|
|
std::string CGObjCRuntime::getSymbolNameForMethod(const ObjCMethodDecl *OMD,
|
||
|
|
bool includeCategoryName) {
|
||
|
|
std::string buffer;
|
||
|
|
llvm::raw_string_ostream out(buffer);
|
||
|
|
CGM.getCXXABI().getMangleContext().mangleObjCMethodName(OMD, out,
|
||
|
|
/*includePrefixByte=*/true,
|
||
|
|
includeCategoryName);
|
||
|
|
return buffer;
|
||
|
|
}
|