forked from OSchip/llvm-project
2279 lines
84 KiB
C++
2279 lines
84 KiB
C++
//===--- CGException.cpp - Emit LLVM Code for C++ exceptions ----*- C++ -*-===//
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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 contains code dealing with C++ exception related code generation.
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//
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//===----------------------------------------------------------------------===//
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#include "CGCXXABI.h"
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#include "CGCleanup.h"
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#include "CGObjCRuntime.h"
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#include "CodeGenFunction.h"
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#include "ConstantEmitter.h"
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#include "TargetInfo.h"
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#include "clang/AST/Mangle.h"
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#include "clang/AST/StmtCXX.h"
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#include "clang/AST/StmtObjC.h"
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#include "clang/AST/StmtVisitor.h"
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#include "clang/Basic/DiagnosticSema.h"
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#include "clang/Basic/TargetBuiltins.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/Intrinsics.h"
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#include "llvm/IR/IntrinsicsWebAssembly.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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static llvm::FunctionCallee getFreeExceptionFn(CodeGenModule &CGM) {
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// void __cxa_free_exception(void *thrown_exception);
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
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return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
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}
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static llvm::FunctionCallee getSehTryBeginFn(CodeGenModule &CGM) {
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
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return CGM.CreateRuntimeFunction(FTy, "llvm.seh.try.begin");
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}
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static llvm::FunctionCallee getSehTryEndFn(CodeGenModule &CGM) {
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
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return CGM.CreateRuntimeFunction(FTy, "llvm.seh.try.end");
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}
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static llvm::FunctionCallee getUnexpectedFn(CodeGenModule &CGM) {
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// void __cxa_call_unexpected(void *thrown_exception);
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
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return CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
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}
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llvm::FunctionCallee CodeGenModule::getTerminateFn() {
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// void __terminate();
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(VoidTy, /*isVarArg=*/false);
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StringRef name;
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// In C++, use std::terminate().
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if (getLangOpts().CPlusPlus &&
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getTarget().getCXXABI().isItaniumFamily()) {
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name = "_ZSt9terminatev";
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} else if (getLangOpts().CPlusPlus &&
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getTarget().getCXXABI().isMicrosoft()) {
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if (getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015))
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name = "__std_terminate";
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else
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name = "?terminate@@YAXXZ";
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} else if (getLangOpts().ObjC &&
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getLangOpts().ObjCRuntime.hasTerminate())
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name = "objc_terminate";
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else
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name = "abort";
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return CreateRuntimeFunction(FTy, name);
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}
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static llvm::FunctionCallee getCatchallRethrowFn(CodeGenModule &CGM,
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StringRef Name) {
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
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return CGM.CreateRuntimeFunction(FTy, Name);
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}
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const EHPersonality EHPersonality::GNU_C = { "__gcc_personality_v0", nullptr };
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const EHPersonality
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EHPersonality::GNU_C_SJLJ = { "__gcc_personality_sj0", nullptr };
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const EHPersonality
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EHPersonality::GNU_C_SEH = { "__gcc_personality_seh0", nullptr };
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const EHPersonality
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EHPersonality::NeXT_ObjC = { "__objc_personality_v0", nullptr };
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const EHPersonality
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EHPersonality::GNU_CPlusPlus = { "__gxx_personality_v0", nullptr };
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const EHPersonality
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EHPersonality::GNU_CPlusPlus_SJLJ = { "__gxx_personality_sj0", nullptr };
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const EHPersonality
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EHPersonality::GNU_CPlusPlus_SEH = { "__gxx_personality_seh0", nullptr };
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const EHPersonality
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EHPersonality::GNU_ObjC = {"__gnu_objc_personality_v0", "objc_exception_throw"};
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const EHPersonality
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EHPersonality::GNU_ObjC_SJLJ = {"__gnu_objc_personality_sj0", "objc_exception_throw"};
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const EHPersonality
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EHPersonality::GNU_ObjC_SEH = {"__gnu_objc_personality_seh0", "objc_exception_throw"};
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const EHPersonality
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EHPersonality::GNU_ObjCXX = { "__gnustep_objcxx_personality_v0", nullptr };
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const EHPersonality
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EHPersonality::GNUstep_ObjC = { "__gnustep_objc_personality_v0", nullptr };
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const EHPersonality
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EHPersonality::MSVC_except_handler = { "_except_handler3", nullptr };
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const EHPersonality
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EHPersonality::MSVC_C_specific_handler = { "__C_specific_handler", nullptr };
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const EHPersonality
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EHPersonality::MSVC_CxxFrameHandler3 = { "__CxxFrameHandler3", nullptr };
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const EHPersonality
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EHPersonality::GNU_Wasm_CPlusPlus = { "__gxx_wasm_personality_v0", nullptr };
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const EHPersonality EHPersonality::XL_CPlusPlus = {"__xlcxx_personality_v1",
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nullptr};
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static const EHPersonality &getCPersonality(const TargetInfo &Target,
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const LangOptions &L) {
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const llvm::Triple &T = Target.getTriple();
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if (T.isWindowsMSVCEnvironment())
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return EHPersonality::MSVC_CxxFrameHandler3;
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if (L.hasSjLjExceptions())
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return EHPersonality::GNU_C_SJLJ;
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if (L.hasDWARFExceptions())
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return EHPersonality::GNU_C;
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if (L.hasSEHExceptions())
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return EHPersonality::GNU_C_SEH;
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return EHPersonality::GNU_C;
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}
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static const EHPersonality &getObjCPersonality(const TargetInfo &Target,
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const LangOptions &L) {
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const llvm::Triple &T = Target.getTriple();
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if (T.isWindowsMSVCEnvironment())
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return EHPersonality::MSVC_CxxFrameHandler3;
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switch (L.ObjCRuntime.getKind()) {
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case ObjCRuntime::FragileMacOSX:
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return getCPersonality(Target, L);
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case ObjCRuntime::MacOSX:
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case ObjCRuntime::iOS:
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case ObjCRuntime::WatchOS:
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return EHPersonality::NeXT_ObjC;
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case ObjCRuntime::GNUstep:
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if (L.ObjCRuntime.getVersion() >= VersionTuple(1, 7))
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return EHPersonality::GNUstep_ObjC;
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LLVM_FALLTHROUGH;
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case ObjCRuntime::GCC:
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case ObjCRuntime::ObjFW:
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if (L.hasSjLjExceptions())
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return EHPersonality::GNU_ObjC_SJLJ;
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if (L.hasSEHExceptions())
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return EHPersonality::GNU_ObjC_SEH;
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return EHPersonality::GNU_ObjC;
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}
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llvm_unreachable("bad runtime kind");
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}
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static const EHPersonality &getCXXPersonality(const TargetInfo &Target,
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const LangOptions &L) {
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const llvm::Triple &T = Target.getTriple();
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if (T.isWindowsMSVCEnvironment())
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return EHPersonality::MSVC_CxxFrameHandler3;
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if (T.isOSAIX())
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return EHPersonality::XL_CPlusPlus;
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if (L.hasSjLjExceptions())
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return EHPersonality::GNU_CPlusPlus_SJLJ;
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if (L.hasDWARFExceptions())
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return EHPersonality::GNU_CPlusPlus;
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if (L.hasSEHExceptions())
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return EHPersonality::GNU_CPlusPlus_SEH;
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if (L.hasWasmExceptions())
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return EHPersonality::GNU_Wasm_CPlusPlus;
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return EHPersonality::GNU_CPlusPlus;
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}
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/// Determines the personality function to use when both C++
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/// and Objective-C exceptions are being caught.
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static const EHPersonality &getObjCXXPersonality(const TargetInfo &Target,
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const LangOptions &L) {
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if (Target.getTriple().isWindowsMSVCEnvironment())
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return EHPersonality::MSVC_CxxFrameHandler3;
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switch (L.ObjCRuntime.getKind()) {
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// In the fragile ABI, just use C++ exception handling and hope
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// they're not doing crazy exception mixing.
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case ObjCRuntime::FragileMacOSX:
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return getCXXPersonality(Target, L);
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// The ObjC personality defers to the C++ personality for non-ObjC
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// handlers. Unlike the C++ case, we use the same personality
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// function on targets using (backend-driven) SJLJ EH.
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case ObjCRuntime::MacOSX:
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case ObjCRuntime::iOS:
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case ObjCRuntime::WatchOS:
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return getObjCPersonality(Target, L);
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case ObjCRuntime::GNUstep:
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return EHPersonality::GNU_ObjCXX;
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// The GCC runtime's personality function inherently doesn't support
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// mixed EH. Use the ObjC personality just to avoid returning null.
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case ObjCRuntime::GCC:
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case ObjCRuntime::ObjFW:
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return getObjCPersonality(Target, L);
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}
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llvm_unreachable("bad runtime kind");
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}
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static const EHPersonality &getSEHPersonalityMSVC(const llvm::Triple &T) {
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if (T.getArch() == llvm::Triple::x86)
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return EHPersonality::MSVC_except_handler;
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return EHPersonality::MSVC_C_specific_handler;
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}
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const EHPersonality &EHPersonality::get(CodeGenModule &CGM,
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const FunctionDecl *FD) {
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const llvm::Triple &T = CGM.getTarget().getTriple();
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const LangOptions &L = CGM.getLangOpts();
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const TargetInfo &Target = CGM.getTarget();
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// Functions using SEH get an SEH personality.
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if (FD && FD->usesSEHTry())
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return getSEHPersonalityMSVC(T);
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if (L.ObjC)
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return L.CPlusPlus ? getObjCXXPersonality(Target, L)
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: getObjCPersonality(Target, L);
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return L.CPlusPlus ? getCXXPersonality(Target, L)
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: getCPersonality(Target, L);
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}
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const EHPersonality &EHPersonality::get(CodeGenFunction &CGF) {
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const auto *FD = CGF.CurCodeDecl;
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// For outlined finallys and filters, use the SEH personality in case they
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// contain more SEH. This mostly only affects finallys. Filters could
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// hypothetically use gnu statement expressions to sneak in nested SEH.
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FD = FD ? FD : CGF.CurSEHParent;
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return get(CGF.CGM, dyn_cast_or_null<FunctionDecl>(FD));
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}
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static llvm::FunctionCallee getPersonalityFn(CodeGenModule &CGM,
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const EHPersonality &Personality) {
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return CGM.CreateRuntimeFunction(llvm::FunctionType::get(CGM.Int32Ty, true),
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Personality.PersonalityFn,
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llvm::AttributeList(), /*Local=*/true);
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}
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static llvm::Constant *getOpaquePersonalityFn(CodeGenModule &CGM,
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const EHPersonality &Personality) {
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llvm::FunctionCallee Fn = getPersonalityFn(CGM, Personality);
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llvm::PointerType* Int8PtrTy = llvm::PointerType::get(
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llvm::Type::getInt8Ty(CGM.getLLVMContext()),
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CGM.getDataLayout().getProgramAddressSpace());
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return llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(Fn.getCallee()),
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Int8PtrTy);
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}
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/// Check whether a landingpad instruction only uses C++ features.
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static bool LandingPadHasOnlyCXXUses(llvm::LandingPadInst *LPI) {
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for (unsigned I = 0, E = LPI->getNumClauses(); I != E; ++I) {
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// Look for something that would've been returned by the ObjC
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// runtime's GetEHType() method.
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llvm::Value *Val = LPI->getClause(I)->stripPointerCasts();
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if (LPI->isCatch(I)) {
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// Check if the catch value has the ObjC prefix.
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if (llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Val))
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// ObjC EH selector entries are always global variables with
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// names starting like this.
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if (GV->getName().startswith("OBJC_EHTYPE"))
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return false;
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} else {
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// Check if any of the filter values have the ObjC prefix.
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llvm::Constant *CVal = cast<llvm::Constant>(Val);
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for (llvm::User::op_iterator
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II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II) {
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if (llvm::GlobalVariable *GV =
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cast<llvm::GlobalVariable>((*II)->stripPointerCasts()))
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// ObjC EH selector entries are always global variables with
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// names starting like this.
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if (GV->getName().startswith("OBJC_EHTYPE"))
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return false;
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}
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}
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}
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return true;
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}
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/// Check whether a personality function could reasonably be swapped
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/// for a C++ personality function.
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static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn) {
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for (llvm::User *U : Fn->users()) {
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// Conditionally white-list bitcasts.
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if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(U)) {
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if (CE->getOpcode() != llvm::Instruction::BitCast) return false;
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if (!PersonalityHasOnlyCXXUses(CE))
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return false;
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continue;
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}
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// Otherwise it must be a function.
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llvm::Function *F = dyn_cast<llvm::Function>(U);
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if (!F) return false;
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for (auto BB = F->begin(), E = F->end(); BB != E; ++BB) {
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if (BB->isLandingPad())
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if (!LandingPadHasOnlyCXXUses(BB->getLandingPadInst()))
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return false;
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}
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}
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return true;
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}
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/// Try to use the C++ personality function in ObjC++. Not doing this
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/// can cause some incompatibilities with gcc, which is more
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/// aggressive about only using the ObjC++ personality in a function
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/// when it really needs it.
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void CodeGenModule::SimplifyPersonality() {
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// If we're not in ObjC++ -fexceptions, there's nothing to do.
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if (!LangOpts.CPlusPlus || !LangOpts.ObjC || !LangOpts.Exceptions)
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return;
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// Both the problem this endeavors to fix and the way the logic
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// above works is specific to the NeXT runtime.
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if (!LangOpts.ObjCRuntime.isNeXTFamily())
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return;
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const EHPersonality &ObjCXX = EHPersonality::get(*this, /*FD=*/nullptr);
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const EHPersonality &CXX = getCXXPersonality(getTarget(), LangOpts);
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if (&ObjCXX == &CXX)
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return;
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assert(std::strcmp(ObjCXX.PersonalityFn, CXX.PersonalityFn) != 0 &&
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"Different EHPersonalities using the same personality function.");
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llvm::Function *Fn = getModule().getFunction(ObjCXX.PersonalityFn);
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// Nothing to do if it's unused.
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if (!Fn || Fn->use_empty()) return;
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// Can't do the optimization if it has non-C++ uses.
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if (!PersonalityHasOnlyCXXUses(Fn)) return;
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// Create the C++ personality function and kill off the old
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// function.
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llvm::FunctionCallee CXXFn = getPersonalityFn(*this, CXX);
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// This can happen if the user is screwing with us.
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if (Fn->getType() != CXXFn.getCallee()->getType())
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return;
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Fn->replaceAllUsesWith(CXXFn.getCallee());
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Fn->eraseFromParent();
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}
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/// Returns the value to inject into a selector to indicate the
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/// presence of a catch-all.
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static llvm::Constant *getCatchAllValue(CodeGenFunction &CGF) {
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// Possibly we should use @llvm.eh.catch.all.value here.
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return llvm::ConstantPointerNull::get(CGF.Int8PtrTy);
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}
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namespace {
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/// A cleanup to free the exception object if its initialization
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/// throws.
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struct FreeException final : EHScopeStack::Cleanup {
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llvm::Value *exn;
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FreeException(llvm::Value *exn) : exn(exn) {}
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void Emit(CodeGenFunction &CGF, Flags flags) override {
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CGF.EmitNounwindRuntimeCall(getFreeExceptionFn(CGF.CGM), exn);
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}
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};
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} // end anonymous namespace
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// Emits an exception expression into the given location. This
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// differs from EmitAnyExprToMem only in that, if a final copy-ctor
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// call is required, an exception within that copy ctor causes
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// std::terminate to be invoked.
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void CodeGenFunction::EmitAnyExprToExn(const Expr *e, Address addr) {
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// Make sure the exception object is cleaned up if there's an
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// exception during initialization.
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pushFullExprCleanup<FreeException>(EHCleanup, addr.getPointer());
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EHScopeStack::stable_iterator cleanup = EHStack.stable_begin();
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// __cxa_allocate_exception returns a void*; we need to cast this
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// to the appropriate type for the object.
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llvm::Type *ty = ConvertTypeForMem(e->getType())->getPointerTo();
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Address typedAddr = Builder.CreateBitCast(addr, ty);
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// FIXME: this isn't quite right! If there's a final unelided call
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// to a copy constructor, then according to [except.terminate]p1 we
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// must call std::terminate() if that constructor throws, because
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// technically that copy occurs after the exception expression is
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// evaluated but before the exception is caught. But the best way
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// to handle that is to teach EmitAggExpr to do the final copy
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// differently if it can't be elided.
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EmitAnyExprToMem(e, typedAddr, e->getType().getQualifiers(),
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/*IsInit*/ true);
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// Deactivate the cleanup block.
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DeactivateCleanupBlock(cleanup,
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cast<llvm::Instruction>(typedAddr.getPointer()));
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}
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Address CodeGenFunction::getExceptionSlot() {
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if (!ExceptionSlot)
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ExceptionSlot = CreateTempAlloca(Int8PtrTy, "exn.slot");
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return Address(ExceptionSlot, getPointerAlign());
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}
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Address CodeGenFunction::getEHSelectorSlot() {
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if (!EHSelectorSlot)
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EHSelectorSlot = CreateTempAlloca(Int32Ty, "ehselector.slot");
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return Address(EHSelectorSlot, CharUnits::fromQuantity(4));
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}
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llvm::Value *CodeGenFunction::getExceptionFromSlot() {
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return Builder.CreateLoad(getExceptionSlot(), "exn");
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}
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llvm::Value *CodeGenFunction::getSelectorFromSlot() {
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return Builder.CreateLoad(getEHSelectorSlot(), "sel");
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}
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void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E,
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bool KeepInsertionPoint) {
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if (const Expr *SubExpr = E->getSubExpr()) {
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QualType ThrowType = SubExpr->getType();
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if (ThrowType->isObjCObjectPointerType()) {
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|
const Stmt *ThrowStmt = E->getSubExpr();
|
|
const ObjCAtThrowStmt S(E->getExprLoc(), const_cast<Stmt *>(ThrowStmt));
|
|
CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
|
|
} else {
|
|
CGM.getCXXABI().emitThrow(*this, E);
|
|
}
|
|
} else {
|
|
CGM.getCXXABI().emitRethrow(*this, /*isNoReturn=*/true);
|
|
}
|
|
|
|
// throw is an expression, and the expression emitters expect us
|
|
// to leave ourselves at a valid insertion point.
|
|
if (KeepInsertionPoint)
|
|
EmitBlock(createBasicBlock("throw.cont"));
|
|
}
|
|
|
|
void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
|
|
if (!CGM.getLangOpts().CXXExceptions)
|
|
return;
|
|
|
|
const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
|
|
if (!FD) {
|
|
// Check if CapturedDecl is nothrow and create terminate scope for it.
|
|
if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
|
|
if (CD->isNothrow())
|
|
EHStack.pushTerminate();
|
|
}
|
|
return;
|
|
}
|
|
const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
|
|
if (!Proto)
|
|
return;
|
|
|
|
ExceptionSpecificationType EST = Proto->getExceptionSpecType();
|
|
if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
|
|
// noexcept functions are simple terminate scopes.
|
|
if (!getLangOpts().EHAsynch) // -EHa: HW exception still can occur
|
|
EHStack.pushTerminate();
|
|
} else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
|
|
// TODO: Revisit exception specifications for the MS ABI. There is a way to
|
|
// encode these in an object file but MSVC doesn't do anything with it.
|
|
if (getTarget().getCXXABI().isMicrosoft())
|
|
return;
|
|
// In Wasm EH we currently treat 'throw()' in the same way as 'noexcept'. In
|
|
// case of throw with types, we ignore it and print a warning for now.
|
|
// TODO Correctly handle exception specification in Wasm EH
|
|
if (CGM.getLangOpts().hasWasmExceptions()) {
|
|
if (EST == EST_DynamicNone)
|
|
EHStack.pushTerminate();
|
|
else
|
|
CGM.getDiags().Report(D->getLocation(),
|
|
diag::warn_wasm_dynamic_exception_spec_ignored)
|
|
<< FD->getExceptionSpecSourceRange();
|
|
return;
|
|
}
|
|
// Currently Emscripten EH only handles 'throw()' but not 'throw' with
|
|
// types. 'throw()' handling will be done in JS glue code so we don't need
|
|
// to do anything in that case. Just print a warning message in case of
|
|
// throw with types.
|
|
// TODO Correctly handle exception specification in Emscripten EH
|
|
if (getTarget().getCXXABI() == TargetCXXABI::WebAssembly &&
|
|
CGM.getLangOpts().getExceptionHandling() ==
|
|
LangOptions::ExceptionHandlingKind::None &&
|
|
EST == EST_Dynamic)
|
|
CGM.getDiags().Report(D->getLocation(),
|
|
diag::warn_wasm_dynamic_exception_spec_ignored)
|
|
<< FD->getExceptionSpecSourceRange();
|
|
|
|
unsigned NumExceptions = Proto->getNumExceptions();
|
|
EHFilterScope *Filter = EHStack.pushFilter(NumExceptions);
|
|
|
|
for (unsigned I = 0; I != NumExceptions; ++I) {
|
|
QualType Ty = Proto->getExceptionType(I);
|
|
QualType ExceptType = Ty.getNonReferenceType().getUnqualifiedType();
|
|
llvm::Value *EHType = CGM.GetAddrOfRTTIDescriptor(ExceptType,
|
|
/*ForEH=*/true);
|
|
Filter->setFilter(I, EHType);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Emit the dispatch block for a filter scope if necessary.
|
|
static void emitFilterDispatchBlock(CodeGenFunction &CGF,
|
|
EHFilterScope &filterScope) {
|
|
llvm::BasicBlock *dispatchBlock = filterScope.getCachedEHDispatchBlock();
|
|
if (!dispatchBlock) return;
|
|
if (dispatchBlock->use_empty()) {
|
|
delete dispatchBlock;
|
|
return;
|
|
}
|
|
|
|
CGF.EmitBlockAfterUses(dispatchBlock);
|
|
|
|
// If this isn't a catch-all filter, we need to check whether we got
|
|
// here because the filter triggered.
|
|
if (filterScope.getNumFilters()) {
|
|
// Load the selector value.
|
|
llvm::Value *selector = CGF.getSelectorFromSlot();
|
|
llvm::BasicBlock *unexpectedBB = CGF.createBasicBlock("ehspec.unexpected");
|
|
|
|
llvm::Value *zero = CGF.Builder.getInt32(0);
|
|
llvm::Value *failsFilter =
|
|
CGF.Builder.CreateICmpSLT(selector, zero, "ehspec.fails");
|
|
CGF.Builder.CreateCondBr(failsFilter, unexpectedBB,
|
|
CGF.getEHResumeBlock(false));
|
|
|
|
CGF.EmitBlock(unexpectedBB);
|
|
}
|
|
|
|
// Call __cxa_call_unexpected. This doesn't need to be an invoke
|
|
// because __cxa_call_unexpected magically filters exceptions
|
|
// according to the last landing pad the exception was thrown
|
|
// into. Seriously.
|
|
llvm::Value *exn = CGF.getExceptionFromSlot();
|
|
CGF.EmitRuntimeCall(getUnexpectedFn(CGF.CGM), exn)
|
|
->setDoesNotReturn();
|
|
CGF.Builder.CreateUnreachable();
|
|
}
|
|
|
|
void CodeGenFunction::EmitEndEHSpec(const Decl *D) {
|
|
if (!CGM.getLangOpts().CXXExceptions)
|
|
return;
|
|
|
|
const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
|
|
if (!FD) {
|
|
// Check if CapturedDecl is nothrow and pop terminate scope for it.
|
|
if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
|
|
if (CD->isNothrow() && !EHStack.empty())
|
|
EHStack.popTerminate();
|
|
}
|
|
return;
|
|
}
|
|
const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
|
|
if (!Proto)
|
|
return;
|
|
|
|
ExceptionSpecificationType EST = Proto->getExceptionSpecType();
|
|
if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot &&
|
|
!EHStack.empty() /* possible empty when under async exceptions */) {
|
|
EHStack.popTerminate();
|
|
} else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
|
|
// TODO: Revisit exception specifications for the MS ABI. There is a way to
|
|
// encode these in an object file but MSVC doesn't do anything with it.
|
|
if (getTarget().getCXXABI().isMicrosoft())
|
|
return;
|
|
// In wasm we currently treat 'throw()' in the same way as 'noexcept'. In
|
|
// case of throw with types, we ignore it and print a warning for now.
|
|
// TODO Correctly handle exception specification in wasm
|
|
if (CGM.getLangOpts().hasWasmExceptions()) {
|
|
if (EST == EST_DynamicNone)
|
|
EHStack.popTerminate();
|
|
return;
|
|
}
|
|
EHFilterScope &filterScope = cast<EHFilterScope>(*EHStack.begin());
|
|
emitFilterDispatchBlock(*this, filterScope);
|
|
EHStack.popFilter();
|
|
}
|
|
}
|
|
|
|
void CodeGenFunction::EmitCXXTryStmt(const CXXTryStmt &S) {
|
|
EnterCXXTryStmt(S);
|
|
EmitStmt(S.getTryBlock());
|
|
ExitCXXTryStmt(S);
|
|
}
|
|
|
|
void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
|
|
unsigned NumHandlers = S.getNumHandlers();
|
|
EHCatchScope *CatchScope = EHStack.pushCatch(NumHandlers);
|
|
|
|
for (unsigned I = 0; I != NumHandlers; ++I) {
|
|
const CXXCatchStmt *C = S.getHandler(I);
|
|
|
|
llvm::BasicBlock *Handler = createBasicBlock("catch");
|
|
if (C->getExceptionDecl()) {
|
|
// FIXME: Dropping the reference type on the type into makes it
|
|
// impossible to correctly implement catch-by-reference
|
|
// semantics for pointers. Unfortunately, this is what all
|
|
// existing compilers do, and it's not clear that the standard
|
|
// personality routine is capable of doing this right. See C++ DR 388:
|
|
// http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#388
|
|
Qualifiers CaughtTypeQuals;
|
|
QualType CaughtType = CGM.getContext().getUnqualifiedArrayType(
|
|
C->getCaughtType().getNonReferenceType(), CaughtTypeQuals);
|
|
|
|
CatchTypeInfo TypeInfo{nullptr, 0};
|
|
if (CaughtType->isObjCObjectPointerType())
|
|
TypeInfo.RTTI = CGM.getObjCRuntime().GetEHType(CaughtType);
|
|
else
|
|
TypeInfo = CGM.getCXXABI().getAddrOfCXXCatchHandlerType(
|
|
CaughtType, C->getCaughtType());
|
|
CatchScope->setHandler(I, TypeInfo, Handler);
|
|
} else {
|
|
// No exception decl indicates '...', a catch-all.
|
|
CatchScope->setHandler(I, CGM.getCXXABI().getCatchAllTypeInfo(), Handler);
|
|
// Under async exceptions, catch(...) need to catch HW exception too
|
|
// Mark scope with SehTryBegin as a SEH __try scope
|
|
if (getLangOpts().EHAsynch)
|
|
EmitRuntimeCallOrInvoke(getSehTryBeginFn(CGM));
|
|
}
|
|
}
|
|
}
|
|
|
|
llvm::BasicBlock *
|
|
CodeGenFunction::getEHDispatchBlock(EHScopeStack::stable_iterator si) {
|
|
if (EHPersonality::get(*this).usesFuncletPads())
|
|
return getFuncletEHDispatchBlock(si);
|
|
|
|
// The dispatch block for the end of the scope chain is a block that
|
|
// just resumes unwinding.
|
|
if (si == EHStack.stable_end())
|
|
return getEHResumeBlock(true);
|
|
|
|
// Otherwise, we should look at the actual scope.
|
|
EHScope &scope = *EHStack.find(si);
|
|
|
|
llvm::BasicBlock *dispatchBlock = scope.getCachedEHDispatchBlock();
|
|
if (!dispatchBlock) {
|
|
switch (scope.getKind()) {
|
|
case EHScope::Catch: {
|
|
// Apply a special case to a single catch-all.
|
|
EHCatchScope &catchScope = cast<EHCatchScope>(scope);
|
|
if (catchScope.getNumHandlers() == 1 &&
|
|
catchScope.getHandler(0).isCatchAll()) {
|
|
dispatchBlock = catchScope.getHandler(0).Block;
|
|
|
|
// Otherwise, make a dispatch block.
|
|
} else {
|
|
dispatchBlock = createBasicBlock("catch.dispatch");
|
|
}
|
|
break;
|
|
}
|
|
|
|
case EHScope::Cleanup:
|
|
dispatchBlock = createBasicBlock("ehcleanup");
|
|
break;
|
|
|
|
case EHScope::Filter:
|
|
dispatchBlock = createBasicBlock("filter.dispatch");
|
|
break;
|
|
|
|
case EHScope::Terminate:
|
|
dispatchBlock = getTerminateHandler();
|
|
break;
|
|
}
|
|
scope.setCachedEHDispatchBlock(dispatchBlock);
|
|
}
|
|
return dispatchBlock;
|
|
}
|
|
|
|
llvm::BasicBlock *
|
|
CodeGenFunction::getFuncletEHDispatchBlock(EHScopeStack::stable_iterator SI) {
|
|
// Returning nullptr indicates that the previous dispatch block should unwind
|
|
// to caller.
|
|
if (SI == EHStack.stable_end())
|
|
return nullptr;
|
|
|
|
// Otherwise, we should look at the actual scope.
|
|
EHScope &EHS = *EHStack.find(SI);
|
|
|
|
llvm::BasicBlock *DispatchBlock = EHS.getCachedEHDispatchBlock();
|
|
if (DispatchBlock)
|
|
return DispatchBlock;
|
|
|
|
if (EHS.getKind() == EHScope::Terminate)
|
|
DispatchBlock = getTerminateFunclet();
|
|
else
|
|
DispatchBlock = createBasicBlock();
|
|
CGBuilderTy Builder(*this, DispatchBlock);
|
|
|
|
switch (EHS.getKind()) {
|
|
case EHScope::Catch:
|
|
DispatchBlock->setName("catch.dispatch");
|
|
break;
|
|
|
|
case EHScope::Cleanup:
|
|
DispatchBlock->setName("ehcleanup");
|
|
break;
|
|
|
|
case EHScope::Filter:
|
|
llvm_unreachable("exception specifications not handled yet!");
|
|
|
|
case EHScope::Terminate:
|
|
DispatchBlock->setName("terminate");
|
|
break;
|
|
}
|
|
EHS.setCachedEHDispatchBlock(DispatchBlock);
|
|
return DispatchBlock;
|
|
}
|
|
|
|
/// Check whether this is a non-EH scope, i.e. a scope which doesn't
|
|
/// affect exception handling. Currently, the only non-EH scopes are
|
|
/// normal-only cleanup scopes.
|
|
static bool isNonEHScope(const EHScope &S) {
|
|
switch (S.getKind()) {
|
|
case EHScope::Cleanup:
|
|
return !cast<EHCleanupScope>(S).isEHCleanup();
|
|
case EHScope::Filter:
|
|
case EHScope::Catch:
|
|
case EHScope::Terminate:
|
|
return false;
|
|
}
|
|
|
|
llvm_unreachable("Invalid EHScope Kind!");
|
|
}
|
|
|
|
llvm::BasicBlock *CodeGenFunction::getInvokeDestImpl() {
|
|
assert(EHStack.requiresLandingPad());
|
|
assert(!EHStack.empty());
|
|
|
|
// If exceptions are disabled/ignored and SEH is not in use, then there is no
|
|
// invoke destination. SEH "works" even if exceptions are off. In practice,
|
|
// this means that C++ destructors and other EH cleanups don't run, which is
|
|
// consistent with MSVC's behavior, except in the presence of -EHa
|
|
const LangOptions &LO = CGM.getLangOpts();
|
|
if (!LO.Exceptions || LO.IgnoreExceptions) {
|
|
if (!LO.Borland && !LO.MicrosoftExt)
|
|
return nullptr;
|
|
if (!currentFunctionUsesSEHTry())
|
|
return nullptr;
|
|
}
|
|
|
|
// CUDA device code doesn't have exceptions.
|
|
if (LO.CUDA && LO.CUDAIsDevice)
|
|
return nullptr;
|
|
|
|
// Check the innermost scope for a cached landing pad. If this is
|
|
// a non-EH cleanup, we'll check enclosing scopes in EmitLandingPad.
|
|
llvm::BasicBlock *LP = EHStack.begin()->getCachedLandingPad();
|
|
if (LP) return LP;
|
|
|
|
const EHPersonality &Personality = EHPersonality::get(*this);
|
|
|
|
if (!CurFn->hasPersonalityFn())
|
|
CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
|
|
|
|
if (Personality.usesFuncletPads()) {
|
|
// We don't need separate landing pads in the funclet model.
|
|
LP = getEHDispatchBlock(EHStack.getInnermostEHScope());
|
|
} else {
|
|
// Build the landing pad for this scope.
|
|
LP = EmitLandingPad();
|
|
}
|
|
|
|
assert(LP);
|
|
|
|
// Cache the landing pad on the innermost scope. If this is a
|
|
// non-EH scope, cache the landing pad on the enclosing scope, too.
|
|
for (EHScopeStack::iterator ir = EHStack.begin(); true; ++ir) {
|
|
ir->setCachedLandingPad(LP);
|
|
if (!isNonEHScope(*ir)) break;
|
|
}
|
|
|
|
return LP;
|
|
}
|
|
|
|
llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
|
|
assert(EHStack.requiresLandingPad());
|
|
assert(!CGM.getLangOpts().IgnoreExceptions &&
|
|
"LandingPad should not be emitted when -fignore-exceptions are in "
|
|
"effect.");
|
|
EHScope &innermostEHScope = *EHStack.find(EHStack.getInnermostEHScope());
|
|
switch (innermostEHScope.getKind()) {
|
|
case EHScope::Terminate:
|
|
return getTerminateLandingPad();
|
|
|
|
case EHScope::Catch:
|
|
case EHScope::Cleanup:
|
|
case EHScope::Filter:
|
|
if (llvm::BasicBlock *lpad = innermostEHScope.getCachedLandingPad())
|
|
return lpad;
|
|
}
|
|
|
|
// Save the current IR generation state.
|
|
CGBuilderTy::InsertPoint savedIP = Builder.saveAndClearIP();
|
|
auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, CurEHLocation);
|
|
|
|
// Create and configure the landing pad.
|
|
llvm::BasicBlock *lpad = createBasicBlock("lpad");
|
|
EmitBlock(lpad);
|
|
|
|
llvm::LandingPadInst *LPadInst =
|
|
Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
|
|
|
|
llvm::Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
|
|
Builder.CreateStore(LPadExn, getExceptionSlot());
|
|
llvm::Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
|
|
Builder.CreateStore(LPadSel, getEHSelectorSlot());
|
|
|
|
// Save the exception pointer. It's safe to use a single exception
|
|
// pointer per function because EH cleanups can never have nested
|
|
// try/catches.
|
|
// Build the landingpad instruction.
|
|
|
|
// Accumulate all the handlers in scope.
|
|
bool hasCatchAll = false;
|
|
bool hasCleanup = false;
|
|
bool hasFilter = false;
|
|
SmallVector<llvm::Value*, 4> filterTypes;
|
|
llvm::SmallPtrSet<llvm::Value*, 4> catchTypes;
|
|
for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end(); I != E;
|
|
++I) {
|
|
|
|
switch (I->getKind()) {
|
|
case EHScope::Cleanup:
|
|
// If we have a cleanup, remember that.
|
|
hasCleanup = (hasCleanup || cast<EHCleanupScope>(*I).isEHCleanup());
|
|
continue;
|
|
|
|
case EHScope::Filter: {
|
|
assert(I.next() == EHStack.end() && "EH filter is not end of EH stack");
|
|
assert(!hasCatchAll && "EH filter reached after catch-all");
|
|
|
|
// Filter scopes get added to the landingpad in weird ways.
|
|
EHFilterScope &filter = cast<EHFilterScope>(*I);
|
|
hasFilter = true;
|
|
|
|
// Add all the filter values.
|
|
for (unsigned i = 0, e = filter.getNumFilters(); i != e; ++i)
|
|
filterTypes.push_back(filter.getFilter(i));
|
|
goto done;
|
|
}
|
|
|
|
case EHScope::Terminate:
|
|
// Terminate scopes are basically catch-alls.
|
|
assert(!hasCatchAll);
|
|
hasCatchAll = true;
|
|
goto done;
|
|
|
|
case EHScope::Catch:
|
|
break;
|
|
}
|
|
|
|
EHCatchScope &catchScope = cast<EHCatchScope>(*I);
|
|
for (unsigned hi = 0, he = catchScope.getNumHandlers(); hi != he; ++hi) {
|
|
EHCatchScope::Handler handler = catchScope.getHandler(hi);
|
|
assert(handler.Type.Flags == 0 &&
|
|
"landingpads do not support catch handler flags");
|
|
|
|
// If this is a catch-all, register that and abort.
|
|
if (!handler.Type.RTTI) {
|
|
assert(!hasCatchAll);
|
|
hasCatchAll = true;
|
|
goto done;
|
|
}
|
|
|
|
// Check whether we already have a handler for this type.
|
|
if (catchTypes.insert(handler.Type.RTTI).second)
|
|
// If not, add it directly to the landingpad.
|
|
LPadInst->addClause(handler.Type.RTTI);
|
|
}
|
|
}
|
|
|
|
done:
|
|
// If we have a catch-all, add null to the landingpad.
|
|
assert(!(hasCatchAll && hasFilter));
|
|
if (hasCatchAll) {
|
|
LPadInst->addClause(getCatchAllValue(*this));
|
|
|
|
// If we have an EH filter, we need to add those handlers in the
|
|
// right place in the landingpad, which is to say, at the end.
|
|
} else if (hasFilter) {
|
|
// Create a filter expression: a constant array indicating which filter
|
|
// types there are. The personality routine only lands here if the filter
|
|
// doesn't match.
|
|
SmallVector<llvm::Constant*, 8> Filters;
|
|
llvm::ArrayType *AType =
|
|
llvm::ArrayType::get(!filterTypes.empty() ?
|
|
filterTypes[0]->getType() : Int8PtrTy,
|
|
filterTypes.size());
|
|
|
|
for (unsigned i = 0, e = filterTypes.size(); i != e; ++i)
|
|
Filters.push_back(cast<llvm::Constant>(filterTypes[i]));
|
|
llvm::Constant *FilterArray = llvm::ConstantArray::get(AType, Filters);
|
|
LPadInst->addClause(FilterArray);
|
|
|
|
// Also check whether we need a cleanup.
|
|
if (hasCleanup)
|
|
LPadInst->setCleanup(true);
|
|
|
|
// Otherwise, signal that we at least have cleanups.
|
|
} else if (hasCleanup) {
|
|
LPadInst->setCleanup(true);
|
|
}
|
|
|
|
assert((LPadInst->getNumClauses() > 0 || LPadInst->isCleanup()) &&
|
|
"landingpad instruction has no clauses!");
|
|
|
|
// Tell the backend how to generate the landing pad.
|
|
Builder.CreateBr(getEHDispatchBlock(EHStack.getInnermostEHScope()));
|
|
|
|
// Restore the old IR generation state.
|
|
Builder.restoreIP(savedIP);
|
|
|
|
return lpad;
|
|
}
|
|
|
|
static void emitCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope) {
|
|
llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
|
|
assert(DispatchBlock);
|
|
|
|
CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
|
|
CGF.EmitBlockAfterUses(DispatchBlock);
|
|
|
|
llvm::Value *ParentPad = CGF.CurrentFuncletPad;
|
|
if (!ParentPad)
|
|
ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
|
|
llvm::BasicBlock *UnwindBB =
|
|
CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
|
|
|
|
unsigned NumHandlers = CatchScope.getNumHandlers();
|
|
llvm::CatchSwitchInst *CatchSwitch =
|
|
CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
|
|
|
|
// Test against each of the exception types we claim to catch.
|
|
for (unsigned I = 0; I < NumHandlers; ++I) {
|
|
const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
|
|
|
|
CatchTypeInfo TypeInfo = Handler.Type;
|
|
if (!TypeInfo.RTTI)
|
|
TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
|
|
|
|
CGF.Builder.SetInsertPoint(Handler.Block);
|
|
|
|
if (EHPersonality::get(CGF).isMSVCXXPersonality()) {
|
|
CGF.Builder.CreateCatchPad(
|
|
CatchSwitch, {TypeInfo.RTTI, CGF.Builder.getInt32(TypeInfo.Flags),
|
|
llvm::Constant::getNullValue(CGF.VoidPtrTy)});
|
|
} else {
|
|
CGF.Builder.CreateCatchPad(CatchSwitch, {TypeInfo.RTTI});
|
|
}
|
|
|
|
CatchSwitch->addHandler(Handler.Block);
|
|
}
|
|
CGF.Builder.restoreIP(SavedIP);
|
|
}
|
|
|
|
// Wasm uses Windows-style EH instructions, but it merges all catch clauses into
|
|
// one big catchpad, within which we use Itanium's landingpad-style selector
|
|
// comparison instructions.
|
|
static void emitWasmCatchPadBlock(CodeGenFunction &CGF,
|
|
EHCatchScope &CatchScope) {
|
|
llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
|
|
assert(DispatchBlock);
|
|
|
|
CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
|
|
CGF.EmitBlockAfterUses(DispatchBlock);
|
|
|
|
llvm::Value *ParentPad = CGF.CurrentFuncletPad;
|
|
if (!ParentPad)
|
|
ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
|
|
llvm::BasicBlock *UnwindBB =
|
|
CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
|
|
|
|
unsigned NumHandlers = CatchScope.getNumHandlers();
|
|
llvm::CatchSwitchInst *CatchSwitch =
|
|
CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
|
|
|
|
// We don't use a landingpad instruction, so generate intrinsic calls to
|
|
// provide exception and selector values.
|
|
llvm::BasicBlock *WasmCatchStartBlock = CGF.createBasicBlock("catch.start");
|
|
CatchSwitch->addHandler(WasmCatchStartBlock);
|
|
CGF.EmitBlockAfterUses(WasmCatchStartBlock);
|
|
|
|
// Create a catchpad instruction.
|
|
SmallVector<llvm::Value *, 4> CatchTypes;
|
|
for (unsigned I = 0, E = NumHandlers; I < E; ++I) {
|
|
const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
|
|
CatchTypeInfo TypeInfo = Handler.Type;
|
|
if (!TypeInfo.RTTI)
|
|
TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
|
|
CatchTypes.push_back(TypeInfo.RTTI);
|
|
}
|
|
auto *CPI = CGF.Builder.CreateCatchPad(CatchSwitch, CatchTypes);
|
|
|
|
// Create calls to wasm.get.exception and wasm.get.ehselector intrinsics.
|
|
// Before they are lowered appropriately later, they provide values for the
|
|
// exception and selector.
|
|
llvm::Function *GetExnFn =
|
|
CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
|
|
llvm::Function *GetSelectorFn =
|
|
CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_ehselector);
|
|
llvm::CallInst *Exn = CGF.Builder.CreateCall(GetExnFn, CPI);
|
|
CGF.Builder.CreateStore(Exn, CGF.getExceptionSlot());
|
|
llvm::CallInst *Selector = CGF.Builder.CreateCall(GetSelectorFn, CPI);
|
|
|
|
llvm::Function *TypeIDFn = CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
|
|
|
|
// If there's only a single catch-all, branch directly to its handler.
|
|
if (CatchScope.getNumHandlers() == 1 &&
|
|
CatchScope.getHandler(0).isCatchAll()) {
|
|
CGF.Builder.CreateBr(CatchScope.getHandler(0).Block);
|
|
CGF.Builder.restoreIP(SavedIP);
|
|
return;
|
|
}
|
|
|
|
// Test against each of the exception types we claim to catch.
|
|
for (unsigned I = 0, E = NumHandlers;; ++I) {
|
|
assert(I < E && "ran off end of handlers!");
|
|
const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
|
|
CatchTypeInfo TypeInfo = Handler.Type;
|
|
if (!TypeInfo.RTTI)
|
|
TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
|
|
|
|
// Figure out the next block.
|
|
llvm::BasicBlock *NextBlock;
|
|
|
|
bool EmitNextBlock = false, NextIsEnd = false;
|
|
|
|
// If this is the last handler, we're at the end, and the next block is a
|
|
// block that contains a call to the rethrow function, so we can unwind to
|
|
// the enclosing EH scope. The call itself will be generated later.
|
|
if (I + 1 == E) {
|
|
NextBlock = CGF.createBasicBlock("rethrow");
|
|
EmitNextBlock = true;
|
|
NextIsEnd = true;
|
|
|
|
// If the next handler is a catch-all, we're at the end, and the
|
|
// next block is that handler.
|
|
} else if (CatchScope.getHandler(I + 1).isCatchAll()) {
|
|
NextBlock = CatchScope.getHandler(I + 1).Block;
|
|
NextIsEnd = true;
|
|
|
|
// Otherwise, we're not at the end and we need a new block.
|
|
} else {
|
|
NextBlock = CGF.createBasicBlock("catch.fallthrough");
|
|
EmitNextBlock = true;
|
|
}
|
|
|
|
// Figure out the catch type's index in the LSDA's type table.
|
|
llvm::CallInst *TypeIndex = CGF.Builder.CreateCall(TypeIDFn, TypeInfo.RTTI);
|
|
TypeIndex->setDoesNotThrow();
|
|
|
|
llvm::Value *MatchesTypeIndex =
|
|
CGF.Builder.CreateICmpEQ(Selector, TypeIndex, "matches");
|
|
CGF.Builder.CreateCondBr(MatchesTypeIndex, Handler.Block, NextBlock);
|
|
|
|
if (EmitNextBlock)
|
|
CGF.EmitBlock(NextBlock);
|
|
if (NextIsEnd)
|
|
break;
|
|
}
|
|
|
|
CGF.Builder.restoreIP(SavedIP);
|
|
}
|
|
|
|
/// Emit the structure of the dispatch block for the given catch scope.
|
|
/// It is an invariant that the dispatch block already exists.
|
|
static void emitCatchDispatchBlock(CodeGenFunction &CGF,
|
|
EHCatchScope &catchScope) {
|
|
if (EHPersonality::get(CGF).isWasmPersonality())
|
|
return emitWasmCatchPadBlock(CGF, catchScope);
|
|
if (EHPersonality::get(CGF).usesFuncletPads())
|
|
return emitCatchPadBlock(CGF, catchScope);
|
|
|
|
llvm::BasicBlock *dispatchBlock = catchScope.getCachedEHDispatchBlock();
|
|
assert(dispatchBlock);
|
|
|
|
// If there's only a single catch-all, getEHDispatchBlock returned
|
|
// that catch-all as the dispatch block.
|
|
if (catchScope.getNumHandlers() == 1 &&
|
|
catchScope.getHandler(0).isCatchAll()) {
|
|
assert(dispatchBlock == catchScope.getHandler(0).Block);
|
|
return;
|
|
}
|
|
|
|
CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveIP();
|
|
CGF.EmitBlockAfterUses(dispatchBlock);
|
|
|
|
// Select the right handler.
|
|
llvm::Function *llvm_eh_typeid_for =
|
|
CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
|
|
|
|
// Load the selector value.
|
|
llvm::Value *selector = CGF.getSelectorFromSlot();
|
|
|
|
// Test against each of the exception types we claim to catch.
|
|
for (unsigned i = 0, e = catchScope.getNumHandlers(); ; ++i) {
|
|
assert(i < e && "ran off end of handlers!");
|
|
const EHCatchScope::Handler &handler = catchScope.getHandler(i);
|
|
|
|
llvm::Value *typeValue = handler.Type.RTTI;
|
|
assert(handler.Type.Flags == 0 &&
|
|
"landingpads do not support catch handler flags");
|
|
assert(typeValue && "fell into catch-all case!");
|
|
typeValue = CGF.Builder.CreateBitCast(typeValue, CGF.Int8PtrTy);
|
|
|
|
// Figure out the next block.
|
|
bool nextIsEnd;
|
|
llvm::BasicBlock *nextBlock;
|
|
|
|
// If this is the last handler, we're at the end, and the next
|
|
// block is the block for the enclosing EH scope.
|
|
if (i + 1 == e) {
|
|
nextBlock = CGF.getEHDispatchBlock(catchScope.getEnclosingEHScope());
|
|
nextIsEnd = true;
|
|
|
|
// If the next handler is a catch-all, we're at the end, and the
|
|
// next block is that handler.
|
|
} else if (catchScope.getHandler(i+1).isCatchAll()) {
|
|
nextBlock = catchScope.getHandler(i+1).Block;
|
|
nextIsEnd = true;
|
|
|
|
// Otherwise, we're not at the end and we need a new block.
|
|
} else {
|
|
nextBlock = CGF.createBasicBlock("catch.fallthrough");
|
|
nextIsEnd = false;
|
|
}
|
|
|
|
// Figure out the catch type's index in the LSDA's type table.
|
|
llvm::CallInst *typeIndex =
|
|
CGF.Builder.CreateCall(llvm_eh_typeid_for, typeValue);
|
|
typeIndex->setDoesNotThrow();
|
|
|
|
llvm::Value *matchesTypeIndex =
|
|
CGF.Builder.CreateICmpEQ(selector, typeIndex, "matches");
|
|
CGF.Builder.CreateCondBr(matchesTypeIndex, handler.Block, nextBlock);
|
|
|
|
// If the next handler is a catch-all, we're completely done.
|
|
if (nextIsEnd) {
|
|
CGF.Builder.restoreIP(savedIP);
|
|
return;
|
|
}
|
|
// Otherwise we need to emit and continue at that block.
|
|
CGF.EmitBlock(nextBlock);
|
|
}
|
|
}
|
|
|
|
void CodeGenFunction::popCatchScope() {
|
|
EHCatchScope &catchScope = cast<EHCatchScope>(*EHStack.begin());
|
|
if (catchScope.hasEHBranches())
|
|
emitCatchDispatchBlock(*this, catchScope);
|
|
EHStack.popCatch();
|
|
}
|
|
|
|
void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
|
|
unsigned NumHandlers = S.getNumHandlers();
|
|
EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
|
|
assert(CatchScope.getNumHandlers() == NumHandlers);
|
|
llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
|
|
|
|
// If the catch was not required, bail out now.
|
|
if (!CatchScope.hasEHBranches()) {
|
|
CatchScope.clearHandlerBlocks();
|
|
EHStack.popCatch();
|
|
return;
|
|
}
|
|
|
|
// Emit the structure of the EH dispatch for this catch.
|
|
emitCatchDispatchBlock(*this, CatchScope);
|
|
|
|
// Copy the handler blocks off before we pop the EH stack. Emitting
|
|
// the handlers might scribble on this memory.
|
|
SmallVector<EHCatchScope::Handler, 8> Handlers(
|
|
CatchScope.begin(), CatchScope.begin() + NumHandlers);
|
|
|
|
EHStack.popCatch();
|
|
|
|
// The fall-through block.
|
|
llvm::BasicBlock *ContBB = createBasicBlock("try.cont");
|
|
|
|
// We just emitted the body of the try; jump to the continue block.
|
|
if (HaveInsertPoint())
|
|
Builder.CreateBr(ContBB);
|
|
|
|
// Determine if we need an implicit rethrow for all these catch handlers;
|
|
// see the comment below.
|
|
bool doImplicitRethrow = false;
|
|
if (IsFnTryBlock)
|
|
doImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
|
|
isa<CXXConstructorDecl>(CurCodeDecl);
|
|
|
|
// Wasm uses Windows-style EH instructions, but merges all catch clauses into
|
|
// one big catchpad. So we save the old funclet pad here before we traverse
|
|
// each catch handler.
|
|
SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
|
|
CurrentFuncletPad);
|
|
llvm::BasicBlock *WasmCatchStartBlock = nullptr;
|
|
if (EHPersonality::get(*this).isWasmPersonality()) {
|
|
auto *CatchSwitch =
|
|
cast<llvm::CatchSwitchInst>(DispatchBlock->getFirstNonPHI());
|
|
WasmCatchStartBlock = CatchSwitch->hasUnwindDest()
|
|
? CatchSwitch->getSuccessor(1)
|
|
: CatchSwitch->getSuccessor(0);
|
|
auto *CPI = cast<llvm::CatchPadInst>(WasmCatchStartBlock->getFirstNonPHI());
|
|
CurrentFuncletPad = CPI;
|
|
}
|
|
|
|
// Perversely, we emit the handlers backwards precisely because we
|
|
// want them to appear in source order. In all of these cases, the
|
|
// catch block will have exactly one predecessor, which will be a
|
|
// particular block in the catch dispatch. However, in the case of
|
|
// a catch-all, one of the dispatch blocks will branch to two
|
|
// different handlers, and EmitBlockAfterUses will cause the second
|
|
// handler to be moved before the first.
|
|
bool HasCatchAll = false;
|
|
for (unsigned I = NumHandlers; I != 0; --I) {
|
|
HasCatchAll |= Handlers[I - 1].isCatchAll();
|
|
llvm::BasicBlock *CatchBlock = Handlers[I-1].Block;
|
|
EmitBlockAfterUses(CatchBlock);
|
|
|
|
// Catch the exception if this isn't a catch-all.
|
|
const CXXCatchStmt *C = S.getHandler(I-1);
|
|
|
|
// Enter a cleanup scope, including the catch variable and the
|
|
// end-catch.
|
|
RunCleanupsScope CatchScope(*this);
|
|
|
|
// Initialize the catch variable and set up the cleanups.
|
|
SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
|
|
CurrentFuncletPad);
|
|
CGM.getCXXABI().emitBeginCatch(*this, C);
|
|
|
|
// Emit the PGO counter increment.
|
|
incrementProfileCounter(C);
|
|
|
|
// Perform the body of the catch.
|
|
EmitStmt(C->getHandlerBlock());
|
|
|
|
// [except.handle]p11:
|
|
// The currently handled exception is rethrown if control
|
|
// reaches the end of a handler of the function-try-block of a
|
|
// constructor or destructor.
|
|
|
|
// It is important that we only do this on fallthrough and not on
|
|
// return. Note that it's illegal to put a return in a
|
|
// constructor function-try-block's catch handler (p14), so this
|
|
// really only applies to destructors.
|
|
if (doImplicitRethrow && HaveInsertPoint()) {
|
|
CGM.getCXXABI().emitRethrow(*this, /*isNoReturn*/false);
|
|
Builder.CreateUnreachable();
|
|
Builder.ClearInsertionPoint();
|
|
}
|
|
|
|
// Fall out through the catch cleanups.
|
|
CatchScope.ForceCleanup();
|
|
|
|
// Branch out of the try.
|
|
if (HaveInsertPoint())
|
|
Builder.CreateBr(ContBB);
|
|
}
|
|
|
|
// Because in wasm we merge all catch clauses into one big catchpad, in case
|
|
// none of the types in catch handlers matches after we test against each of
|
|
// them, we should unwind to the next EH enclosing scope. We generate a call
|
|
// to rethrow function here to do that.
|
|
if (EHPersonality::get(*this).isWasmPersonality() && !HasCatchAll) {
|
|
assert(WasmCatchStartBlock);
|
|
// Navigate for the "rethrow" block we created in emitWasmCatchPadBlock().
|
|
// Wasm uses landingpad-style conditional branches to compare selectors, so
|
|
// we follow the false destination for each of the cond branches to reach
|
|
// the rethrow block.
|
|
llvm::BasicBlock *RethrowBlock = WasmCatchStartBlock;
|
|
while (llvm::Instruction *TI = RethrowBlock->getTerminator()) {
|
|
auto *BI = cast<llvm::BranchInst>(TI);
|
|
assert(BI->isConditional());
|
|
RethrowBlock = BI->getSuccessor(1);
|
|
}
|
|
assert(RethrowBlock != WasmCatchStartBlock && RethrowBlock->empty());
|
|
Builder.SetInsertPoint(RethrowBlock);
|
|
llvm::Function *RethrowInCatchFn =
|
|
CGM.getIntrinsic(llvm::Intrinsic::wasm_rethrow);
|
|
EmitNoreturnRuntimeCallOrInvoke(RethrowInCatchFn, {});
|
|
}
|
|
|
|
EmitBlock(ContBB);
|
|
incrementProfileCounter(&S);
|
|
}
|
|
|
|
namespace {
|
|
struct CallEndCatchForFinally final : EHScopeStack::Cleanup {
|
|
llvm::Value *ForEHVar;
|
|
llvm::FunctionCallee EndCatchFn;
|
|
CallEndCatchForFinally(llvm::Value *ForEHVar,
|
|
llvm::FunctionCallee EndCatchFn)
|
|
: ForEHVar(ForEHVar), EndCatchFn(EndCatchFn) {}
|
|
|
|
void Emit(CodeGenFunction &CGF, Flags flags) override {
|
|
llvm::BasicBlock *EndCatchBB = CGF.createBasicBlock("finally.endcatch");
|
|
llvm::BasicBlock *CleanupContBB =
|
|
CGF.createBasicBlock("finally.cleanup.cont");
|
|
|
|
llvm::Value *ShouldEndCatch =
|
|
CGF.Builder.CreateFlagLoad(ForEHVar, "finally.endcatch");
|
|
CGF.Builder.CreateCondBr(ShouldEndCatch, EndCatchBB, CleanupContBB);
|
|
CGF.EmitBlock(EndCatchBB);
|
|
CGF.EmitRuntimeCallOrInvoke(EndCatchFn); // catch-all, so might throw
|
|
CGF.EmitBlock(CleanupContBB);
|
|
}
|
|
};
|
|
|
|
struct PerformFinally final : EHScopeStack::Cleanup {
|
|
const Stmt *Body;
|
|
llvm::Value *ForEHVar;
|
|
llvm::FunctionCallee EndCatchFn;
|
|
llvm::FunctionCallee RethrowFn;
|
|
llvm::Value *SavedExnVar;
|
|
|
|
PerformFinally(const Stmt *Body, llvm::Value *ForEHVar,
|
|
llvm::FunctionCallee EndCatchFn,
|
|
llvm::FunctionCallee RethrowFn, llvm::Value *SavedExnVar)
|
|
: Body(Body), ForEHVar(ForEHVar), EndCatchFn(EndCatchFn),
|
|
RethrowFn(RethrowFn), SavedExnVar(SavedExnVar) {}
|
|
|
|
void Emit(CodeGenFunction &CGF, Flags flags) override {
|
|
// Enter a cleanup to call the end-catch function if one was provided.
|
|
if (EndCatchFn)
|
|
CGF.EHStack.pushCleanup<CallEndCatchForFinally>(NormalAndEHCleanup,
|
|
ForEHVar, EndCatchFn);
|
|
|
|
// Save the current cleanup destination in case there are
|
|
// cleanups in the finally block.
|
|
llvm::Value *SavedCleanupDest =
|
|
CGF.Builder.CreateLoad(CGF.getNormalCleanupDestSlot(),
|
|
"cleanup.dest.saved");
|
|
|
|
// Emit the finally block.
|
|
CGF.EmitStmt(Body);
|
|
|
|
// If the end of the finally is reachable, check whether this was
|
|
// for EH. If so, rethrow.
|
|
if (CGF.HaveInsertPoint()) {
|
|
llvm::BasicBlock *RethrowBB = CGF.createBasicBlock("finally.rethrow");
|
|
llvm::BasicBlock *ContBB = CGF.createBasicBlock("finally.cont");
|
|
|
|
llvm::Value *ShouldRethrow =
|
|
CGF.Builder.CreateFlagLoad(ForEHVar, "finally.shouldthrow");
|
|
CGF.Builder.CreateCondBr(ShouldRethrow, RethrowBB, ContBB);
|
|
|
|
CGF.EmitBlock(RethrowBB);
|
|
if (SavedExnVar) {
|
|
CGF.EmitRuntimeCallOrInvoke(RethrowFn,
|
|
CGF.Builder.CreateAlignedLoad(CGF.Int8PtrTy, SavedExnVar,
|
|
CGF.getPointerAlign()));
|
|
} else {
|
|
CGF.EmitRuntimeCallOrInvoke(RethrowFn);
|
|
}
|
|
CGF.Builder.CreateUnreachable();
|
|
|
|
CGF.EmitBlock(ContBB);
|
|
|
|
// Restore the cleanup destination.
|
|
CGF.Builder.CreateStore(SavedCleanupDest,
|
|
CGF.getNormalCleanupDestSlot());
|
|
}
|
|
|
|
// Leave the end-catch cleanup. As an optimization, pretend that
|
|
// the fallthrough path was inaccessible; we've dynamically proven
|
|
// that we're not in the EH case along that path.
|
|
if (EndCatchFn) {
|
|
CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
|
|
CGF.PopCleanupBlock();
|
|
CGF.Builder.restoreIP(SavedIP);
|
|
}
|
|
|
|
// Now make sure we actually have an insertion point or the
|
|
// cleanup gods will hate us.
|
|
CGF.EnsureInsertPoint();
|
|
}
|
|
};
|
|
} // end anonymous namespace
|
|
|
|
/// Enters a finally block for an implementation using zero-cost
|
|
/// exceptions. This is mostly general, but hard-codes some
|
|
/// language/ABI-specific behavior in the catch-all sections.
|
|
void CodeGenFunction::FinallyInfo::enter(CodeGenFunction &CGF, const Stmt *body,
|
|
llvm::FunctionCallee beginCatchFn,
|
|
llvm::FunctionCallee endCatchFn,
|
|
llvm::FunctionCallee rethrowFn) {
|
|
assert((!!beginCatchFn) == (!!endCatchFn) &&
|
|
"begin/end catch functions not paired");
|
|
assert(rethrowFn && "rethrow function is required");
|
|
|
|
BeginCatchFn = beginCatchFn;
|
|
|
|
// The rethrow function has one of the following two types:
|
|
// void (*)()
|
|
// void (*)(void*)
|
|
// In the latter case we need to pass it the exception object.
|
|
// But we can't use the exception slot because the @finally might
|
|
// have a landing pad (which would overwrite the exception slot).
|
|
llvm::FunctionType *rethrowFnTy = rethrowFn.getFunctionType();
|
|
SavedExnVar = nullptr;
|
|
if (rethrowFnTy->getNumParams())
|
|
SavedExnVar = CGF.CreateTempAlloca(CGF.Int8PtrTy, "finally.exn");
|
|
|
|
// A finally block is a statement which must be executed on any edge
|
|
// out of a given scope. Unlike a cleanup, the finally block may
|
|
// contain arbitrary control flow leading out of itself. In
|
|
// addition, finally blocks should always be executed, even if there
|
|
// are no catch handlers higher on the stack. Therefore, we
|
|
// surround the protected scope with a combination of a normal
|
|
// cleanup (to catch attempts to break out of the block via normal
|
|
// control flow) and an EH catch-all (semantically "outside" any try
|
|
// statement to which the finally block might have been attached).
|
|
// The finally block itself is generated in the context of a cleanup
|
|
// which conditionally leaves the catch-all.
|
|
|
|
// Jump destination for performing the finally block on an exception
|
|
// edge. We'll never actually reach this block, so unreachable is
|
|
// fine.
|
|
RethrowDest = CGF.getJumpDestInCurrentScope(CGF.getUnreachableBlock());
|
|
|
|
// Whether the finally block is being executed for EH purposes.
|
|
ForEHVar = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), "finally.for-eh");
|
|
CGF.Builder.CreateFlagStore(false, ForEHVar);
|
|
|
|
// Enter a normal cleanup which will perform the @finally block.
|
|
CGF.EHStack.pushCleanup<PerformFinally>(NormalCleanup, body,
|
|
ForEHVar, endCatchFn,
|
|
rethrowFn, SavedExnVar);
|
|
|
|
// Enter a catch-all scope.
|
|
llvm::BasicBlock *catchBB = CGF.createBasicBlock("finally.catchall");
|
|
EHCatchScope *catchScope = CGF.EHStack.pushCatch(1);
|
|
catchScope->setCatchAllHandler(0, catchBB);
|
|
}
|
|
|
|
void CodeGenFunction::FinallyInfo::exit(CodeGenFunction &CGF) {
|
|
// Leave the finally catch-all.
|
|
EHCatchScope &catchScope = cast<EHCatchScope>(*CGF.EHStack.begin());
|
|
llvm::BasicBlock *catchBB = catchScope.getHandler(0).Block;
|
|
|
|
CGF.popCatchScope();
|
|
|
|
// If there are any references to the catch-all block, emit it.
|
|
if (catchBB->use_empty()) {
|
|
delete catchBB;
|
|
} else {
|
|
CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveAndClearIP();
|
|
CGF.EmitBlock(catchBB);
|
|
|
|
llvm::Value *exn = nullptr;
|
|
|
|
// If there's a begin-catch function, call it.
|
|
if (BeginCatchFn) {
|
|
exn = CGF.getExceptionFromSlot();
|
|
CGF.EmitNounwindRuntimeCall(BeginCatchFn, exn);
|
|
}
|
|
|
|
// If we need to remember the exception pointer to rethrow later, do so.
|
|
if (SavedExnVar) {
|
|
if (!exn) exn = CGF.getExceptionFromSlot();
|
|
CGF.Builder.CreateAlignedStore(exn, SavedExnVar, CGF.getPointerAlign());
|
|
}
|
|
|
|
// Tell the cleanups in the finally block that we're do this for EH.
|
|
CGF.Builder.CreateFlagStore(true, ForEHVar);
|
|
|
|
// Thread a jump through the finally cleanup.
|
|
CGF.EmitBranchThroughCleanup(RethrowDest);
|
|
|
|
CGF.Builder.restoreIP(savedIP);
|
|
}
|
|
|
|
// Finally, leave the @finally cleanup.
|
|
CGF.PopCleanupBlock();
|
|
}
|
|
|
|
llvm::BasicBlock *CodeGenFunction::getTerminateLandingPad() {
|
|
if (TerminateLandingPad)
|
|
return TerminateLandingPad;
|
|
|
|
CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
|
|
|
|
// This will get inserted at the end of the function.
|
|
TerminateLandingPad = createBasicBlock("terminate.lpad");
|
|
Builder.SetInsertPoint(TerminateLandingPad);
|
|
|
|
// Tell the backend that this is a landing pad.
|
|
const EHPersonality &Personality = EHPersonality::get(*this);
|
|
|
|
if (!CurFn->hasPersonalityFn())
|
|
CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
|
|
|
|
llvm::LandingPadInst *LPadInst =
|
|
Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
|
|
LPadInst->addClause(getCatchAllValue(*this));
|
|
|
|
llvm::Value *Exn = nullptr;
|
|
if (getLangOpts().CPlusPlus)
|
|
Exn = Builder.CreateExtractValue(LPadInst, 0);
|
|
llvm::CallInst *terminateCall =
|
|
CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
|
|
terminateCall->setDoesNotReturn();
|
|
Builder.CreateUnreachable();
|
|
|
|
// Restore the saved insertion state.
|
|
Builder.restoreIP(SavedIP);
|
|
|
|
return TerminateLandingPad;
|
|
}
|
|
|
|
llvm::BasicBlock *CodeGenFunction::getTerminateHandler() {
|
|
if (TerminateHandler)
|
|
return TerminateHandler;
|
|
|
|
// Set up the terminate handler. This block is inserted at the very
|
|
// end of the function by FinishFunction.
|
|
TerminateHandler = createBasicBlock("terminate.handler");
|
|
CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
|
|
Builder.SetInsertPoint(TerminateHandler);
|
|
|
|
llvm::Value *Exn = nullptr;
|
|
if (getLangOpts().CPlusPlus)
|
|
Exn = getExceptionFromSlot();
|
|
llvm::CallInst *terminateCall =
|
|
CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
|
|
terminateCall->setDoesNotReturn();
|
|
Builder.CreateUnreachable();
|
|
|
|
// Restore the saved insertion state.
|
|
Builder.restoreIP(SavedIP);
|
|
|
|
return TerminateHandler;
|
|
}
|
|
|
|
llvm::BasicBlock *CodeGenFunction::getTerminateFunclet() {
|
|
assert(EHPersonality::get(*this).usesFuncletPads() &&
|
|
"use getTerminateLandingPad for non-funclet EH");
|
|
|
|
llvm::BasicBlock *&TerminateFunclet = TerminateFunclets[CurrentFuncletPad];
|
|
if (TerminateFunclet)
|
|
return TerminateFunclet;
|
|
|
|
CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
|
|
|
|
// Set up the terminate handler. This block is inserted at the very
|
|
// end of the function by FinishFunction.
|
|
TerminateFunclet = createBasicBlock("terminate.handler");
|
|
Builder.SetInsertPoint(TerminateFunclet);
|
|
|
|
// Create the cleanuppad using the current parent pad as its token. Use 'none'
|
|
// if this is a top-level terminate scope, which is the common case.
|
|
SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
|
|
CurrentFuncletPad);
|
|
llvm::Value *ParentPad = CurrentFuncletPad;
|
|
if (!ParentPad)
|
|
ParentPad = llvm::ConstantTokenNone::get(CGM.getLLVMContext());
|
|
CurrentFuncletPad = Builder.CreateCleanupPad(ParentPad);
|
|
|
|
// Emit the __std_terminate call.
|
|
llvm::CallInst *terminateCall =
|
|
CGM.getCXXABI().emitTerminateForUnexpectedException(*this, nullptr);
|
|
terminateCall->setDoesNotReturn();
|
|
Builder.CreateUnreachable();
|
|
|
|
// Restore the saved insertion state.
|
|
Builder.restoreIP(SavedIP);
|
|
|
|
return TerminateFunclet;
|
|
}
|
|
|
|
llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
|
|
if (EHResumeBlock) return EHResumeBlock;
|
|
|
|
CGBuilderTy::InsertPoint SavedIP = Builder.saveIP();
|
|
|
|
// We emit a jump to a notional label at the outermost unwind state.
|
|
EHResumeBlock = createBasicBlock("eh.resume");
|
|
Builder.SetInsertPoint(EHResumeBlock);
|
|
|
|
const EHPersonality &Personality = EHPersonality::get(*this);
|
|
|
|
// This can always be a call because we necessarily didn't find
|
|
// anything on the EH stack which needs our help.
|
|
const char *RethrowName = Personality.CatchallRethrowFn;
|
|
if (RethrowName != nullptr && !isCleanup) {
|
|
EmitRuntimeCall(getCatchallRethrowFn(CGM, RethrowName),
|
|
getExceptionFromSlot())->setDoesNotReturn();
|
|
Builder.CreateUnreachable();
|
|
Builder.restoreIP(SavedIP);
|
|
return EHResumeBlock;
|
|
}
|
|
|
|
// Recreate the landingpad's return value for the 'resume' instruction.
|
|
llvm::Value *Exn = getExceptionFromSlot();
|
|
llvm::Value *Sel = getSelectorFromSlot();
|
|
|
|
llvm::Type *LPadType = llvm::StructType::get(Exn->getType(), Sel->getType());
|
|
llvm::Value *LPadVal = llvm::UndefValue::get(LPadType);
|
|
LPadVal = Builder.CreateInsertValue(LPadVal, Exn, 0, "lpad.val");
|
|
LPadVal = Builder.CreateInsertValue(LPadVal, Sel, 1, "lpad.val");
|
|
|
|
Builder.CreateResume(LPadVal);
|
|
Builder.restoreIP(SavedIP);
|
|
return EHResumeBlock;
|
|
}
|
|
|
|
void CodeGenFunction::EmitSEHTryStmt(const SEHTryStmt &S) {
|
|
EnterSEHTryStmt(S);
|
|
{
|
|
JumpDest TryExit = getJumpDestInCurrentScope("__try.__leave");
|
|
|
|
SEHTryEpilogueStack.push_back(&TryExit);
|
|
|
|
llvm::BasicBlock *TryBB = nullptr;
|
|
// IsEHa: emit an invoke to _seh_try_begin() runtime for -EHa
|
|
if (getLangOpts().EHAsynch) {
|
|
EmitRuntimeCallOrInvoke(getSehTryBeginFn(CGM));
|
|
if (SEHTryEpilogueStack.size() == 1) // outermost only
|
|
TryBB = Builder.GetInsertBlock();
|
|
}
|
|
|
|
EmitStmt(S.getTryBlock());
|
|
|
|
// Volatilize all blocks in Try, till current insert point
|
|
if (TryBB) {
|
|
llvm::SmallPtrSet<llvm::BasicBlock *, 10> Visited;
|
|
VolatilizeTryBlocks(TryBB, Visited);
|
|
}
|
|
|
|
SEHTryEpilogueStack.pop_back();
|
|
|
|
if (!TryExit.getBlock()->use_empty())
|
|
EmitBlock(TryExit.getBlock(), /*IsFinished=*/true);
|
|
else
|
|
delete TryExit.getBlock();
|
|
}
|
|
ExitSEHTryStmt(S);
|
|
}
|
|
|
|
// Recursively walk through blocks in a _try
|
|
// and make all memory instructions volatile
|
|
void CodeGenFunction::VolatilizeTryBlocks(
|
|
llvm::BasicBlock *BB, llvm::SmallPtrSet<llvm::BasicBlock *, 10> &V) {
|
|
if (BB == SEHTryEpilogueStack.back()->getBlock() /* end of Try */ ||
|
|
!V.insert(BB).second /* already visited */ ||
|
|
!BB->getParent() /* not emitted */ || BB->empty())
|
|
return;
|
|
|
|
if (!BB->isEHPad()) {
|
|
for (llvm::BasicBlock::iterator J = BB->begin(), JE = BB->end(); J != JE;
|
|
++J) {
|
|
if (auto LI = dyn_cast<llvm::LoadInst>(J)) {
|
|
LI->setVolatile(true);
|
|
} else if (auto SI = dyn_cast<llvm::StoreInst>(J)) {
|
|
SI->setVolatile(true);
|
|
} else if (auto* MCI = dyn_cast<llvm::MemIntrinsic>(J)) {
|
|
MCI->setVolatile(llvm::ConstantInt::get(Builder.getInt1Ty(), 1));
|
|
}
|
|
}
|
|
}
|
|
const llvm::Instruction *TI = BB->getTerminator();
|
|
if (TI) {
|
|
unsigned N = TI->getNumSuccessors();
|
|
for (unsigned I = 0; I < N; I++)
|
|
VolatilizeTryBlocks(TI->getSuccessor(I), V);
|
|
}
|
|
}
|
|
|
|
namespace {
|
|
struct PerformSEHFinally final : EHScopeStack::Cleanup {
|
|
llvm::Function *OutlinedFinally;
|
|
PerformSEHFinally(llvm::Function *OutlinedFinally)
|
|
: OutlinedFinally(OutlinedFinally) {}
|
|
|
|
void Emit(CodeGenFunction &CGF, Flags F) override {
|
|
ASTContext &Context = CGF.getContext();
|
|
CodeGenModule &CGM = CGF.CGM;
|
|
|
|
CallArgList Args;
|
|
|
|
// Compute the two argument values.
|
|
QualType ArgTys[2] = {Context.UnsignedCharTy, Context.VoidPtrTy};
|
|
llvm::Value *FP = nullptr;
|
|
// If CFG.IsOutlinedSEHHelper is true, then we are within a finally block.
|
|
if (CGF.IsOutlinedSEHHelper) {
|
|
FP = &CGF.CurFn->arg_begin()[1];
|
|
} else {
|
|
llvm::Function *LocalAddrFn =
|
|
CGM.getIntrinsic(llvm::Intrinsic::localaddress);
|
|
FP = CGF.Builder.CreateCall(LocalAddrFn);
|
|
}
|
|
|
|
llvm::Value *IsForEH =
|
|
llvm::ConstantInt::get(CGF.ConvertType(ArgTys[0]), F.isForEHCleanup());
|
|
|
|
// Except _leave and fall-through at the end, all other exits in a _try
|
|
// (return/goto/continue/break) are considered as abnormal terminations
|
|
// since _leave/fall-through is always Indexed 0,
|
|
// just use NormalCleanupDestSlot (>= 1 for goto/return/..),
|
|
// as 1st Arg to indicate abnormal termination
|
|
if (!F.isForEHCleanup() && F.hasExitSwitch()) {
|
|
Address Addr = CGF.getNormalCleanupDestSlot();
|
|
llvm::Value *Load = CGF.Builder.CreateLoad(Addr, "cleanup.dest");
|
|
llvm::Value *Zero = llvm::Constant::getNullValue(CGM.Int32Ty);
|
|
IsForEH = CGF.Builder.CreateICmpNE(Load, Zero);
|
|
}
|
|
|
|
Args.add(RValue::get(IsForEH), ArgTys[0]);
|
|
Args.add(RValue::get(FP), ArgTys[1]);
|
|
|
|
// Arrange a two-arg function info and type.
|
|
const CGFunctionInfo &FnInfo =
|
|
CGM.getTypes().arrangeBuiltinFunctionCall(Context.VoidTy, Args);
|
|
|
|
auto Callee = CGCallee::forDirect(OutlinedFinally);
|
|
CGF.EmitCall(FnInfo, Callee, ReturnValueSlot(), Args);
|
|
}
|
|
};
|
|
} // end anonymous namespace
|
|
|
|
namespace {
|
|
/// Find all local variable captures in the statement.
|
|
struct CaptureFinder : ConstStmtVisitor<CaptureFinder> {
|
|
CodeGenFunction &ParentCGF;
|
|
const VarDecl *ParentThis;
|
|
llvm::SmallSetVector<const VarDecl *, 4> Captures;
|
|
Address SEHCodeSlot = Address::invalid();
|
|
CaptureFinder(CodeGenFunction &ParentCGF, const VarDecl *ParentThis)
|
|
: ParentCGF(ParentCGF), ParentThis(ParentThis) {}
|
|
|
|
// Return true if we need to do any capturing work.
|
|
bool foundCaptures() {
|
|
return !Captures.empty() || SEHCodeSlot.isValid();
|
|
}
|
|
|
|
void Visit(const Stmt *S) {
|
|
// See if this is a capture, then recurse.
|
|
ConstStmtVisitor<CaptureFinder>::Visit(S);
|
|
for (const Stmt *Child : S->children())
|
|
if (Child)
|
|
Visit(Child);
|
|
}
|
|
|
|
void VisitDeclRefExpr(const DeclRefExpr *E) {
|
|
// If this is already a capture, just make sure we capture 'this'.
|
|
if (E->refersToEnclosingVariableOrCapture())
|
|
Captures.insert(ParentThis);
|
|
|
|
const auto *D = dyn_cast<VarDecl>(E->getDecl());
|
|
if (D && D->isLocalVarDeclOrParm() && D->hasLocalStorage())
|
|
Captures.insert(D);
|
|
}
|
|
|
|
void VisitCXXThisExpr(const CXXThisExpr *E) {
|
|
Captures.insert(ParentThis);
|
|
}
|
|
|
|
void VisitCallExpr(const CallExpr *E) {
|
|
// We only need to add parent frame allocations for these builtins in x86.
|
|
if (ParentCGF.getTarget().getTriple().getArch() != llvm::Triple::x86)
|
|
return;
|
|
|
|
unsigned ID = E->getBuiltinCallee();
|
|
switch (ID) {
|
|
case Builtin::BI__exception_code:
|
|
case Builtin::BI_exception_code:
|
|
// This is the simple case where we are the outermost finally. All we
|
|
// have to do here is make sure we escape this and recover it in the
|
|
// outlined handler.
|
|
if (!SEHCodeSlot.isValid())
|
|
SEHCodeSlot = ParentCGF.SEHCodeSlotStack.back();
|
|
break;
|
|
}
|
|
}
|
|
};
|
|
} // end anonymous namespace
|
|
|
|
Address CodeGenFunction::recoverAddrOfEscapedLocal(CodeGenFunction &ParentCGF,
|
|
Address ParentVar,
|
|
llvm::Value *ParentFP) {
|
|
llvm::CallInst *RecoverCall = nullptr;
|
|
CGBuilderTy Builder(*this, AllocaInsertPt);
|
|
if (auto *ParentAlloca = dyn_cast<llvm::AllocaInst>(ParentVar.getPointer())) {
|
|
// Mark the variable escaped if nobody else referenced it and compute the
|
|
// localescape index.
|
|
auto InsertPair = ParentCGF.EscapedLocals.insert(
|
|
std::make_pair(ParentAlloca, ParentCGF.EscapedLocals.size()));
|
|
int FrameEscapeIdx = InsertPair.first->second;
|
|
// call i8* @llvm.localrecover(i8* bitcast(@parentFn), i8* %fp, i32 N)
|
|
llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
|
|
&CGM.getModule(), llvm::Intrinsic::localrecover);
|
|
llvm::Constant *ParentI8Fn =
|
|
llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
|
|
RecoverCall = Builder.CreateCall(
|
|
FrameRecoverFn, {ParentI8Fn, ParentFP,
|
|
llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
|
|
|
|
} else {
|
|
// If the parent didn't have an alloca, we're doing some nested outlining.
|
|
// Just clone the existing localrecover call, but tweak the FP argument to
|
|
// use our FP value. All other arguments are constants.
|
|
auto *ParentRecover =
|
|
cast<llvm::IntrinsicInst>(ParentVar.getPointer()->stripPointerCasts());
|
|
assert(ParentRecover->getIntrinsicID() == llvm::Intrinsic::localrecover &&
|
|
"expected alloca or localrecover in parent LocalDeclMap");
|
|
RecoverCall = cast<llvm::CallInst>(ParentRecover->clone());
|
|
RecoverCall->setArgOperand(1, ParentFP);
|
|
RecoverCall->insertBefore(AllocaInsertPt);
|
|
}
|
|
|
|
// Bitcast the variable, rename it, and insert it in the local decl map.
|
|
llvm::Value *ChildVar =
|
|
Builder.CreateBitCast(RecoverCall, ParentVar.getType());
|
|
ChildVar->setName(ParentVar.getName());
|
|
return Address(ChildVar, ParentVar.getAlignment());
|
|
}
|
|
|
|
void CodeGenFunction::EmitCapturedLocals(CodeGenFunction &ParentCGF,
|
|
const Stmt *OutlinedStmt,
|
|
bool IsFilter) {
|
|
// Find all captures in the Stmt.
|
|
CaptureFinder Finder(ParentCGF, ParentCGF.CXXABIThisDecl);
|
|
Finder.Visit(OutlinedStmt);
|
|
|
|
// We can exit early on x86_64 when there are no captures. We just have to
|
|
// save the exception code in filters so that __exception_code() works.
|
|
if (!Finder.foundCaptures() &&
|
|
CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
|
|
if (IsFilter)
|
|
EmitSEHExceptionCodeSave(ParentCGF, nullptr, nullptr);
|
|
return;
|
|
}
|
|
|
|
llvm::Value *EntryFP = nullptr;
|
|
CGBuilderTy Builder(CGM, AllocaInsertPt);
|
|
if (IsFilter && CGM.getTarget().getTriple().getArch() == llvm::Triple::x86) {
|
|
// 32-bit SEH filters need to be careful about FP recovery. The end of the
|
|
// EH registration is passed in as the EBP physical register. We can
|
|
// recover that with llvm.frameaddress(1).
|
|
EntryFP = Builder.CreateCall(
|
|
CGM.getIntrinsic(llvm::Intrinsic::frameaddress, AllocaInt8PtrTy),
|
|
{Builder.getInt32(1)});
|
|
} else {
|
|
// Otherwise, for x64 and 32-bit finally functions, the parent FP is the
|
|
// second parameter.
|
|
auto AI = CurFn->arg_begin();
|
|
++AI;
|
|
EntryFP = &*AI;
|
|
}
|
|
|
|
llvm::Value *ParentFP = EntryFP;
|
|
if (IsFilter) {
|
|
// Given whatever FP the runtime provided us in EntryFP, recover the true
|
|
// frame pointer of the parent function. We only need to do this in filters,
|
|
// since finally funclets recover the parent FP for us.
|
|
llvm::Function *RecoverFPIntrin =
|
|
CGM.getIntrinsic(llvm::Intrinsic::eh_recoverfp);
|
|
llvm::Constant *ParentI8Fn =
|
|
llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
|
|
ParentFP = Builder.CreateCall(RecoverFPIntrin, {ParentI8Fn, EntryFP});
|
|
|
|
// if the parent is a _finally, the passed-in ParentFP is the FP
|
|
// of parent _finally, not Establisher's FP (FP of outermost function).
|
|
// Establkisher FP is 2nd paramenter passed into parent _finally.
|
|
// Fortunately, it's always saved in parent's frame. The following
|
|
// code retrieves it, and escapes it so that spill instruction won't be
|
|
// optimized away.
|
|
if (ParentCGF.ParentCGF != nullptr) {
|
|
// Locate and escape Parent's frame_pointer.addr alloca
|
|
// Depending on target, should be 1st/2nd one in LocalDeclMap.
|
|
// Let's just scan for ImplicitParamDecl with VoidPtrTy.
|
|
llvm::AllocaInst *FramePtrAddrAlloca = nullptr;
|
|
for (auto &I : ParentCGF.LocalDeclMap) {
|
|
const VarDecl *D = cast<VarDecl>(I.first);
|
|
if (isa<ImplicitParamDecl>(D) &&
|
|
D->getType() == getContext().VoidPtrTy) {
|
|
assert(D->getName().startswith("frame_pointer"));
|
|
FramePtrAddrAlloca = cast<llvm::AllocaInst>(I.second.getPointer());
|
|
break;
|
|
}
|
|
}
|
|
assert(FramePtrAddrAlloca);
|
|
auto InsertPair = ParentCGF.EscapedLocals.insert(
|
|
std::make_pair(FramePtrAddrAlloca, ParentCGF.EscapedLocals.size()));
|
|
int FrameEscapeIdx = InsertPair.first->second;
|
|
|
|
// an example of a filter's prolog::
|
|
// %0 = call i8* @llvm.eh.recoverfp(bitcast(@"?fin$0@0@main@@"),..)
|
|
// %1 = call i8* @llvm.localrecover(bitcast(@"?fin$0@0@main@@"),..)
|
|
// %2 = bitcast i8* %1 to i8**
|
|
// %3 = load i8*, i8* *%2, align 8
|
|
// ==> %3 is the frame-pointer of outermost host function
|
|
llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
|
|
&CGM.getModule(), llvm::Intrinsic::localrecover);
|
|
llvm::Constant *ParentI8Fn =
|
|
llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
|
|
ParentFP = Builder.CreateCall(
|
|
FrameRecoverFn, {ParentI8Fn, ParentFP,
|
|
llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
|
|
ParentFP = Builder.CreateBitCast(ParentFP, CGM.VoidPtrPtrTy);
|
|
ParentFP = Builder.CreateLoad(Address(ParentFP, getPointerAlign()));
|
|
}
|
|
}
|
|
|
|
// Create llvm.localrecover calls for all captures.
|
|
for (const VarDecl *VD : Finder.Captures) {
|
|
if (VD->getType()->isVariablyModifiedType()) {
|
|
CGM.ErrorUnsupported(VD, "VLA captured by SEH");
|
|
continue;
|
|
}
|
|
assert((isa<ImplicitParamDecl>(VD) || VD->isLocalVarDeclOrParm()) &&
|
|
"captured non-local variable");
|
|
|
|
auto L = ParentCGF.LambdaCaptureFields.find(VD);
|
|
if (L != ParentCGF.LambdaCaptureFields.end()) {
|
|
LambdaCaptureFields[VD] = L->second;
|
|
continue;
|
|
}
|
|
|
|
// If this decl hasn't been declared yet, it will be declared in the
|
|
// OutlinedStmt.
|
|
auto I = ParentCGF.LocalDeclMap.find(VD);
|
|
if (I == ParentCGF.LocalDeclMap.end())
|
|
continue;
|
|
|
|
Address ParentVar = I->second;
|
|
Address Recovered =
|
|
recoverAddrOfEscapedLocal(ParentCGF, ParentVar, ParentFP);
|
|
setAddrOfLocalVar(VD, Recovered);
|
|
|
|
if (isa<ImplicitParamDecl>(VD)) {
|
|
CXXABIThisAlignment = ParentCGF.CXXABIThisAlignment;
|
|
CXXThisAlignment = ParentCGF.CXXThisAlignment;
|
|
CXXABIThisValue = Builder.CreateLoad(Recovered, "this");
|
|
if (ParentCGF.LambdaThisCaptureField) {
|
|
LambdaThisCaptureField = ParentCGF.LambdaThisCaptureField;
|
|
// We are in a lambda function where "this" is captured so the
|
|
// CXXThisValue need to be loaded from the lambda capture
|
|
LValue ThisFieldLValue =
|
|
EmitLValueForLambdaField(LambdaThisCaptureField);
|
|
if (!LambdaThisCaptureField->getType()->isPointerType()) {
|
|
CXXThisValue = ThisFieldLValue.getAddress(*this).getPointer();
|
|
} else {
|
|
CXXThisValue = EmitLoadOfLValue(ThisFieldLValue, SourceLocation())
|
|
.getScalarVal();
|
|
}
|
|
} else {
|
|
CXXThisValue = CXXABIThisValue;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (Finder.SEHCodeSlot.isValid()) {
|
|
SEHCodeSlotStack.push_back(
|
|
recoverAddrOfEscapedLocal(ParentCGF, Finder.SEHCodeSlot, ParentFP));
|
|
}
|
|
|
|
if (IsFilter)
|
|
EmitSEHExceptionCodeSave(ParentCGF, ParentFP, EntryFP);
|
|
}
|
|
|
|
/// Arrange a function prototype that can be called by Windows exception
|
|
/// handling personalities. On Win64, the prototype looks like:
|
|
/// RetTy func(void *EHPtrs, void *ParentFP);
|
|
void CodeGenFunction::startOutlinedSEHHelper(CodeGenFunction &ParentCGF,
|
|
bool IsFilter,
|
|
const Stmt *OutlinedStmt) {
|
|
SourceLocation StartLoc = OutlinedStmt->getBeginLoc();
|
|
|
|
// Get the mangled function name.
|
|
SmallString<128> Name;
|
|
{
|
|
llvm::raw_svector_ostream OS(Name);
|
|
const NamedDecl *ParentSEHFn = ParentCGF.CurSEHParent;
|
|
assert(ParentSEHFn && "No CurSEHParent!");
|
|
MangleContext &Mangler = CGM.getCXXABI().getMangleContext();
|
|
if (IsFilter)
|
|
Mangler.mangleSEHFilterExpression(ParentSEHFn, OS);
|
|
else
|
|
Mangler.mangleSEHFinallyBlock(ParentSEHFn, OS);
|
|
}
|
|
|
|
FunctionArgList Args;
|
|
if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 || !IsFilter) {
|
|
// All SEH finally functions take two parameters. Win64 filters take two
|
|
// parameters. Win32 filters take no parameters.
|
|
if (IsFilter) {
|
|
Args.push_back(ImplicitParamDecl::Create(
|
|
getContext(), /*DC=*/nullptr, StartLoc,
|
|
&getContext().Idents.get("exception_pointers"),
|
|
getContext().VoidPtrTy, ImplicitParamDecl::Other));
|
|
} else {
|
|
Args.push_back(ImplicitParamDecl::Create(
|
|
getContext(), /*DC=*/nullptr, StartLoc,
|
|
&getContext().Idents.get("abnormal_termination"),
|
|
getContext().UnsignedCharTy, ImplicitParamDecl::Other));
|
|
}
|
|
Args.push_back(ImplicitParamDecl::Create(
|
|
getContext(), /*DC=*/nullptr, StartLoc,
|
|
&getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy,
|
|
ImplicitParamDecl::Other));
|
|
}
|
|
|
|
QualType RetTy = IsFilter ? getContext().LongTy : getContext().VoidTy;
|
|
|
|
const CGFunctionInfo &FnInfo =
|
|
CGM.getTypes().arrangeBuiltinFunctionDeclaration(RetTy, Args);
|
|
|
|
llvm::FunctionType *FnTy = CGM.getTypes().GetFunctionType(FnInfo);
|
|
llvm::Function *Fn = llvm::Function::Create(
|
|
FnTy, llvm::GlobalValue::InternalLinkage, Name.str(), &CGM.getModule());
|
|
|
|
IsOutlinedSEHHelper = true;
|
|
|
|
StartFunction(GlobalDecl(), RetTy, Fn, FnInfo, Args,
|
|
OutlinedStmt->getBeginLoc(), OutlinedStmt->getBeginLoc());
|
|
CurSEHParent = ParentCGF.CurSEHParent;
|
|
|
|
CGM.SetInternalFunctionAttributes(GlobalDecl(), CurFn, FnInfo);
|
|
EmitCapturedLocals(ParentCGF, OutlinedStmt, IsFilter);
|
|
}
|
|
|
|
/// Create a stub filter function that will ultimately hold the code of the
|
|
/// filter expression. The EH preparation passes in LLVM will outline the code
|
|
/// from the main function body into this stub.
|
|
llvm::Function *
|
|
CodeGenFunction::GenerateSEHFilterFunction(CodeGenFunction &ParentCGF,
|
|
const SEHExceptStmt &Except) {
|
|
const Expr *FilterExpr = Except.getFilterExpr();
|
|
startOutlinedSEHHelper(ParentCGF, true, FilterExpr);
|
|
|
|
// Emit the original filter expression, convert to i32, and return.
|
|
llvm::Value *R = EmitScalarExpr(FilterExpr);
|
|
R = Builder.CreateIntCast(R, ConvertType(getContext().LongTy),
|
|
FilterExpr->getType()->isSignedIntegerType());
|
|
Builder.CreateStore(R, ReturnValue);
|
|
|
|
FinishFunction(FilterExpr->getEndLoc());
|
|
|
|
return CurFn;
|
|
}
|
|
|
|
llvm::Function *
|
|
CodeGenFunction::GenerateSEHFinallyFunction(CodeGenFunction &ParentCGF,
|
|
const SEHFinallyStmt &Finally) {
|
|
const Stmt *FinallyBlock = Finally.getBlock();
|
|
startOutlinedSEHHelper(ParentCGF, false, FinallyBlock);
|
|
|
|
// Emit the original filter expression, convert to i32, and return.
|
|
EmitStmt(FinallyBlock);
|
|
|
|
FinishFunction(FinallyBlock->getEndLoc());
|
|
|
|
return CurFn;
|
|
}
|
|
|
|
void CodeGenFunction::EmitSEHExceptionCodeSave(CodeGenFunction &ParentCGF,
|
|
llvm::Value *ParentFP,
|
|
llvm::Value *EntryFP) {
|
|
// Get the pointer to the EXCEPTION_POINTERS struct. This is returned by the
|
|
// __exception_info intrinsic.
|
|
if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
|
|
// On Win64, the info is passed as the first parameter to the filter.
|
|
SEHInfo = &*CurFn->arg_begin();
|
|
SEHCodeSlotStack.push_back(
|
|
CreateMemTemp(getContext().IntTy, "__exception_code"));
|
|
} else {
|
|
// On Win32, the EBP on entry to the filter points to the end of an
|
|
// exception registration object. It contains 6 32-bit fields, and the info
|
|
// pointer is stored in the second field. So, GEP 20 bytes backwards and
|
|
// load the pointer.
|
|
SEHInfo = Builder.CreateConstInBoundsGEP1_32(Int8Ty, EntryFP, -20);
|
|
SEHInfo = Builder.CreateBitCast(SEHInfo, Int8PtrTy->getPointerTo());
|
|
SEHInfo = Builder.CreateAlignedLoad(Int8PtrTy, SEHInfo, getPointerAlign());
|
|
SEHCodeSlotStack.push_back(recoverAddrOfEscapedLocal(
|
|
ParentCGF, ParentCGF.SEHCodeSlotStack.back(), ParentFP));
|
|
}
|
|
|
|
// Save the exception code in the exception slot to unify exception access in
|
|
// the filter function and the landing pad.
|
|
// struct EXCEPTION_POINTERS {
|
|
// EXCEPTION_RECORD *ExceptionRecord;
|
|
// CONTEXT *ContextRecord;
|
|
// };
|
|
// int exceptioncode = exception_pointers->ExceptionRecord->ExceptionCode;
|
|
llvm::Type *RecordTy = CGM.Int32Ty->getPointerTo();
|
|
llvm::Type *PtrsTy = llvm::StructType::get(RecordTy, CGM.VoidPtrTy);
|
|
llvm::Value *Ptrs = Builder.CreateBitCast(SEHInfo, PtrsTy->getPointerTo());
|
|
llvm::Value *Rec = Builder.CreateStructGEP(PtrsTy, Ptrs, 0);
|
|
Rec = Builder.CreateAlignedLoad(RecordTy, Rec, getPointerAlign());
|
|
llvm::Value *Code = Builder.CreateAlignedLoad(Int32Ty, Rec, getIntAlign());
|
|
assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
|
|
Builder.CreateStore(Code, SEHCodeSlotStack.back());
|
|
}
|
|
|
|
llvm::Value *CodeGenFunction::EmitSEHExceptionInfo() {
|
|
// Sema should diagnose calling this builtin outside of a filter context, but
|
|
// don't crash if we screw up.
|
|
if (!SEHInfo)
|
|
return llvm::UndefValue::get(Int8PtrTy);
|
|
assert(SEHInfo->getType() == Int8PtrTy);
|
|
return SEHInfo;
|
|
}
|
|
|
|
llvm::Value *CodeGenFunction::EmitSEHExceptionCode() {
|
|
assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
|
|
return Builder.CreateLoad(SEHCodeSlotStack.back());
|
|
}
|
|
|
|
llvm::Value *CodeGenFunction::EmitSEHAbnormalTermination() {
|
|
// Abnormal termination is just the first parameter to the outlined finally
|
|
// helper.
|
|
auto AI = CurFn->arg_begin();
|
|
return Builder.CreateZExt(&*AI, Int32Ty);
|
|
}
|
|
|
|
void CodeGenFunction::pushSEHCleanup(CleanupKind Kind,
|
|
llvm::Function *FinallyFunc) {
|
|
EHStack.pushCleanup<PerformSEHFinally>(Kind, FinallyFunc);
|
|
}
|
|
|
|
void CodeGenFunction::EnterSEHTryStmt(const SEHTryStmt &S) {
|
|
CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
|
|
HelperCGF.ParentCGF = this;
|
|
if (const SEHFinallyStmt *Finally = S.getFinallyHandler()) {
|
|
// Outline the finally block.
|
|
llvm::Function *FinallyFunc =
|
|
HelperCGF.GenerateSEHFinallyFunction(*this, *Finally);
|
|
|
|
// Push a cleanup for __finally blocks.
|
|
EHStack.pushCleanup<PerformSEHFinally>(NormalAndEHCleanup, FinallyFunc);
|
|
return;
|
|
}
|
|
|
|
// Otherwise, we must have an __except block.
|
|
const SEHExceptStmt *Except = S.getExceptHandler();
|
|
assert(Except);
|
|
EHCatchScope *CatchScope = EHStack.pushCatch(1);
|
|
SEHCodeSlotStack.push_back(
|
|
CreateMemTemp(getContext().IntTy, "__exception_code"));
|
|
|
|
// If the filter is known to evaluate to 1, then we can use the clause
|
|
// "catch i8* null". We can't do this on x86 because the filter has to save
|
|
// the exception code.
|
|
llvm::Constant *C =
|
|
ConstantEmitter(*this).tryEmitAbstract(Except->getFilterExpr(),
|
|
getContext().IntTy);
|
|
if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 && C &&
|
|
C->isOneValue()) {
|
|
CatchScope->setCatchAllHandler(0, createBasicBlock("__except"));
|
|
return;
|
|
}
|
|
|
|
// In general, we have to emit an outlined filter function. Use the function
|
|
// in place of the RTTI typeinfo global that C++ EH uses.
|
|
llvm::Function *FilterFunc =
|
|
HelperCGF.GenerateSEHFilterFunction(*this, *Except);
|
|
llvm::Constant *OpaqueFunc =
|
|
llvm::ConstantExpr::getBitCast(FilterFunc, Int8PtrTy);
|
|
CatchScope->setHandler(0, OpaqueFunc, createBasicBlock("__except.ret"));
|
|
}
|
|
|
|
void CodeGenFunction::ExitSEHTryStmt(const SEHTryStmt &S) {
|
|
// Just pop the cleanup if it's a __finally block.
|
|
if (S.getFinallyHandler()) {
|
|
PopCleanupBlock();
|
|
return;
|
|
}
|
|
|
|
// IsEHa: emit an invoke _seh_try_end() to mark end of FT flow
|
|
if (getLangOpts().EHAsynch && Builder.GetInsertBlock()) {
|
|
llvm::FunctionCallee SehTryEnd = getSehTryEndFn(CGM);
|
|
EmitRuntimeCallOrInvoke(SehTryEnd);
|
|
}
|
|
|
|
// Otherwise, we must have an __except block.
|
|
const SEHExceptStmt *Except = S.getExceptHandler();
|
|
assert(Except && "__try must have __finally xor __except");
|
|
EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
|
|
|
|
// Don't emit the __except block if the __try block lacked invokes.
|
|
// TODO: Model unwind edges from instructions, either with iload / istore or
|
|
// a try body function.
|
|
if (!CatchScope.hasEHBranches()) {
|
|
CatchScope.clearHandlerBlocks();
|
|
EHStack.popCatch();
|
|
SEHCodeSlotStack.pop_back();
|
|
return;
|
|
}
|
|
|
|
// The fall-through block.
|
|
llvm::BasicBlock *ContBB = createBasicBlock("__try.cont");
|
|
|
|
// We just emitted the body of the __try; jump to the continue block.
|
|
if (HaveInsertPoint())
|
|
Builder.CreateBr(ContBB);
|
|
|
|
// Check if our filter function returned true.
|
|
emitCatchDispatchBlock(*this, CatchScope);
|
|
|
|
// Grab the block before we pop the handler.
|
|
llvm::BasicBlock *CatchPadBB = CatchScope.getHandler(0).Block;
|
|
EHStack.popCatch();
|
|
|
|
EmitBlockAfterUses(CatchPadBB);
|
|
|
|
// __except blocks don't get outlined into funclets, so immediately do a
|
|
// catchret.
|
|
llvm::CatchPadInst *CPI =
|
|
cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
|
|
llvm::BasicBlock *ExceptBB = createBasicBlock("__except");
|
|
Builder.CreateCatchRet(CPI, ExceptBB);
|
|
EmitBlock(ExceptBB);
|
|
|
|
// On Win64, the exception code is returned in EAX. Copy it into the slot.
|
|
if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
|
|
llvm::Function *SEHCodeIntrin =
|
|
CGM.getIntrinsic(llvm::Intrinsic::eh_exceptioncode);
|
|
llvm::Value *Code = Builder.CreateCall(SEHCodeIntrin, {CPI});
|
|
Builder.CreateStore(Code, SEHCodeSlotStack.back());
|
|
}
|
|
|
|
// Emit the __except body.
|
|
EmitStmt(Except->getBlock());
|
|
|
|
// End the lifetime of the exception code.
|
|
SEHCodeSlotStack.pop_back();
|
|
|
|
if (HaveInsertPoint())
|
|
Builder.CreateBr(ContBB);
|
|
|
|
EmitBlock(ContBB);
|
|
}
|
|
|
|
void CodeGenFunction::EmitSEHLeaveStmt(const SEHLeaveStmt &S) {
|
|
// If this code is reachable then emit a stop point (if generating
|
|
// debug info). We have to do this ourselves because we are on the
|
|
// "simple" statement path.
|
|
if (HaveInsertPoint())
|
|
EmitStopPoint(&S);
|
|
|
|
// This must be a __leave from a __finally block, which we warn on and is UB.
|
|
// Just emit unreachable.
|
|
if (!isSEHTryScope()) {
|
|
Builder.CreateUnreachable();
|
|
Builder.ClearInsertionPoint();
|
|
return;
|
|
}
|
|
|
|
EmitBranchThroughCleanup(*SEHTryEpilogueStack.back());
|
|
}
|