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1274 lines
49 KiB
1274 lines
49 KiB
//===-- CodeGen/AsmPrinter/WinException.cpp - Dwarf Exception Impl ------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains support for writing Win64 exception info into asm files.
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//
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//===----------------------------------------------------------------------===//
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#include "WinException.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/CodeGen/AsmPrinter.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/CodeGen/WinEHFuncInfo.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/Mangler.h"
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#include "llvm/IR/Module.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCSection.h"
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#include "llvm/MC/MCStreamer.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/MC/MCWin64EH.h"
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#include "llvm/Support/COFF.h"
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#include "llvm/Support/Dwarf.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/FormattedStream.h"
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#include "llvm/Target/TargetFrameLowering.h"
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#include "llvm/Target/TargetLowering.h"
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#include "llvm/Target/TargetLoweringObjectFile.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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#include "llvm/Target/TargetSubtargetInfo.h"
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using namespace llvm;
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WinException::WinException(AsmPrinter *A) : EHStreamer(A) {
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// MSVC's EH tables are always composed of 32-bit words. All known 64-bit
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// platforms use an imagerel32 relocation to refer to symbols.
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useImageRel32 = (A->getDataLayout().getPointerSizeInBits() == 64);
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}
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WinException::~WinException() {}
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/// endModule - Emit all exception information that should come after the
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/// content.
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void WinException::endModule() {
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auto &OS = *Asm->OutStreamer;
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const Module *M = MMI->getModule();
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for (const Function &F : *M)
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if (F.hasFnAttribute("safeseh"))
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OS.EmitCOFFSafeSEH(Asm->getSymbol(&F));
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}
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void WinException::beginFunction(const MachineFunction *MF) {
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shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
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// If any landing pads survive, we need an EH table.
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bool hasLandingPads = !MMI->getLandingPads().empty();
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bool hasEHFunclets = MMI->hasEHFunclets();
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const Function *F = MF->getFunction();
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shouldEmitMoves = Asm->needsSEHMoves();
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const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
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unsigned PerEncoding = TLOF.getPersonalityEncoding();
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const Function *Per = nullptr;
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if (F->hasPersonalityFn())
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Per = dyn_cast<Function>(F->getPersonalityFn()->stripPointerCasts());
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bool forceEmitPersonality =
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F->hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
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F->needsUnwindTableEntry();
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shouldEmitPersonality =
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forceEmitPersonality || ((hasLandingPads || hasEHFunclets) &&
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PerEncoding != dwarf::DW_EH_PE_omit && Per);
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unsigned LSDAEncoding = TLOF.getLSDAEncoding();
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shouldEmitLSDA = shouldEmitPersonality &&
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LSDAEncoding != dwarf::DW_EH_PE_omit;
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// If we're not using CFI, we don't want the CFI or the personality, but we
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// might want EH tables if we had EH pads.
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if (!Asm->MAI->usesWindowsCFI()) {
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shouldEmitLSDA = hasEHFunclets;
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shouldEmitPersonality = false;
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return;
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}
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beginFunclet(MF->front(), Asm->CurrentFnSym);
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}
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/// endFunction - Gather and emit post-function exception information.
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///
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void WinException::endFunction(const MachineFunction *MF) {
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if (!shouldEmitPersonality && !shouldEmitMoves && !shouldEmitLSDA)
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return;
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const Function *F = MF->getFunction();
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EHPersonality Per = EHPersonality::Unknown;
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if (F->hasPersonalityFn())
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Per = classifyEHPersonality(F->getPersonalityFn());
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// Get rid of any dead landing pads if we're not using funclets. In funclet
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// schemes, the landing pad is not actually reachable. It only exists so
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// that we can emit the right table data.
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if (!isFuncletEHPersonality(Per))
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MMI->TidyLandingPads();
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endFunclet();
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// endFunclet will emit the necessary .xdata tables for x64 SEH.
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if (Per == EHPersonality::MSVC_Win64SEH && MMI->hasEHFunclets())
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return;
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if (shouldEmitPersonality || shouldEmitLSDA) {
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Asm->OutStreamer->PushSection();
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// Just switch sections to the right xdata section.
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MCSection *XData = Asm->OutStreamer->getAssociatedXDataSection(
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Asm->OutStreamer->getCurrentSectionOnly());
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Asm->OutStreamer->SwitchSection(XData);
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// Emit the tables appropriate to the personality function in use. If we
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// don't recognize the personality, assume it uses an Itanium-style LSDA.
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if (Per == EHPersonality::MSVC_Win64SEH)
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emitCSpecificHandlerTable(MF);
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else if (Per == EHPersonality::MSVC_X86SEH)
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emitExceptHandlerTable(MF);
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else if (Per == EHPersonality::MSVC_CXX)
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emitCXXFrameHandler3Table(MF);
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else if (Per == EHPersonality::CoreCLR)
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emitCLRExceptionTable(MF);
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else
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emitExceptionTable();
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Asm->OutStreamer->PopSection();
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}
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}
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/// Retreive the MCSymbol for a GlobalValue or MachineBasicBlock.
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static MCSymbol *getMCSymbolForMBB(AsmPrinter *Asm,
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const MachineBasicBlock *MBB) {
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if (!MBB)
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return nullptr;
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assert(MBB->isEHFuncletEntry());
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// Give catches and cleanups a name based off of their parent function and
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// their funclet entry block's number.
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const MachineFunction *MF = MBB->getParent();
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const Function *F = MF->getFunction();
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StringRef FuncLinkageName = GlobalValue::getRealLinkageName(F->getName());
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MCContext &Ctx = MF->getContext();
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StringRef HandlerPrefix = MBB->isCleanupFuncletEntry() ? "dtor" : "catch";
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return Ctx.getOrCreateSymbol("?" + HandlerPrefix + "$" +
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Twine(MBB->getNumber()) + "@?0?" +
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FuncLinkageName + "@4HA");
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}
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void WinException::beginFunclet(const MachineBasicBlock &MBB,
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MCSymbol *Sym) {
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CurrentFuncletEntry = &MBB;
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const Function *F = Asm->MF->getFunction();
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// If a symbol was not provided for the funclet, invent one.
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if (!Sym) {
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Sym = getMCSymbolForMBB(Asm, &MBB);
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// Describe our funclet symbol as a function with internal linkage.
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Asm->OutStreamer->BeginCOFFSymbolDef(Sym);
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Asm->OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
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Asm->OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
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<< COFF::SCT_COMPLEX_TYPE_SHIFT);
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Asm->OutStreamer->EndCOFFSymbolDef();
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// We want our funclet's entry point to be aligned such that no nops will be
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// present after the label.
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Asm->EmitAlignment(std::max(Asm->MF->getAlignment(), MBB.getAlignment()),
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F);
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// Now that we've emitted the alignment directive, point at our funclet.
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Asm->OutStreamer->EmitLabel(Sym);
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}
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// Mark 'Sym' as starting our funclet.
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if (shouldEmitMoves || shouldEmitPersonality)
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Asm->OutStreamer->EmitWinCFIStartProc(Sym);
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if (shouldEmitPersonality) {
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const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
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const Function *PerFn = nullptr;
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// Determine which personality routine we are using for this funclet.
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if (F->hasPersonalityFn())
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PerFn = dyn_cast<Function>(F->getPersonalityFn()->stripPointerCasts());
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const MCSymbol *PersHandlerSym =
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TLOF.getCFIPersonalitySymbol(PerFn, *Asm->Mang, Asm->TM, MMI);
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// Classify the personality routine so that we may reason about it.
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EHPersonality Per = EHPersonality::Unknown;
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if (F->hasPersonalityFn())
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Per = classifyEHPersonality(F->getPersonalityFn());
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// Do not emit a .seh_handler directive if it is a C++ cleanup funclet.
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if (Per != EHPersonality::MSVC_CXX ||
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!CurrentFuncletEntry->isCleanupFuncletEntry())
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Asm->OutStreamer->EmitWinEHHandler(PersHandlerSym, true, true);
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}
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}
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void WinException::endFunclet() {
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// No funclet to process? Great, we have nothing to do.
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if (!CurrentFuncletEntry)
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return;
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if (shouldEmitMoves || shouldEmitPersonality) {
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const Function *F = Asm->MF->getFunction();
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EHPersonality Per = EHPersonality::Unknown;
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if (F->hasPersonalityFn())
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Per = classifyEHPersonality(F->getPersonalityFn());
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// The .seh_handlerdata directive implicitly switches section, push the
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// current section so that we may return to it.
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Asm->OutStreamer->PushSection();
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// Emit an UNWIND_INFO struct describing the prologue.
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Asm->OutStreamer->EmitWinEHHandlerData();
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if (Per == EHPersonality::MSVC_CXX && shouldEmitPersonality &&
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!CurrentFuncletEntry->isCleanupFuncletEntry()) {
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// If this is a C++ catch funclet (or the parent function),
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// emit a reference to the LSDA for the parent function.
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StringRef FuncLinkageName = GlobalValue::getRealLinkageName(F->getName());
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MCSymbol *FuncInfoXData = Asm->OutContext.getOrCreateSymbol(
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Twine("$cppxdata$", FuncLinkageName));
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Asm->OutStreamer->EmitValue(create32bitRef(FuncInfoXData), 4);
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} else if (Per == EHPersonality::MSVC_Win64SEH && MMI->hasEHFunclets() &&
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!CurrentFuncletEntry->isEHFuncletEntry()) {
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// If this is the parent function in Win64 SEH, emit the LSDA immediately
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// following .seh_handlerdata.
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emitCSpecificHandlerTable(Asm->MF);
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}
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// Switch back to the previous section now that we are done writing to
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// .xdata.
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Asm->OutStreamer->PopSection();
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// Emit a .seh_endproc directive to mark the end of the function.
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Asm->OutStreamer->EmitWinCFIEndProc();
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}
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// Let's make sure we don't try to end the same funclet twice.
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CurrentFuncletEntry = nullptr;
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}
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const MCExpr *WinException::create32bitRef(const MCSymbol *Value) {
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if (!Value)
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return MCConstantExpr::create(0, Asm->OutContext);
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return MCSymbolRefExpr::create(Value, useImageRel32
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? MCSymbolRefExpr::VK_COFF_IMGREL32
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: MCSymbolRefExpr::VK_None,
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Asm->OutContext);
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}
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const MCExpr *WinException::create32bitRef(const GlobalValue *GV) {
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if (!GV)
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return MCConstantExpr::create(0, Asm->OutContext);
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return create32bitRef(Asm->getSymbol(GV));
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}
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const MCExpr *WinException::getLabelPlusOne(const MCSymbol *Label) {
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return MCBinaryExpr::createAdd(create32bitRef(Label),
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MCConstantExpr::create(1, Asm->OutContext),
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Asm->OutContext);
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}
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const MCExpr *WinException::getOffset(const MCSymbol *OffsetOf,
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const MCSymbol *OffsetFrom) {
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return MCBinaryExpr::createSub(
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MCSymbolRefExpr::create(OffsetOf, Asm->OutContext),
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MCSymbolRefExpr::create(OffsetFrom, Asm->OutContext), Asm->OutContext);
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}
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const MCExpr *WinException::getOffsetPlusOne(const MCSymbol *OffsetOf,
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const MCSymbol *OffsetFrom) {
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return MCBinaryExpr::createAdd(getOffset(OffsetOf, OffsetFrom),
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MCConstantExpr::create(1, Asm->OutContext),
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Asm->OutContext);
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}
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int WinException::getFrameIndexOffset(int FrameIndex,
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const WinEHFuncInfo &FuncInfo) {
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const TargetFrameLowering &TFI = *Asm->MF->getSubtarget().getFrameLowering();
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unsigned UnusedReg;
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if (Asm->MAI->usesWindowsCFI()) {
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int Offset =
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TFI.getFrameIndexReferencePreferSP(*Asm->MF, FrameIndex, UnusedReg,
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/*IgnoreSPUpdates*/ true);
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assert(UnusedReg ==
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Asm->MF->getSubtarget()
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.getTargetLowering()
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->getStackPointerRegisterToSaveRestore());
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return Offset;
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}
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// For 32-bit, offsets should be relative to the end of the EH registration
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// node. For 64-bit, it's relative to SP at the end of the prologue.
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assert(FuncInfo.EHRegNodeEndOffset != INT_MAX);
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int Offset = TFI.getFrameIndexReference(*Asm->MF, FrameIndex, UnusedReg);
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Offset += FuncInfo.EHRegNodeEndOffset;
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return Offset;
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}
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namespace {
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/// Top-level state used to represent unwind to caller
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const int NullState = -1;
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struct InvokeStateChange {
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/// EH Label immediately after the last invoke in the previous state, or
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/// nullptr if the previous state was the null state.
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const MCSymbol *PreviousEndLabel;
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/// EH label immediately before the first invoke in the new state, or nullptr
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/// if the new state is the null state.
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const MCSymbol *NewStartLabel;
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/// State of the invoke following NewStartLabel, or NullState to indicate
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/// the presence of calls which may unwind to caller.
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int NewState;
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};
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/// Iterator that reports all the invoke state changes in a range of machine
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/// basic blocks. Changes to the null state are reported whenever a call that
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/// may unwind to caller is encountered. The MBB range is expected to be an
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/// entire function or funclet, and the start and end of the range are treated
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/// as being in the NullState even if there's not an unwind-to-caller call
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/// before the first invoke or after the last one (i.e., the first state change
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/// reported is the first change to something other than NullState, and a
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/// change back to NullState is always reported at the end of iteration).
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class InvokeStateChangeIterator {
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InvokeStateChangeIterator(const WinEHFuncInfo &EHInfo,
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MachineFunction::const_iterator MFI,
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MachineFunction::const_iterator MFE,
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MachineBasicBlock::const_iterator MBBI,
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int BaseState)
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: EHInfo(EHInfo), MFI(MFI), MFE(MFE), MBBI(MBBI), BaseState(BaseState) {
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LastStateChange.PreviousEndLabel = nullptr;
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LastStateChange.NewStartLabel = nullptr;
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LastStateChange.NewState = BaseState;
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scan();
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}
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public:
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static iterator_range<InvokeStateChangeIterator>
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range(const WinEHFuncInfo &EHInfo, MachineFunction::const_iterator Begin,
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MachineFunction::const_iterator End, int BaseState = NullState) {
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// Reject empty ranges to simplify bookkeeping by ensuring that we can get
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// the end of the last block.
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assert(Begin != End);
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auto BlockBegin = Begin->begin();
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auto BlockEnd = std::prev(End)->end();
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return make_range(
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InvokeStateChangeIterator(EHInfo, Begin, End, BlockBegin, BaseState),
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InvokeStateChangeIterator(EHInfo, End, End, BlockEnd, BaseState));
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}
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// Iterator methods.
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bool operator==(const InvokeStateChangeIterator &O) const {
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assert(BaseState == O.BaseState);
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// Must be visiting same block.
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if (MFI != O.MFI)
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return false;
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// Must be visiting same isntr.
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if (MBBI != O.MBBI)
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return false;
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// At end of block/instr iteration, we can still have two distinct states:
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// one to report the final EndLabel, and another indicating the end of the
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// state change iteration. Check for CurrentEndLabel equality to
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// distinguish these.
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return CurrentEndLabel == O.CurrentEndLabel;
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}
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bool operator!=(const InvokeStateChangeIterator &O) const {
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return !operator==(O);
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}
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InvokeStateChange &operator*() { return LastStateChange; }
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InvokeStateChange *operator->() { return &LastStateChange; }
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InvokeStateChangeIterator &operator++() { return scan(); }
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private:
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InvokeStateChangeIterator &scan();
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const WinEHFuncInfo &EHInfo;
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const MCSymbol *CurrentEndLabel = nullptr;
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MachineFunction::const_iterator MFI;
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MachineFunction::const_iterator MFE;
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MachineBasicBlock::const_iterator MBBI;
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InvokeStateChange LastStateChange;
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bool VisitingInvoke = false;
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int BaseState;
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};
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} // end anonymous namespace
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InvokeStateChangeIterator &InvokeStateChangeIterator::scan() {
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bool IsNewBlock = false;
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for (; MFI != MFE; ++MFI, IsNewBlock = true) {
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if (IsNewBlock)
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MBBI = MFI->begin();
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for (auto MBBE = MFI->end(); MBBI != MBBE; ++MBBI) {
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const MachineInstr &MI = *MBBI;
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if (!VisitingInvoke && LastStateChange.NewState != BaseState &&
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MI.isCall() && !EHStreamer::callToNoUnwindFunction(&MI)) {
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// Indicate a change of state to the null state. We don't have
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// start/end EH labels handy but the caller won't expect them for
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// null state regions.
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LastStateChange.PreviousEndLabel = CurrentEndLabel;
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LastStateChange.NewStartLabel = nullptr;
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LastStateChange.NewState = BaseState;
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CurrentEndLabel = nullptr;
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// Don't re-visit this instr on the next scan
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++MBBI;
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return *this;
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}
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// All other state changes are at EH labels before/after invokes.
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if (!MI.isEHLabel())
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continue;
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MCSymbol *Label = MI.getOperand(0).getMCSymbol();
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if (Label == CurrentEndLabel) {
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VisitingInvoke = false;
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continue;
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}
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auto InvokeMapIter = EHInfo.LabelToStateMap.find(Label);
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// Ignore EH labels that aren't the ones inserted before an invoke
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if (InvokeMapIter == EHInfo.LabelToStateMap.end())
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continue;
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auto &StateAndEnd = InvokeMapIter->second;
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int NewState = StateAndEnd.first;
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// Keep track of the fact that we're between EH start/end labels so
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// we know not to treat the inoke we'll see as unwinding to caller.
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VisitingInvoke = true;
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if (NewState == LastStateChange.NewState) {
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// The state isn't actually changing here. Record the new end and
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// keep going.
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CurrentEndLabel = StateAndEnd.second;
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continue;
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}
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// Found a state change to report
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LastStateChange.PreviousEndLabel = CurrentEndLabel;
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LastStateChange.NewStartLabel = Label;
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LastStateChange.NewState = NewState;
|
|
// Start keeping track of the new current end
|
|
CurrentEndLabel = StateAndEnd.second;
|
|
// Don't re-visit this instr on the next scan
|
|
++MBBI;
|
|
return *this;
|
|
}
|
|
}
|
|
// Iteration hit the end of the block range.
|
|
if (LastStateChange.NewState != BaseState) {
|
|
// Report the end of the last new state
|
|
LastStateChange.PreviousEndLabel = CurrentEndLabel;
|
|
LastStateChange.NewStartLabel = nullptr;
|
|
LastStateChange.NewState = BaseState;
|
|
// Leave CurrentEndLabel non-null to distinguish this state from end.
|
|
assert(CurrentEndLabel != nullptr);
|
|
return *this;
|
|
}
|
|
// We've reported all state changes and hit the end state.
|
|
CurrentEndLabel = nullptr;
|
|
return *this;
|
|
}
|
|
|
|
/// Emit the language-specific data that __C_specific_handler expects. This
|
|
/// handler lives in the x64 Microsoft C runtime and allows catching or cleaning
|
|
/// up after faults with __try, __except, and __finally. The typeinfo values
|
|
/// are not really RTTI data, but pointers to filter functions that return an
|
|
/// integer (1, 0, or -1) indicating how to handle the exception. For __finally
|
|
/// blocks and other cleanups, the landing pad label is zero, and the filter
|
|
/// function is actually a cleanup handler with the same prototype. A catch-all
|
|
/// entry is modeled with a null filter function field and a non-zero landing
|
|
/// pad label.
|
|
///
|
|
/// Possible filter function return values:
|
|
/// EXCEPTION_EXECUTE_HANDLER (1):
|
|
/// Jump to the landing pad label after cleanups.
|
|
/// EXCEPTION_CONTINUE_SEARCH (0):
|
|
/// Continue searching this table or continue unwinding.
|
|
/// EXCEPTION_CONTINUE_EXECUTION (-1):
|
|
/// Resume execution at the trapping PC.
|
|
///
|
|
/// Inferred table structure:
|
|
/// struct Table {
|
|
/// int NumEntries;
|
|
/// struct Entry {
|
|
/// imagerel32 LabelStart;
|
|
/// imagerel32 LabelEnd;
|
|
/// imagerel32 FilterOrFinally; // One means catch-all.
|
|
/// imagerel32 LabelLPad; // Zero means __finally.
|
|
/// } Entries[NumEntries];
|
|
/// };
|
|
void WinException::emitCSpecificHandlerTable(const MachineFunction *MF) {
|
|
auto &OS = *Asm->OutStreamer;
|
|
MCContext &Ctx = Asm->OutContext;
|
|
const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
|
|
|
|
bool VerboseAsm = OS.isVerboseAsm();
|
|
auto AddComment = [&](const Twine &Comment) {
|
|
if (VerboseAsm)
|
|
OS.AddComment(Comment);
|
|
};
|
|
|
|
// Emit a label assignment with the SEH frame offset so we can use it for
|
|
// llvm.x86.seh.recoverfp.
|
|
StringRef FLinkageName =
|
|
GlobalValue::getRealLinkageName(MF->getFunction()->getName());
|
|
MCSymbol *ParentFrameOffset =
|
|
Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
|
|
const MCExpr *MCOffset =
|
|
MCConstantExpr::create(FuncInfo.SEHSetFrameOffset, Ctx);
|
|
Asm->OutStreamer->EmitAssignment(ParentFrameOffset, MCOffset);
|
|
|
|
// Use the assembler to compute the number of table entries through label
|
|
// difference and division.
|
|
MCSymbol *TableBegin =
|
|
Ctx.createTempSymbol("lsda_begin", /*AlwaysAddSuffix=*/true);
|
|
MCSymbol *TableEnd =
|
|
Ctx.createTempSymbol("lsda_end", /*AlwaysAddSuffix=*/true);
|
|
const MCExpr *LabelDiff = getOffset(TableEnd, TableBegin);
|
|
const MCExpr *EntrySize = MCConstantExpr::create(16, Ctx);
|
|
const MCExpr *EntryCount = MCBinaryExpr::createDiv(LabelDiff, EntrySize, Ctx);
|
|
AddComment("Number of call sites");
|
|
OS.EmitValue(EntryCount, 4);
|
|
|
|
OS.EmitLabel(TableBegin);
|
|
|
|
// Iterate over all the invoke try ranges. Unlike MSVC, LLVM currently only
|
|
// models exceptions from invokes. LLVM also allows arbitrary reordering of
|
|
// the code, so our tables end up looking a bit different. Rather than
|
|
// trying to match MSVC's tables exactly, we emit a denormalized table. For
|
|
// each range of invokes in the same state, we emit table entries for all
|
|
// the actions that would be taken in that state. This means our tables are
|
|
// slightly bigger, which is OK.
|
|
const MCSymbol *LastStartLabel = nullptr;
|
|
int LastEHState = -1;
|
|
// Break out before we enter into a finally funclet.
|
|
// FIXME: We need to emit separate EH tables for cleanups.
|
|
MachineFunction::const_iterator End = MF->end();
|
|
MachineFunction::const_iterator Stop = std::next(MF->begin());
|
|
while (Stop != End && !Stop->isEHFuncletEntry())
|
|
++Stop;
|
|
for (const auto &StateChange :
|
|
InvokeStateChangeIterator::range(FuncInfo, MF->begin(), Stop)) {
|
|
// Emit all the actions for the state we just transitioned out of
|
|
// if it was not the null state
|
|
if (LastEHState != -1)
|
|
emitSEHActionsForRange(FuncInfo, LastStartLabel,
|
|
StateChange.PreviousEndLabel, LastEHState);
|
|
LastStartLabel = StateChange.NewStartLabel;
|
|
LastEHState = StateChange.NewState;
|
|
}
|
|
|
|
OS.EmitLabel(TableEnd);
|
|
}
|
|
|
|
void WinException::emitSEHActionsForRange(const WinEHFuncInfo &FuncInfo,
|
|
const MCSymbol *BeginLabel,
|
|
const MCSymbol *EndLabel, int State) {
|
|
auto &OS = *Asm->OutStreamer;
|
|
MCContext &Ctx = Asm->OutContext;
|
|
|
|
bool VerboseAsm = OS.isVerboseAsm();
|
|
auto AddComment = [&](const Twine &Comment) {
|
|
if (VerboseAsm)
|
|
OS.AddComment(Comment);
|
|
};
|
|
|
|
assert(BeginLabel && EndLabel);
|
|
while (State != -1) {
|
|
const SEHUnwindMapEntry &UME = FuncInfo.SEHUnwindMap[State];
|
|
const MCExpr *FilterOrFinally;
|
|
const MCExpr *ExceptOrNull;
|
|
auto *Handler = UME.Handler.get<MachineBasicBlock *>();
|
|
if (UME.IsFinally) {
|
|
FilterOrFinally = create32bitRef(getMCSymbolForMBB(Asm, Handler));
|
|
ExceptOrNull = MCConstantExpr::create(0, Ctx);
|
|
} else {
|
|
// For an except, the filter can be 1 (catch-all) or a function
|
|
// label.
|
|
FilterOrFinally = UME.Filter ? create32bitRef(UME.Filter)
|
|
: MCConstantExpr::create(1, Ctx);
|
|
ExceptOrNull = create32bitRef(Handler->getSymbol());
|
|
}
|
|
|
|
AddComment("LabelStart");
|
|
OS.EmitValue(getLabelPlusOne(BeginLabel), 4);
|
|
AddComment("LabelEnd");
|
|
OS.EmitValue(getLabelPlusOne(EndLabel), 4);
|
|
AddComment(UME.IsFinally ? "FinallyFunclet" : UME.Filter ? "FilterFunction"
|
|
: "CatchAll");
|
|
OS.EmitValue(FilterOrFinally, 4);
|
|
AddComment(UME.IsFinally ? "Null" : "ExceptionHandler");
|
|
OS.EmitValue(ExceptOrNull, 4);
|
|
|
|
assert(UME.ToState < State && "states should decrease");
|
|
State = UME.ToState;
|
|
}
|
|
}
|
|
|
|
void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) {
|
|
const Function *F = MF->getFunction();
|
|
auto &OS = *Asm->OutStreamer;
|
|
const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
|
|
|
|
StringRef FuncLinkageName = GlobalValue::getRealLinkageName(F->getName());
|
|
|
|
SmallVector<std::pair<const MCExpr *, int>, 4> IPToStateTable;
|
|
MCSymbol *FuncInfoXData = nullptr;
|
|
if (shouldEmitPersonality) {
|
|
// If we're 64-bit, emit a pointer to the C++ EH data, and build a map from
|
|
// IPs to state numbers.
|
|
FuncInfoXData =
|
|
Asm->OutContext.getOrCreateSymbol(Twine("$cppxdata$", FuncLinkageName));
|
|
computeIP2StateTable(MF, FuncInfo, IPToStateTable);
|
|
} else {
|
|
FuncInfoXData = Asm->OutContext.getOrCreateLSDASymbol(FuncLinkageName);
|
|
}
|
|
|
|
int UnwindHelpOffset = 0;
|
|
if (Asm->MAI->usesWindowsCFI())
|
|
UnwindHelpOffset =
|
|
getFrameIndexOffset(FuncInfo.UnwindHelpFrameIdx, FuncInfo);
|
|
|
|
MCSymbol *UnwindMapXData = nullptr;
|
|
MCSymbol *TryBlockMapXData = nullptr;
|
|
MCSymbol *IPToStateXData = nullptr;
|
|
if (!FuncInfo.CxxUnwindMap.empty())
|
|
UnwindMapXData = Asm->OutContext.getOrCreateSymbol(
|
|
Twine("$stateUnwindMap$", FuncLinkageName));
|
|
if (!FuncInfo.TryBlockMap.empty())
|
|
TryBlockMapXData =
|
|
Asm->OutContext.getOrCreateSymbol(Twine("$tryMap$", FuncLinkageName));
|
|
if (!IPToStateTable.empty())
|
|
IPToStateXData =
|
|
Asm->OutContext.getOrCreateSymbol(Twine("$ip2state$", FuncLinkageName));
|
|
|
|
bool VerboseAsm = OS.isVerboseAsm();
|
|
auto AddComment = [&](const Twine &Comment) {
|
|
if (VerboseAsm)
|
|
OS.AddComment(Comment);
|
|
};
|
|
|
|
// FuncInfo {
|
|
// uint32_t MagicNumber
|
|
// int32_t MaxState;
|
|
// UnwindMapEntry *UnwindMap;
|
|
// uint32_t NumTryBlocks;
|
|
// TryBlockMapEntry *TryBlockMap;
|
|
// uint32_t IPMapEntries; // always 0 for x86
|
|
// IPToStateMapEntry *IPToStateMap; // always 0 for x86
|
|
// uint32_t UnwindHelp; // non-x86 only
|
|
// ESTypeList *ESTypeList;
|
|
// int32_t EHFlags;
|
|
// }
|
|
// EHFlags & 1 -> Synchronous exceptions only, no async exceptions.
|
|
// EHFlags & 2 -> ???
|
|
// EHFlags & 4 -> The function is noexcept(true), unwinding can't continue.
|
|
OS.EmitValueToAlignment(4);
|
|
OS.EmitLabel(FuncInfoXData);
|
|
|
|
AddComment("MagicNumber");
|
|
OS.EmitIntValue(0x19930522, 4);
|
|
|
|
AddComment("MaxState");
|
|
OS.EmitIntValue(FuncInfo.CxxUnwindMap.size(), 4);
|
|
|
|
AddComment("UnwindMap");
|
|
OS.EmitValue(create32bitRef(UnwindMapXData), 4);
|
|
|
|
AddComment("NumTryBlocks");
|
|
OS.EmitIntValue(FuncInfo.TryBlockMap.size(), 4);
|
|
|
|
AddComment("TryBlockMap");
|
|
OS.EmitValue(create32bitRef(TryBlockMapXData), 4);
|
|
|
|
AddComment("IPMapEntries");
|
|
OS.EmitIntValue(IPToStateTable.size(), 4);
|
|
|
|
AddComment("IPToStateXData");
|
|
OS.EmitValue(create32bitRef(IPToStateXData), 4);
|
|
|
|
if (Asm->MAI->usesWindowsCFI()) {
|
|
AddComment("UnwindHelp");
|
|
OS.EmitIntValue(UnwindHelpOffset, 4);
|
|
}
|
|
|
|
AddComment("ESTypeList");
|
|
OS.EmitIntValue(0, 4);
|
|
|
|
AddComment("EHFlags");
|
|
OS.EmitIntValue(1, 4);
|
|
|
|
// UnwindMapEntry {
|
|
// int32_t ToState;
|
|
// void (*Action)();
|
|
// };
|
|
if (UnwindMapXData) {
|
|
OS.EmitLabel(UnwindMapXData);
|
|
for (const CxxUnwindMapEntry &UME : FuncInfo.CxxUnwindMap) {
|
|
MCSymbol *CleanupSym =
|
|
getMCSymbolForMBB(Asm, UME.Cleanup.dyn_cast<MachineBasicBlock *>());
|
|
AddComment("ToState");
|
|
OS.EmitIntValue(UME.ToState, 4);
|
|
|
|
AddComment("Action");
|
|
OS.EmitValue(create32bitRef(CleanupSym), 4);
|
|
}
|
|
}
|
|
|
|
// TryBlockMap {
|
|
// int32_t TryLow;
|
|
// int32_t TryHigh;
|
|
// int32_t CatchHigh;
|
|
// int32_t NumCatches;
|
|
// HandlerType *HandlerArray;
|
|
// };
|
|
if (TryBlockMapXData) {
|
|
OS.EmitLabel(TryBlockMapXData);
|
|
SmallVector<MCSymbol *, 1> HandlerMaps;
|
|
for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
|
|
const WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
|
|
|
|
MCSymbol *HandlerMapXData = nullptr;
|
|
if (!TBME.HandlerArray.empty())
|
|
HandlerMapXData =
|
|
Asm->OutContext.getOrCreateSymbol(Twine("$handlerMap$")
|
|
.concat(Twine(I))
|
|
.concat("$")
|
|
.concat(FuncLinkageName));
|
|
HandlerMaps.push_back(HandlerMapXData);
|
|
|
|
// TBMEs should form intervals.
|
|
assert(0 <= TBME.TryLow && "bad trymap interval");
|
|
assert(TBME.TryLow <= TBME.TryHigh && "bad trymap interval");
|
|
assert(TBME.TryHigh < TBME.CatchHigh && "bad trymap interval");
|
|
assert(TBME.CatchHigh < int(FuncInfo.CxxUnwindMap.size()) &&
|
|
"bad trymap interval");
|
|
|
|
AddComment("TryLow");
|
|
OS.EmitIntValue(TBME.TryLow, 4);
|
|
|
|
AddComment("TryHigh");
|
|
OS.EmitIntValue(TBME.TryHigh, 4);
|
|
|
|
AddComment("CatchHigh");
|
|
OS.EmitIntValue(TBME.CatchHigh, 4);
|
|
|
|
AddComment("NumCatches");
|
|
OS.EmitIntValue(TBME.HandlerArray.size(), 4);
|
|
|
|
AddComment("HandlerArray");
|
|
OS.EmitValue(create32bitRef(HandlerMapXData), 4);
|
|
}
|
|
|
|
// All funclets use the same parent frame offset currently.
|
|
unsigned ParentFrameOffset = 0;
|
|
if (shouldEmitPersonality) {
|
|
const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
|
|
ParentFrameOffset = TFI->getWinEHParentFrameOffset(*MF);
|
|
}
|
|
|
|
for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
|
|
const WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
|
|
MCSymbol *HandlerMapXData = HandlerMaps[I];
|
|
if (!HandlerMapXData)
|
|
continue;
|
|
// HandlerType {
|
|
// int32_t Adjectives;
|
|
// TypeDescriptor *Type;
|
|
// int32_t CatchObjOffset;
|
|
// void (*Handler)();
|
|
// int32_t ParentFrameOffset; // x64 only
|
|
// };
|
|
OS.EmitLabel(HandlerMapXData);
|
|
for (const WinEHHandlerType &HT : TBME.HandlerArray) {
|
|
// Get the frame escape label with the offset of the catch object. If
|
|
// the index is INT_MAX, then there is no catch object, and we should
|
|
// emit an offset of zero, indicating that no copy will occur.
|
|
const MCExpr *FrameAllocOffsetRef = nullptr;
|
|
if (HT.CatchObj.FrameIndex != INT_MAX) {
|
|
int Offset = getFrameIndexOffset(HT.CatchObj.FrameIndex, FuncInfo);
|
|
assert(Offset != 0 && "Illegal offset for catch object!");
|
|
FrameAllocOffsetRef = MCConstantExpr::create(Offset, Asm->OutContext);
|
|
} else {
|
|
FrameAllocOffsetRef = MCConstantExpr::create(0, Asm->OutContext);
|
|
}
|
|
|
|
MCSymbol *HandlerSym =
|
|
getMCSymbolForMBB(Asm, HT.Handler.dyn_cast<MachineBasicBlock *>());
|
|
|
|
AddComment("Adjectives");
|
|
OS.EmitIntValue(HT.Adjectives, 4);
|
|
|
|
AddComment("Type");
|
|
OS.EmitValue(create32bitRef(HT.TypeDescriptor), 4);
|
|
|
|
AddComment("CatchObjOffset");
|
|
OS.EmitValue(FrameAllocOffsetRef, 4);
|
|
|
|
AddComment("Handler");
|
|
OS.EmitValue(create32bitRef(HandlerSym), 4);
|
|
|
|
if (shouldEmitPersonality) {
|
|
AddComment("ParentFrameOffset");
|
|
OS.EmitIntValue(ParentFrameOffset, 4);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// IPToStateMapEntry {
|
|
// void *IP;
|
|
// int32_t State;
|
|
// };
|
|
if (IPToStateXData) {
|
|
OS.EmitLabel(IPToStateXData);
|
|
for (auto &IPStatePair : IPToStateTable) {
|
|
AddComment("IP");
|
|
OS.EmitValue(IPStatePair.first, 4);
|
|
AddComment("ToState");
|
|
OS.EmitIntValue(IPStatePair.second, 4);
|
|
}
|
|
}
|
|
}
|
|
|
|
void WinException::computeIP2StateTable(
|
|
const MachineFunction *MF, const WinEHFuncInfo &FuncInfo,
|
|
SmallVectorImpl<std::pair<const MCExpr *, int>> &IPToStateTable) {
|
|
|
|
for (MachineFunction::const_iterator FuncletStart = MF->begin(),
|
|
FuncletEnd = MF->begin(),
|
|
End = MF->end();
|
|
FuncletStart != End; FuncletStart = FuncletEnd) {
|
|
// Find the end of the funclet
|
|
while (++FuncletEnd != End) {
|
|
if (FuncletEnd->isEHFuncletEntry()) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Don't emit ip2state entries for cleanup funclets. Any interesting
|
|
// exceptional actions in cleanups must be handled in a separate IR
|
|
// function.
|
|
if (FuncletStart->isCleanupFuncletEntry())
|
|
continue;
|
|
|
|
MCSymbol *StartLabel;
|
|
int BaseState;
|
|
if (FuncletStart == MF->begin()) {
|
|
BaseState = NullState;
|
|
StartLabel = Asm->getFunctionBegin();
|
|
} else {
|
|
auto *FuncletPad =
|
|
cast<FuncletPadInst>(FuncletStart->getBasicBlock()->getFirstNonPHI());
|
|
assert(FuncInfo.FuncletBaseStateMap.count(FuncletPad) != 0);
|
|
BaseState = FuncInfo.FuncletBaseStateMap.find(FuncletPad)->second;
|
|
StartLabel = getMCSymbolForMBB(Asm, &*FuncletStart);
|
|
}
|
|
assert(StartLabel && "need local function start label");
|
|
IPToStateTable.push_back(
|
|
std::make_pair(create32bitRef(StartLabel), BaseState));
|
|
|
|
for (const auto &StateChange : InvokeStateChangeIterator::range(
|
|
FuncInfo, FuncletStart, FuncletEnd, BaseState)) {
|
|
// Compute the label to report as the start of this entry; use the EH
|
|
// start label for the invoke if we have one, otherwise (this is a call
|
|
// which may unwind to our caller and does not have an EH start label, so)
|
|
// use the previous end label.
|
|
const MCSymbol *ChangeLabel = StateChange.NewStartLabel;
|
|
if (!ChangeLabel)
|
|
ChangeLabel = StateChange.PreviousEndLabel;
|
|
// Emit an entry indicating that PCs after 'Label' have this EH state.
|
|
IPToStateTable.push_back(
|
|
std::make_pair(getLabelPlusOne(ChangeLabel), StateChange.NewState));
|
|
// FIXME: assert that NewState is between CatchLow and CatchHigh.
|
|
}
|
|
}
|
|
}
|
|
|
|
void WinException::emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,
|
|
StringRef FLinkageName) {
|
|
// Outlined helpers called by the EH runtime need to know the offset of the EH
|
|
// registration in order to recover the parent frame pointer. Now that we know
|
|
// we've code generated the parent, we can emit the label assignment that
|
|
// those helpers use to get the offset of the registration node.
|
|
MCContext &Ctx = Asm->OutContext;
|
|
MCSymbol *ParentFrameOffset =
|
|
Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
|
|
unsigned UnusedReg;
|
|
const TargetFrameLowering *TFI = Asm->MF->getSubtarget().getFrameLowering();
|
|
int64_t Offset = TFI->getFrameIndexReference(
|
|
*Asm->MF, FuncInfo.EHRegNodeFrameIndex, UnusedReg);
|
|
const MCExpr *MCOffset = MCConstantExpr::create(Offset, Ctx);
|
|
Asm->OutStreamer->EmitAssignment(ParentFrameOffset, MCOffset);
|
|
}
|
|
|
|
/// Emit the language-specific data that _except_handler3 and 4 expect. This is
|
|
/// functionally equivalent to the __C_specific_handler table, except it is
|
|
/// indexed by state number instead of IP.
|
|
void WinException::emitExceptHandlerTable(const MachineFunction *MF) {
|
|
MCStreamer &OS = *Asm->OutStreamer;
|
|
const Function *F = MF->getFunction();
|
|
StringRef FLinkageName = GlobalValue::getRealLinkageName(F->getName());
|
|
|
|
bool VerboseAsm = OS.isVerboseAsm();
|
|
auto AddComment = [&](const Twine &Comment) {
|
|
if (VerboseAsm)
|
|
OS.AddComment(Comment);
|
|
};
|
|
|
|
const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
|
|
emitEHRegistrationOffsetLabel(FuncInfo, FLinkageName);
|
|
|
|
// Emit the __ehtable label that we use for llvm.x86.seh.lsda.
|
|
MCSymbol *LSDALabel = Asm->OutContext.getOrCreateLSDASymbol(FLinkageName);
|
|
OS.EmitValueToAlignment(4);
|
|
OS.EmitLabel(LSDALabel);
|
|
|
|
const Function *Per =
|
|
dyn_cast<Function>(F->getPersonalityFn()->stripPointerCasts());
|
|
StringRef PerName = Per->getName();
|
|
int BaseState = -1;
|
|
if (PerName == "_except_handler4") {
|
|
// The LSDA for _except_handler4 starts with this struct, followed by the
|
|
// scope table:
|
|
//
|
|
// struct EH4ScopeTable {
|
|
// int32_t GSCookieOffset;
|
|
// int32_t GSCookieXOROffset;
|
|
// int32_t EHCookieOffset;
|
|
// int32_t EHCookieXOROffset;
|
|
// ScopeTableEntry ScopeRecord[];
|
|
// };
|
|
//
|
|
// Offsets are %ebp relative.
|
|
//
|
|
// The GS cookie is present only if the function needs stack protection.
|
|
// GSCookieOffset = -2 means that GS cookie is not used.
|
|
//
|
|
// The EH cookie is always present.
|
|
//
|
|
// Check is done the following way:
|
|
// (ebp+CookieXOROffset) ^ [ebp+CookieOffset] == _security_cookie
|
|
|
|
// Retrieve the Guard Stack slot.
|
|
int GSCookieOffset = -2;
|
|
const MachineFrameInfo *MFI = MF->getFrameInfo();
|
|
if (MFI->hasStackProtectorIndex()) {
|
|
unsigned UnusedReg;
|
|
const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
|
|
int SSPIdx = MFI->getStackProtectorIndex();
|
|
GSCookieOffset = TFI->getFrameIndexReference(*MF, SSPIdx, UnusedReg);
|
|
}
|
|
|
|
// Retrieve the EH Guard slot.
|
|
// TODO(etienneb): Get rid of this value and change it for and assertion.
|
|
int EHCookieOffset = 9999;
|
|
if (FuncInfo.EHGuardFrameIndex != INT_MAX) {
|
|
unsigned UnusedReg;
|
|
const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
|
|
int EHGuardIdx = FuncInfo.EHGuardFrameIndex;
|
|
EHCookieOffset = TFI->getFrameIndexReference(*MF, EHGuardIdx, UnusedReg);
|
|
}
|
|
|
|
AddComment("GSCookieOffset");
|
|
OS.EmitIntValue(GSCookieOffset, 4);
|
|
AddComment("GSCookieXOROffset");
|
|
OS.EmitIntValue(0, 4);
|
|
AddComment("EHCookieOffset");
|
|
OS.EmitIntValue(EHCookieOffset, 4);
|
|
AddComment("EHCookieXOROffset");
|
|
OS.EmitIntValue(0, 4);
|
|
BaseState = -2;
|
|
}
|
|
|
|
assert(!FuncInfo.SEHUnwindMap.empty());
|
|
for (const SEHUnwindMapEntry &UME : FuncInfo.SEHUnwindMap) {
|
|
auto *Handler = UME.Handler.get<MachineBasicBlock *>();
|
|
const MCSymbol *ExceptOrFinally =
|
|
UME.IsFinally ? getMCSymbolForMBB(Asm, Handler) : Handler->getSymbol();
|
|
// -1 is usually the base state for "unwind to caller", but for
|
|
// _except_handler4 it's -2. Do that replacement here if necessary.
|
|
int ToState = UME.ToState == -1 ? BaseState : UME.ToState;
|
|
AddComment("ToState");
|
|
OS.EmitIntValue(ToState, 4);
|
|
AddComment(UME.IsFinally ? "Null" : "FilterFunction");
|
|
OS.EmitValue(create32bitRef(UME.Filter), 4);
|
|
AddComment(UME.IsFinally ? "FinallyFunclet" : "ExceptionHandler");
|
|
OS.EmitValue(create32bitRef(ExceptOrFinally), 4);
|
|
}
|
|
}
|
|
|
|
static int getTryRank(const WinEHFuncInfo &FuncInfo, int State) {
|
|
int Rank = 0;
|
|
while (State != -1) {
|
|
++Rank;
|
|
State = FuncInfo.ClrEHUnwindMap[State].TryParentState;
|
|
}
|
|
return Rank;
|
|
}
|
|
|
|
static int getTryAncestor(const WinEHFuncInfo &FuncInfo, int Left, int Right) {
|
|
int LeftRank = getTryRank(FuncInfo, Left);
|
|
int RightRank = getTryRank(FuncInfo, Right);
|
|
|
|
while (LeftRank < RightRank) {
|
|
Right = FuncInfo.ClrEHUnwindMap[Right].TryParentState;
|
|
--RightRank;
|
|
}
|
|
|
|
while (RightRank < LeftRank) {
|
|
Left = FuncInfo.ClrEHUnwindMap[Left].TryParentState;
|
|
--LeftRank;
|
|
}
|
|
|
|
while (Left != Right) {
|
|
Left = FuncInfo.ClrEHUnwindMap[Left].TryParentState;
|
|
Right = FuncInfo.ClrEHUnwindMap[Right].TryParentState;
|
|
}
|
|
|
|
return Left;
|
|
}
|
|
|
|
void WinException::emitCLRExceptionTable(const MachineFunction *MF) {
|
|
// CLR EH "states" are really just IDs that identify handlers/funclets;
|
|
// states, handlers, and funclets all have 1:1 mappings between them, and a
|
|
// handler/funclet's "state" is its index in the ClrEHUnwindMap.
|
|
MCStreamer &OS = *Asm->OutStreamer;
|
|
const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
|
|
MCSymbol *FuncBeginSym = Asm->getFunctionBegin();
|
|
MCSymbol *FuncEndSym = Asm->getFunctionEnd();
|
|
|
|
// A ClrClause describes a protected region.
|
|
struct ClrClause {
|
|
const MCSymbol *StartLabel; // Start of protected region
|
|
const MCSymbol *EndLabel; // End of protected region
|
|
int State; // Index of handler protecting the protected region
|
|
int EnclosingState; // Index of funclet enclosing the protected region
|
|
};
|
|
SmallVector<ClrClause, 8> Clauses;
|
|
|
|
// Build a map from handler MBBs to their corresponding states (i.e. their
|
|
// indices in the ClrEHUnwindMap).
|
|
int NumStates = FuncInfo.ClrEHUnwindMap.size();
|
|
assert(NumStates > 0 && "Don't need exception table!");
|
|
DenseMap<const MachineBasicBlock *, int> HandlerStates;
|
|
for (int State = 0; State < NumStates; ++State) {
|
|
MachineBasicBlock *HandlerBlock =
|
|
FuncInfo.ClrEHUnwindMap[State].Handler.get<MachineBasicBlock *>();
|
|
HandlerStates[HandlerBlock] = State;
|
|
// Use this loop through all handlers to verify our assumption (used in
|
|
// the MinEnclosingState computation) that enclosing funclets have lower
|
|
// state numbers than their enclosed funclets.
|
|
assert(FuncInfo.ClrEHUnwindMap[State].HandlerParentState < State &&
|
|
"ill-formed state numbering");
|
|
}
|
|
// Map the main function to the NullState.
|
|
HandlerStates[&MF->front()] = NullState;
|
|
|
|
// Write out a sentinel indicating the end of the standard (Windows) xdata
|
|
// and the start of the additional (CLR) info.
|
|
OS.EmitIntValue(0xffffffff, 4);
|
|
// Write out the number of funclets
|
|
OS.EmitIntValue(NumStates, 4);
|
|
|
|
// Walk the machine blocks/instrs, computing and emitting a few things:
|
|
// 1. Emit a list of the offsets to each handler entry, in lexical order.
|
|
// 2. Compute a map (EndSymbolMap) from each funclet to the symbol at its end.
|
|
// 3. Compute the list of ClrClauses, in the required order (inner before
|
|
// outer, earlier before later; the order by which a forward scan with
|
|
// early termination will find the innermost enclosing clause covering
|
|
// a given address).
|
|
// 4. A map (MinClauseMap) from each handler index to the index of the
|
|
// outermost funclet/function which contains a try clause targeting the
|
|
// key handler. This will be used to determine IsDuplicate-ness when
|
|
// emitting ClrClauses. The NullState value is used to indicate that the
|
|
// top-level function contains a try clause targeting the key handler.
|
|
// HandlerStack is a stack of (PendingStartLabel, PendingState) pairs for
|
|
// try regions we entered before entering the PendingState try but which
|
|
// we haven't yet exited.
|
|
SmallVector<std::pair<const MCSymbol *, int>, 4> HandlerStack;
|
|
// EndSymbolMap and MinClauseMap are maps described above.
|
|
std::unique_ptr<MCSymbol *[]> EndSymbolMap(new MCSymbol *[NumStates]);
|
|
SmallVector<int, 4> MinClauseMap((size_t)NumStates, NumStates);
|
|
|
|
// Visit the root function and each funclet.
|
|
for (MachineFunction::const_iterator FuncletStart = MF->begin(),
|
|
FuncletEnd = MF->begin(),
|
|
End = MF->end();
|
|
FuncletStart != End; FuncletStart = FuncletEnd) {
|
|
int FuncletState = HandlerStates[&*FuncletStart];
|
|
// Find the end of the funclet
|
|
MCSymbol *EndSymbol = FuncEndSym;
|
|
while (++FuncletEnd != End) {
|
|
if (FuncletEnd->isEHFuncletEntry()) {
|
|
EndSymbol = getMCSymbolForMBB(Asm, &*FuncletEnd);
|
|
break;
|
|
}
|
|
}
|
|
// Emit the function/funclet end and, if this is a funclet (and not the
|
|
// root function), record it in the EndSymbolMap.
|
|
OS.EmitValue(getOffset(EndSymbol, FuncBeginSym), 4);
|
|
if (FuncletState != NullState) {
|
|
// Record the end of the handler.
|
|
EndSymbolMap[FuncletState] = EndSymbol;
|
|
}
|
|
|
|
// Walk the state changes in this function/funclet and compute its clauses.
|
|
// Funclets always start in the null state.
|
|
const MCSymbol *CurrentStartLabel = nullptr;
|
|
int CurrentState = NullState;
|
|
assert(HandlerStack.empty());
|
|
for (const auto &StateChange :
|
|
InvokeStateChangeIterator::range(FuncInfo, FuncletStart, FuncletEnd)) {
|
|
// Close any try regions we're not still under
|
|
int StillPendingState =
|
|
getTryAncestor(FuncInfo, CurrentState, StateChange.NewState);
|
|
while (CurrentState != StillPendingState) {
|
|
assert(CurrentState != NullState &&
|
|
"Failed to find still-pending state!");
|
|
// Close the pending clause
|
|
Clauses.push_back({CurrentStartLabel, StateChange.PreviousEndLabel,
|
|
CurrentState, FuncletState});
|
|
// Now the next-outer try region is current
|
|
CurrentState = FuncInfo.ClrEHUnwindMap[CurrentState].TryParentState;
|
|
// Pop the new start label from the handler stack if we've exited all
|
|
// inner try regions of the corresponding try region.
|
|
if (HandlerStack.back().second == CurrentState)
|
|
CurrentStartLabel = HandlerStack.pop_back_val().first;
|
|
}
|
|
|
|
if (StateChange.NewState != CurrentState) {
|
|
// For each clause we're starting, update the MinClauseMap so we can
|
|
// know which is the topmost funclet containing a clause targeting
|
|
// it.
|
|
for (int EnteredState = StateChange.NewState;
|
|
EnteredState != CurrentState;
|
|
EnteredState =
|
|
FuncInfo.ClrEHUnwindMap[EnteredState].TryParentState) {
|
|
int &MinEnclosingState = MinClauseMap[EnteredState];
|
|
if (FuncletState < MinEnclosingState)
|
|
MinEnclosingState = FuncletState;
|
|
}
|
|
// Save the previous current start/label on the stack and update to
|
|
// the newly-current start/state.
|
|
HandlerStack.emplace_back(CurrentStartLabel, CurrentState);
|
|
CurrentStartLabel = StateChange.NewStartLabel;
|
|
CurrentState = StateChange.NewState;
|
|
}
|
|
}
|
|
assert(HandlerStack.empty());
|
|
}
|
|
|
|
// Now emit the clause info, starting with the number of clauses.
|
|
OS.EmitIntValue(Clauses.size(), 4);
|
|
for (ClrClause &Clause : Clauses) {
|
|
// Emit a CORINFO_EH_CLAUSE :
|
|
/*
|
|
struct CORINFO_EH_CLAUSE
|
|
{
|
|
CORINFO_EH_CLAUSE_FLAGS Flags; // actually a CorExceptionFlag
|
|
DWORD TryOffset;
|
|
DWORD TryLength; // actually TryEndOffset
|
|
DWORD HandlerOffset;
|
|
DWORD HandlerLength; // actually HandlerEndOffset
|
|
union
|
|
{
|
|
DWORD ClassToken; // use for catch clauses
|
|
DWORD FilterOffset; // use for filter clauses
|
|
};
|
|
};
|
|
|
|
enum CORINFO_EH_CLAUSE_FLAGS
|
|
{
|
|
CORINFO_EH_CLAUSE_NONE = 0,
|
|
CORINFO_EH_CLAUSE_FILTER = 0x0001, // This clause is for a filter
|
|
CORINFO_EH_CLAUSE_FINALLY = 0x0002, // This clause is a finally clause
|
|
CORINFO_EH_CLAUSE_FAULT = 0x0004, // This clause is a fault clause
|
|
};
|
|
typedef enum CorExceptionFlag
|
|
{
|
|
COR_ILEXCEPTION_CLAUSE_NONE,
|
|
COR_ILEXCEPTION_CLAUSE_FILTER = 0x0001, // This is a filter clause
|
|
COR_ILEXCEPTION_CLAUSE_FINALLY = 0x0002, // This is a finally clause
|
|
COR_ILEXCEPTION_CLAUSE_FAULT = 0x0004, // This is a fault clause
|
|
COR_ILEXCEPTION_CLAUSE_DUPLICATED = 0x0008, // duplicated clause. This
|
|
// clause was duplicated
|
|
// to a funclet which was
|
|
// pulled out of line
|
|
} CorExceptionFlag;
|
|
*/
|
|
// Add 1 to the start/end of the EH clause; the IP associated with a
|
|
// call when the runtime does its scan is the IP of the next instruction
|
|
// (the one to which control will return after the call), so we need
|
|
// to add 1 to the end of the clause to cover that offset. We also add
|
|
// 1 to the start of the clause to make sure that the ranges reported
|
|
// for all clauses are disjoint. Note that we'll need some additional
|
|
// logic when machine traps are supported, since in that case the IP
|
|
// that the runtime uses is the offset of the faulting instruction
|
|
// itself; if such an instruction immediately follows a call but the
|
|
// two belong to different clauses, we'll need to insert a nop between
|
|
// them so the runtime can distinguish the point to which the call will
|
|
// return from the point at which the fault occurs.
|
|
|
|
const MCExpr *ClauseBegin =
|
|
getOffsetPlusOne(Clause.StartLabel, FuncBeginSym);
|
|
const MCExpr *ClauseEnd = getOffsetPlusOne(Clause.EndLabel, FuncBeginSym);
|
|
|
|
const ClrEHUnwindMapEntry &Entry = FuncInfo.ClrEHUnwindMap[Clause.State];
|
|
MachineBasicBlock *HandlerBlock = Entry.Handler.get<MachineBasicBlock *>();
|
|
MCSymbol *BeginSym = getMCSymbolForMBB(Asm, HandlerBlock);
|
|
const MCExpr *HandlerBegin = getOffset(BeginSym, FuncBeginSym);
|
|
MCSymbol *EndSym = EndSymbolMap[Clause.State];
|
|
const MCExpr *HandlerEnd = getOffset(EndSym, FuncBeginSym);
|
|
|
|
uint32_t Flags = 0;
|
|
switch (Entry.HandlerType) {
|
|
case ClrHandlerType::Catch:
|
|
// Leaving bits 0-2 clear indicates catch.
|
|
break;
|
|
case ClrHandlerType::Filter:
|
|
Flags |= 1;
|
|
break;
|
|
case ClrHandlerType::Finally:
|
|
Flags |= 2;
|
|
break;
|
|
case ClrHandlerType::Fault:
|
|
Flags |= 4;
|
|
break;
|
|
}
|
|
if (Clause.EnclosingState != MinClauseMap[Clause.State]) {
|
|
// This is a "duplicate" clause; the handler needs to be entered from a
|
|
// frame above the one holding the invoke.
|
|
assert(Clause.EnclosingState > MinClauseMap[Clause.State]);
|
|
Flags |= 8;
|
|
}
|
|
OS.EmitIntValue(Flags, 4);
|
|
|
|
// Write the clause start/end
|
|
OS.EmitValue(ClauseBegin, 4);
|
|
OS.EmitValue(ClauseEnd, 4);
|
|
|
|
// Write out the handler start/end
|
|
OS.EmitValue(HandlerBegin, 4);
|
|
OS.EmitValue(HandlerEnd, 4);
|
|
|
|
// Write out the type token or filter offset
|
|
assert(Entry.HandlerType != ClrHandlerType::Filter && "NYI: filters");
|
|
OS.EmitIntValue(Entry.TypeToken, 4);
|
|
}
|
|
}
|