1 files changed, 171 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
new file mode 100644
index 000000000000..207a7284dafa
--- /dev/null
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
@@ -0,0 +1,171 @@
+//===-- CodeGen/AsmPrinter/DwarfException.cpp - Dwarf Exception Impl ------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains support for writing DWARF exception info into asm files.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DwarfException.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Mangler.h"
+#include "llvm/IR/Module.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCSection.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MachineLocation.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Target/TargetLoweringObjectFile.h"
+#include "llvm/Target/TargetOptions.h"
+using namespace llvm;
+
+DwarfCFIExceptionBase::DwarfCFIExceptionBase(AsmPrinter *A)
+    : EHStreamer(A), shouldEmitCFI(false), hasEmittedCFISections(false) {}
+
+void DwarfCFIExceptionBase::markFunctionEnd() {
+  endFragment();
+
+  // Map all labels and get rid of any dead landing pads.
+  if (!Asm->MF->getLandingPads().empty()) {
+    MachineFunction *NonConstMF = const_cast<MachineFunction*>(Asm->MF);
+    NonConstMF->tidyLandingPads();
+  }
+}
+
+void DwarfCFIExceptionBase::endFragment() {
+  if (shouldEmitCFI)
+    Asm->OutStreamer->EmitCFIEndProc();
+}
+
+DwarfCFIException::DwarfCFIException(AsmPrinter *A)
+    : DwarfCFIExceptionBase(A), shouldEmitPersonality(false),
+      forceEmitPersonality(false), shouldEmitLSDA(false),
+      shouldEmitMoves(false) {}
+
+DwarfCFIException::~DwarfCFIException() {}
+
+/// endModule - Emit all exception information that should come after the
+/// content.
+void DwarfCFIException::endModule() {
+  // SjLj uses this pass and it doesn't need this info.
+  if (!Asm->MAI->usesCFIForEH())
+    return;
+
+  const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
+
+  unsigned PerEncoding = TLOF.getPersonalityEncoding();
+
+  if ((PerEncoding & 0x80) != dwarf::DW_EH_PE_indirect)
+    return;
+
+  // Emit references to all used personality functions
+  for (const Function *Personality : MMI->getPersonalities()) {
+    if (!Personality)
+      continue;
+    MCSymbol *Sym = Asm->getSymbol(Personality);
+    TLOF.emitPersonalityValue(*Asm->OutStreamer, Asm->getDataLayout(), Sym);
+  }
+}
+
+static MCSymbol *getExceptionSym(AsmPrinter *Asm) {
+  return Asm->getCurExceptionSym();
+}
+
+void DwarfCFIException::beginFunction(const MachineFunction *MF) {
+  shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
+  const Function &F = MF->getFunction();
+
+  // If any landing pads survive, we need an EH table.
+  bool hasLandingPads = !MF->getLandingPads().empty();
+
+  // See if we need frame move info.
+  AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
+
+  shouldEmitMoves = MoveType != AsmPrinter::CFI_M_None;
+
+  const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
+  unsigned PerEncoding = TLOF.getPersonalityEncoding();
+  const Function *Per = nullptr;
+  if (F.hasPersonalityFn())
+    Per = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
+
+  // Emit a personality function even when there are no landing pads
+  forceEmitPersonality =
+      // ...if a personality function is explicitly specified
+      F.hasPersonalityFn() &&
+      // ... and it's not known to be a noop in the absence of invokes
+      !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
+      // ... and we're not explicitly asked not to emit it
+      F.needsUnwindTableEntry();
+
+  shouldEmitPersonality =
+      (forceEmitPersonality ||
+       (hasLandingPads && PerEncoding != dwarf::DW_EH_PE_omit)) &&
+      Per;
+
+  unsigned LSDAEncoding = TLOF.getLSDAEncoding();
+  shouldEmitLSDA = shouldEmitPersonality &&
+    LSDAEncoding != dwarf::DW_EH_PE_omit;
+
+  shouldEmitCFI = MF->getMMI().getContext().getAsmInfo()->usesCFIForEH() &&
+                  (shouldEmitPersonality || shouldEmitMoves);
+  beginFragment(&*MF->begin(), getExceptionSym);
+}
+
+void DwarfCFIException::beginFragment(const MachineBasicBlock *MBB,
+                                      ExceptionSymbolProvider ESP) {
+  if (!shouldEmitCFI)
+    return;
+
+  if (!hasEmittedCFISections) {
+    if (Asm->needsOnlyDebugCFIMoves())
+      Asm->OutStreamer->EmitCFISections(false, true);
+    hasEmittedCFISections = true;
+  }
+
+  Asm->OutStreamer->EmitCFIStartProc(/*IsSimple=*/false);
+
+  // Indicate personality routine, if any.
+  if (!shouldEmitPersonality)
+    return;
+
+  auto &F = MBB->getParent()->getFunction();
+  auto *P = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
+  assert(P && "Expected personality function");
+
+  // If we are forced to emit this personality, make sure to record
+  // it because it might not appear in any landingpad
+  if (forceEmitPersonality)
+    MMI->addPersonality(P);
+
+  const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
+  unsigned PerEncoding = TLOF.getPersonalityEncoding();
+  const MCSymbol *Sym = TLOF.getCFIPersonalitySymbol(P, Asm->TM, MMI);
+  Asm->OutStreamer->EmitCFIPersonality(Sym, PerEncoding);
+
+  // Provide LSDA information.
+  if (shouldEmitLSDA)
+    Asm->OutStreamer->EmitCFILsda(ESP(Asm), TLOF.getLSDAEncoding());
+}
+
+/// endFunction - Gather and emit post-function exception information.
+///
+void DwarfCFIException::endFunction(const MachineFunction *MF) {
+  if (!shouldEmitPersonality)
+    return;
+
+  emitExceptionTable();
+}