1 files changed, 227 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMWinCOFFStreamer.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMWinCOFFStreamer.cpp
index e6f649164a29..cdd7f6fb715a 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMWinCOFFStreamer.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMWinCOFFStreamer.cpp
@@ -8,30 +8,59 @@
 
 #include "ARMMCTargetDesc.h"
 #include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCWin64EH.h"
 #include "llvm/MC/MCWinCOFFStreamer.h"
 
 using namespace llvm;
 
 namespace {
 class ARMWinCOFFStreamer : public MCWinCOFFStreamer {
+  Win64EH::ARMUnwindEmitter EHStreamer;
+
 public:
   ARMWinCOFFStreamer(MCContext &C, std::unique_ptr<MCAsmBackend> AB,
                      std::unique_ptr<MCCodeEmitter> CE,
                      std::unique_ptr<MCObjectWriter> OW)
       : MCWinCOFFStreamer(C, std::move(AB), std::move(CE), std::move(OW)) {}
 
+  void emitWinEHHandlerData(SMLoc Loc) override;
+  void emitWindowsUnwindTables() override;
+  void emitWindowsUnwindTables(WinEH::FrameInfo *Frame) override;
+
   void emitThumbFunc(MCSymbol *Symbol) override;
   void finishImpl() override;
 };
 
+void ARMWinCOFFStreamer::emitWinEHHandlerData(SMLoc Loc) {
+  MCStreamer::emitWinEHHandlerData(Loc);
+
+  // We have to emit the unwind info now, because this directive
+  // actually switches to the .xdata section!
+  EHStreamer.EmitUnwindInfo(*this, getCurrentWinFrameInfo(),
+                            /* HandlerData = */ true);
+}
+
+void ARMWinCOFFStreamer::emitWindowsUnwindTables(WinEH::FrameInfo *Frame) {
+  EHStreamer.EmitUnwindInfo(*this, Frame, /* HandlerData = */ false);
+}
+
+void ARMWinCOFFStreamer::emitWindowsUnwindTables() {
+  if (!getNumWinFrameInfos())
+    return;
+  EHStreamer.Emit(*this);
+}
+
 void ARMWinCOFFStreamer::emitThumbFunc(MCSymbol *Symbol) {
   getAssembler().setIsThumbFunc(Symbol);
 }
 
 void ARMWinCOFFStreamer::finishImpl() {
   emitFrames(nullptr);
+  emitWindowsUnwindTables();
 
   MCWinCOFFStreamer::finishImpl();
 }
@@ -48,3 +77,201 @@ MCStreamer *llvm::createARMWinCOFFStreamer(
   return S;
 }
 
+namespace {
+class ARMTargetWinCOFFStreamer : public llvm::ARMTargetStreamer {
+private:
+  // True if we are processing SEH directives in an epilogue.
+  bool InEpilogCFI = false;
+
+  // Symbol of the current epilog for which we are processing SEH directives.
+  MCSymbol *CurrentEpilog = nullptr;
+
+public:
+  ARMTargetWinCOFFStreamer(llvm::MCStreamer &S) : ARMTargetStreamer(S) {}
+
+  // The unwind codes on ARM Windows are documented at
+  // https://docs.microsoft.com/en-us/cpp/build/arm-exception-handling
+  void emitARMWinCFIAllocStack(unsigned Size, bool Wide) override;
+  void emitARMWinCFISaveRegMask(unsigned Mask, bool Wide) override;
+  void emitARMWinCFISaveSP(unsigned Reg) override;
+  void emitARMWinCFISaveFRegs(unsigned First, unsigned Last) override;
+  void emitARMWinCFISaveLR(unsigned Offset) override;
+  void emitARMWinCFIPrologEnd(bool Fragment) override;
+  void emitARMWinCFINop(bool Wide) override;
+  void emitARMWinCFIEpilogStart(unsigned Condition) override;
+  void emitARMWinCFIEpilogEnd() override;
+  void emitARMWinCFICustom(unsigned Opcode) override;
+
+private:
+  void emitARMWinUnwindCode(unsigned UnwindCode, int Reg, int Offset);
+};
+
+// Helper function to common out unwind code setup for those codes that can
+// belong to both prolog and epilog.
+void ARMTargetWinCOFFStreamer::emitARMWinUnwindCode(unsigned UnwindCode,
+                                                    int Reg, int Offset) {
+  auto &S = getStreamer();
+  WinEH::FrameInfo *CurFrame = S.EnsureValidWinFrameInfo(SMLoc());
+  if (!CurFrame)
+    return;
+  MCSymbol *Label = S.emitCFILabel();
+  auto Inst = WinEH::Instruction(UnwindCode, Label, Reg, Offset);
+  if (InEpilogCFI)
+    CurFrame->EpilogMap[CurrentEpilog].Instructions.push_back(Inst);
+  else
+    CurFrame->Instructions.push_back(Inst);
+}
+
+void ARMTargetWinCOFFStreamer::emitARMWinCFIAllocStack(unsigned Size,
+                                                       bool Wide) {
+  unsigned Op = Win64EH::UOP_AllocSmall;
+  if (!Wide) {
+    if (Size / 4 > 0xffff)
+      Op = Win64EH::UOP_AllocHuge;
+    else if (Size / 4 > 0x7f)
+      Op = Win64EH::UOP_AllocLarge;
+  } else {
+    Op = Win64EH::UOP_WideAllocMedium;
+    if (Size / 4 > 0xffff)
+      Op = Win64EH::UOP_WideAllocHuge;
+    else if (Size / 4 > 0x3ff)
+      Op = Win64EH::UOP_WideAllocLarge;
+  }
+  emitARMWinUnwindCode(Op, -1, Size);
+}
+
+void ARMTargetWinCOFFStreamer::emitARMWinCFISaveRegMask(unsigned Mask,
+                                                        bool Wide) {
+  assert(Mask != 0);
+  int Lr = (Mask & 0x4000) ? 1 : 0;
+  Mask &= ~0x4000;
+  if (Wide)
+    assert((Mask & ~0x1fff) == 0);
+  else
+    assert((Mask & ~0x00ff) == 0);
+  if (Mask && ((Mask + (1 << 4)) & Mask) == 0) {
+    if (Wide && (Mask & 0x1000) == 0 && (Mask & 0xff) == 0xf0) {
+      // One continuous range from r4 to r8-r11
+      for (int I = 11; I >= 8; I--) {
+        if (Mask & (1 << I)) {
+          emitARMWinUnwindCode(Win64EH::UOP_WideSaveRegsR4R11LR, I, Lr);
+          return;
+        }
+      }
+      // If it actually was from r4 to r4-r7, continue below.
+    } else if (!Wide) {
+      // One continuous range from r4 to r4-r7
+      for (int I = 7; I >= 4; I--) {
+        if (Mask & (1 << I)) {
+          emitARMWinUnwindCode(Win64EH::UOP_SaveRegsR4R7LR, I, Lr);
+          return;
+        }
+      }
+      llvm_unreachable("logic error");
+    }
+  }
+  Mask |= Lr << 14;
+  if (Wide)
+    emitARMWinUnwindCode(Win64EH::UOP_WideSaveRegMask, Mask, 0);
+  else
+    emitARMWinUnwindCode(Win64EH::UOP_SaveRegMask, Mask, 0);
+}
+
+void ARMTargetWinCOFFStreamer::emitARMWinCFISaveSP(unsigned Reg) {
+  emitARMWinUnwindCode(Win64EH::UOP_SaveSP, Reg, 0);
+}
+
+void ARMTargetWinCOFFStreamer::emitARMWinCFISaveFRegs(unsigned First,
+                                                      unsigned Last) {
+  assert(First <= Last);
+  assert(First >= 16 || Last < 16);
+  assert(First <= 31 && Last <= 31);
+  if (First == 8)
+    emitARMWinUnwindCode(Win64EH::UOP_SaveFRegD8D15, Last, 0);
+  else if (First <= 15)
+    emitARMWinUnwindCode(Win64EH::UOP_SaveFRegD0D15, First, Last);
+  else
+    emitARMWinUnwindCode(Win64EH::UOP_SaveFRegD16D31, First, Last);
+}
+
+void ARMTargetWinCOFFStreamer::emitARMWinCFISaveLR(unsigned Offset) {
+  emitARMWinUnwindCode(Win64EH::UOP_SaveLR, 0, Offset);
+}
+
+void ARMTargetWinCOFFStreamer::emitARMWinCFINop(bool Wide) {
+  if (Wide)
+    emitARMWinUnwindCode(Win64EH::UOP_WideNop, -1, 0);
+  else
+    emitARMWinUnwindCode(Win64EH::UOP_Nop, -1, 0);
+}
+
+void ARMTargetWinCOFFStreamer::emitARMWinCFIPrologEnd(bool Fragment) {
+  auto &S = getStreamer();
+  WinEH::FrameInfo *CurFrame = S.EnsureValidWinFrameInfo(SMLoc());
+  if (!CurFrame)
+    return;
+
+  MCSymbol *Label = S.emitCFILabel();
+  CurFrame->PrologEnd = Label;
+  WinEH::Instruction Inst =
+      WinEH::Instruction(Win64EH::UOP_End, /*Label=*/nullptr, -1, 0);
+  auto it = CurFrame->Instructions.begin();
+  CurFrame->Instructions.insert(it, Inst);
+  CurFrame->Fragment = Fragment;
+}
+
+void ARMTargetWinCOFFStreamer::emitARMWinCFIEpilogStart(unsigned Condition) {
+  auto &S = getStreamer();
+  WinEH::FrameInfo *CurFrame = S.EnsureValidWinFrameInfo(SMLoc());
+  if (!CurFrame)
+    return;
+
+  InEpilogCFI = true;
+  CurrentEpilog = S.emitCFILabel();
+  CurFrame->EpilogMap[CurrentEpilog].Condition = Condition;
+}
+
+void ARMTargetWinCOFFStreamer::emitARMWinCFIEpilogEnd() {
+  auto &S = getStreamer();
+  WinEH::FrameInfo *CurFrame = S.EnsureValidWinFrameInfo(SMLoc());
+  if (!CurFrame)
+    return;
+
+  if (!CurrentEpilog) {
+    S.getContext().reportError(SMLoc(), "Stray .seh_endepilogue in " +
+                                            CurFrame->Function->getName());
+    return;
+  }
+
+  std::vector<WinEH::Instruction> &Epilog =
+      CurFrame->EpilogMap[CurrentEpilog].Instructions;
+
+  unsigned UnwindCode = Win64EH::UOP_End;
+  if (!Epilog.empty()) {
+    WinEH::Instruction EndInstr = Epilog.back();
+    if (EndInstr.Operation == Win64EH::UOP_Nop) {
+      UnwindCode = Win64EH::UOP_EndNop;
+      Epilog.pop_back();
+    } else if (EndInstr.Operation == Win64EH::UOP_WideNop) {
+      UnwindCode = Win64EH::UOP_WideEndNop;
+      Epilog.pop_back();
+    }
+  }
+
+  InEpilogCFI = false;
+  WinEH::Instruction Inst = WinEH::Instruction(UnwindCode, nullptr, -1, 0);
+  CurFrame->EpilogMap[CurrentEpilog].Instructions.push_back(Inst);
+  MCSymbol *Label = S.emitCFILabel();
+  CurFrame->EpilogMap[CurrentEpilog].End = Label;
+  CurrentEpilog = nullptr;
+}
+
+void ARMTargetWinCOFFStreamer::emitARMWinCFICustom(unsigned Opcode) {
+  emitARMWinUnwindCode(Win64EH::UOP_Custom, 0, Opcode);
+}
+
+} // end anonymous namespace
+
+MCTargetStreamer *llvm::createARMObjectTargetWinCOFFStreamer(MCStreamer &S) {
+  return new ARMTargetWinCOFFStreamer(S);
+}