8 files changed, 49 insertions, 8 deletions
diff --git a/llvm/lib/MC/MCAsmBackend.cpp b/llvm/lib/MC/MCAsmBackend.cpp
index c4e5051..cf3b3ae 100644
--- a/llvm/lib/MC/MCAsmBackend.cpp
+++ b/llvm/lib/MC/MCAsmBackend.cpp
@@ -115,3 +115,14 @@ bool MCAsmBackend::fixupNeedsRelaxationAdvanced(
     return true;
   return fixupNeedsRelaxation(Fixup, Value, DF, Layout);
 }
+
+bool MCAsmBackend::isDarwinCanonicalPersonality(const MCSymbol *Sym) const {
+  if (Sym && Sym->isMachO()) {
+    StringRef name = Sym->getName();
+    // XXX: We intentionally leave out "___gcc_personality_v0" because, despite
+    // being system-defined like these two, it is not very commonly-used.
+    // Reserving an empty slot for it seems silly.
+    return name == "___gxx_personality_v0" || name == "___objc_personality_v0";
+  }
+  return false;
+}
diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index f84aa4a..80d593b 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -922,6 +922,12 @@ EmitDwarfUnwindType MCContext::emitDwarfUnwindInfo() const {
   return TargetOptions->EmitDwarfUnwind;
 }
 
+bool MCContext::emitCompactUnwindNonCanonical() const {
+  if (TargetOptions)
+    return TargetOptions->EmitCompactUnwindNonCanonical;
+  return false;
+}
+
 void MCContext::setGenDwarfRootFile(StringRef InputFileName, StringRef Buffer) {
   // MCDwarf needs the root file as well as the compilation directory.
   // If we find a '.file 0' directive that will supersede these values.
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 0cb0459..c0e9f42 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -126,7 +126,7 @@ void MCStreamer::emitExplicitComments() {}
 void MCStreamer::generateCompactUnwindEncodings(MCAsmBackend *MAB) {
   for (auto &FI : DwarfFrameInfos)
     FI.CompactUnwindEncoding =
-        (MAB ? MAB->generateCompactUnwindEncoding(FI.Instructions) : 0);
+        (MAB ? MAB->generateCompactUnwindEncoding(&FI, &Context) : 0);
 }
 
 /// EmitIntValue - Special case of EmitValue that avoids the client having to
diff --git a/llvm/lib/MC/MCTargetOptionsCommandFlags.cpp b/llvm/lib/MC/MCTargetOptionsCommandFlags.cpp
index 0667ca5..8a4923e 100644
--- a/llvm/lib/MC/MCTargetOptionsCommandFlags.cpp
+++ b/llvm/lib/MC/MCTargetOptionsCommandFlags.cpp
@@ -39,6 +39,7 @@ MCOPT(bool, IncrementalLinkerCompatible)
 MCOPT(int, DwarfVersion)
 MCOPT(bool, Dwarf64)
 MCOPT(EmitDwarfUnwindType, EmitDwarfUnwind)
+MCOPT(bool, EmitCompactUnwindNonCanonical)
 MCOPT(bool, ShowMCInst)
 MCOPT(bool, FatalWarnings)
 MCOPT(bool, NoWarn)
@@ -87,6 +88,14 @@ llvm::mc::RegisterMCTargetOptionsFlags::RegisterMCTargetOptionsFlags() {
                             "Use target platform default")));
   MCBINDOPT(EmitDwarfUnwind);
 
+  static cl::opt<bool> EmitCompactUnwindNonCanonical(
+      "emit-compact-unwind-non-canonical",
+      cl::desc(
+          "Whether to try to emit Compact Unwind for non canonical entries."),
+      cl::init(
+          false)); // By default, use DWARF for non-canonical personalities.
+  MCBINDOPT(EmitCompactUnwindNonCanonical);
+
   static cl::opt<bool> ShowMCInst(
       "asm-show-inst",
       cl::desc("Emit internal instruction representation to assembly file"));
@@ -135,6 +144,7 @@ MCTargetOptions llvm::mc::InitMCTargetOptionsFromFlags() {
   Options.MCNoDeprecatedWarn = getNoDeprecatedWarn();
   Options.MCNoTypeCheck = getNoTypeCheck();
   Options.EmitDwarfUnwind = getEmitDwarfUnwind();
+  Options.EmitCompactUnwindNonCanonical = getEmitCompactUnwindNonCanonical();
   Options.AsSecureLogFile = getAsSecureLogFile();
 
   return Options;
diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
index 2089a24..7f20d73 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
@@ -564,10 +564,14 @@ public:
   }
 
   /// Generate the compact unwind encoding from the CFI directives.
-  uint32_t generateCompactUnwindEncoding(
-                             ArrayRef<MCCFIInstruction> Instrs) const override {
+  uint32_t generateCompactUnwindEncoding(const MCDwarfFrameInfo *FI,
+                                         const MCContext *Ctxt) const override {
+    ArrayRef<MCCFIInstruction> Instrs = FI->Instructions;
     if (Instrs.empty())
       return CU::UNWIND_ARM64_MODE_FRAMELESS;
+    if (!isDarwinCanonicalPersonality(FI->Personality) &&
+        !Ctxt->emitCompactUnwindNonCanonical())
+      return CU::UNWIND_ARM64_MODE_DWARF;
 
     bool HasFP = false;
     unsigned StackSize = 0;
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
index df142b8..ea13634 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
@@ -1107,14 +1107,19 @@ enum CompactUnwindEncodings {
 /// encoded in compact unwind, the method returns UNWIND_ARM_MODE_DWARF which
 /// tells the runtime to fallback and unwind using dwarf.
 uint32_t ARMAsmBackendDarwin::generateCompactUnwindEncoding(
-    ArrayRef<MCCFIInstruction> Instrs) const {
+    const MCDwarfFrameInfo *FI, const MCContext *Ctxt) const {
   DEBUG_WITH_TYPE("compact-unwind", llvm::dbgs() << "generateCU()\n");
   // Only armv7k uses CFI based unwinding.
   if (Subtype != MachO::CPU_SUBTYPE_ARM_V7K)
     return 0;
   // No .cfi directives means no frame.
+  ArrayRef<MCCFIInstruction> Instrs = FI->Instructions;
   if (Instrs.empty())
     return 0;
+  if (!isDarwinCanonicalPersonality(FI->Personality) &&
+      !Ctxt->emitCompactUnwindNonCanonical())
+    return CU::UNWIND_ARM_MODE_DWARF;
+
   // Start off assuming CFA is at SP+0.
   unsigned CFARegister = ARM::SP;
   int CFARegisterOffset = 0;
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackendDarwin.h b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackendDarwin.h
index 85013b5..ace573c 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackendDarwin.h
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackendDarwin.h
@@ -11,6 +11,7 @@
 
 #include "ARMAsmBackend.h"
 #include "llvm/BinaryFormat/MachO.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCObjectWriter.h"
 
 namespace llvm {
@@ -32,8 +33,8 @@ public:
         /*Is64Bit=*/false, cantFail(MachO::getCPUType(TT)), Subtype);
   }
 
-  uint32_t generateCompactUnwindEncoding(
-      ArrayRef<MCCFIInstruction> Instrs) const override;
+  uint32_t generateCompactUnwindEncoding(const MCDwarfFrameInfo *FI,
+                                         const MCContext *Ctxt) const override;
 };
 } // end namespace llvm
 
diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
index 92344d4..8380f00 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
@@ -1327,9 +1327,13 @@ public:
 
   /// Implementation of algorithm to generate the compact unwind encoding
   /// for the CFI instructions.
-  uint32_t
-  generateCompactUnwindEncoding(ArrayRef<MCCFIInstruction> Instrs) const override {
+  uint32_t generateCompactUnwindEncoding(const MCDwarfFrameInfo *FI,
+                                         const MCContext *Ctxt) const override {
+    ArrayRef<MCCFIInstruction> Instrs = FI->Instructions;
     if (Instrs.empty()) return 0;
+    if (!isDarwinCanonicalPersonality(FI->Personality) &&
+        !Ctxt->emitCompactUnwindNonCanonical())
+      return CU::UNWIND_MODE_DWARF;
 
     // Reset the saved registers.
     unsigned SavedRegIdx = 0;