Reland "D144999 [MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs."

Reasons for rolling forward:
    - the crash reported from Chromium was fixed in D151824 (not related to this patch at all)
    - since D152824 was committed, it should now be safe to roll this forward.

New change:
    - add an additional _ in name check

This reverts commit 4980eead4d0b4666d53dad07afb091375b3a13a0.

1 files changed, 10 insertions, 0 deletions

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;