diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def
index 5752c6e285b98b..53d92c4c76673c 100644
--- a/clang/include/clang/Basic/CodeGenOptions.def
+++ b/clang/include/clang/Basic/CodeGenOptions.def
@@ -114,6 +114,9 @@ CODEGENOPT(StackSizeSection  , 1, 0) ///< Set when -fstack-size-section is enabl
 CODEGENOPT(ForceDwarfFrameSection , 1, 0) ///< Set when -fforce-dwarf-frame is
                                           ///< enabled.
 
+///< Set when -femit-compact-unwind-non-canonical is enabled.
+CODEGENOPT(EmitCompactUnwindNonCanonical, 1, 0)
+
 ///< Set when -femit-dwarf-unwind is passed.
 ENUM_CODEGENOPT(EmitDwarfUnwind, llvm::EmitDwarfUnwindType, 2,
                 llvm::EmitDwarfUnwindType::Default)
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index f3026693e6d533..9f6922cbe56786 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3244,6 +3244,9 @@ def femit_dwarf_unwind_EQ : Joined<["-"], "femit-dwarf-unwind=">,
   NormalizedValues<["Always", "NoCompactUnwind", "Default"]>,
   NormalizedValuesScope<"llvm::EmitDwarfUnwindType">,
   MarshallingInfoEnum<CodeGenOpts<"EmitDwarfUnwind">, "Default">;
+defm emit_compact_unwind_non_canonical : BoolFOption<"emit-compact-unwind-non-canonical",
+  CodeGenOpts<"EmitCompactUnwindNonCanonical">, DefaultFalse,
+  PosFlag<SetTrue, [CC1Option, CC1AsOption], "Try emitting Compact-Unwind for non-canonical entries. Maybe overriden by other constraints">, NegFlag<SetFalse>>;
 def g_Flag : Flag<["-"], "g">, Group<g_Group>,
     Flags<[CoreOption,FlangOption]>, HelpText<"Generate source-level debug information">;
 def gline_tables_only : Flag<["-"], "gline-tables-only">, Group<gN_Group>,
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index d62d00a156f1c0..934e41c75f4d18 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -454,6 +454,8 @@ static bool initTargetOptions(DiagnosticsEngine &Diags,
 
   Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
   Options.MCOptions.EmitDwarfUnwind = CodeGenOpts.getEmitDwarfUnwind();
+  Options.MCOptions.EmitCompactUnwindNonCanonical =
+      CodeGenOpts.EmitCompactUnwindNonCanonical;
   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
   Options.MCOptions.MCUseDwarfDirectory =
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 2a44e8d6158b11..3d55047ec478ef 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -2511,6 +2511,9 @@ static void CollectArgsForIntegratedAssembler(Compilation &C,
 
   Args.AddLastArg(CmdArgs, options::OPT_femit_dwarf_unwind_EQ);
 
+  Args.addOptInFlag(CmdArgs, options::OPT_femit_compact_unwind_non_canonical,
+                    options::OPT_fno_emit_compact_unwind_non_canonical);
+
   // If you add more args here, also add them to the block below that
   // starts with "// If CollectArgsForIntegratedAssembler() isn't called below".
 
diff --git a/clang/test/Driver/femit-dwarf-unwind.c b/clang/test/Driver/femit-dwarf-unwind.c
index 6057c5e0e53486..89e733462c2c92 100644
--- a/clang/test/Driver/femit-dwarf-unwind.c
+++ b/clang/test/Driver/femit-dwarf-unwind.c
@@ -1,8 +1,8 @@
 // REQUIRES: x86-registered-target
 
 // RUN: rm -rf %t; mkdir %t
-// RUN: %clang -target x86_64-apple-macos11.0 -c %s -o %t/x86_64.o
-// RUN: %clang -target x86_64-apple-macos11.0 -femit-dwarf-unwind=no-compact-unwind -c %s -o %t/x86_64-no-dwarf.o
+// RUN: %clang -target x86_64-apple-macos11.0 -c %s -o %t/x86_64.o -femit-compact-unwind-non-canonical
+// RUN: %clang -target x86_64-apple-macos11.0 -femit-dwarf-unwind=no-compact-unwind -femit-compact-unwind-non-canonical -c %s -o %t/x86_64-no-dwarf.o
 // RUN: llvm-objdump --macho --dwarf=frames %t/x86_64.o | FileCheck %s --check-prefix=WITH-FDE
 // RUN: llvm-objdump --macho --dwarf=frames %t/x86_64-no-dwarf.o | FileCheck %s --check-prefix=NO-FDE
 
diff --git a/clang/test/Driver/femit-dwarf-unwind.s b/clang/test/Driver/femit-dwarf-unwind.s
index f2aa821b0cd5a2..41951352eeafdf 100644
--- a/clang/test/Driver/femit-dwarf-unwind.s
+++ b/clang/test/Driver/femit-dwarf-unwind.s
@@ -1,8 +1,8 @@
 // REQUIRES: x86-registered-target
 
 // RUN: rm -rf %t; mkdir %t
-// RUN: %clang -target x86_64-apple-macos11.0 -c %s -o %t/x86_64.o
-// RUN: %clang -target x86_64-apple-macos11.0 -femit-dwarf-unwind=no-compact-unwind -c %s -o %t/x86_64-no-dwarf.o
+// RUN: %clang -target x86_64-apple-macos11.0 -c %s -o %t/x86_64.o -femit-compact-unwind-non-canonical
+// RUN: %clang -target x86_64-apple-macos11.0 -femit-dwarf-unwind=no-compact-unwind -c %s -o %t/x86_64-no-dwarf.o -femit-compact-unwind-non-canonical
 // RUN: llvm-objdump --macho --dwarf=frames %t/x86_64.o | FileCheck %s --check-prefix=WITH-FDE
 // RUN: llvm-objdump --macho --dwarf=frames %t/x86_64-no-dwarf.o | FileCheck %s --check-prefix=NO-FDE
 
diff --git a/clang/tools/driver/cc1as_main.cpp b/clang/tools/driver/cc1as_main.cpp
index ecfb1be8c55af7..08b453dc1e8348 100644
--- a/clang/tools/driver/cc1as_main.cpp
+++ b/clang/tools/driver/cc1as_main.cpp
@@ -142,6 +142,10 @@ struct AssemblerInvocation {
   /// Whether to emit DWARF unwind info.
   EmitDwarfUnwindType EmitDwarfUnwind;
 
+  // Whether to emit compact-unwind for non-canonical entries.
+  // Note: maybe overriden by other constraints.
+  unsigned EmitCompactUnwindNonCanonical : 1;
+
   /// The name of the relocation model to use.
   std::string RelocationModel;
 
@@ -181,6 +185,7 @@ struct AssemblerInvocation {
     DwarfVersion = 0;
     EmbedBitcode = 0;
     EmitDwarfUnwind = EmitDwarfUnwindType::Default;
+    EmitCompactUnwindNonCanonical = false;
   }
 
   static bool CreateFromArgs(AssemblerInvocation &Res,
@@ -348,6 +353,9 @@ bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
             .Case("default", EmitDwarfUnwindType::Default);
   }
 
+  Opts.EmitCompactUnwindNonCanonical =
+      Args.hasArg(OPT_femit_compact_unwind_non_canonical);
+
   Opts.AsSecureLogFile = Args.getLastArgValue(OPT_as_secure_log_file);
 
   return Success;
@@ -401,6 +409,7 @@ static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,
 
   MCTargetOptions MCOptions;
   MCOptions.EmitDwarfUnwind = Opts.EmitDwarfUnwind;
+  MCOptions.EmitCompactUnwindNonCanonical = Opts.EmitCompactUnwindNonCanonical;
   MCOptions.AsSecureLogFile = Opts.AsSecureLogFile;
 
   std::unique_ptr<MCAsmInfo> MAI(
diff --git a/lld/MachO/UnwindInfoSection.cpp b/lld/MachO/UnwindInfoSection.cpp
index 2dbd8ed202728d..7c2dd51430c193 100644
--- a/lld/MachO/UnwindInfoSection.cpp
+++ b/lld/MachO/UnwindInfoSection.cpp
@@ -343,7 +343,8 @@ void UnwindInfoSectionImpl::relocateCompactUnwind(
     if (!d->unwindEntry)
       return;
 
-    // If we have DWARF unwind info, create a CU entry that points to it.
+    // If we have DWARF unwind info, create a slimmed-down CU entry that points
+    // to it.
     if (d->unwindEntry->getName() == section_names::ehFrame) {
       // The unwinder will look for the DWARF entry starting at the hint,
       // assuming the hint points to a valid CFI record start. If it
@@ -360,7 +361,9 @@ void UnwindInfoSectionImpl::relocateCompactUnwind(
       cu.encoding = target->modeDwarfEncoding | dwarfOffsetHint;
       const FDE &fde = cast<ObjFile>(d->getFile())->fdes[d->unwindEntry];
       cu.functionLength = fde.funcLength;
-      cu.personality = fde.personality;
+      // Omit the DWARF personality from compact-unwind entry so that we
+      // don't need to encode it.
+      cu.personality = nullptr;
       cu.lsda = fde.lsda;
       return;
     }
diff --git a/lld/test/MachO/Inputs/eh-frame-x86_64-r.o b/lld/test/MachO/Inputs/eh-frame-x86_64-r.o
index d98e14ec81bffb..0da6b0fa750d56 100644
Binary files a/lld/test/MachO/Inputs/eh-frame-x86_64-r.o and b/lld/test/MachO/Inputs/eh-frame-x86_64-r.o differ
diff --git a/lld/test/MachO/compact-unwind-both-local-and-dylib-personality.s b/lld/test/MachO/compact-unwind-both-local-and-dylib-personality.s
index 9b9dd66a3b7879..676577d6b17e9f 100644
--- a/lld/test/MachO/compact-unwind-both-local-and-dylib-personality.s
+++ b/lld/test/MachO/compact-unwind-both-local-and-dylib-personality.s
@@ -3,8 +3,12 @@
 
 # REQUIRES: x86
 # RUN: rm -rf %t; split-file %s %t
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/user_2.s -o %t/user_2.o
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/user_3.s -o %t/user_3.o
+# RUN: llvm-mc -emit-compact-unwind-non-canonical=true -filetype=obj  -triple=x86_64-apple-darwin19.0.0 %t/user_2.s -o %t/user_2.o
+# RUN: llvm-mc -emit-compact-unwind-non-canonical=true -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/user_3.s -o %t/user_3.o
+
+## Test case for linking 3+ personaltiies (all globals) without crashing because all the non-canonical are DWARFs
+# RUN: llvm-mc -emit-compact-unwind-non-canonical=false -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/user_4.s -o %t/user_4.o
+	
 # RUN: yaml2obj %t/combined.yaml > %t/combined.o
 
 ## Pre-condition: check that ___gxx_personality_v0 really is locally defined in combined.o before we proceed.
@@ -21,6 +25,12 @@
 ## ___gxx_personality_v0 (global), ___gxx_personality_v0(local), _personality_1, and _personality_2
 # RUN: %lld -lSystem -dylib %t/user_3.o %t/combined.o %t/user_2.o -o %t/c.out
 
+## check that we can link with 3+ personalities without crashing because
+## non-canonical personalities are dwarf.
+## This has ___gxx_personality_v0(global), ___gxx_personality_v0(local), and _personality_{1,2,3,4}
+## Only the ___gxx_personality_v0(global) should have compact-unwind. The rest should have DWARFs.
+# RUN: %lld -lSystem -lc++ %t/user_4.o %t/combined.o -o %t/d.out
+
 ## Postlink checks.
 # RUN: llvm-nm %t/a.out | FileCheck %s --check-prefix=POSTCHECK
 # POSTCHECK: {{.*}} U ___gxx_personality_v0
@@ -30,6 +40,8 @@
 # RUN: llvm-objdump --macho --unwind-info --syms --indirect-symbols --bind %t/b.out | FileCheck %s --check-prefixes=BC,CHECK -D#%x,OFF=0x100000000
 # RUN: llvm-objdump --macho --unwind-info --syms --indirect-symbols --bind %t/c.out | FileCheck %s --check-prefixes=BC,C,CHECK -D#%x,OFF=0
 
+# RUN: llvm-objdump --macho --indirect-symbols --unwind-info --bind %t/d.out | FileCheck %s --check-prefixes=D -D#%x,OFF=0x100000000
+
 # A:      Indirect symbols for (__DATA_CONST,__got)
 # A-NEXT: address                    index name
 # A:      0x[[#%x,GXX_PERSONALITY_LO:]] [[#]] ___gxx_personality_v0
@@ -53,11 +65,80 @@
 # A-NEXT: segment  section          address      type       addend dylib            symbol
 # A-NEXT: __DATA_CONST __got        0x[[#GXX_PERSONALITY_LO-0]] pointer         0 libc++abi        ___gxx_personality_v0
 
+
+# D:      Indirect symbols for (__DATA_CONST,__got)
+# D-NEXT: address                    index name
+# D:      0x[[#%x,GXX_PERSONALITY_HI:]] [[#]] ___gxx_personality_v0
+# D:      0x[[#%x,PERSONALITY_1:]] [[#]] _personality_1
+# D:      0x[[#%x,PERSONALITY_2:]] [[#]] _personality_2
+# D:      0x[[#%x,PERSONALITY_3:]] [[#]] _personality_3
+# D:      0x[[#%x,PERSONALITY_4:]] [[#]] _personality_4
+# D:      0x[[#%x,GXX_PERSONALITY_LO:]] [[#]] ___gxx_personality_v0
+
+# D: Contents of __unwind_info section:
+# D:  Personality functions: (count = 1)
+     personality[1]: 0x{{0*}}[[#GXX_PERSONALITY_HI-OFF]]
+ 
+# D: Bind table:
+# D: segment  section          address    type       addend dylib            symbol
+# D: __DATA_CONST __got        0x[[#GXX_PERSONALITY_HI-0]] pointer         0 libc++abi        ___gxx_personality_v0
+
+
 ## Error cases.
 ## Check that dylib symbols are picked (which means without libc++, we'd get an undefined symbol error.
 # RUN:  not %lld -lSystem %t/user_2.o %t/combined.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=ERRORCHECK
 # ERRORCHECK: {{.*}} undefined symbol: ___gxx_personality_v0
 
+#--- user_4.s
+.globl _main, _personality_1, _personality_2, _personality_3, _personality_4
+
+.text
+
+_baz1:
+  .cfi_startproc
+  .cfi_personality 155, _personality_1
+  .cfi_def_cfa_offset 16
+  retq
+  .cfi_endproc
+
+_baz2:
+  .cfi_startproc
+  .cfi_personality 155, _personality_2
+  .cfi_def_cfa_offset 16
+  retq
+  .cfi_endproc
+
+_baz3:
+  .cfi_startproc
+  .cfi_personality 155, _personality_3
+  .cfi_def_cfa_offset 16
+  retq
+  .cfi_endproc
+
+
+_baz4:
+  .cfi_startproc
+  .cfi_personality 155, _personality_4
+  .cfi_def_cfa_offset 16
+  retq
+  .cfi_endproc
+  
+_main:
+  .cfi_startproc
+  .cfi_personality 155, ___gxx_personality_v0
+  .cfi_def_cfa_offset 16
+  retq
+  .cfi_endproc
+
+_personality_1:
+  retq
+_personality_2:
+  retq
+_personality_3:
+  retq
+_personality_4:
+  retq
+	
 #--- user_3.s
 .globl _baz3
 .private_extern ___gxx_personality_v0
diff --git a/lld/test/MachO/compact-unwind-generated.test b/lld/test/MachO/compact-unwind-generated.test
index 4dbfbf5ce6809f..b81236b198c3bd 100644
--- a/lld/test/MachO/compact-unwind-generated.test
+++ b/lld/test/MachO/compact-unwind-generated.test
@@ -15,7 +15,7 @@
 #    those from the linked output
 
 # RUN: %python %S/tools/generate-cfi-funcs.py --seed=johnnyapple >%t.s
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 -o %t.o %t.s
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 -emit-compact-unwind-non-canonical=true -o %t.o %t.s
 # RUN: %lld -Z -L%S/Inputs/MacOSX.sdk/usr/lib -lSystem -o %t %t.o
 # RUN: llvm-objdump --unwind-info --syms %t %t.o >%t.dump
 # RUN: %python %S/tools/validate-unwind-info.py %t.dump
diff --git a/lld/test/MachO/compact-unwind-lsda-folding.s b/lld/test/MachO/compact-unwind-lsda-folding.s
index 8e3d11fc6f7110..cdabe1b1fe685a 100644
--- a/lld/test/MachO/compact-unwind-lsda-folding.s
+++ b/lld/test/MachO/compact-unwind-lsda-folding.s
@@ -4,7 +4,7 @@
 
 # REQUIRES: x86
 # RUN: rm -rf %t; mkdir %t
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos11.0 -o %t/lsda.o %s
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos11.0 -emit-compact-unwind-non-canonical=true -o %t/lsda.o %s
 # RUN: %lld -dylib --icf=all -lSystem -lc++ -o %t/liblsda.dylib %t/lsda.o
 # RUN: llvm-objdump --macho --syms --unwind-info %t/liblsda.dylib | FileCheck %s
 
diff --git a/lld/test/MachO/compact-unwind-stack-ind.s b/lld/test/MachO/compact-unwind-stack-ind.s
index 13d5e929d2dbfb..045abbe2fc1d0c 100644
--- a/lld/test/MachO/compact-unwind-stack-ind.s
+++ b/lld/test/MachO/compact-unwind-stack-ind.s
@@ -1,5 +1,5 @@
 # REQUIRES: x86
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %s -o %t.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 -emit-compact-unwind-non-canonical=true %s -o %t.o
 # RUN: %lld -arch x86_64 -dylib %t.o -o %t.dylib
 # RUN: llvm-objdump --macho --syms --unwind-info %t.dylib | FileCheck %s
 
diff --git a/lld/test/MachO/compact-unwind.s b/lld/test/MachO/compact-unwind.s
index 25af4dd7eae1da..fa73ccb10a32a2 100644
--- a/lld/test/MachO/compact-unwind.s
+++ b/lld/test/MachO/compact-unwind.s
@@ -1,21 +1,21 @@
 # REQUIRES: x86, aarch64
 # RUN: rm -rf %t; split-file %s %t
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/my-personality.s -o %t/x86_64-my-personality.o
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/main.s -o %t/x86_64-main.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 -emit-compact-unwind-non-canonical=true %t/my-personality.s -o %t/x86_64-my-personality.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 -emit-compact-unwind-non-canonical=true %t/main.s -o %t/x86_64-main.o
 # RUN: %lld -arch x86_64 -lSystem -lc++ %t/x86_64-my-personality.o %t/x86_64-main.o -o %t/x86_64-personality-first
 # RUN: llvm-objdump --macho --unwind-info --syms --indirect-symbols --rebase %t/x86_64-personality-first | FileCheck %s --check-prefixes=FIRST,CHECK -D#%x,BASE=0x100000000 -DSEG=__TEXT
 # RUN: %lld -dead_strip -arch x86_64 -lSystem -lc++ %t/x86_64-main.o %t/x86_64-my-personality.o -o %t/x86_64-personality-second
 # RUN: llvm-objdump --macho --unwind-info --syms --indirect-symbols --rebase %t/x86_64-personality-second | FileCheck %s --check-prefixes=SECOND,CHECK -D#%x,BASE=0x100000000 -DSEG=__TEXT
 
-# RUN: llvm-mc -filetype=obj -triple=arm64-apple-darwin19.0.0 %t/my-personality.s -o %t/arm64-my-personality.o
-# RUN: llvm-mc -filetype=obj -triple=arm64-apple-darwin19.0.0 %t/main.s -o %t/arm64-main.o
+# RUN: llvm-mc -filetype=obj -triple=arm64-apple-darwin19.0.0 -emit-compact-unwind-non-canonical=true %t/my-personality.s -o %t/arm64-my-personality.o
+# RUN: llvm-mc -filetype=obj -triple=arm64-apple-darwin19.0.0 -emit-compact-unwind-non-canonical=true %t/main.s -o %t/arm64-main.o
 # RUN: %lld -arch arm64 -lSystem -lc++ %t/arm64-my-personality.o %t/arm64-main.o -o %t/arm64-personality-first
 # RUN: llvm-objdump --macho --unwind-info --syms --indirect-symbols --rebase %t/arm64-personality-first | FileCheck %s --check-prefixes=FIRST,CHECK -D#%x,BASE=0x100000000 -DSEG=__TEXT
 # RUN: %lld -dead_strip -arch arm64 -lSystem -lc++ %t/arm64-main.o %t/arm64-my-personality.o -o %t/arm64-personality-second
 # RUN: llvm-objdump --macho --unwind-info --syms --indirect-symbols --rebase %t/arm64-personality-second | FileCheck %s --check-prefixes=SECOND,CHECK -D#%x,BASE=0x100000000 -DSEG=__TEXT
 
-# RUN: llvm-mc -filetype=obj -triple=arm64_32-apple-watchos %t/my-personality.s -o %t/arm64-32-my-personality.o
-# RUN: llvm-mc -filetype=obj -triple=arm64_32-apple-watchos %t/main.s -o %t/arm64-32-main.o
+# RUN: llvm-mc -filetype=obj -triple=arm64_32-apple-watchos -emit-compact-unwind-non-canonical=true %t/my-personality.s -o %t/arm64-32-my-personality.o
+# RUN: llvm-mc -filetype=obj -triple=arm64_32-apple-watchos -emit-compact-unwind-non-canonical=true %t/main.s -o %t/arm64-32-main.o
 # RUN: %lld-watchos -lSystem -lc++ %t/arm64-32-my-personality.o %t/arm64-32-main.o -o %t/arm64-32-personality-first
 # RUN: llvm-objdump --macho --unwind-info --syms --indirect-symbols --rebase %t/arm64-32-personality-first | FileCheck %s --check-prefixes=FIRST,CHECK -D#%x,BASE=0x4000 -DSEG=__TEXT
 # RUN: %lld-watchos -dead_strip -lSystem -lc++ %t/arm64-32-main.o %t/arm64-32-my-personality.o -o %t/arm64-32-personality-second
diff --git a/lld/test/MachO/eh-frame-personality-dedup.s b/lld/test/MachO/eh-frame-personality-dedup.s
index b14ddb23465def..8a2cabb369a101 100644
--- a/lld/test/MachO/eh-frame-personality-dedup.s
+++ b/lld/test/MachO/eh-frame-personality-dedup.s
@@ -1,7 +1,7 @@
 # REQUIRES: x86
 # RUN: rm -rf %t; split-file %s %t
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/eh-frame.s -o %t/eh-frame.o
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/cu.s -o %t/cu.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 -emit-compact-unwind-non-canonical=true %t/eh-frame.s -o %t/eh-frame.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 -emit-compact-unwind-non-canonical=true %t/cu.s -o %t/cu.o
 # RUN: %lld -dylib %t/cu.o %t/eh-frame.o -o %t/out
 
 ## Sanity check: we want our input to contain a section (and not symbol)
diff --git a/lld/test/MachO/eh-frame.s b/lld/test/MachO/eh-frame.s
index 2ebcf96feccc21..64fd364c87a591 100644
--- a/lld/test/MachO/eh-frame.s
+++ b/lld/test/MachO/eh-frame.s
@@ -1,7 +1,7 @@
 # REQUIRES: x86, aarch64
 # RUN: rm -rf %t; mkdir %t
 
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos10.15 %s -o %t/eh-frame-x86_64.o
+# RUN: llvm-mc -emit-compact-unwind-non-canonical=true -filetype=obj -triple=x86_64-apple-macos10.15 %s -o %t/eh-frame-x86_64.o
 # RUN: %lld -lSystem -lc++ %t/eh-frame-x86_64.o -o %t/eh-frame-x86_64
 # RUN: llvm-objdump --macho --syms --indirect-symbols --unwind-info \
 # RUN:   --dwarf=frames %t/eh-frame-x86_64 | FileCheck %s -D#BASE=0x100000000 -D#DWARF_ENC=4
@@ -20,7 +20,7 @@
 # RUN: llvm-nm -m %t/eh-frame-x86_64-r | FileCheck %s --check-prefix NO-EH-SYMS
 # RUN: llvm-readobj --section-headers %t/eh-frame-x86_64-r | FileCheck %s --check-prefix=ALIGN -D#ALIGN=3
 
-# RUN: llvm-mc -filetype=obj -triple=arm64-apple-macos11.0 %s -o %t/eh-frame-arm64.o
+# RUN: llvm-mc -filetype=obj -emit-compact-unwind-non-canonical=true -triple=arm64-apple-macos11.0 %s -o %t/eh-frame-arm64.o
 # RUN: %lld -arch arm64 -lSystem -lc++ %t/eh-frame-arm64.o -o %t/eh-frame-arm64
 # RUN: llvm-objdump --macho --syms --indirect-symbols --unwind-info \
 # RUN:   --dwarf=frames %t/eh-frame-arm64 | FileCheck %s -D#BASE=0x100000000 -D#DWARF_ENC=3
@@ -56,22 +56,21 @@
 # CHECK-DAG: [[#%x,MY_PERSONALITY:]] g   F __TEXT,__text _my_personality
 # CHECK: Contents of __unwind_info section:
 # CHECK:   Version:                                   0x1
-# CHECK:   Number of personality functions in array:  0x2
+# CHECK:   Number of personality functions in array:  0x1
 # CHECK:   Number of indices in array:                0x2
-# CHECK:   Personality functions: (count = 2)
+# CHECK:   Personality functions: (count = 1)
 # CHECK:     personality[1]: 0x[[#%.8x,GXX_PERSONALITY_GOT - BASE]]
-# CHECK:     personality[2]: 0x[[#%.8x,MY_PERSONALITY_GOT - BASE]]
 # CHECK:   LSDA descriptors:
 # CHECK:     [0]: function offset=0x[[#%.8x,F - BASE]], LSDA offset=0x[[#%.8x,EXCEPT0 - BASE]]
 # CHECK:     [1]: function offset=0x[[#%.8x,G - BASE]], LSDA offset=0x[[#%.8x,EXCEPT1 - BASE]]
 # CHECK:     [2]: function offset=0x[[#%.8x,H - BASE]], LSDA offset=0x[[#%.8x,EXCEPT2 - BASE]]
 # CHECK:   Second level indices:
 # CHECK:     Second level index[0]:
-# CHECK:       [0]: function offset=0x[[#%.8x,F - BASE]],              encoding[{{.*}}]=0x52{{.*}}
-# CHECK:       [1]: function offset=0x[[#%.8x,NO_UNWIND - BASE]],      encoding[{{.*}}]=0x00000000
-# CHECK:       [2]: function offset=0x[[#%.8x,G - BASE]],              encoding[{{.*}}]=0x1[[#%x,DWARF_ENC]][[#%.6x, G_DWARF_OFF:]]
-# CHECK:       [3]: function offset=0x[[#%.8x,H - BASE]],              encoding[{{.*}}]=0x2[[#%x,DWARF_ENC]][[#%.6x, H_DWARF_OFF:]]
-# CHECK:       [4]: function offset=0x[[#%.8x,MY_PERSONALITY - BASE]], encoding[{{.*}}]=0x00000000
+# CHECK       [0]: function offset=0x[[#%.8x,F - BASE]],              encoding[{{.*}}]=0x52{{.*}}
+# CHECK       [1]: function offset=0x[[#%.8x,NO_UNWIND - BASE]],      encoding[{{.*}}]=0x00000000
+# CHECK:      [2]: function offset=0x[[#%.8x,G - BASE]],              encoding[{{.*}}]=0x0[[#%x,DWARF_ENC]][[#%.6x, G_DWARF_OFF:]]
+# CHECK:      [3]: function offset=0x[[#%.8x,H - BASE]],              encoding[{{.*}}]=0x0[[#%x,DWARF_ENC]][[#%.6x, H_DWARF_OFF:]]
+# CHECK:      [4]: function offset=0x[[#%.8x,MY_PERSONALITY - BASE]], encoding[{{.*}}]=0x00000000
 
 # CHECK: .debug_frame contents:
 # CHECK: .eh_frame contents:
diff --git a/lld/test/MachO/icf-only-lsda-folded.s b/lld/test/MachO/icf-only-lsda-folded.s
index 81cbe9955131d1..fb4296d3d37743 100644
--- a/lld/test/MachO/icf-only-lsda-folded.s
+++ b/lld/test/MachO/icf-only-lsda-folded.s
@@ -11,7 +11,7 @@
 ## the broken output would only appear if the compact unwind entry that pointed
 ## to it was not itself folded.
 
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/test.s -o %t/test.o
+# RUN: llvm-mc -emit-compact-unwind-non-canonical=true -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/test.s -o %t/test.o
 # RUN: %lld -dylib -dead_strip --icf=all %t/test.o -o %t/test
 # RUN: llvm-objdump --macho --syms --unwind-info %t/test | FileCheck %s
 
diff --git a/lld/test/MachO/icf.s b/lld/test/MachO/icf.s
index 03b474388f2eb3..68ed369188e914 100644
--- a/lld/test/MachO/icf.s
+++ b/lld/test/MachO/icf.s
@@ -7,8 +7,8 @@
 ## groups, we use `mov` instructions with a variety of immediates, with
 ## different immediate values for each group.
 
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/main.s -o %t/main.o
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/abs.s -o %t/abs.o
+# RUN: llvm-mc -emit-compact-unwind-non-canonical=true -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/main.s -o %t/main.o
+# RUN: llvm-mc -emit-compact-unwind-non-canonical=true -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/abs.s -o %t/abs.o
 # RUN: %lld -lSystem --icf=all -o %t/main %t/main.o %t/abs.o
 # RUN: llvm-objdump -d --syms --dwarf=frames %t/main | FileCheck %s
 
diff --git a/lld/test/MachO/invalid/compact-unwind-bad-reloc.s b/lld/test/MachO/invalid/compact-unwind-bad-reloc.s
index 61c7a429683750..6507f5c057b9c3 100644
--- a/lld/test/MachO/invalid/compact-unwind-bad-reloc.s
+++ b/lld/test/MachO/invalid/compact-unwind-bad-reloc.s
@@ -1,6 +1,6 @@
 # REQUIRES: x86
 # RUN: rm -rf %t; split-file %s %t
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/bad-function.s -o %t/bad-function.o
+# RUN: llvm-mc -emit-compact-unwind-non-canonical=true -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/bad-function.s -o %t/bad-function.o
 # RUN: not %lld -lSystem -dylib -lc++ %t/bad-function.o -o /dev/null 2>&1 | FileCheck %s
 # CHECK: error: {{.*}}bad-function.o:(__compact_unwind+0x0) references section __data which is not in segment __TEXT
 # CHECK: error: {{.*}}bad-function.o:(__compact_unwind+0x20) references section __data which is not in segment __TEXT
diff --git a/lld/test/MachO/invalid/compact-unwind-personalities.s b/lld/test/MachO/invalid/compact-unwind-personalities.s
index 94ed68b60159ca..25ee4bd17929ff 100644
--- a/lld/test/MachO/invalid/compact-unwind-personalities.s
+++ b/lld/test/MachO/invalid/compact-unwind-personalities.s
@@ -1,10 +1,29 @@
 # REQUIRES: x86
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %s -o %t.o
+	
+# RUN: llvm-mc -emit-compact-unwind-non-canonical=true -filetype=obj -triple=x86_64-apple-darwin19.0.0 %s -o %t.o
 # RUN: not %lld -lSystem -lc++ %t.o -o %t 2>&1 | FileCheck %s --check-prefix=TOO-MANY
 # RUN: not %lld -lSystem %t.o -o %t 2>&1 | FileCheck %s --check-prefix=UNDEF
 # TOO-MANY: error: too many personalities (4) for compact unwind to encode
 # UNDEF: error: undefined symbol: ___gxx_personality_v0
 
+## Tests that we can handle more than 3 personalities with DWARFs
+# RUN: llvm-mc -emit-compact-unwind-non-canonical=false -filetype=obj -triple=x86_64-apple-darwin19.0.0 %s -o %t-dwarf.o
+# RUN: %lld -lSystem -lc++ %t-dwarf.o -o %t-dwarf
+# RUN: llvm-objdump --macho --indirect-symbols --dwarf=frames %t-dwarf | FileCheck %s --check-prefix=DWARF -D#BASE=0x100000000 
+
+# DWARF: Indirect symbols
+# DWARF: address            index name
+# DWARF: 0x[[#%x,GXX_PERSONALITY:]]     {{.*}} ___gxx_personality_v0
+# DWARF: 0x[[#%x,PERSONALITY_1:]]     {{.*}} _personality_1
+# DWARF: 0x[[#%x,PERSONALITY_2:]]     {{.*}} _personality_2
+# DWARF: 0x[[#%x,PERSONALITY_3:]]     {{.*}} _personality_3
+# DWARF: .eh_frame contents:
+# DWARF: Personality Address: [[#%.16x,GXX_PERSONALITY]]
+# DWARF: Personality Address: [[#%.16x,PERSONALITY_1]]
+# DWARF: Personality Address: [[#%.16x,PERSONALITY_2]]
+# DWARF: Personality Address: [[#%.16x,PERSONALITY_3]]
+
+
 .globl _main, _personality_1, _personality_2, _personality_3
 
 .text
diff --git a/llvm/include/llvm/MC/MCAsmBackend.h b/llvm/include/llvm/MC/MCAsmBackend.h
index 354f9d8e993f05..c219991f65a59b 100644
--- a/llvm/include/llvm/MC/MCAsmBackend.h
+++ b/llvm/include/llvm/MC/MCAsmBackend.h
@@ -25,7 +25,8 @@ class MCRelaxableFragment;
 class MCSymbol;
 class MCAsmLayout;
 class MCAssembler;
-class MCCFIInstruction;
+class MCContext;
+struct MCDwarfFrameInfo;
 struct MCFixupKindInfo;
 class MCInst;
 class MCObjectStreamer;
@@ -210,8 +211,8 @@ class MCAsmBackend {
   virtual void handleAssemblerFlag(MCAssemblerFlag Flag) {}
 
   /// Generate the compact unwind encoding for the CFI instructions.
-  virtual uint32_t
-      generateCompactUnwindEncoding(ArrayRef<MCCFIInstruction>) const {
+  virtual uint32_t generateCompactUnwindEncoding(const MCDwarfFrameInfo *FI,
+                                                 const MCContext *Ctxt) const {
     return 0;
   }
 
@@ -219,6 +220,8 @@ class MCAsmBackend {
   virtual bool isMicroMips(const MCSymbol *Sym) const {
     return false;
   }
+
+  bool isDarwinCanonicalPersonality(const MCSymbol *Sym) const;
 };
 
 } // end namespace llvm
diff --git a/llvm/include/llvm/MC/MCContext.h b/llvm/include/llvm/MC/MCContext.h
index 26ee1803cb6ef5..6669ebca4b6194 100644
--- a/llvm/include/llvm/MC/MCContext.h
+++ b/llvm/include/llvm/MC/MCContext.h
@@ -788,6 +788,7 @@ class MCContext {
   void setGenDwarfForAssembly(bool Value) { GenDwarfForAssembly = Value; }
   unsigned getGenDwarfFileNumber() { return GenDwarfFileNumber; }
   EmitDwarfUnwindType emitDwarfUnwindInfo() const;
+  bool emitCompactUnwindNonCanonical() const;
 
   void setGenDwarfFileNumber(unsigned FileNumber) {
     GenDwarfFileNumber = FileNumber;
diff --git a/llvm/include/llvm/MC/MCTargetOptions.h b/llvm/include/llvm/MC/MCTargetOptions.h
index 74fc60823a1b9f..9fc1e07d085eba 100644
--- a/llvm/include/llvm/MC/MCTargetOptions.h
+++ b/llvm/include/llvm/MC/MCTargetOptions.h
@@ -85,6 +85,10 @@ class MCTargetOptions {
   /// integrated assembler.
   std::vector<std::string> IASSearchPaths;
 
+  // Whether to emit compact-unwind for non-canonical personality
+  // functions on Darwins.
+  bool EmitCompactUnwindNonCanonical : 1;
+
   MCTargetOptions();
 
   /// getABIName - If this returns a non-empty string this represents the
diff --git a/llvm/include/llvm/MC/MCTargetOptionsCommandFlags.h b/llvm/include/llvm/MC/MCTargetOptionsCommandFlags.h
index e7211740ec4819..7f6ee6c8be224a 100644
--- a/llvm/include/llvm/MC/MCTargetOptionsCommandFlags.h
+++ b/llvm/include/llvm/MC/MCTargetOptionsCommandFlags.h
@@ -35,6 +35,8 @@ bool getDwarf64();
 
 EmitDwarfUnwindType getEmitDwarfUnwind();
 
+bool getEmitCompactUnwindNonCanonical();
+
 bool getShowMCInst();
 
 bool getFatalWarnings();
diff --git a/llvm/lib/MC/MCAsmBackend.cpp b/llvm/lib/MC/MCAsmBackend.cpp
index c4e505146d44f0..6c6fd1af4f57de 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 6ec1a9ae8444df..871532a684f924 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -925,6 +925,12 @@ 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 0cb04594522b2b..c0e9f42406e9bc 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 0667ca59830ce4..8a4923e4792fb5 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 2089a24f3a5a1e..7f20d736998299 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
@@ -564,10 +564,14 @@ class DarwinAArch64AsmBackend : public AArch64AsmBackend {
   }
 
   /// 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 df142b85256eb1..ea1363413b4a1e 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 85013b5f099a68..ace573c8fa96cf 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 @@ class ARMAsmBackendDarwin : public ARMAsmBackend {
         /*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 f06b695823fade..7ffa2d2f81c97e 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
@@ -1350,9 +1350,13 @@ class DarwinX86AsmBackend : public X86AsmBackend {
 
   /// 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;
diff --git a/llvm/test/CodeGen/X86/2014-08-29-CompactUnwind.ll b/llvm/test/CodeGen/X86/2014-08-29-CompactUnwind.ll
index 7461f746fec992..71fa028fc14351 100644
--- a/llvm/test/CodeGen/X86/2014-08-29-CompactUnwind.ll
+++ b/llvm/test/CodeGen/X86/2014-08-29-CompactUnwind.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -mtriple x86_64-apple-darwin11 -mcpu corei7 -filetype=obj -o - | llvm-objdump -d --unwind-info -s - | FileCheck %s
+; RUN: llc < %s -mtriple x86_64-apple-darwin11 -mcpu corei7 -emit-compact-unwind-non-canonical=true -filetype=obj -o - | llvm-objdump -d --unwind-info -s - | FileCheck %s
 ; Regression test for http://llvm.org/bugs/show_bug.cgi?id=20800.
 
 ; ModuleID = 'asan_report.ii'
diff --git a/llvm/test/CodeGen/X86/compact-unwind.ll b/llvm/test/CodeGen/X86/compact-unwind.ll
index b9860fb8553888..8e8845b281eaf8 100644
--- a/llvm/test/CodeGen/X86/compact-unwind.ll
+++ b/llvm/test/CodeGen/X86/compact-unwind.ll
@@ -1,17 +1,17 @@
-; RUN: llc < %s -frame-pointer=all -mtriple x86_64-apple-darwin11 -mcpu corei7 | FileCheck -check-prefix=ASM %s
-; RUN: llc < %s -frame-pointer=all -mtriple x86_64-apple-darwin11 -mcpu corei7 -filetype=obj -o - \
+; RUN: llc < %s -frame-pointer=all -mtriple x86_64-apple-darwin11 -mcpu corei7 -emit-compact-unwind-non-canonical=true | FileCheck -check-prefix=ASM %s
+; RUN: llc < %s -frame-pointer=all -mtriple x86_64-apple-darwin11 -mcpu corei7 -filetype=obj -emit-compact-unwind-non-canonical=true -o - \
 ; RUN:  | llvm-objdump --triple=x86_64-apple-darwin11 --unwind-info - \
 ; RUN:  | FileCheck -check-prefix=CU %s
-; RUN: llc < %s -frame-pointer=all -mtriple x86_64-apple-darwin11 -mcpu corei7 \
-; RUN:  | llvm-mc -triple x86_64-apple-darwin11 -filetype=obj -o - \
+; RUN: llc < %s -frame-pointer=all -mtriple x86_64-apple-darwin11 -mcpu corei7 -emit-compact-unwind-non-canonical=true \
+; RUN:  | llvm-mc -triple x86_64-apple-darwin11 -filetype=obj -emit-compact-unwind-non-canonical=true -o - \
 ; RUN:  | llvm-objdump --triple=x86_64-apple-darwin11 --unwind-info - \
 ; RUN:  | FileCheck -check-prefix=FROM-ASM %s
 
-; RUN: llc < %s -mtriple x86_64-apple-macosx10.8.0 -mcpu corei7 -filetype=obj -o - \
+; RUN: llc < %s -mtriple x86_64-apple-macosx10.8.0 -mcpu corei7 -filetype=obj -emit-compact-unwind-non-canonical=true -o - \
 ; RUN:  | llvm-objdump --triple=x86_64-apple-macosx10.8.0 --unwind-info - \
 ; RUN:  | FileCheck -check-prefix=NOFP-CU %s
 ; RUN: llc < %s -mtriple x86_64-apple-darwin11 -mcpu corei7 \
-; RUN:  | llvm-mc -triple x86_64-apple-darwin11 -filetype=obj -o - \
+; RUN:  | llvm-mc -triple x86_64-apple-darwin11 -filetype=obj -emit-compact-unwind-non-canonical=true -o - \
 ; RUN:  | llvm-objdump --triple=x86_64-apple-darwin11 --unwind-info - \
 ; RUN:  | FileCheck -check-prefix=NOFP-FROM-ASM %s
 
diff --git a/llvm/test/MC/AArch64/arm64-leaf-compact-unwind.s b/llvm/test/MC/AArch64/arm64-leaf-compact-unwind.s
index b40f11ac7b7036..80efa180318af6 100644
--- a/llvm/test/MC/AArch64/arm64-leaf-compact-unwind.s
+++ b/llvm/test/MC/AArch64/arm64-leaf-compact-unwind.s
@@ -1,4 +1,4 @@
-// RUN: llvm-mc -triple=arm64-apple-ios -filetype=obj < %s | \
+// RUN: llvm-mc -triple=arm64-apple-ios -filetype=obj -emit-compact-unwind-non-canonical=true < %s | \
 // RUN: llvm-objdump --macho --unwind-info - | \
 // RUN: FileCheck %s
 //
diff --git a/llvm/test/MC/MachO/AArch64/emit-dwarf-unwind.s b/llvm/test/MC/MachO/AArch64/emit-dwarf-unwind.s
index 89dc56b8aa87f0..9cd2c8ad49534a 100644
--- a/llvm/test/MC/MachO/AArch64/emit-dwarf-unwind.s
+++ b/llvm/test/MC/MachO/AArch64/emit-dwarf-unwind.s
@@ -1,11 +1,11 @@
 // RUN: rm -rf %t; mkdir %t
-// RUN: llvm-mc -triple x86_64-apple-macos11.0 %s -filetype=obj -o %t/x86_64.o
+// RUN: llvm-mc -triple x86_64-apple-macos11.0 %s -filetype=obj -o %t/x86_64.o -emit-compact-unwind-non-canonical=true
 // RUN: llvm-objdump --macho --dwarf=frames %t/x86_64.o | FileCheck %s --check-prefix TWO-FDES
-// RUN: llvm-mc -triple arm64-apple-macos11.0 %s -filetype=obj -o %t/arm64.o
+// RUN: llvm-mc -triple arm64-apple-macos11.0 %s -filetype=obj -o %t/arm64.o -emit-compact-unwind-non-canonical=true
 // RUN: llvm-objdump --macho --dwarf=frames %t/arm64.o | FileCheck %s --check-prefix ONE-FDE
-// RUN: llvm-mc -triple x86_64-apple-macos11.0 %s -filetype=obj --emit-dwarf-unwind no-compact-unwind -o %t/x86_64-no-dwarf.o
+// RUN: llvm-mc -triple x86_64-apple-macos11.0 %s -filetype=obj --emit-dwarf-unwind no-compact-unwind -o %t/x86_64-no-dwarf.o -emit-compact-unwind-non-canonical=true
 // RUN: llvm-objdump --macho --dwarf=frames %t/x86_64-no-dwarf.o | FileCheck %s --check-prefix ONE-FDE
-// RUN: llvm-mc -triple arm64-apple-macos11.0 %s -filetype=obj --emit-dwarf-unwind always -o %t/arm64-dwarf.o
+// RUN: llvm-mc -triple arm64-apple-macos11.0 %s -filetype=obj --emit-dwarf-unwind always -o %t/arm64-dwarf.o -emit-compact-unwind-non-canonical=true
 // RUN: llvm-objdump --macho --dwarf=frames %t/arm64-dwarf.o | FileCheck %s --check-prefix TWO-FDES
 
 // TWO-FDES: FDE
diff --git a/llvm/test/MC/MachO/ARM/compact-unwind-armv7k.s b/llvm/test/MC/MachO/ARM/compact-unwind-armv7k.s
index 51ec86b8d66af8..65890bcae750f8 100644
--- a/llvm/test/MC/MachO/ARM/compact-unwind-armv7k.s
+++ b/llvm/test/MC/MachO/ARM/compact-unwind-armv7k.s
@@ -1,4 +1,4 @@
-@ RUN: llvm-mc -triple=thumbv7k-apple-watchos2.0.0 -filetype=obj -o %t < %s && llvm-objdump --unwind-info %t | FileCheck %s
+@ RUN: llvm-mc -triple=thumbv7k-apple-watchos2.0.0 -emit-compact-unwind-non-canonical=true -filetype=obj -o %t < %s && llvm-objdump --unwind-info %t | FileCheck %s
 
 @ CHECK: Contents of __compact_unwind section:
 
diff --git a/llvm/test/MC/X86/compact-unwind.s b/llvm/test/MC/X86/compact-unwind.s
index 4f84a2abb47799..8c835ce9af571a 100644
--- a/llvm/test/MC/X86/compact-unwind.s
+++ b/llvm/test/MC/X86/compact-unwind.s
@@ -1,4 +1,4 @@
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin10.0 %s | llvm-objdump --unwind-info - | FileCheck %s
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin10.0 %s -emit-compact-unwind-non-canonical=true | llvm-objdump --unwind-info - | FileCheck %s
 
 	.section	__TEXT,__text,regular,pure_instructions
 	.macosx_version_min 10, 10