An option to selectively enable parts of ARM EHABI support.

This change adds an new value to the --arm-enable-ehabi option that
disables emitting unwinding descriptors. This mode gives a working
backtrace() without the (currently broken) exception support.

llvm-svn: 148686

1 files changed, 20 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp b/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
index 3f238732536..e5a7d05f4c5 100644
--- a/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
@@ -29,6 +29,7 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Dwarf.h"
 #include "llvm/Support/FormattedStream.h"
 #include "llvm/ADT/SmallString.h"
@@ -36,6 +37,18 @@
 #include "llvm/ADT/Twine.h"
 using namespace llvm;
 
+cl::opt<ExceptionHandling::ARMEHABIMode>
+EnableARMEHABI("arm-enable-ehabi", cl::Hidden,
+    cl::desc("Generate ARM EHABI tables:"),
+    cl::values(clEnumValN(ExceptionHandling::ARMEHABIDisabled, "no",
+            "Do not generate ARM EHABI tables"),
+        clEnumValN(ExceptionHandling::ARMEHABIUnwind, "unwind",
+            "Emit unwinding instructions, but not descriptors"),
+        clEnumValN(ExceptionHandling::ARMEHABIFull, "full",
+            "Generate full ARM EHABI tables"),
+        clEnumValEnd));
+
+
 ARMException::ARMException(AsmPrinter *A)
   : DwarfException(A),
     shouldEmitTable(false), shouldEmitMoves(false), shouldEmitTableModule(false)
@@ -72,13 +85,15 @@ void ARMException::EndFunction() {
       Asm->OutStreamer.EmitPersonality(PerSym);
     }
 
-    // Map all labels and get rid of any dead landing pads.
-    MMI->TidyLandingPads();
+    if (EnableARMEHABI == ExceptionHandling::ARMEHABIFull) {
+      // Map all labels and get rid of any dead landing pads.
+      MMI->TidyLandingPads();
 
-    Asm->OutStreamer.EmitHandlerData();
+      Asm->OutStreamer.EmitHandlerData();
 
-    // Emit actual exception table
-    EmitExceptionTable();
+      // Emit actual exception table
+      EmitExceptionTable();
+    }
   }
 
   Asm->OutStreamer.EmitFnEnd();