Add an option that allows one to "decode" the LSDA.

The LSDA is a bit difficult for the non-initiated to read. Even with comments,
it's not always clear what's going on. This wraps the ASM streamer in a class
that retains the LSDA and then emits a human-readable description of what's
going on in it.

So instead of having to make sense of:

Lexception1:
        .byte   255
        .byte   155
        .byte   168
        .space  1
        .byte   3
        .byte   26
Lset0 = Ltmp7-Leh_func_begin1
      .long     Lset0
Lset1 = Ltmp812-Ltmp7
      .long     Lset1
Lset2 = Ltmp913-Leh_func_begin1
      .long     Lset2
      .byte     3
Lset3 = Ltmp812-Leh_func_begin1
      .long     Lset3
Lset4 = Leh_func_end1-Ltmp812
      .long     Lset4
      .long     0
      .byte     0
      .byte     1
      .byte     0
      .byte     2
      .byte     125
      .long     __ZTIi@GOTPCREL+4
      .long     __ZTIPKc@GOTPCREL+4

you can read this instead:

## Exception Handling Table: Lexception1
##  @LPStart Encoding: omit
##    @TType Encoding: indirect pcrel sdata4
##        @TType Base: 40 bytes
## @CallSite Encoding: udata4
## @Action Table Size: 26 bytes

## Action 1:
##   A throw between Ltmp7 and Ltmp812 jumps to Ltmp913 on an exception.
##     For type(s):  __ZTIi@GOTPCREL+4 __ZTIPKc@GOTPCREL+4
## Action 2:
##   A throw between Ltmp812 and Leh_func_end1 does not have a landing pad.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133286 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 6 deletions

diff --git a/tools/llvm-mc/llvm-mc.cpp b/tools/llvm-mc/llvm-mc.cpp
index eb23a1a467..48e2a61af8 100644
--- a/tools/llvm-mc/llvm-mc.cpp
+++ b/tools/llvm-mc/llvm-mc.cpp
@@ -61,6 +61,10 @@ static cl::opt<bool>
 ShowInstOperands("show-inst-operands",
                  cl::desc("Show instructions operands as parsed"));
 
+static cl::opt<bool>
+DecodeLSDA("decode-lsda",
+           cl::desc("Print LSDA in human readable format"));
+
 static cl::opt<unsigned>
 OutputAsmVariant("output-asm-variant",
                  cl::desc("Syntax variant to use for output printing"));
@@ -97,7 +101,7 @@ IncludeDirs("I", cl::desc("Directory of include files"),
 
 static cl::opt<std::string>
 ArchName("arch", cl::desc("Target arch to assemble for, "
-                            "see -version for available targets"));
+                          "see -version for available targets"));
 
 static cl::opt<std::string>
 TripleName("triple", cl::desc("Target triple to assemble for, "
@@ -110,12 +114,11 @@ MCPU("mcpu",
      cl::init(""));
 
 static cl::opt<bool>
-NoInitialTextSection("n", cl::desc(
-                   "Don't assume assembly file starts in the text section"));
+NoInitialTextSection("n", cl::desc("Don't assume assembly file starts "
+                                   "in the text section"));
 
 static cl::opt<bool>
-SaveTempLabels("L", cl::desc(
-                 "Don't discard temporary labels"));
+SaveTempLabels("L", cl::desc("Don't discard temporary labels"));
 
 enum ActionType {
   AC_AsLex,
@@ -358,7 +361,8 @@ static int AssembleInput(const char *ProgName) {
     Str.reset(TheTarget->createAsmStreamer(Ctx, FOS, /*asmverbose*/true,
                                            /*useLoc*/ true,
                                            /*useCFI*/ true, IP, CE, TAB,
-                                           ShowInst));
+                                           ShowInst,
+                                           DecodeLSDA));
   } else if (FileType == OFT_Null) {
     Str.reset(createNullStreamer(Ctx));
   } else {