Add ability for MCInstPrinters to add comments for instructions.

Enhance the x86 backend to show the hex values of immediates in
comments when they are large.  For example:

        movl    $1072693248, 4(%esp)    ## imm = 0x3FF00000



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95728 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 12 insertions, 2 deletions

diff --git a/include/llvm/MC/MCFixup.h b/include/llvm/MC/MCFixup.h
index da8e92e..3c2edfb 100644
--- a/include/llvm/MC/MCFixup.h
+++ b/include/llvm/MC/MCFixup.h
@@ -16,7 +16,7 @@ namespace llvm {
 
 // Private constants, do not use.
 //
-// This is currently layed out so that the MCFixup fields can be efficiently
+// This is currently laid out so that the MCFixup fields can be efficiently
 // accessed, while keeping the offset field large enought that the assembler
 // backend can reasonably use the MCFixup representation for an entire fragment
 // (splitting any overly large fragments).
diff --git a/include/llvm/MC/MCInstPrinter.h b/include/llvm/MC/MCInstPrinter.h
index d62a9da..8829518 100644
--- a/include/llvm/MC/MCInstPrinter.h
+++ b/include/llvm/MC/MCInstPrinter.h
@@ -20,12 +20,22 @@ class MCAsmInfo;
 /// that converts an MCInst to valid target assembly syntax.
 class MCInstPrinter {
 protected:
+  /// O - The main stream to emit instruction text to.
   raw_ostream &O;
+  
+  /// CommentStream - a stream that comments can be emitted to if desired.
+  /// Each comment must end with a newline.  This will be null if verbose
+  /// assembly emission is disable.
+  raw_ostream *CommentStream;
   const MCAsmInfo &MAI;
 public:
-  MCInstPrinter(raw_ostream &o, const MCAsmInfo &mai) : O(o), MAI(mai) {}
+  MCInstPrinter(raw_ostream &o, const MCAsmInfo &mai)
+    : O(o), CommentStream(0), MAI(mai) {}
   
   virtual ~MCInstPrinter();
+
+  /// setCommentStream - Specify a stream to emit comments to.
+  void setCommentStream(raw_ostream &OS) { CommentStream = &OS; }
   
   /// printInst - Print the specified MCInst to the current raw_ostream.
   ///