Teach raw_ostream to support hex formatting without a prefix '0x'.

Previously using format_hex() would always print a 0x prior to the
hex characters.  This allows this to be optional, so that one can
choose to print (e.g.) 255 as either 0xFF or just FF.

Differential Revision: http://reviews.llvm.org/D7151

llvm-svn: 227108

1 files changed, 5 insertions, 2 deletions

diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
index 1bcc31b40a4..aa618b9d392 100644
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -410,9 +410,12 @@ raw_ostream &raw_ostream::operator<<(const FormattedString &FS) {
 raw_ostream &raw_ostream::operator<<(const FormattedNumber &FN) {
   if (FN.Hex) {
     unsigned Nibbles = (64 - countLeadingZeros(FN.HexValue)+3)/4;
-    unsigned Width = (FN.Width > Nibbles+2) ? FN.Width : Nibbles+2;
-        
+    unsigned PrefixChars = FN.HexPrefix ? 2 : 0;
+    unsigned Width = std::max(FN.Width, Nibbles + PrefixChars);
+
     char NumberBuffer[20] = "0x0000000000000000";
+    if (!FN.HexPrefix)
+      NumberBuffer[1] = '0';
     char *EndPtr = NumberBuffer+Width;
     char *CurPtr = EndPtr;
     const char A = FN.Upper ? 'A' : 'a';