Fix off-by-one in llvm::Format::print.

 - This also shortens the Format.h implementation, and uses the print buffer
   fully (it was wasting a character).

 - This manifested as llvm-test failures, because one side effect was that
   raw_ostream would write garbage '\x00' values into the output stream if it
   happened that the string was at the end of the buffer. This meant that grep
   would report 'Binary file matches', which meant the silly pattern matching
   llvm-test eventually does would fail. Cute. :)

llvm-svn: 79862

1 files changed, 5 insertions, 5 deletions

diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
index 2181ccec0b1..221859d5337 100644
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -253,12 +253,12 @@ raw_ostream &raw_ostream::operator<<(const format_object_base &Fmt) {
   // If we have more than a few bytes left in our output buffer, try
   // formatting directly onto its end.
   size_t NextBufferSize = 127;
-  if (OutBufEnd-OutBufCur > 3) {
-    size_t BufferBytesLeft = OutBufEnd-OutBufCur;
+  size_t BufferBytesLeft = OutBufEnd - OutBufCur;
+  if (BufferBytesLeft > 3) {
     size_t BytesUsed = Fmt.print(OutBufCur, BufferBytesLeft);
     
     // Common case is that we have plenty of space.
-    if (BytesUsed < BufferBytesLeft) {
+    if (BytesUsed <= BufferBytesLeft) {
       OutBufCur += BytesUsed;
       return *this;
     }
@@ -277,11 +277,11 @@ raw_ostream &raw_ostream::operator<<(const format_object_base &Fmt) {
     V.resize(NextBufferSize);
     
     // Try formatting into the SmallVector.
-    size_t BytesUsed = Fmt.print(&V[0], NextBufferSize);
+    size_t BytesUsed = Fmt.print(V.data(), NextBufferSize);
     
     // If BytesUsed fit into the vector, we win.
     if (BytesUsed <= NextBufferSize)
-      return write(&V[0], BytesUsed);
+      return write(V.data(), BytesUsed);
     
     // Otherwise, try again with a new size.
     assert(BytesUsed > NextBufferSize && "Didn't grow buffer!?");