raw_ostream: << operator for callables with raw_stream argument

This allows easier construction of print helpers. Example:

Printable PrintLaneMask(unsigned LaneMask) {
  return Printable([LaneMask](raw_ostream &OS) {
    OS << format("%08X", LaneMask);
  });
}

// Usage:
OS << PrintLaneMask(Mask);

Differential Revision: http://reviews.llvm.org/D14348

llvm-svn: 254655

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
index 49ef400..5b1dcec 100644
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -264,6 +264,10 @@ raw_ostream &raw_ostream::operator<<(double N) {
   return this->operator<<(format("%e", N));
 }
 
+raw_ostream &raw_ostream::operator<<(Printable P) {
+  P(*this);
+  return *this;
+}
 
 
 void raw_ostream::flush_nonempty() {