[PATCH] D17741: adds __FILE_BASENAME__ builtin macro

[Weiming Zhao via cfe-commits]

weimingz created this revision.
weimingz added a subscriber: cfe-commits.

__FILE__ will be expanded to the full path. In some embedded system scenarios, the final images is linked from many objs and the image size is a very important factor.
The full filenames can occupy a lot space in the string pool and most of the time,  knowing the base name is sufficient.
__FILE_BASENAME__ can be used in this scenario.

http://reviews.llvm.org/D17741

Files:
  include/clang/Lex/Preprocessor.h
  lib/Lex/PPMacroExpansion.cpp
  test/Lexer/file_basename.c

Index: test/Lexer/file_basename.c
===================================================================
--- /dev/null
+++ test/Lexer/file_basename.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -E %s | FileCheck %s
+
+const char *filename (const char *name) {
+  // CHECK:  static const char this_file_basename[] = "file_basename.c";
+  static const char this_file_basename[] = __FILE_BASENAME__;
+  // CHECK:  static const char this_file[] = "{{.*}}/Lexer/file_basename.c";
+  static const char this_file[] = __FILE__;
+  return this_file;
+}
Index: lib/Lex/PPMacroExpansion.cpp
===================================================================
--- lib/Lex/PPMacroExpansion.cpp
+++ lib/Lex/PPMacroExpansion.cpp
@@ -28,6 +28,7 @@
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Format.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstdio>
 #include <ctime>
@@ -292,6 +293,7 @@
 void Preprocessor::RegisterBuiltinMacros() {
   Ident__LINE__ = RegisterBuiltinMacro(*this, "__LINE__");
   Ident__FILE__ = RegisterBuiltinMacro(*this, "__FILE__");
+  Ident__FILE_BASENAME__ = RegisterBuiltinMacro(*this, "__FILE_BASENAME__");
   Ident__DATE__ = RegisterBuiltinMacro(*this, "__DATE__");
   Ident__TIME__ = RegisterBuiltinMacro(*this, "__TIME__");
   Ident__COUNTER__ = RegisterBuiltinMacro(*this, "__COUNTER__");
@@ -1509,7 +1511,8 @@
     // __LINE__ expands to a simple numeric value.
     OS << (PLoc.isValid()? PLoc.getLine() : 1);
     Tok.setKind(tok::numeric_constant);
-  } else if (II == Ident__FILE__ || II == Ident__BASE_FILE__) {
+  } else if (II == Ident__FILE__ || II == Ident__BASE_FILE__ ||
+             II == Ident__FILE_BASENAME__) {
     // C99 6.10.8: "__FILE__: The presumed name of the current source file (a
     // character string literal)". This can be affected by #line.
     PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation());
@@ -1530,7 +1533,9 @@
     // Escape this filename.  Turn '\' -> '\\' '"' -> '\"'
     SmallString<128> FN;
     if (PLoc.isValid()) {
-      FN += PLoc.getFilename();
+      FN += II == Ident__FILE_BASENAME__
+          ? llvm::sys::path::filename(PLoc.getFilename())
+          : PLoc.getFilename();
       Lexer::Stringify(FN);
       OS << '"' << FN << '"';
     }
Index: include/clang/Lex/Preprocessor.h
===================================================================
--- include/clang/Lex/Preprocessor.h
+++ include/clang/Lex/Preprocessor.h
@@ -119,6 +119,7 @@
 
   /// Identifiers for builtin macros and other builtins.
   IdentifierInfo *Ident__LINE__, *Ident__FILE__;   // __LINE__, __FILE__
+  IdentifierInfo *Ident__FILE_BASENAME__;          //  __FILE_BASENAME__
   IdentifierInfo *Ident__DATE__, *Ident__TIME__;   // __DATE__, __TIME__
   IdentifierInfo *Ident__INCLUDE_LEVEL__;          // __INCLUDE_LEVEL__
   IdentifierInfo *Ident__BASE_FILE__;              // __BASE_FILE__


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