From ad46ec8bd011716899d7bc0251a2994f2777655b Mon Sep 17 00:00:00 2001
From: Frits van Bommel <fvbommel@wxs.nl>
Date: Fri, 13 Mar 2009 16:18:43 +0100
Subject: [PATCH] Split out LLVM_REV into separate header, to reduce rebuilding
 when only the LDC revision has changed.

---
 .hgignore       |  1 +
 CMakeLists.txt  |  2 +-
 dmd2/mars.c     |  2 +-
 gen/linkage.h   |  2 +-
 revisions.pl.in | 21 ++++++++++++++++++---
 5 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/.hgignore b/.hgignore
index b3c092aa..320ab928 100644
--- a/.hgignore
+++ b/.hgignore
@@ -29,6 +29,7 @@ syntax: regexp
 ^ldc\.make$
 ^revisions\.pl$
 ^gen/revisions\.h$
+^gen/llvm-version\.h$
 ^dmd2?/idgen$
 ^dmd2?/impcnvgen$
 ^dmd2?/impcnvtab\.c$
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1f76b2cf..6532a0dc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -195,7 +195,7 @@ add_custom_target(
 	gen_revs_h
 	COMMAND ${PERL_EXECUTABLE} ${PROJECT_BINARY_DIR}/revisions.pl
 	DEPENDS ${PROJECT_BINARY_DIR}/revisions.pl
-	COMMENT "Generating revisions.h"
+	COMMENT "Generating revisions.h and llvm-version.h"
 	WORKING_DIRECTORY ${PROJECT_BINARY_DIR}/gen
 )
 add_dependencies(${LDC_EXE} gen_revs_h)
diff --git a/dmd2/mars.c b/dmd2/mars.c
index ad41d0c5..ea5ccb93 100644
--- a/dmd2/mars.c
+++ b/dmd2/mars.c
@@ -61,7 +61,7 @@ Global::Global()
     written = "written by Walter Bright and Tomas Lindquist Olsen";
     version = "v2.021";
     ldc_version = LDC_REV;
-    llvm_version = LLVM_REV;
+    llvm_version = LLVM_REV_STR;
     global.structalign = 8;
 
     // This should only be used as a global, so the other fields are
diff --git a/gen/linkage.h b/gen/linkage.h
index fba8432a..506ce50b 100644
--- a/gen/linkage.h
+++ b/gen/linkage.h
@@ -1,7 +1,7 @@
 #ifndef LDC_GEN_LINKAGE_H
 #define LDC_GEN_LINKAGE_H
 
-#include "gen/revisions.h"
+#include "gen/llvm-version.h"
 
 // Make it easier to test new linkage types
 // Also used to adapt to some changes in LLVM between 2.5 and 2.6
diff --git a/revisions.pl.in b/revisions.pl.in
index 8a00aea0..4e59d567 100644
--- a/revisions.pl.in
+++ b/revisions.pl.in
@@ -46,9 +46,6 @@ $extra_includes
 
 // LLVM version string, for use in -version output
 #define LLVM_REV_STR $llvm_rev_str$llvm_date
-// LLVM svn revision number, used to adapt to changes in LLVM
-// (Is 0 if LLVM is not an SVN trunk version)
-#define LLVM_REV $llvm_rev_nr
 // LDC version string, for use in -version output
 #define LDC_REV "rev. $ldc_rev"
 
@@ -63,3 +60,21 @@ if ($old ne $out) {
 	print $revh $out;
 	close $revh;
 }
+
+$out = qq!#ifndef LDC_LLVM_VERSION_H
+#define LDC_LLVM_VERSION_H
+
+// LLVM svn revision number, used to adapt to changes in LLVM
+// (Is 0 if LLVM is not an SVN trunk version)
+#define LLVM_REV $llvm_rev_nr
+
+#endif // LDC_LLVM_VERSION_H\n!;
+
+$old = "";
+open $revh, "llvm-version.h" and $old = join "", <$revh>;
+
+if ($old ne $out) {
+	open $revh, ">llvm-version.h" or die "cannot create llvm-version.h: $!";
+	print $revh $out;
+	close $revh;
+}