Bug 409803 - gcc (4.1 only) zealously avoids inlining at -Os. make -finline-limit=50 the default on linux -Os builds. r=ted, blocking1.9+

config/autoconf.mk.in

@@ -281,6 +281,7 @@ WARNINGS_AS_ERRORS = @WARNINGS_AS_ERRORS@
 MOZ_OPTIMIZE	= @MOZ_OPTIMIZE@
 MOZ_OPTIMIZE_FLAGS = @MOZ_OPTIMIZE_FLAGS@
 MOZ_OPTIMIZE_LDFLAGS = @MOZ_OPTIMIZE_LDFLAGS@
+MOZ_OPTIMIZE_SIZE_TWEAK = @MOZ_OPTIMIZE_SIZE_TWEAK@
 
 MOZ_RTTI_FLAGS_ON = @_MOZ_RTTI_FLAGS_ON@
 

configure.in

@@ -1744,8 +1744,17 @@ case "$target" in
     ;;
 
 *-*linux*)
+    if test "$GNU_CC"; then
+        GCC_VERSION=`$CC -v 2>&1 | awk '/version/ { print $3 }'`
+        case $GCC_VERSION in
+        4.1.*)
+            # -Os is broken on gcc 4.1.x, we need to tweak it to get good results.
+            MOZ_OPTIMIZE_SIZE_TWEAK="-finline-limit=50"
+        esac
+    fi
+
     TARGET_NSPR_MDCPUCFG='\"md/_linux.cfg\"'
-    MOZ_OPTIMIZE_FLAGS="-Os -freorder-blocks -fno-reorder-functions"
+    MOZ_OPTIMIZE_FLAGS="-Os -freorder-blocks -fno-reorder-functions $MOZ_OPTIMIZE_SIZE_TWEAK"
     MOZ_DEBUG_FLAGS="-g -fno-inline"  # most people on linux use gcc/gdb,
                                       # and that combo is not yet good at
                                       # debugging inlined functions (even
@@ -5986,6 +5995,7 @@ fi # COMPILE_ENVIRONMENT
 AC_SUBST(MOZ_OPTIMIZE)
 AC_SUBST(MOZ_OPTIMIZE_FLAGS)
 AC_SUBST(MOZ_OPTIMIZE_LDFLAGS)
+AC_SUBST(MOZ_OPTIMIZE_SIZE_TWEAK)
 
 dnl ========================================================
 dnl = Enable/disable debug for specific modules only

xpcom/io/Makefile.in

@@ -53,7 +53,7 @@ REQUIRES	= string \
 # work around bug 408258
 ifdef GNU_CC 
 ifneq ($(OS_ARCH), Darwin)
-MODULE_OPTIMIZE_FLAGS = -Os -fno-strict-aliasing
+MODULE_OPTIMIZE_FLAGS = -Os -fno-strict-aliasing $(MOZ_OPTIMIZE_SIZE_TWEAK)
 endif
 endif