Disable canonical prefixes of system headers

GCC know a few pre-defined paths (relative to its location) to
search for headers, libraries, program, etc.  By default GCC prefixes
its own path(argv[0]) and calls realpath() which result in absolute
path with all symlink, . and .. removed.

It's usually good to have canonicalised paths, but absolute paths
in *.d file can cause unnecessary relinking when stale entries
in ccache cache hit

Add -no-canonical-prefixes (gcc>=4.6) and
-fno-canonical-system-headers (gcc>4.6) to disable realpath() on
prefixed paths

Change-Id: I58d739e61fb013015fb05a9c98b2132b307f915a

diff --git a/core/clang/config.mk b/core/clang/config.mk
index b8f76f2..c598e7d 100644 (file)
--- a/core/clang/config.mk
+++ b/core/clang/config.mk
@@ -31,7 +31,8 @@ CLANG_CONFIG_UNKNOWN_CFLAGS := \
   -funswitch-loops \
   -Wno-psabi \
   -Wno-unused-but-set-variable \
-  -Wno-unused-but-set-parameter
+  -Wno-unused-but-set-parameter \
+  -fno-canonical-system-headers
 
 # Clang flags for all host rules
 CLANG_CONFIG_HOST_EXTRA_ASFLAGS :=

diff --git a/core/combo/HOST_linux-x86.mk b/core/combo/HOST_linux-x86.mk
index 85d536b..1472849 100644 (file)
--- a/core/combo/HOST_linux-x86.mk
+++ b/core/combo/HOST_linux-x86.mk
@@ -52,7 +52,8 @@ HOST_GLOBAL_LDFLAGS += -static
 endif # BUILD_HOST_static
 
 HOST_GLOBAL_CFLAGS += -fPIC \
-    -include $(call select-android-config-h,linux-x86)
+  -no-canonical-prefixes \
+  -include $(call select-android-config-h,linux-x86)
 
 # Disable new longjmp in glibc 2.11 and later. See bug 2967937.
 HOST_GLOBAL_CFLAGS += -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0

diff --git a/core/combo/TARGET_linux-arm.mk b/core/combo/TARGET_linux-arm.mk
index 81d0813..8c8a01a 100644 (file)
--- a/core/combo/TARGET_linux-arm.mk
+++ b/core/combo/TARGET_linux-arm.mk
@@ -103,6 +103,8 @@ $(combo_2nd_arch_prefix)TARGET_GLOBAL_CFLAGS += \
                        -Werror=format-security \
                        -D_FORTIFY_SOURCE=2 \
                        -fno-short-enums \
+                       -no-canonical-prefixes \
+                       -fno-canonical-system-headers \
                        $(arch_variant_cflags) \
                        -include $(android_config_h) \
                        -I $(dir $(android_config_h))

diff --git a/core/combo/TARGET_linux-arm64.mk b/core/combo/TARGET_linux-arm64.mk
index 5e50f9f..6515eb5 100644 (file)
--- a/core/combo/TARGET_linux-arm64.mk
+++ b/core/combo/TARGET_linux-arm64.mk
@@ -87,6 +87,8 @@ TARGET_GLOBAL_CFLAGS += \
                        -Werror=format-security \
                        -D_FORTIFY_SOURCE=2 \
                        -fno-short-enums \
+                       -no-canonical-prefixes \
+                       -fno-canonical-system-headers \
                        $(arch_variant_cflags) \
                        -include $(android_config_h) \
                        -I $(dir $(android_config_h))

diff --git a/core/combo/TARGET_linux-mips.mk b/core/combo/TARGET_linux-mips.mk
index 1250767..015d46b 100644 (file)
--- a/core/combo/TARGET_linux-mips.mk
+++ b/core/combo/TARGET_linux-mips.mk
@@ -90,6 +90,8 @@ $(combo_2nd_arch_prefix)TARGET_GLOBAL_CFLAGS += \
                        -Wa,--noexecstack \
                        -Werror=format-security \
                        -D_FORTIFY_SOURCE=2 \
+                       -no-canonical-prefixes \
+                       -fno-canonical-system-headers \
                        $(arch_variant_cflags) \
                        -include $(android_config_h) \
                        -I $(dir $(android_config_h))

diff --git a/core/combo/TARGET_linux-mips64.mk b/core/combo/TARGET_linux-mips64.mk
index 2130d03..a7b03b2 100644 (file)
--- a/core/combo/TARGET_linux-mips64.mk
+++ b/core/combo/TARGET_linux-mips64.mk
@@ -95,6 +95,8 @@ TARGET_GLOBAL_CFLAGS += \
                        -Wa,--noexecstack \
                        -Werror=format-security \
                        -D_FORTIFY_SOURCE=2 \
+                       -no-canonical-prefixes \
+                       -fno-canonical-system-headers \
                        $(arch_variant_cflags) \
                        -include $(android_config_h) \
                        -I $(dir $(android_config_h))

diff --git a/core/combo/TARGET_linux-x86.mk b/core/combo/TARGET_linux-x86.mk
index 4f66765..4ebcd93 100644 (file)
--- a/core/combo/TARGET_linux-x86.mk
+++ b/core/combo/TARGET_linux-x86.mk
@@ -122,6 +122,8 @@ $(combo_2nd_arch_prefix)TARGET_GLOBAL_CFLAGS += \
                        -fstack-protector \
                        -m32 \
                        -msse2 \
+                       -no-canonical-prefixes \
+                       -fno-canonical-system-headers \
                        -include $(android_config_h) \
                        -I $(dir $(android_config_h))
 

diff --git a/core/combo/TARGET_linux-x86_64.mk b/core/combo/TARGET_linux-x86_64.mk
index 42953ae..ee6c6e2 100644 (file)
--- a/core/combo/TARGET_linux-x86_64.mk
+++ b/core/combo/TARGET_linux-x86_64.mk
@@ -120,7 +120,9 @@ TARGET_GLOBAL_CFLAGS += \
                        -funswitch-loops \
                        -funwind-tables \
                        -fstack-protector \
-                       -m64
+                       -m64 \
+                       -no-canonical-prefixes \
+                       -fno-canonical-system-headers
 
 # Help catch common 32/64-bit errors.
 TARGET_GLOBAL_CFLAGS += \