From 81fe2b16dc3ac8f17719964d3d01e92e2dc3cc4c Mon Sep 17 00:00:00 2001
From: Chih-Hung Hsieh <chh@google.com>
Date: Thu, 4 Sep 2014 15:19:52 -0700
Subject: [PATCH] Enable clang compilation with libc but not linker.

Clang is still disabled for x86 and x86_64 long double code,
for x86_64 special assembly instruction, and the linker module.

BUG: 17163651
BUG: 17302991
BUG: 17403674

(cherry picked from commit b58db8b083ce41798a5310616e4f20885cec611f)

Change-Id: I916c05056d37a9c287b0a5ae3b1a209d98c8f70e
---
 libc/Android.mk             | 26 +++++++++++++++++++++++---
 linker/linker_executable.mk |  2 ++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/libc/Android.mk b/libc/Android.mk
index 9c5e785ae..fe1f31577 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -503,7 +503,10 @@ ifneq ($(TARGET_USES_LOGD),false)
 libc_common_cflags += -DTARGET_USES_LOGD
 endif
 
-use_clang := false
+use_clang := $(USE_CLANG_PLATFORM_BUILD)
+ifeq ($(use_clang),)
+  use_clang := false
+endif
 
 # Try to catch typical 32-bit assumptions that break with 64-bit pointers.
 libc_common_cflags += \
@@ -733,6 +736,13 @@ include $(BUILD_STATIC_LIBRARY)
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := $(libc_upstream_openbsd_src_files)
+ifneq (,$(filter $(TARGET_ARCH),x86 x86_64))
+  # Clang has wrong long double size or LDBL_MANT_DIG, http://b/17163651.
+  LOCAL_CLANG := false
+else
+  LOCAL_CLANG := $(use_clang)
+endif
+
 LOCAL_CFLAGS := \
     $(libc_common_cflags) \
     -Wno-sign-compare -Wno-uninitialized -Wno-unused-parameter \
@@ -746,7 +756,6 @@ LOCAL_CONLYFLAGS := $(libc_common_conlyflags)
 LOCAL_CPPFLAGS := $(libc_common_cppflags)
 LOCAL_C_INCLUDES := $(libc_common_c_includes)
 LOCAL_MODULE := libc_openbsd
-LOCAL_CLANG := $(use_clang)
 LOCAL_ADDITIONAL_DEPENDENCIES := $(libc_common_additional_dependencies)
 LOCAL_SYSTEM_SHARED_LIBRARIES :=
 
@@ -765,6 +774,13 @@ include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES_32 := $(libc_upstream_openbsd_gdtoa_src_files_32)
 LOCAL_SRC_FILES_64 := $(libc_upstream_openbsd_gdtoa_src_files_64)
+ifneq (,$(filter $(TARGET_ARCH),x86 x86_64))
+  # Clang has wrong long double size or LDBL_MANT_DIG, http://b/17163651.
+  LOCAL_CLANG := false
+else
+  LOCAL_CLANG := $(use_clang)
+endif
+
 LOCAL_CFLAGS := \
     $(libc_common_cflags) \
     -Wno-sign-compare -Wno-uninitialized \
@@ -778,7 +794,6 @@ LOCAL_CONLYFLAGS := $(libc_common_conlyflags)
 LOCAL_CPPFLAGS := $(libc_common_cppflags)
 LOCAL_C_INCLUDES := $(libc_common_c_includes)
 LOCAL_MODULE := libc_gdtoa
-LOCAL_CLANG := $(use_clang)
 LOCAL_ADDITIONAL_DEPENDENCIES := $(libc_common_additional_dependencies)
 LOCAL_SYSTEM_SHARED_LIBRARIES :=
 
@@ -796,6 +811,11 @@ LOCAL_SRC_FILES := $(libc_bionic_src_files)
 LOCAL_CFLAGS := $(libc_common_cflags) \
     -Wframe-larger-than=2048 \
 
+ifeq ($(TARGET_ARCH),x86_64)
+  # Clang assembler has problem with ssse3-strcmp-slm.S, http://b/17302991
+  LOCAL_CLANG_ASFLAGS += -no-integrated-as
+endif
+
 LOCAL_CONLYFLAGS := $(libc_common_conlyflags)
 LOCAL_CPPFLAGS := $(libc_common_cppflags)
 LOCAL_C_INCLUDES := $(libc_common_c_includes)
diff --git a/linker/linker_executable.mk b/linker/linker_executable.mk
index 4902a0cc5..a596a4805 100644
--- a/linker/linker_executable.mk
+++ b/linker/linker_executable.mk
@@ -9,6 +9,8 @@
 LOCAL_MODULE_CLASS := EXECUTABLES
 LOCAL_MODULE_SUFFIX := $(TARGET_EXECUTABLE_SUFFIX)
 
+# Clang calls /usr/bin/ld: unrecognized option '--icf=safe', http://b/17403674.
+LOCAL_CLANG := false
 include $(BUILD_SYSTEM)/dynamic_binary.mk
 
 # See build/core/executable_internal.mk