When patching gcc specs file use existing specs if found

build_tools/common.sh

 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 # Environment variable NACL_ARCH should be set to one of the following
 # values: i686 x86_64 pnacl arm
 
 
 # NAMING CONVENTION
 # =================
@@ skipping 278 matching lines @@
       if cmp ${TC_INCLUDES}${INC} ${NACLPORTS_INCLUDE}${INC} > /dev/null; then
         continue
       fi
     fi
     MakeDir $(dirname ${NACLPORTS_INCLUDE}${INC})
     LogExecute install  -m 644 ${TC_INCLUDES}${INC} ${NACLPORTS_INCLUDE}${INC}
   done
 }
 
 
-PatchSpecFile() {
+PatchSpecsFile() {
   if [ "${NACL_ARCH}" = "pnacl" -o \
        "${NACL_ARCH}" = "emscripten" ]; then
-    # The arm compiler doesn't currently need a patched specs file
-    # as it ships with the correct paths.  As does the pnacl toolchain.
+    # The emscripten and PNaCl toolchains already include the required
+    # include and library paths by defaut. No need to patch them.
     return
   fi
 
   # SPECS_FILE is where nacl-gcc 'specs' file will be installed
   local SPECS_DIR=
   if [ "${NACL_ARCH}" = "arm" ]; then
     SPECS_DIR=${NACL_TOOLCHAIN_ROOT}/lib/gcc/arm-nacl/4.8.2
     if [ ! -d "${SPECS_DIR}" ]; then
       SPECS_DIR=${NACL_TOOLCHAIN_ROOT}/lib/gcc/arm-nacl/4.8.3
     fi
   else
     SPECS_DIR=${NACL_TOOLCHAIN_ROOT}/lib/gcc/x86_64-nacl/4.4.3
   fi
   local SPECS_FILE=${SPECS_DIR}/specs
 
   # NACL_SDK_MULITARCH_USR is a version of NACL_TOOLCHAIN_ROOT that gets passed
   # into the gcc specs file.  It has a gcc spec-file conditional for
   # ${NACL_ARCH}
   local NACL_SDK_MULTIARCH_USR=${NACL_TOOLCHAIN_ROOT}/\%\(nacl_arch\)/usr
   local NACL_SDK_MULTIARCH_USR_INCLUDE=${NACL_SDK_MULTIARCH_USR}/include
   local NACL_SDK_MULTIARCH_USR_LIB=${NACL_SDK_MULTIARCH_USR}/lib
   local ERROR_MSG="Shared libraries are not supported by newlib toolchain"
 
   # fix up spaces so gcc sees entire path
   local SED_SAFE_SPACES_USR_INCLUDE=${NACL_SDK_MULTIARCH_USR_INCLUDE/ /\ /}
   local SED_SAFE_SPACES_USR_LIB=${NACL_SDK_MULTIARCH_USR_LIB/ /\ /}
 
+  if [ -f ${SPECS_FILE} ]; then
+    if grep -q "${NACL_SDK_MULTIARCH_USR_LIB}" ${SPECS_FILE}; then
+      echo "Specs file already patched"
+      return
+    fi
+    echo "Patching existing specs file"
+    cp ${SPECS_FILE} ${SPECS_FILE}.current
+  else
+    echo "Creating new specs file"
+    ${NACLCC} -dumpspecs > ${SPECS_FILE}.current
+  fi
+
+  # add include & lib search paths to specs file
   if [ "${NACL_ARCH}" = "arm" ]; then
     local ARCH_SUBST='/\*cpp:/ { \
         printf("*nacl_arch:\narm-nacl\n\n", $1); } \
         { print $0; }'
   else
     local ARCH_SUBST='/\*cpp:/ { \
         printf("*nacl_arch:\n%%{m64:x86_64-nacl; m32:i686-nacl; :x86_64-nacl}\n\n", $1); } \
         { print $0; }'
   fi
 
-  # have nacl-gcc dump specs file & add include & lib search paths
-  ${NACLCC} -dumpspecs |\
+  cat ${SPECS_FILE}.current |\
     awk "${ARCH_SUBST}" |\
     sed "/*cpp:/{
       N
       s|$| -isystem ${SED_SAFE_SPACES_USR_INCLUDE}|
     }" |\
     sed "/*link_libgcc:/{
       N
       s|$| -rpath-link=${SED_SAFE_SPACES_USR_LIB} -L${SED_SAFE_SPACES_USR_LIB}|
     }" > ${SPECS_FILE}
 
-  # For newlib toolchain, modify the specs file to give an error when attempting
-  # to create a shared object.
-  if [ "${NACL_LIBC}" = "newlib" ]; then
+  # For static-only toolchains (i.e. newlib), modify the specs file to give an
+  # error when attempting to create a shared object.
+  if [ "${NACL_SHARED}" != "1" ]; then
     sed -i.bak "s/%{shared:-shared/%{shared:%e${ERROR_MSG}/" "${SPECS_FILE}"
   fi
 }
 
 
 CheckSDKVersion() {
   if [ -z "${MIN_SDK_VERSION:-}" ]; then
     return
   fi
   local GETOS=${NACL_SDK_ROOT}/tools/getos.py
@@ skipping 1268 matching lines @@
 
 
 ######################################################################
 # Always run
 # These functions are called when this script is imported to do
 # any essential checking/setup operations.
 ######################################################################
 CheckToolchain
 CheckPatchVersion
 CheckSDKVersion
-PatchSpecFile
+PatchSpecsFile
 InjectSystemHeaders
 InstallConfigSite
 GetRevision