From 5f2680086b7622cc877c82aafe3c973134a20ad4 Mon Sep 17 00:00:00 2001
From: Yunlian Jiang <yunlian@google.com>
Date: Thu, 22 Sep 2016 14:31:58 -0700
Subject: gcc: add a python wrapper for gcc.

This add a python wrapper for gcc to make goma do not need to
hand gcc and clang separately.

BUG  31444867
TEST= build new gcc. Call arm-linux-androideabi-c++ -v
      and arm-linux-androideabi-g++ -v in/out the directory of
      the gcc binary, it works.

Change-Id: Ib02cff8f33306b089e13ade51033a3b0927b4308
---
 build-gcc.sh     | 18 ++++++++++++++++
 compiler_wrapper | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 84 insertions(+)
 create mode 100755 compiler_wrapper

diff --git a/build-gcc.sh b/build-gcc.sh
index 4893461cf..c21accf17 100755
--- a/build-gcc.sh
+++ b/build-gcc.sh
@@ -569,8 +569,26 @@ do_relink_bin () {
         $ABI_CONFIGURE_TARGET-$DST_FILE$HOST_EXE
 }
 
+# $1: The file to be replaced by wrapper.
+do_install_gcc_wrapper() {
+  WRAPPER=$SRC_DIR/gcc/compiler_wrapper
+  local DST_FILE=$TOOLCHAIN_INSTALL_PATH/bin/$ABI_CONFIGURE_TARGET-$1
+  local REAL_DST_FILE=$TOOLCHAIN_INSTALL_PATH/bin/real-$ABI_CONFIGURE_TARGET-$1
+  if [ ! -f "$WRAPPER" ]; then
+      echo "ERROR: Can't install wrapper because $WRAPPER doesn't exist"
+      exit 1
+  fi
+  if [ ! -f "$DST_FILE$HOST_EXE" ]; then
+      echo "ERROR: Can't install wrapper because $DST_FILE$HOST_EXE doesn't exist"
+  fi
+  mv $DST_FILE$HOST_EXE $REAL_DST_FILE
+  cp -p $WRAPPER $DST_FILE$HOST_EXE
+}
+
 do_relink_bin c++ g++
 do_relink_bin gcc-$GCC_VERSION gcc
+do_install_gcc_wrapper gcc
+do_install_gcc_wrapper g++
 # symlink ld to either ld.gold or ld.bfd
 case "$TOOLCHAIN" in
     aarch64*)
diff --git a/compiler_wrapper b/compiler_wrapper
new file mode 100755
index 000000000..15d50f473
--- /dev/null
+++ b/compiler_wrapper
@@ -0,0 +1,66 @@
+#!/usr/bin/python
+
+import os
+import sys
+
+class CompilerWrapper():
+  def __init__(self, argv):
+    self.args = argv
+    self.execargs = []
+    self.real_compiler = None
+    self.argv0 = None
+    self.append_flags = []
+    self.prepend_flags = []
+    self.custom_flags = {
+      '--gomacc-path': None
+    }
+
+  def set_real_compiler(self):
+    """Find the real compiler with the absolute path."""
+    compiler_path = os.path.dirname(os.path.abspath(__file__))
+    if os.path.islink(__file__):
+      compiler = os.path.basename(os.readlink(__file__))
+    else:
+      compiler = os.path.basename(os.path.abspath(__file__))
+    self.real_compiler = os.path.join(
+        compiler_path,
+        "real-" + compiler)
+    self.argv0 = self.real_compiler
+
+  def process_gomacc_command(self):
+    """Return the gomacc command if '--gomacc-path' is set."""
+    gomacc = self.custom_flag['--gomacc-path']
+    if gomacc and os.path.isfile(gomacc):
+      self.argv0 = gomacc
+      self.execargs += [gomacc]
+
+  def parse_custom_flags(self):
+    i = 0
+    args = []
+    while i < len(self.args):
+      if self.args[i] in self.custom_flag:
+        self.custom_flags[self.args[i]] = self.args[i + 1]
+        i = i + 2
+      else:
+        args.append(self.args[i])
+        i = i + 1
+    self.args = args
+
+  def add_flags(self):
+    self.args = self.prepend_flags + self.args + self.append_flags
+
+  def invoke_compiler(self):
+    self.set_real_compiler()
+    self.parse_custom_flags()
+    self.process_gomacc_command()
+    self.add_flags()
+    self.execargs += [self.real_compiler] + self.args
+    os.execv(self.argv0, self.execargs)
+
+
+def main(argv):
+  cw = CompilerWrapper(argv[1:])
+  cw.invoke_compiler()
+
+if __name__ == "__main__":
+  main(sys.argv)
-- 
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