Fix solink and add a postsolink hook (use the hook for android strip)

build/toolchain/gcc_toolchain.gni

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This template defines a toolchain for something that works like gcc
 # (including clang).
 #
 # It requires the following variables specifying the executables to run:
 #  - cc
 #  - cxx
 #  - ar
 #  - ld
 # and the following which is used in the toolchain_args
 #  - toolchain_cpu_arch  (What "cpu_arch" should be set to when invoking a
 #                         build using this toolchain.)
 #  - toolchain_os  (What "os" should be set to when invoking a build using this
 #                   toolchain.)
 #
 # Optional parameters:
 #  - libs_section_prefix
 #  - libs_section_postfix
 #      The contents of these strings, if specified, will be placed around
 #      the libs section of the linker line. It allows one to inject libraries
 #      at the beginning and end for all targets in a toolchain.
 #  - solink_libs_section_prefix
 #  - solink_libs_section_postfix
 #      Same as libs_section_{pre,post}fix except used for solink instead of link.
+#  - post_solink
+#      The content of this string, if specified, will be appended to the solink
+#      command.
 #  - deps
-#      Just fowarded to the toolchain definition.
+#      Just forwarded to the toolchain definition.
 #  - is_clang
 template("gcc_toolchain") {
   toolchain(target_name) {
     assert(defined(invoker.cc), "gcc_toolchain() must specify a \"cc\" value")
     assert(defined(invoker.cxx), "gcc_toolchain() must specify a \"cxx\" value")
     assert(defined(invoker.ar), "gcc_toolchain() must specify a \"ar\" value")
     assert(defined(invoker.ld), "gcc_toolchain() must specify a \"ld\" value")
     assert(defined(invoker.toolchain_cpu_arch),
            "gcc_toolchain() must specify a \"toolchain_cpu_arch\"")
     assert(defined(invoker.toolchain_os),
@@ skipping 50 matching lines @@
       depfile = "\$out.d"
       depsformat = "gcc"
     }
     tool("alink") {
       command = "rm -f \$out && $ar rcs \$out @\$rspfile"
       description = "AR \$out"
       rspfile = "\$out.rsp"
       rspfile_content = "\$in"
     }
     tool("solink") {
-      command = "if [ ! -e \$lib -o ! -e \${lib}.TOC ]; then $ld -shared \$ldflags -o \$lib -Wl,-soname=\$soname @\$rspfile && { readelf -d \${lib} | grep SONAME ; nm -gD -f p \${lib} | cut -f1-2 -d' '; } > \${lib}.TOC; else $ld -shared \$ldflags -o \$lib -Wl,-soname=\$soname -Wl,--whole-archive \$in \$solibs -Wl,--no-whole-archive $solink_libs_section_prefix \$libs $solink_libs_section_postfix && { readelf -d \${lib} | grep SONAME ; nm -gD -f p \${lib} | cut -f1-2 -d' '; } > \${lib}.tmp && if ! cmp -s \${lib}.tmp \${lib}.TOC; then mv \${lib}.tmp \${lib}.TOC ; fi; fi"
+      rspfile = "\$out.rsp"
+      rspfile_content = "-Wl,--whole-archive \$in \$solibs -Wl,--no-whole-archive $solink_libs_section_prefix \$libs $solink_libs_section_postfix"
+
+      # TODO(cjhopman): There needs to be a way for gn to correctly figure out
+      # the outputs of a solink command.
+
+      link_command = "$ld -shared \$ldflags -o \$lib -Wl,-soname=\$soname $rspfile_content"
+      toc_command = "{ readelf -d \${lib} | grep SONAME ; nm -gD -f p \${lib} | cut -f1-2 -d' '; } > \${lib}.tmp"
+      replace_command = "if ! cmp -s \${lib}.tmp \${lib}.TOC; then mv \${lib}.tmp \${lib}.TOC; fi"
+      command = "$link_command && $toc_command && $replace_command"
+
+      if (defined(invoker.postsolink)) {
+        command += " && " + invoker.postsolink
+      }
+
       description = "SOLINK \$lib"
-      rspfile = "\$out.rsp"
-      rspfile_content = "-Wl,--whole-archive \$in \$solibs -Wl,--no-whole-archive \$libs"
       #pool = "link_pool"
       restat = "1"
     }
     tool("link") {
       command = "$ld \$ldflags -o \$out -Wl,--start-group @\$rspfile \$solibs -Wl,--end-group $libs_section_prefix \$libs $libs_section_postfix"
       description = "LINK \$out"
       rspfile = "\$out.rsp"
       rspfile_content = "\$in"
       #pool = "link_pool"
     }
@@ skipping 14 matching lines @@
       if (defined(invoker.is_clang)) {
         is_clang = invoker.is_clang
       }
     }
 
     if (defined(invoker.deps)) {
       deps = invoker.deps
     }
   }
 }