Pull new GN, update toolchain definitions

build/toolchain/mac/BUILD.gn

Index: build/toolchain/mac/BUILD.gn
diff --git a/build/toolchain/mac/BUILD.gn b/build/toolchain/mac/BUILD.gn
index c43049cd88ad6dd63a46f46d6b9128fd67959f86..65fb7c661b198b6eeda1b55f1fde59f51be6e202 100644
--- a/build/toolchain/mac/BUILD.gn
+++ b/build/toolchain/mac/BUILD.gn
@@ -52,71 +52,135 @@ template("mac_clang_toolchain") {
     ld = invoker.ld
 
     # Make these apply to all tools below.
-    lib_prefix = "-l"
-    lib_dir_prefix="-L"
+    lib_switch = "-l"
+    lib_dir_switch = "-L"
 
     tool("cc") {
-      command = "$cc -MMD -MF \$out.d \$defines \$includes \$cflags \$cflags_c \$cflags_pch_c -c \$in -o \$out"
-      description = "CC \$out"
-      depfile = "\$out.d"
+      depfile = "{{output}}.d"
+      command = "$cc -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
+      description = "CC {{output}}"
+      outputs = [
+        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
+      ]
     }
+
     tool("cxx") {
-      command = "$cxx -MMD -MF \$out.d \$defines \$includes \$cflags \$cflags_cc \$cflags_pch_cc -c \$in -o \$out"
-      description = "CXX \$out"
-      depfile = "\$out.d"
+      depfile = "{{output}}.d"
+      command = "$cxx -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
+      description = "CXX {{output}}"
+      outputs = [
+        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
+      ]
     }
+
+    tool("asm") {
+      # For GCC we can just use the C compiler to compile assembly.
+      depfile = "{{output}}.d"
+      command = "$cc -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} -c {{source}} -o {{output}}"
+      depsformat = "gcc"
+      description = "ASM {{output}}"
+      outputs = [
+        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
+      ]
+    }
+
     tool("objc") {
-      command = "$cc -MMD -MF \$out.d \$defines \$includes \$cflags \$cflags_c \$cflags_objc \$cflags_pch_objc -c \$in -o \$out"
-      description = "OBJC \$out"
-      depfile = "\$out.d"
+      depfile = "{{output}}.d"
+      command = "$cxx -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} {{cflags_objc}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
+      description = "OBJC {{output}}"
+      outputs = [
+        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
+      ]
     }
+
     tool("objcxx") {
-      command = "$cxx -MMD -MF \$out.d \$defines \$includes \$cflags \$cflags_cc \$cflags_objcc \$cflags_pch_objcc -c \$in -o \$out"
-      description = "OBJCXX \$out"
-      depfile = "\$out.d"
+      depfile = "{{output}}.d"
+      command = "$cxx -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}} {{cflags_objcc}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
+      description = "OBJCXX {{output}}"
+      outputs = [
+        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
+      ]
     }
+
     tool("alink") {
-      command = "rm -f \$out && ./gyp-mac-tool filter-libtool libtool \$libtool_flags -static -o \$out \$in \$postbuilds"
-      description = "LIBTOOL-STATIC \$out"
+      command = "rm -f {{output}} && ./gyp-mac-tool filter-libtool libtool -static -o {{output}} {{inputs}}"
+      description = "LIBTOOL-STATIC {{output}}"
+      outputs = [
+        "{{target_out_dir}}/{{target_output_name}}{{output_extension}}"
+      ]
+      default_output_extension = ".a"
+      output_prefix = "lib"
     }
+
     tool("solink") {
-      command = "if [ ! -e \$lib -o ! -e \${lib}.TOC ] || otool -l \$lib | grep -q LC_REEXPORT_DYLIB ; then $ld -shared \$ldflags -o \$lib -Wl,-filelist,\$rspfile \$solibs \$libs \$postbuilds && { otool -l \$lib | grep LC_ID_DYLIB -A 5; nm -gP \$lib | cut -f1-2 -d' ' | grep -v U\$\$; true; } > \${lib}.TOC; else $ld -shared \$ldflags -o \$lib \$in \$solibs \$libs \$postbuilds && { otool -l \$lib | grep LC_ID_DYLIB -A 5; nm -gP \$lib | cut -f1-2 -d' ' | grep -v U\$\$; true; } > \${lib}.tmp && if ! cmp -s \${lib}.tmp \${lib}.TOC; then mv \${lib}.tmp \${lib}.TOC ; fi; fi"
-      description = "SOLINK \$lib"
-      rspfile = "\$out.rsp"
-      rspfile_content = "\$in_newline"
-      #pool = "link_pool"
-      restat = "1"
+      dylib = "{{target_output_name}}{{output_extension}}"  # eg "libfoo.dylib"
+      rspfile = dylib + ".rsp"
+
+      # These variables are not build into GN but are helpers that implement
+      # (1) linking to produce a .so, (2) extracting the symbols from that file
+      # to a temporary file, (3) if the temporary file has differences from the
+      # existing .TOC file, overwrite it, oterwise, don't change it.
+      #
+      # As a special case, if the library reexports symbols from other dynamic
+      # libraries, we always update the .TOC and skip the temporary file and
+      # diffing steps, since that library always needs to be re-linked.
+      tocname = dylib + ".TOC"
+      temporary_tocname = dylib + ".tmp"
+
+      does_reexport_command = "[ ! -e $dylib -o ! -e $tocname ] || otool -l $dylib | grep -q LC_REEXPORT_DYLIB"
+      link_command = "$ld -shared {{ldflags}} -o $dylib -Wl,-filelist,$rspfile {{solibs}} {{libs}}"
+      replace_command = "if ! cmp -s $temporary_tocname $tocname; then mv $temporary_tocname $tocname"
+      extract_toc_command = "{ otool -l $dylib | grep LC_ID_DYLIB -A 5; nm -gP $dylib | cut -f1-2 -d' ' | grep -v U\$\$; true; }"
+
+      command = "if $does_reexport_command ; then $link_command && $extract_toc_command > $tocname; else $link_command && $extract_toc_command > $temporary_tocname && $replace_command ; fi; fi"
+
+      rspfile_content = "{{inputs_newline}}"
+
+      description = "SOLINK {{output}}"
+
+      # Use this for {{output_extension}} expansions unless a target manually
+      # overrides it (in which case {{output_extension}} will be what the target
+      # specifies).
+      default_output_extension = ".dylib"
+
+      output_prefix = "lib"
+
+      # Since the above commands only updates the .TOC file when it changes, ask
+      # Ninja to check if the timestamp actually changed to know if downstream
+      # dependencies should be recompiled.
+      restat = true
+
+      # Tell GN about the output files. It will link to the dylib but use the
+      # tocname for dependency management.
+      outputs = [
+        dylib,
+        tocname,
+      ]
+      link_output = dylib
+      depend_output = tocname
     }
+
     tool("link") {
-      command = "$ld \$ldflags -o \$out -Wl,-filelist,\$rspfile \$solibs \$libs \$postbuilds"
-      description = "LINK \$out"
-      rspfile = "\$out.rsp"
-      rspfile_content = "\$in_newline"
-      #pool = "link_pool"
+      outfile = "{{target_output_name}}{{output_extension}}"
+      rspfile = "$outfile.rsp"
+      command = "$ld {{ldflags}} -o $outfile -Wl,-filelist,$rspfile {{solibs}} {{libs}}"
+      description = "LINK $outfile"
+      rspfile_content = "{{inputs_newline}}"
+      outputs = [ outfile ]
     }
-    #tool("infoplist") {
-    #  command = "$cc -E -P -Wno-trigraphs -x c \$defines \$in -o \$out && plutil -convert xml1 \$out \$out"
-    #  description = "INFOPLIST \$out"
-    #}
-    #tool("mac_tool") {
-    #  command = "\$env ./gyp-mac-tool \$mactool_cmd \$in \$out"
-    #  description = "MACTOOL \$mactool_cmd \$in"
-    #}
-    #tool("package_framework") {
-    #  command = "./gyp-mac-tool package-framework \$out \$version \$postbuilds && touch \$out"
-    #  description = "PACKAGE FRAMEWORK \$out, POSTBUILDS"
-    #}
+
     tool("stamp") {
-      command = "\${postbuilds}touch \$out"
-      description = "STAMP \$out"
+      command = "touch {{output}}"
+      description = "STAMP {{output}}"
     }
+
     tool("copy") {
-      command = "ln -f \$in \$out 2>/dev/null || (rm -rf \$out && cp -af \$in \$out)"
-      description = "COPY \$in \$out"
+      command = "ln -f {{source}} {{output}} 2>/dev/null || (rm -rf {{output}} && cp -af {{source}} {{output}})"
+      description = "COPY {{source}} {{output}}"
     }
 
     toolchain_args() {