Do not use wrapper for link in win cross build

This is follow up of
https://chromium.googlesource.com/chromium/src/+/f7d47b7e8c03400343d4b6753ff79ade9d09ca68

This CL specifies libpath explicitly for LIB directories.

Bug: 854849, 787903
Change-Id: I9b65b0c0980af1f7eb4ece2ffbb31d8bde44e7ce
Reviewed-on: https://chromium-review.googlesource.com/1109452
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569486}

build/toolchain/win/BUILD.gn

@@ -133,16 +133,23 @@ template("msvc_toolchain") {
       sys_include_flags = ""
     }
 
-    if (use_lld) {
+    # ninja does not have -t msvc other than windows, and lld doesn't depend on
+    # mt.exe in PATH on non-Windows, so it's not needed there anyways.
+    if (defined(invoker.sys_lib_flags)) {
+      linker_wrapper = ""
+      sys_lib_flags = "${invoker.sys_lib_flags} "  # Note trailing space
+    } else if (use_lld) {
       # Invoke ninja as wrapper instead of tool wrapper, because python
       # invocation requires higher cpu usage compared to ninja invocation, and
       # the python wrapper is only needed to work around link.exe problems.
       # TODO(thakis): Remove wrapper once lld-link can merge manifests without
       # relying on mt.exe being in %PATH% on Windows.
       linker_wrapper = "ninja -t msvc -e $env -- "  # Note trailing space.
+      sys_lib_flags = ""
     } else {
       linker_wrapper =
           "$python_path $tool_wrapper_path link-wrapper $env False "  # Note trailing space.
+      sys_lib_flags = ""
     }
 
     clflags = ""
@@ -208,8 +215,7 @@ template("msvc_toolchain") {
 
     tool("alink") {
       rspfile = "{{output}}.rsp"
-      command =
-          "$linker_wrapper$lib /nologo {{arflags}} /OUT:{{output}} @$rspfile"
+      command = "$linker_wrapper$lib /nologo ${sys_lib_flags}{{arflags}} /OUT:{{output}} @$rspfile"
       description = "LIB {{output}}"
       outputs = [
         # Ignore {{output_extension}} and always use .lib, there's no reason to
@@ -231,7 +237,7 @@ template("msvc_toolchain") {
       rspfile = "${dllname}.rsp"
       pool = "//build/toolchain:link_pool($default_toolchain)"
 
-      command = "$linker_wrapper$link /nologo /IMPLIB:$libname /DLL /OUT:$dllname /PDB:$pdbname @$rspfile"
+      command = "$linker_wrapper$link /nologo ${sys_lib_flags}/IMPLIB:$libname /DLL /OUT:$dllname /PDB:$pdbname @$rspfile"
 
       default_output_extension = ".dll"
       default_output_dir = "{{root_out_dir}}"
@@ -264,7 +270,7 @@ template("msvc_toolchain") {
       rspfile = "${dllname}.rsp"
       pool = "//build/toolchain:link_pool($default_toolchain)"
 
-      command = "$linker_wrapper$link /nologo /DLL /OUT:$dllname /PDB:$pdbname @$rspfile"
+      command = "$linker_wrapper$link /nologo ${sys_lib_flags}/DLL /OUT:$dllname /PDB:$pdbname @$rspfile"
 
       default_output_extension = ".dll"
       default_output_dir = "{{root_out_dir}}"
@@ -288,8 +294,7 @@ template("msvc_toolchain") {
       rspfile = "$exename.rsp"
       pool = "//build/toolchain:link_pool($default_toolchain)"
 
-      command =
-          "$linker_wrapper$link /nologo /OUT:$exename /PDB:$pdbname @$rspfile"
+      command = "$linker_wrapper$link /nologo ${sys_lib_flags}/OUT:$exename /PDB:$pdbname @$rspfile"
 
       if (host_os == "win") {
         shellprefix = "cmd /c"
@@ -373,6 +378,10 @@ if (win_build_host_cpu != "x64") {
   msvc_toolchain(win_build_host_cpu) {
     environment = "environment." + win_build_host_cpu
     cl = "${goma_prefix}\"${build_cpu_toolchain_data.vc_bin_dir}/cl.exe\""
+    if (host_os != "win") {
+      # For win cross build.
+      sys_lib_flags = "${build_cpu_toolchain_data.libpath_flags}"
+    }
     toolchain_args = {
       current_os = "win"
       current_cpu = win_build_host_cpu
@@ -385,6 +394,10 @@ if (win_build_host_cpu != "x64") {
     prefix = rebase_path("$clang_base_path/bin", root_build_dir)
     cl = "${goma_prefix}$prefix/${clang_cl}"
     sys_include_flags = "${build_cpu_toolchain_data.include_flags_imsvc}"
+    if (host_os != "win") {
+      # For win cross build.
+      sys_lib_flags = "${build_cpu_toolchain_data.libpath_flags}"
+    }
 
     toolchain_args = {
       current_os = "win"
@@ -410,6 +423,10 @@ template("win_x64_toolchains") {
   msvc_toolchain(target_name) {
     environment = "environment.x64"
     cl = "${goma_prefix}\"${x64_toolchain_data.vc_bin_dir}/cl.exe\""
+    if (host_os != "win") {
+      # For win cross build
+      sys_lib_flags = "${x64_toolchain_data.libpath_flags}"
+    }
 
     toolchain_args = {
       if (defined(invoker.toolchain_args)) {
@@ -426,6 +443,10 @@ template("win_x64_toolchains") {
     prefix = rebase_path("$clang_base_path/bin", root_build_dir)
     cl = "${goma_prefix}$prefix/${clang_cl}"
     sys_include_flags = "${x64_toolchain_data.include_flags_imsvc}"
+    if (host_os != "win") {
+      # For win cross build
+      sys_lib_flags = "${x64_toolchain_data.libpath_flags}"
+    }
 
     toolchain_args = {
       if (defined(invoker.toolchain_args)) {

build/toolchain/win/setup_toolchain.py

@@ -207,6 +207,7 @@ def main():
   vc_lib_atlmfc_path = ''
   vc_lib_um_path = ''
   include = ''
+  lib = ''
 
   # TODO(scottmg|goma): Do we need an equivalent of
   # ninja_use_custom_environment_files?
@@ -247,10 +248,18 @@ def main():
       except ValueError:
         pass
 
+      lib = [p.replace('"', r'\"') for p in env['LIB'].split(';') if p]
+      # Make lib path relative to builddir when cwd and sdk in same drive.
+      try:
+        lib = map(os.path.relpath, lib)
+      except ValueError:
+        pass
+
       def q(s):  # Quote s if it contains spaces or other weird characters.
         return s if re.match(r'^[a-zA-Z0-9._/\\:-]*$', s) else '"' + s + '"'
       include_I = ' '.join([q('/I' + i) for i in include])
       include_imsvc = ' '.join([q('-imsvc' + i) for i in include])
+      libpath_flags = ' '.join([q('-libpath:' + i) for i in lib])
 
       if (environment_block_name != ''):
         env_block = _FormatAsEnvironmentBlock(env)
@@ -275,6 +284,9 @@ def main():
   assert vc_lib_um_path
   print 'vc_lib_um_path = ' + gn_helpers.ToGNString(vc_lib_um_path)
   print 'paths = ' + gn_helpers.ToGNString(env['PATH'])
+  assert libpath_flags
+  print 'libpath_flags = ' + gn_helpers.ToGNString(libpath_flags)
+
 
 if __name__ == '__main__':
   main()