Reland "[dart2wasm] Include wasm-opt in the shipped dart-sdk."

This is a reland of commit 6271d26

The change broke the gcc riscv64 builders, due to a `unused-variable`
warning coming from binaryen sources. That warning has now been
disabled for binaryen targets.

Original change's description:
> [dart2wasm] Include wasm-opt in the shipped dart-sdk.
>
> Change-Id: Ib224f0b92fa28019ad3cf67d7ba2bef5c31b92ef
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/280840
> Reviewed-by: Martin Kustermann <[email protected]>
> Commit-Queue: Jackson Gardner <[email protected]>
> Reviewed-by: Aske Simon Christensen <[email protected]>

Change-Id: I76bf4ad5d1f6a8116631df4b91cbc5a52cac4f31
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/283240
Reviewed-by: Martin Kustermann <[email protected]>
Commit-Queue: Jackson Gardner <[email protected]>

Author: eyebrowsoffire

build/config/compiler/BUILD.gn

@@ -610,12 +610,12 @@ if (is_win) {
     default_warning_flags += [
       "-Wno-tautological-constant-compare",
       "-Wno-unused-but-set-variable",  # icu
-      "-Wno-unused-but-set-parameter",  # binaryen
       "-Wno-deprecated-non-prototype",  # zlib
     ]
   } else {
-    default_warning_flags +=
-        [ "-Wno-ignored-qualifiers" ]  # Warnings in BoringSSL headers
+    default_warning_flags += [
+      "-Wno-ignored-qualifiers",  # Warnings in BoringSSL headers
+    ]
   }
 
   if (is_mac) {
@@ -729,6 +729,15 @@ config("no_rtti") {
   }
 }
 
+config("enable_exceptions") {
+  if (is_win) {
+    cflags_cc = [ "/EHsc" ]
+    defines = [ "_HAS_EXCEPTIONS=1" ]
+  } else if (is_clang) {
+    cflags_cc = [ "-fexceptions" ]
+  }
+}
+
 # Optimization -----------------------------------------------------------------
 #
 # Note that BUILDCONFIG.gn sets up a variable "default_optimization_config"

build/toolchain/win/tool_wrapper.py

@@ -8,6 +8,7 @@
 """
 
 import os
+import pathlib
 import re
 import shutil
 import subprocess
@@ -149,7 +150,28 @@ def ExecLinkWrapper(self, arch, use_separate_mspdbsrv, *args):
                     not line.startswith('Generating code') and
                     not line.startswith('Finished generating code')):
                 print(line)
-        return link.wait()
+        link_result = link.wait()
+
+        if link_result != 0:
+            return link_result
+
+        # The toolchain configuration in gn always expects a .lib file to be
+        # included in the output of the link step. However, this only happens
+        # when the output has exports, and that is not always the case. In
+        # order to satisfy the expected outputs, we create a dummy .lib file
+        # in cases where the link step didn't actually create one.
+        for arg in args:
+            m = _LINK_EXE_OUT_ARG.match(arg)
+            if m:
+                output_filename = m.group('out')
+                (basename, extension) = os.path.splitext(output_filename)
+                if extension == '.exe':
+                    lib_path = pathlib.Path(basename + ".lib")
+                    if not os.path.exists(lib_path):
+                        lib_path.touch()
+                    break
+
+        return link_result
 
     def ExecMidlWrapper(self, arch, outdir, tlb, h, dlldata, iid, proxy, idl,
                         *flags):

sdk/BUILD.gn

@@ -27,6 +27,7 @@ declare_args() {
   dart_precompiled_runtime_stripped_binary = "dart_precompiled_runtime_product"
   gen_snapshot_stripped_binary = "gen_snapshot_product"
   analyze_snapshot_binary = "analyze_snapshot"
+  wasm_opt_stripped_binary = "wasm-opt"
 }
 
 # The directory layout of the SDK is as follows:
@@ -518,6 +519,16 @@ copy("copy_dart2wasm_snapshot") {
       [ "$root_out_dir/$dart_sdk_output/bin/snapshots/{{source_file_part}}" ]
 }
 
+copy("copy_wasm_opt") {
+  visibility = [ ":create_full_sdk" ]
+  deps = [
+    ":copy_libraries",
+    "../third_party/binaryen:wasm-opt",
+  ]
+  sources = [ "$root_out_dir/${wasm_opt_stripped_binary}${executable_suffix}" ]
+  outputs = [ "$root_out_dir/$dart_sdk_output/bin/utils/{{source_file_part}}" ]
+}
+
 # Copies DDC's SDK full and outline .dill files to lib/_internal.
 copy("copy_dev_compiler_dills") {
   visibility = [ ":copy_dev_compiler_sdk" ]
@@ -755,6 +766,7 @@ group("create_full_sdk") {
     public_deps += [
       ":copy_dart2wasm_platform",
       ":copy_dart2wasm_snapshot",
+      ":copy_wasm_opt",
     ]
   }
 }

third_party/binaryen/BUILD.gn

@@ -4,6 +4,14 @@
 
 import("../../sdk_args.gni")
 
+config("binaryen_warnings") {
+  if (is_clang) {
+    cflags = [ "-Wno-unused-but-set-parameter" ]
+  } else if (!is_win) {
+    cflags = [ "-Wno-unused-variable" ]
+  }
+}
+
 action("generate_needed_files") {
   script = "generate_needed_files.py"
 
@@ -59,6 +67,11 @@ source_set("binaryen_sources") {
 
   # Ensure generated config.h file is include path.
   include_dirs += [ "$target_gen_dir" ]
+
+  configs += [
+    "//build/config/compiler:enable_exceptions",
+    ":binaryen_warnings",
+  ]
 }
 
 template("wasm_tool") {
@@ -72,6 +85,11 @@ template("wasm_tool") {
     include_dirs = [ "src/src" ]
     deps = [ ":binaryen_sources" ]
     forward_variables_from(invoker, "*")
+
+    configs += [
+      "//build/config/compiler:enable_exceptions",
+      ":binaryen_warnings",
+    ]
   }
 }
 

tools/gn.py

@@ -300,6 +300,7 @@ def ToGnArgs(args, mode, arch, target_os, sanitizer, verify_sdk_hash):
         gn_args['gen_snapshot_stripped_binary'] = (
             'exe.stripped/gen_snapshot_product')
         gn_args['analyze_snapshot_binary'] = ('exe.stripped/analyze_snapshot')
+        gn_args['wasm_opt_stripped_binary'] = 'exe.stripped/wasm-opt'
 
     # Setup the user-defined sysroot.
     if UseSysroot(args, gn_args):