SuperSize: Enable LTO for caspian

Didn't meaningfully change runtime nor file size, but seems like a flag
we should be using.

Bug: None
Change-Id: I7e42cb4bac8036d97f6db61c4906c1ff6ae88e80
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2040910
Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Samuel Huang <huangs@chromium.org>
Commit-Queue: Samuel Huang <huangs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741539}

tools/binary_size/libsupersize/caspian/wasmbuild.patch

@@ -15,19 +15,40 @@ index f89e7e831b79..ebfb4ba88b35 100644
  # =============================================================================
  # SOURCES FILTERS
 diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
-index 0f91977e1352..acd5ab11f111 100644
+index 912906e15e76..e00bf81e6b20 100644
 --- a/build/config/compiler/BUILD.gn
 +++ b/build/config/compiler/BUILD.gn
-@@ -1508,7 +1508,7 @@ config("default_warnings") {
+@@ -564,6 +564,19 @@ config("compiler") {
+     ldflags += [ "-stdlib=libc++" ]
+   }
+ 
++  if (is_wasm && is_official_build) {
++    cflags_c += [
++      "-s",
++      "WASM_OBJECT_FILES=0",
++    ]
++    ldflags += [
++      "-s",
++      "WASM_OBJECT_FILES=0",
++      "--llvm-lto",
++      "1",
++    ]
++  }
++
+   # Add flags for link-time optimization. These flags enable
+   # optimizations/transformations that require whole-program visibility at link
+   # time, so they need to be applied to all translation units, and we may end up
+@@ -1507,7 +1520,8 @@ config("default_warnings") {
          cflags += [ "-Wno-nonportable-include-path" ]
        }
  
 -      if (current_toolchain == host_toolchain || !use_xcode_clang) {
-+      if ((current_toolchain == host_toolchain || !use_xcode_clang) && !is_wasm) {
++      if ((current_toolchain == host_toolchain || !use_xcode_clang) &&
++          !is_wasm) {
          # Flags NaCl (Clang 3.7) and Xcode 9.2 (Clang clang-900.0.39.2) do not
          # recognize.
          cflags += [
-@@ -2296,6 +2296,9 @@ config("symbols") {
+@@ -2303,6 +2317,9 @@ config("symbols") {
          cflags += [ "-fno-standalone-debug" ]
        }
      }
@@ -38,7 +59,7 @@ index 0f91977e1352..acd5ab11f111 100644
      cflags = []
      if (is_mac && enable_dsyms) {
 diff --git a/build/toolchain/toolchain.gni b/build/toolchain/toolchain.gni
-index 3edc9762907d..ab483e44a11c 100644
+index 2b6f05231c63..134e9ee77107 100644
 --- a/build/toolchain/toolchain.gni
 +++ b/build/toolchain/toolchain.gni
 @@ -58,6 +58,9 @@ if (is_mac || is_ios) {
@@ -51,40 +72,98 @@ index 3edc9762907d..ab483e44a11c 100644
  } else {
    assert(false, "Platform not supported")
  }
-diff --git a/build/toolchain/wasm/BUILD.gn b/build/toolchain/wasm/BUILD.gn
-new file mode 100644
-index 000000000000..15bc7a4ea258
---- /dev/null
-+++ b/build/toolchain/wasm/BUILD.gn
-@@ -0,0 +1,31 @@
-+# Copyright 2019 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.
-+
-+import("//build/toolchain/gcc_toolchain.gni")
-+
-+gcc_toolchain("wasm") {
-+  cc = "emcc"
-+  cxx = "em++"
-+  nm = "emcc"
-+  ar = "emar"
-+  ld = cxx
-+
-+  toolchain_args = {
-+    current_cpu = "wasm"
-+    current_os = "wasm"
-+
-+    is_clang = true
-+    use_goma = false
-+    use_debug_fission = false
-+    clang_use_chrome_plugins = false
-+    use_allocator_shim = false
-+    is_component_build = false
-+  }
-+  extra_ldflags = "-s BINARYEN_METHOD='native-wasm'"
-+  executable_extension = ".js"
-+  link_outputs = [
-+    "{{output_dir}}/{{target_output_name}}.wasm",
-+    "{{output_dir}}/{{target_output_name}}.wasm.map",
-+  ]
-+}
+diff --git a/tools/binary_size/libsupersize/caspian/wasmbuild.patch b/tools/binary_size/libsupersize/caspian/wasmbuild.patch
+index 065bb27f795a..e69de29bb2d1 100644
+--- a/tools/binary_size/libsupersize/caspian/wasmbuild.patch
++++ b/tools/binary_size/libsupersize/caspian/wasmbuild.patch
+@@ -1,90 +0,0 @@
+-diff --git a/build/config/BUILDCONFIG.gn b/build/config/BUILDCONFIG.gn
+-index f89e7e831b79..ebfb4ba88b35 100644
+---- a/build/config/BUILDCONFIG.gn
+-+++ b/build/config/BUILDCONFIG.gn
+-@@ -291,9 +291,10 @@ is_ios = current_os == "ios"
+- is_linux = current_os == "chromeos" || current_os == "linux"
+- is_mac = current_os == "mac"
+- is_nacl = current_os == "nacl"
+-+is_wasm = current_os == "wasm"
+- is_win = current_os == "win" || current_os == "winuwp"
+- 
+--is_posix = !is_win && !is_fuchsia
+-+is_posix = !is_win && !is_fuchsia && !is_wasm
+- 
+- # =============================================================================
+- # SOURCES FILTERS
+-diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
+-index 0f91977e1352..acd5ab11f111 100644
+---- a/build/config/compiler/BUILD.gn
+-+++ b/build/config/compiler/BUILD.gn
+-@@ -1508,7 +1508,7 @@ config("default_warnings") {
+-         cflags += [ "-Wno-nonportable-include-path" ]
+-       }
+- 
+--      if (current_toolchain == host_toolchain || !use_xcode_clang) {
+-+      if ((current_toolchain == host_toolchain || !use_xcode_clang) && !is_wasm) {
+-         # Flags NaCl (Clang 3.7) and Xcode 9.2 (Clang clang-900.0.39.2) do not
+-         # recognize.
+-         cflags += [
+-@@ -2296,6 +2296,9 @@ config("symbols") {
+-         cflags += [ "-fno-standalone-debug" ]
+-       }
+-     }
+-+  } else if (is_wasm) {
+-+    cflags = [ "-g4" ]
+-+    ldflags = [ "-g4" ]
+-   } else {
+-     cflags = []
+-     if (is_mac && enable_dsyms) {
+-diff --git a/build/toolchain/toolchain.gni b/build/toolchain/toolchain.gni
+-index 3edc9762907d..ab483e44a11c 100644
+---- a/build/toolchain/toolchain.gni
+-+++ b/build/toolchain/toolchain.gni
+-@@ -58,6 +58,9 @@ if (is_mac || is_ios) {
+-   shlib_extension = ".so"
+- } else if (is_win) {
+-   shlib_extension = ".dll"
+-+} else if (is_wasm) {
+-+  # WebAssembly does not stably support shared libraries. (as of Oct 2019)
+-+  shlib_extension = ".wasm"
+- } else {
+-   assert(false, "Platform not supported")
+- }
+-diff --git a/build/toolchain/wasm/BUILD.gn b/build/toolchain/wasm/BUILD.gn
+-new file mode 100644
+-index 000000000000..15bc7a4ea258
+---- /dev/null
+-+++ b/build/toolchain/wasm/BUILD.gn
+-@@ -0,0 +1,31 @@
+-+# Copyright 2019 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.
+-+
+-+import("//build/toolchain/gcc_toolchain.gni")
+-+
+-+gcc_toolchain("wasm") {
+-+  cc = "emcc"
+-+  cxx = "em++"
+-+  nm = "emcc"
+-+  ar = "emar"
+-+  ld = cxx
+-+
+-+  toolchain_args = {
+-+    current_cpu = "wasm"
+-+    current_os = "wasm"
+-+
+-+    is_clang = true
+-+    use_goma = false
+-+    use_debug_fission = false
+-+    clang_use_chrome_plugins = false
+-+    use_allocator_shim = false
+-+    is_component_build = false
+-+  }
+-+  extra_ldflags = "-s BINARYEN_METHOD='native-wasm'"
+-+  executable_extension = ".js"
+-+  link_outputs = [
+-+    "{{output_dir}}/{{target_output_name}}.wasm",
+-+    "{{output_dir}}/{{target_output_name}}.wasm.map",
+-+  ]
+-+}