1 files changed, 100 insertions, 0 deletions
diff --git a/third_party/libwebrtc/build/config/compiler/pgo/BUILD.gn b/third_party/libwebrtc/build/config/compiler/pgo/BUILD.gn
new file mode 100644
index 0000000000..3e8502ed77
--- /dev/null
+++ b/third_party/libwebrtc/build/config/compiler/pgo/BUILD.gn
@@ -0,0 +1,100 @@
+# Copyright 2016 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/config/chromeos/ui_mode.gni")
+import("//build/config/clang/clang.gni")
+import("//build/config/compiler/compiler.gni")
+import("//build/config/compiler/pgo/pgo.gni")
+import("//build/toolchain/toolchain.gni")
+
+# Configuration that enables PGO instrumentation.
+config("pgo_instrumentation_flags") {
+  visibility = [ ":default_pgo_flags" ]
+
+  # Only add flags when chrome_pgo_phase == 1, so that variables we would use
+  # are not required to be defined when we're not actually using PGO.
+  if (chrome_pgo_phase == 1 && is_clang && !is_nacl && is_a_target_toolchain) {
+    cflags = [ "-fprofile-generate" ]
+    if (!is_win) {
+      # Windows directly calls link.exe instead of the compiler driver when
+      # linking, and embeds the path to the profile runtime library as
+      # dependent library into each object file.
+      ldflags = [ "-fprofile-generate" ]
+    }
+  }
+}
+
+# Configuration that enables optimization using profile data.
+config("pgo_optimization_flags") {
+  visibility = [ ":default_pgo_flags" ]
+
+  # Only add flags when chrome_pgo_phase == 2, so that variables we would use
+  # are not required to be defined when we're not actually using PGO.
+  if (chrome_pgo_phase == 2 && is_clang && !is_nacl && is_a_target_toolchain) {
+    _pgo_target = ""
+
+    # There are txt files used by //tools/update_pgo_profiles.py to decide which
+    # profiles to use, adding them as inputs so that analyzer recognizes the
+    # dependencies.
+    inputs = []
+
+    if (is_win) {
+      if (target_cpu == "x64") {
+        _pgo_target = "win64"
+        inputs = [ "//chrome/build/win64.pgo.txt" ]
+      } else {
+        _pgo_target = "win32"
+        inputs = [ "//chrome/build/win32.pgo.txt" ]
+      }
+    } else if (is_mac) {
+      _pgo_target = "mac"
+      inputs = [ "//chrome/build/mac.pgo.txt" ]
+    } else if (is_linux || is_chromeos_lacros) {
+      _pgo_target = "linux"
+      inputs = [ "//chrome/build/linux.pgo.txt" ]
+    }
+
+    if (pgo_data_path == "" && _pgo_target != "") {
+      pgo_data_path = rebase_path(exec_script("//tools/update_pgo_profiles.py",
+                                              [
+                                                "--target",
+                                                _pgo_target,
+                                                "get_profile_path",
+                                              ],
+                                              "value"),
+                                  root_build_dir)
+    }
+    assert(pgo_data_path != "",
+           "Please set pgo_data_path to point at the profile data")
+    cflags = [
+      "-fprofile-instr-use=$pgo_data_path",
+
+      # It's possible to have some profile data legitimately missing,
+      # and at least some profile data always ends up being considered
+      # out of date, so make sure we don't error for those cases.
+      "-Wno-profile-instr-unprofiled",
+      "-Wno-profile-instr-out-of-date",
+
+      # Some hashing conflict results in a lot of warning like this when doing
+      # a PGO build:
+      #   warning: foo.cc: Function control flow change detected (hash mismatch)
+      #   [-Wbackend-plugin]
+      # See https://crbug.com/978401
+      "-Wno-backend-plugin",
+    ]
+  }
+}
+
+# Applies flags necessary when profile-guided optimization is used.
+# Flags are only added if PGO is enabled, so that this config is safe to
+# include by default.
+config("default_pgo_flags") {
+  if (chrome_pgo_phase == 0) {
+    # Nothing. This config should be a no-op when chrome_pgo_phase == 0.
+  } else if (chrome_pgo_phase == 1) {
+    configs = [ ":pgo_instrumentation_flags" ]
+  } else if (chrome_pgo_phase == 2) {
+    configs = [ ":pgo_optimization_flags" ]
+  }
+}