| # 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/clang/clang.gni") |
| import("//build/config/compiler/compiler.gni") |
| import("//build/config/compiler/pgo/pgo.gni") |
| |
| # Configuration that enables PGO instrumentation. |
| config("pgo_instrumentation_flags") { |
| visibility = [ ":default_pgo_flags" ] |
| cflags = [] |
| ldflags = [] |
| |
| # 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) { |
| if (is_clang) { |
| cflags = [ "-fprofile-instr-generate" ] |
| if (is_win) { |
| # Normally, we pass -fprofile-instr-generate to the compiler and it |
| # automatically passes the right flags to the linker. |
| # However, on Windows, we call the linker directly, without going |
| # through the compiler driver. This means we need to pass the right |
| # flags ourselves. |
| _clang_rt_base_path = |
| "$clang_base_path/lib/clang/$clang_version/lib/windows" |
| if (target_cpu == "x86") { |
| _clang_rt_suffix = "-i386.lib" |
| } else if (target_cpu == "x64") { |
| _clang_rt_suffix = "-x86_64.lib" |
| } |
| assert(_clang_rt_suffix != "", "target CPU $target_cpu not supported") |
| ldflags += [ "$_clang_rt_base_path/clang_rt.profile$_clang_rt_suffix" ] |
| } else { |
| ldflags += [ "-fprofile-instr-generate" ] |
| } |
| } else if (is_win) { |
| ldflags = [ |
| # In MSVC, we must use /LTCG when using PGO. |
| "/LTCG", |
| |
| # Make sure that enough memory gets allocated for the PGO profiling |
| # buffers and also cap this memory. Usually a PGI instrumented build |
| # of chrome_child.dll requires ~55MB of memory for storing its counter |
| # etc, normally the linker should automatically choose an appropriate |
| # amount of memory but it doesn't always do a good estimate and |
| # sometime allocates too little or too much (and so the instrumented |
| # image fails to start). Making sure that the buffer has a size in the |
| # [128 MB, 512 MB] range should prevent this from happening. |
| "/GENPROFILE:MEMMIN=134217728", |
| "/GENPROFILE:MEMMAX=536870912", |
| "/PogoSafeMode", |
| ] |
| } |
| } |
| } |
| |
| # Configuration that enables optimization using profile data. |
| config("pgo_optimization_flags") { |
| visibility = [ ":default_pgo_flags" ] |
| cflags = [] |
| ldflags = [] |
| |
| # Only add flags when chrome_pgo_phase == 2, so that variables we would use |
| # are not required to be defined when we're not actually using PGO. |
| if (chrome_pgo_phase == 2) { |
| if (is_clang) { |
| assert(pgo_data_path != "", |
| "Please set pgo_data_path to point at the profile data") |
| cflags += [ |
| "-fprofile-instr-use=$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-error=profile-instr-out-of-date", |
| ] |
| } else if (is_win) { |
| ldflags += [ |
| # In MSVC, we must use /LTCG when using PGO. |
| "/LTCG", |
| "/USEPROFILE", |
| ] |
| } |
| } |
| } |
| |
| # 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" ] |
| } |
| } |