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# 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" ]
}
}
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