Add tcmalloc to GN build

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 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/android/config.gni")
 if (current_cpu == "arm") {
   import("//build/config/arm.gni")
 }
 if (current_cpu == "mipsel" || current_cpu == "mips64el") {
   import("//build/config/mips.gni")
@@ skipping 96 matching lines @@
       }
     }
   } else {
     # Common GCC compiler flags setup.
     # --------------------------------
     common_flags = [
       # Not exporting C++ inline functions can generally be applied anywhere
       # so we do so here. Normal function visibility is controlled by
       # //build/config/gcc:symbol_visibility_hidden.
       "-fvisibility-inlines-hidden",
+
+      # We need the frame pointer for CPU and heap profiling.
+      "-fno-omit-frame-pointer",
     ]
     cflags_cc += common_flags
     cflags_objcc += common_flags
 
     # Linker warnings.
     if ((current_cpu != "arm") && !is_mac) {
       # TODO(jochen): Enable this on chromeos on arm. http://crbug.com/356580
       ldflags += [ "-Wl,--fatal-warnings" ]
     }
 
     # Common options for AddressSanitizer, LeakSanitizer, ThreadSanitizer and
     # MemorySanitizer
     if (using_sanitizer) {
       cflags += [
-        "-fno-omit-frame-pointer",
         "-gline-tables-only",
       ]
     }
     if (is_asan) {
       asan_blacklist_path =
           rebase_path("//tools/memory/asan/blacklist.txt", root_build_dir)
       cflags += [
         "-fsanitize=address",
         "-fsanitize-blacklist=$asan_blacklist_path",
       ]
@@ skipping 53 matching lines @@
     defines +=
         [ "CR_CLANG_REVISION=" + exec_script("//tools/clang/scripts/update.py",
                                              [ "--print-revision" ],
                                              "trim string") ]
   }
 
   # Mac-specific compiler flags setup.
   # ----------------------------------
   if (is_mac) {
     # These flags are shared between the C compiler and linker.
-    common_mac_flags = []
+    common_mac_flags = [ "-fno-exceptions" ]
 
     # CPU architecture.
     if (current_cpu == "x64") {
       common_mac_flags += [
         "-arch",
         "x86_64",
       ]
     } else if (current_cpu == "x86") {
       common_mac_flags += [
         "-arch",
@@ skipping 20 matching lines @@
     cflags_c += [ "-std=c99" ]
 
     ldflags += common_mac_flags
   } else if (is_posix) {
     # CPU architecture. We may or may not be doing a cross compile now, so for
     # simplicity we always explicitly set the architecture.
     if (current_cpu == "x64") {
       cflags += [
         "-m64",
         "-march=x86-64",
+        "-msse2",
       ]
       ldflags += [ "-m64" ]
     } else if (current_cpu == "x86") {
-      cflags += [ "-m32" ]
+      cflags += [
+        "-m32",
+        "-msse2",
+        "-mfpmath=sse",
+      ]
       ldflags += [ "-m32" ]
       if (is_clang) {
         cflags += [
           # Else building libyuv gives clang's register allocator issues,
           # see llvm.org/PR15798 / crbug.com/233709
-          "-momit-leaf-frame-pointer",
+          "-mno-omit-leaf-frame-pointer",
 
           # Align the stack on 16-byte boundaries, http://crbug.com/418554.
           "-mstack-alignment=16",
           "-mstackrealign",
         ]
       }
     } else if (current_cpu == "arm") {
 
       cflags += [
         "-march=$arm_arch",
@@ skipping 17 matching lines @@
           # compiler (r5-r7). This can be verified using
           # webkit_unit_tests' WTF.Checked_int8_t test.
           "-fno-tree-sra",
 
           # The following option is disabled to improve binary
           # size and performance in gcc 4.9.
           "-fno-caller-saves",
         ]
       }
     } else if (current_cpu == "mipsel") {
+      # We have to explicitly request exceptions to get good heap profiles from
+      # tcmalloc.
+      if (is_debug || is_release) {
+        cflags += [
+          "-fexceptions",
+          "-funwind-tables"
+        ]
+      }
+
       if (mips_arch_variant == "r6") {
         cflags += [
           "-mips32r6",
           "-Wa,-mips32r6",
         ]
         if (is_android) {
           ldflags += [
             "-mips32r6",
             "-Wl,-melf32ltsmip",
           ]
@@ skipping 29 matching lines @@
         ldflags += [ "-mips64r6" ]
       } else if (mips_arch_variant == "r2") {
         cflags += [
           "-mips64r2",
           "-Wa,-mips64r2",
         ]
         ldflags += [ "-mips64r2" ]
       }
     }
 
-    cflags += [ "-funwind-tables" ]
+    if (current_cpu != "mipsel") {
+      cflags += [ "-fno-exceptions" ]
+    }
   }
 
   # Linux/Android common flags setup.
   # ---------------------------------
   if (is_linux || is_android) {
     cflags += [
       "-fPIC",
     ]
 
     ldflags += [
@@ skipping 537 matching lines @@
   } else if (is_android) {
     # On Android we kind of optimize some things that don't affect debugging
     # much even when optimization is disabled to get the binary size down.
     cflags = [
       "-Os",
       "-fdata-sections",
       "-ffunction-sections",
     ]
     ldflags = common_optimize_on_ldflags
   } else {
-    cflags = [ "-O1" ]
+    cflags = [
+      "-O1",
+      "-fdata-sections",
+      "-ffunction-sections",
+    ]
   }
 }
 
 # Symbols ----------------------------------------------------------------------
 
 config("symbols") {
   if (is_win) {
     import("//build/toolchain/goma.gni")
     if (use_goma) {
       cflags = [ "/Z7" ]  # No PDB file
     } else {
       cflags = [ "/Zi" ]  # Produce PDB file, no edit and continue.
     }
     ldflags = [ "/DEBUG" ]
   } else {
     cflags = [
       "-g3",
       "-ggdb3",
     ]
   }
 }