Add loop optimizations & instr_import_limit=100

build/config/compiler/BUILD.gn

@@ -579,30 +579,43 @@ config("compiler") {
     }
 
     cflags_c += [ "-std=${standard_prefix}11" ]
-    cflags_cc += [ "-std=${standard_prefix}++14" ]
-  } else if (!is_win && !is_nacl) {
+
+    # TODO(https://crbug.com/1273966): Use C++17 with is_cfi once
+    # https://chromium-review.googlesource.com/c/v8/v8/+/3304143/ is rolled in.
+    if ((is_nacl && !is_nacl_saigo) || is_cfi) {
+      # This is for the pnacl_newlib toolchain. It's only used to build
+      # a few independent ppapi test files that don't pull in any other
+      # dependencies.
+      cflags_cc += [
+        "-std=${standard_prefix}++14",
+        "-fno-trigraphs",
+      ]
+    } else {
+      cflags_cc += [ "-std=${standard_prefix}++17" ]
+    }
+  } else if (is_win) {
+    cflags_cc += [ "/std:c++17" ]
+  } else if (!is_nacl) {
     # TODO(mcgrathr) - the NaCl GCC toolchain doesn't support either gnu11/gnu++11
     # or c11/c++11; we technically don't need this toolchain any more, but there
     # are still a few buildbots using it, so until those are turned off
     # we need the !is_nacl clause and the (is_nacl && is_clang) clause, above.
     cflags_c += [ "-std=c11" ]
-    cflags_cc += [ "-std=c++14" ]
+
+    if (is_apple) {
+      # TODO(thakis): Use C++17 on macOS and iOS once it works.
+      cflags_cc += [
+        "-std=c++14",
+        "-fno-trigraphs",
+      ]
+    } else {
+      cflags_cc += [ "-std=c++17" ]
+    }
   }
 
-  # C++17 removes trigraph support, so preemptively disable trigraphs. This is
-  # especially useful given the collision with ecmascript's logical assignment
-  # operators: https://github.com/tc39/proposal-logical-assignment
   if (is_clang && current_os != "zos") {
-    # clang-cl disables trigraphs by default
-    if (!is_win) {
-      # The gnu variants of C++11 and C++14 already disable trigraph support,
-      # but when building with clang, we use -std=c++11 / -std=c++14, which
-      # enables trigraph support: override that here.
-      cflags_cc += [ "-fno-trigraphs" ]
-    }
-
-    # Don't warn that trigraphs are ignored, since trigraphs are disabled
-    # anyway.
+    # C++17 removes trigraph support, but clang still warns that it ignores
+    # them when seeing them.  Don't.
     cflags_cc += [ "-Wno-trigraphs" ]
   }
 
@@ -675,9 +688,9 @@ config("compiler") {
         # bloat of ThinLTO to <10%, but that's potentially no longer true.
         # FIXME(inglorion): maybe tune these?
         if (target_cpu == "arm" || target_cpu == "arm64") {
-          import_instr_limit = 30
+          import_instr_limit = 100
         } else {
-          import_instr_limit = 30
+          import_instr_limit = 100
         }
       }
 
@@ -890,6 +903,10 @@ config("compiler_cpu_abi") {
         cflags += [ "--target=aarch64-linux-gnu" ]
         ldflags += [ "--target=aarch64-linux-gnu" ]
       }
+      if (is_android) {
+        # Outline atomics crash on Exynos 9810. http://crbug.com/1272795
+        cflags += [ "-mno-outline-atomics" ]
+      }
     } else if (current_cpu == "mipsel" && !is_nacl) {
       ldflags += [ "-Wl,--hash-style=sysv" ]
       if (custom_toolchain == "") {
@@ -1265,7 +1282,7 @@ config("compiler_deterministic") {
   # Tells the compiler not to use absolute paths when passing the default
   # paths to the tools it invokes. We don't want this because we don't
   # really need it and it can mess up the goma cache entries.
-  if (is_clang && !is_nacl) {
+  if (is_clang && (!is_nacl || is_nacl_saigo)) {
     cflags += [ "-no-canonical-prefixes" ]
 
     # Same for links: Let the compiler driver invoke the linker
@@ -1599,12 +1616,12 @@ config("chromium_code") {
 
     # TODO(thakis): Enable this more often, https://crbug.com/346399
     # use_libfuzzer: https://crbug.com/1063180
-    if (!is_nacl && !use_libfuzzer) {
+    if ((!is_nacl || is_nacl_saigo) && !use_libfuzzer) {
       cflags += [ "-Wunreachable-code-aggressive" ]
     }
 
     # Thread safety analysis is broken under nacl: https://crbug.com/982423.
-    if (!is_nacl) {
+    if (!is_nacl || is_nacl_saigo) {
       cflags += [
         # Thread safety analysis. See base/thread_annotations.h and
         # https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
@@ -1689,7 +1706,7 @@ config("no_chromium_code") {
 config("noshadowing") {
   # This flag has to be disabled for nacl because the nacl compiler is too
   # strict about shadowing.
-  if (is_clang && !is_nacl) {
+  if (is_clang && (!is_nacl || is_nacl_saigo)) {
     cflags = [ "-Wshadow" ]
   }
 }
@@ -1927,7 +1944,7 @@ if (is_win) {
       "-fdata-sections",
       "-ffunction-sections",
     ]
-    if (!is_nacl && is_clang) {
+    if ((!is_nacl || is_nacl_saigo) && is_clang) {
       # We don't care about unique section names, this makes object files a bit
       # smaller.
       common_optimize_on_cflags += [ "-fno-unique-section-names" ]
@@ -1983,8 +2000,6 @@ config("optimize") {
     }
   } else if (optimize_for_size) {
     # Favor size over speed.
-    # TODO(crbug.com/718650): Fix -Os in PNaCl compiler and remove the is_nacl
-    # guard above.
     if (is_clang) {
       cflags = [ "-O3" ] + common_optimize_on_cflags
     } else {
@@ -2330,7 +2345,7 @@ config("symbols") {
     }
   }
 
-  if (is_clang && !is_nacl && current_os != "zos") {
+  if (is_clang && (!is_nacl || is_nacl_saigo) && current_os != "zos") {
     if (is_apple) {
       # TODO(https://crbug.com/1050118): Investigate missing debug info on mac.
       # Make sure we don't use constructor homing on mac.
@@ -2424,7 +2439,7 @@ config("minimal_symbols") {
 # names in the final debug information.
 config("no_symbols") {
   if (is_win) {
-    ldflags = [ "/DEBUG:NONE" ]
+    ldflags = [ "/DEBUG" ]
 
     # All configs using /DEBUG should include this:
     configs = [ ":win_pdbaltpath" ]