chromium68: custom toolchain, target v8 snapshot

Modify the chromium68 recipe to make it more like the one available in
meta-browser: https://github.com/OSSystems/meta-browser

Instead of passing Yocto's build flags to the cros (=ChromeOS)
toolchain, generate a toolchain definition file specifically for this
build.

For the generation of the V8 memory snapshot, build the required files
for the target architecture, then use qemu-native to run them.
Upstream chromium addresses this problem by downloading a specific
native toolchain for every target platform, which we cannot do in this
context.

The toolchain changes trigger an issue with ARMv7 builds; backported
one patch to address that specific issue.

This changes also triggered a problem with 32 bit targets, the
generated binaries were too big. Forced the DEBUG_ARGS to use -g1 (or
-g0 otherwise).

Bug-AGL: SPEC-2514

Change-Id: Ib18431b628415c58a3c29595bfff10057e355a4b
Signed-off-by: Jacobo Aragunde Pérez <jaragunde@igalia.com>

2 files changed, 100 insertions, 0 deletions

diff --git a/meta-html5-framework/recipes-wam/chromium/chromium68/0001-skia-Build-skcms-with-mfp16-format-ieee-on-GCC-ARM-b.patch b/meta-html5-framework/recipes-wam/chromium/chromium68/0001-skia-Build-skcms-with-mfp16-format-ieee-on-GCC-ARM-b.patch
new file mode 100644
index 00000000..22f50266
--- /dev/null
+++ b/meta-html5-framework/recipes-wam/chromium/chromium68/0001-skia-Build-skcms-with-mfp16-format-ieee-on-GCC-ARM-b.patch
@@ -0,0 +1,60 @@
+From a01fb357a1ce755834779c905a14c3376e1a6239 Mon Sep 17 00:00:00 2001
+From: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
+Date: Tue, 17 Jul 2018 11:56:52 +0000
+Subject: [PATCH] skia: Build skcms with -mfp16-format=ieee on GCC ARM builds
+
+skcms' Transform_inl.h assumes support for 16-bit floating point in the
+__ARM_FP macro means the __fp16 (and corresponding SIMD data type) is
+present.
+
+While this is currently true for LLVM, which always sets the equivalent of
+GCC's -mfp16-format=ieee internally on ARM builds, GCC explicitly needs that
+option to be specified in order to enable support for __fp16. Doing so
+allows GCC ARM builds to proceed without the following error:
+
+    ../../third_party/skia/third_party/skcms/src/Transform_inl.h: In function 'F_from_Half_':
+    ../../third_party/skia/third_party/skcms/src/Transform_inl.h:101:72: error: 'float16x4_t' undeclared (first use in this function); did you mean 'float32x4_t'?
+         SI ATTR F   NS(F_from_Half_(U16 half)) { return      vcvt_f32_f16((float16x4_t)half); }
+                                                                            ^~~~~~~~~~~
+                                                                            float32x4_t
+    ../../third_party/skia/third_party/skcms/src/Transform_inl.h:101:72: note: each undeclared identifier is reported only once for each function it appears in
+    ../../third_party/skia/third_party/skcms/src/Transform_inl.h:101:84: error: expected ')' before 'half'
+         SI ATTR F   NS(F_from_Half_(U16 half)) { return      vcvt_f32_f16((float16x4_t)half); }
+                                                                                        ^~~~
+                                                                                        )
+    ../../third_party/skia/third_party/skcms/src/Transform_inl.h: In function 'Half_from_F_':
+    ../../third_party/skia/third_party/skcms/src/Transform_inl.h:102:5: error: can't convert a value of type 'int' to vector type '__vector(4) short unsigned int' which has different size
+         SI ATTR U16 NS(Half_from_F_(F      f)) { return (U16)vcvt_f16_f32(                f); }
+         ^~
+
+Bug: 819294
+Change-Id: Ib7417fb9bdc6bd93553084053ba69f9d3409b112
+Reviewed-on: https://chromium-review.googlesource.com/1138251
+Reviewed-by: Florin Malita <fmalita@chromium.org>
+Commit-Queue: Raphael Kubo da Costa (CET) <raphael.kubo.da.costa@intel.com>
+Cr-Commit-Position: refs/heads/master@{#575608}
+---
+ src/skia/BUILD.gn | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/src/skia/BUILD.gn b/src/skia/BUILD.gn
+index 294b9ac16..6efada326 100644
+--- a/src/skia/BUILD.gn
++++ b/src/skia/BUILD.gn
+@@ -242,6 +242,13 @@ source_set("skcms") {
+     ]
+   }
+ 
++  # LLVM automatically sets the equivalent of GCC's -mfp16-format=ieee on ARM
++  # builds by default, while GCC itself does not. We need it to enable support
++  # for half-precision floating point data types used by SKCMS on ARM.
++  if (is_linux && !is_clang && current_cpu == "arm") {
++    cflags += [ "-mfp16-format=ieee" ]
++  }
++
+   public = [
+     "//third_party/skia/third_party/skcms/skcms.h",
+   ]
+-- 
+2.11.0
+
diff --git a/meta-html5-framework/recipes-wam/chromium/chromium68/v8-qemu-wrapper.patch b/meta-html5-framework/recipes-wam/chromium/chromium68/v8-qemu-wrapper.patch
new file mode 100644
index 00000000..485766b0
--- /dev/null
+++ b/meta-html5-framework/recipes-wam/chromium/chromium68/v8-qemu-wrapper.patch
@@ -0,0 +1,40 @@
+Upstream-Status: Inappropriate [embedder specific]
+
+The patch below makes the V8 binaries run during the build be invoked through
+QEMU, as they are built for the target.
+
+Signed-off-by: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
+Signed-off-by: Maksim Sisov <msisov@igalia.com>
+
+Index: git/src/tools/v8_context_snapshot/BUILD.gn
+===================================================================
+--- git.orig/src/tools/v8_context_snapshot/BUILD.gn
++++ git/src/tools/v8_context_snapshot/BUILD.gn
+@@ -62,6 +62,7 @@ if (use_v8_context_snapshot) {
+     output_path = rebase_path(output_file, root_build_dir)
+ 
+     args = [
++      "./v8-qemu-wrapper.sh",
+       "./" + rebase_path(
+               get_label_info(
+                       ":v8_context_snapshot_generator($v8_snapshot_toolchain)",
+Index: git/src/v8/BUILD.gn
+===================================================================
+--- git.orig/src/v8/BUILD.gn
++++ git/src/v8/BUILD.gn
+@@ -900,6 +900,7 @@ action("run_torque") {
+   }
+ 
+   args = [
++    "./v8-qemu-wrapper.sh",
+     "./" + rebase_path(get_label_info(":torque($v8_torque_toolchain)",
+                                       "root_out_dir") + "/torque",
+                        root_build_dir),
+@@ -977,6 +978,7 @@ template("run_mksnapshot") {
+     data = []
+ 
+     args = [
++      "./v8-qemu-wrapper.sh",
+       "./" + rebase_path(get_label_info(":mksnapshot($v8_snapshot_toolchain)",
+                                         "root_out_dir") + "/mksnapshot",
+                          root_build_dir),