[interpeter] Move to table based peephole optimizer.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index a11b1467e286fdc799183bca0d3c358bc29fcb31..260c6a37220365330cc5063d89ad5519e096c87b 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -632,6 +632,29 @@ action("run_mksnapshot") {
   }
 }
 
+action("run_mkpeephole") {
+  visibility = [ ":*" ]  # Only targets in this file can depend on this.
+
+  deps = [
+    ":mkpeephole($v8_snapshot_toolchain)",
+  ]
+
+  outputs = [
+    "$target_gen_dir/bytecode-peephole-table.h"
+  ]
+
+  sources = []
+
+  script = "tools/run.py"
+
+  args = [
+    "./" + rebase_path(get_label_info(":mkpeephole($v8_snapshot_toolchain)",
+                                      "root_out_dir") + "/mkpeephole",
+                                      root_build_dir),
+   rebase_path("$target_gen_dir/bytecode-peephole-table.h", root_build_dir),
+  ]
+}
+
 action("v8_dump_build_config") {
   script = "tools/testrunner/utils/dump_build_config.py"
   outputs = [
@@ -1286,6 +1309,7 @@ v8_source_set("v8_base") {
     "src/interpreter/bytecode-label.h",
     "src/interpreter/bytecode-peephole-optimizer.cc",
     "src/interpreter/bytecode-peephole-optimizer.h",
+    "$target_gen_dir/bytecode-peephole-table.h",

[rmcilroy, 2016/07/08 13:18:25]

I think this should be a separate target which needs to be built before trying
to build the rest of v8_base (otherwise bytecode-peephole-optimizer.cc could be
built before you build or rebuild bytecode-peephole-table.h, thus meaning it
would be built with the wrong table (or the build would break due to a missing
header). 

Thinking about it, could you make this a cc file and just rely on linking to the
table with a known name? That would mean you could make only the v8_*_snapshot
targets depend on this new target (in the same way as they depend on js2c).

[oth, 2016/07/08 15:12:33]

I'm not a GN expert, but it definitely detects if there is not action that
outputs this header and refuses to build. It knows that is a dependency and
builds it. I believe it's down to the specific value of the prefix held in
$target_gen_dir.
What happens in this path is rather convoluted. Okay, let's try it.

     "src/interpreter/bytecode-pipeline.cc",
     "src/interpreter/bytecode-pipeline.h",
     "src/interpreter/bytecode-register-allocator.cc",
@@ -1871,6 +1895,7 @@ v8_source_set("v8_base") {
   deps = [
     ":v8_libbase",
     ":v8_libsampler",
+    "//:run_mkpeephole"
   ]
 
   if (is_win) {
@@ -2094,6 +2119,24 @@ if (current_toolchain == v8_snapshot_toolchain) {
       "//build/win:default_exe_manifest",
     ]
   }
+
+  v8_executable("mkpeephole") {
+    # mkpeephole needs to be built for the build host so the peephole lookup
+    # table can built during build. The table depends on the properties of
+    # bytecodes that are described in bytecodes.{cc,h}.
+    visibility = [ ":*" ]  # Only targets in this file can depend on this.
+
+    sources = [
+      "src/interpreter/bytecode-peephole-optimizer.h",
+      "src/interpreter/bytecodes.cc",
+      "src/interpreter/bytecodes.h",
+      "src/interpreter/mkpeephole.cc"
+    ]
+
+    configs = [ ":internal_config" ]
+
+    deps = [ ":v8_libbase" ]
+  }
 }
 
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