Reviewers: marja, dcarney,
Message:
Does this version of the API make any sense?
Also, any ideas for unit tests? I'll add one that the tag changes when the
flag
list changes; but I don't see how I can easily unit test any of the other
issues.
Description:
Add a version tag for cached data.
BUG=399580,431699
LOG=N
Please review this at https://codereview.chromium.org/718043002/
Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+42, -0 lines):
M include/v8.h
M src/api.cc
M src/flags.h
M src/flags.cc
Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index
e4a8be6aea4f63071d21b633c815f1ac306f23f4..963ebf535787d4d7844dc011f338b57c629f6873
100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -1238,6 +1238,26 @@ class V8_EXPORT ScriptCompiler {
static Local<Script> Compile(Isolate* isolate, StreamedSource* source,
Handle<String> full_source_string,
const ScriptOrigin& origin);
+
+ /**
+ * Return a version tag for CachedData for the current V8 version &
flags.
+ *
+ * This value is meant only for determining whether a previously
generated
+ * CachedData instance is still valid; the tag has no other meaing.
+ *
+ * Background: The data carried by CachedData may depend on the exact
+ * V8 version number or currently compiler flags. This means when
+ * persisting CachedData, the embedder must take care to not pass in
+ * data from another V8 version, or the same version with different
+ * features enabled.
+ *
+ * The easiest way to do so is to clear the embedder's cache on any
+ * such change.
+ *
+ * Alternatively, this tag can be stored alongside the cached data and
+ * compared when it is being used.
+ */
+ static uint32_t CachedDataVersionTag();
};
Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index
dfb452b2a2707f1a697cc248bcff8b8a3c995b84..fddd9e82f4b286cdd49952833d81f87d300f8297
100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -1846,6 +1846,12 @@ Local<Script> ScriptCompiler::Compile(Isolate*
v8_isolate,
}
+uint32_t ScriptCompiler::CachedDataVersionTag() {
+ return internal::Version::Hash() ^ internal::FlagList::Hash() ^
+ internal::CpuFeatures::SupportedFeatures();
+}
+
+
Local<Script> Script::Compile(v8::Handle<String> source,
v8::ScriptOrigin* origin) {
i::Handle<i::String> str = Utils::OpenHandle(*source);
Index: src/flags.cc
diff --git a/src/flags.cc b/src/flags.cc
index
e53c45e69d3a35e904f6853035cf6f7c24826f12..90ce752fea871fb57b009cefa6669b0298378711
100644
--- a/src/flags.cc
+++ b/src/flags.cc
@@ -549,4 +549,17 @@ void FlagList::EnforceFlagImplications() {
#undef FLAG_MODE_DEFINE_IMPLICATIONS
}
+
+uint32_t FlagList::Hash() {
+ std::ostringstream modified_args_as_string;
+ for (size_t i = 0; i < num_flags; ++i) {
+ Flag* current = &flags[i];
+ if (!current->IsDefault()) {
+ modified_args_as_string << *current;
+ }
+ }
+ std::string args(modified_args_as_string.str());
+ return StringHasher::HashSequentialString(args.c_str(), args.length(),
+ StringHasher::kZeroHash);
+}
} } // namespace v8::internal
Index: src/flags.h
diff --git a/src/flags.h b/src/flags.h
index
78522ffce62b52a707953e15333e944d994bd2b6..9ec5d30119fd3547283ca94683bae30d80ba08ef
100644
--- a/src/flags.h
+++ b/src/flags.h
@@ -57,6 +57,9 @@ class FlagList {
// Set flags as consequence of being implied by another flag.
static void EnforceFlagImplications();
+
+ // Hash of current flags (to quickly determine flag changes).
+ static uint32_t Hash();
};
} } // namespace v8::internal
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