Reviewers: Michael Starzinger,
Description:
Bailout for %_FastOneByteArrayJoin again.
This recovers the performance loss for some ancient benchmarks.
Added some comments/UNIMPLEMENTED on the way.
BUG=v8:3947
LOG=n
Please review this at https://codereview.chromium.org/996153002/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+20, -4 lines):
M src/bailout-reason.h
M src/hydrogen.h
M src/hydrogen.cc
M src/runtime/runtime-array.cc
M src/runtime/runtime-classes.cc
Index: src/bailout-reason.h
diff --git a/src/bailout-reason.h b/src/bailout-reason.h
index
403a1b41856a4967378a5fc2d4abc2968781c0db..9b801c841d5ce02bc4dc8c3d1eacb45afa89630f
100644
--- a/src/bailout-reason.h
+++ b/src/bailout-reason.h
@@ -116,6 +116,8 @@ namespace internal {
"Improper object on prototype chain for
store") \
V(kIndexIsNegative, "Index is
negative") \
V(kIndexIsTooLarge, "Index is too
large") \
+
V(kInlinedRuntimeFunctionFastOneByteArrayJoin,
\
+ "Inlined runtime function:
FastOneByteArrayJoin") \
V(kInlinedRuntimeFunctionGetFromCache,
\
"Inlined runtime function:
GetFromCache") \
V(kInliningBailedOut, "Inlining bailed
out") \
Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index
3246dfa8e4cd0114e8664a03269da6fb01d2e88b..5b332b3aada09edb8399bfd9c56325f9cbfaffa9
100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -12677,6 +12677,16 @@ void
HOptimizedGraphBuilder::GenerateGetCachedArrayIndex(CallRuntime* call) {
}
+void HOptimizedGraphBuilder::GenerateFastOneByteArrayJoin(CallRuntime*
call) {
+ // Simply returning undefined here would be semantically correct and even
+ // avoid the bailout. Nevertheless, some ancient benchmarks like
SunSpider's
+ // string-fasta would tank, because fullcode contains an optimized
version.
+ // Obviously the fullcode => Crankshaft => bailout => fullcode dance is
+ // faster... *sigh*
+ return Bailout(kInlinedRuntimeFunctionFastOneByteArrayJoin);
+}
+
+
void HOptimizedGraphBuilder::GenerateDebugBreakInOptimizedCode(
CallRuntime* call) {
Add<HDebugBreak>();
Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index
da76657c03be400a6472558db4960213572ada7f..2e7a5dd17bdb26ed12a34c309c36cd946a5e3d4d
100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -2187,6 +2187,7 @@ class HOptimizedGraphBuilder : public HGraphBuilder,
public AstVisitor {
F(IsMinusZero) \
F(HasCachedArrayIndex) \
F(GetCachedArrayIndex) \
+ F(FastOneByteArrayJoin) \
F(DebugBreakInOptimizedCode) \
F(StringCharCodeAt) \
F(StringAdd) \
Index: src/runtime/runtime-array.cc
diff --git a/src/runtime/runtime-array.cc b/src/runtime/runtime-array.cc
index
90a1e2c1ef3266405709491b9d61dec0bb808242..87d4f263ef42b135ee66a9914d8be384d4c389af
100644
--- a/src/runtime/runtime-array.cc
+++ b/src/runtime/runtime-array.cc
@@ -1338,15 +1338,18 @@ RUNTIME_FUNCTION(Runtime_HasCachedArrayIndex) {
RUNTIME_FUNCTION(Runtime_GetCachedArrayIndex) {
- SealHandleScope shs(isolate);
- DCHECK(args.length() == 1);
- return isolate->heap()->undefined_value();
+ // This can never be reached, because Runtime_GetCachedArrayIndex always
+ // returns false.
+ UNIMPLEMENTED();
+ return nullptr;
}
RUNTIME_FUNCTION(Runtime_FastOneByteArrayJoin) {
SealHandleScope shs(isolate);
DCHECK(args.length() == 2);
+ // Returning undefined means that this fast path fails and one has to
resort
+ // to a slow path.
return isolate->heap()->undefined_value();
}
}
Index: src/runtime/runtime-classes.cc
diff --git a/src/runtime/runtime-classes.cc b/src/runtime/runtime-classes.cc
index
36619b0bf0f9e6b9f5636e747ee18aa2a2ba96c4..67d7e6939a634213440744b054796355d6e3bd44
100644
--- a/src/runtime/runtime-classes.cc
+++ b/src/runtime/runtime-classes.cc
@@ -454,7 +454,7 @@
RUNTIME_FUNCTION(Runtime_HandleStepInForDerivedConstructors) {
RUNTIME_FUNCTION(Runtime_DefaultConstructorCallSuper) {
- UNREACHABLE();
+ UNIMPLEMENTED();
return nullptr;
}
}
--
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