Reviewers: Toon Verwaest,
Message:
PTAL (unfortunately I have no easy repro)
Description:
Harden IsMoreGeneralElementsKindTransition.
[email protected]
Please review this at https://codereview.chromium.org/213783004/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+27, -19 lines):
M src/elements-kind.cc
Index: src/elements-kind.cc
diff --git a/src/elements-kind.cc b/src/elements-kind.cc
index
7b1a65aae1eb169ac019c37e3095900a21d43603..d77b74bc0ea09d87ae5efaae7f8958124a5b32c1
100644
--- a/src/elements-kind.cc
+++ b/src/elements-kind.cc
@@ -178,6 +178,11 @@ static bool IsTypedArrayElementsKind(ElementsKind
elements_kind) {
}
+static inline bool IsFastTransitionTarget(ElementsKind elements_kind) {
+ return IsFastElementsKind(elements_kind) ||
+ elements_kind == DICTIONARY_ELEMENTS;
+}
+
bool IsMoreGeneralElementsKindTransition(ElementsKind from_kind,
ElementsKind to_kind) {
if (IsTypedArrayElementsKind(from_kind) ||
@@ -193,26 +198,29 @@ bool IsMoreGeneralElementsKindTransition(ElementsKind
from_kind,
return false;
}
}
- switch (from_kind) {
- case FAST_SMI_ELEMENTS:
- return to_kind != FAST_SMI_ELEMENTS;
- case FAST_HOLEY_SMI_ELEMENTS:
- return to_kind != FAST_SMI_ELEMENTS &&
- to_kind != FAST_HOLEY_SMI_ELEMENTS;
- case FAST_DOUBLE_ELEMENTS:
- return to_kind != FAST_SMI_ELEMENTS &&
- to_kind != FAST_HOLEY_SMI_ELEMENTS &&
- to_kind != FAST_DOUBLE_ELEMENTS;
- case FAST_HOLEY_DOUBLE_ELEMENTS:
- return to_kind == FAST_ELEMENTS ||
- to_kind == FAST_HOLEY_ELEMENTS;
- case FAST_ELEMENTS:
- return to_kind == FAST_HOLEY_ELEMENTS;
- case FAST_HOLEY_ELEMENTS:
- return false;
- default:
- return false;
+ if (IsFastElementsKind(from_kind) && IsFastTransitionTarget(to_kind)) {
+ switch (from_kind) {
+ case FAST_SMI_ELEMENTS:
+ return to_kind != FAST_SMI_ELEMENTS;
+ case FAST_HOLEY_SMI_ELEMENTS:
+ return to_kind != FAST_SMI_ELEMENTS &&
+ to_kind != FAST_HOLEY_SMI_ELEMENTS;
+ case FAST_DOUBLE_ELEMENTS:
+ return to_kind != FAST_SMI_ELEMENTS &&
+ to_kind != FAST_HOLEY_SMI_ELEMENTS &&
+ to_kind != FAST_DOUBLE_ELEMENTS;
+ case FAST_HOLEY_DOUBLE_ELEMENTS:
+ return to_kind == FAST_ELEMENTS ||
+ to_kind == FAST_HOLEY_ELEMENTS;
+ case FAST_ELEMENTS:
+ return to_kind == FAST_HOLEY_ELEMENTS;
+ case FAST_HOLEY_ELEMENTS:
+ return false;
+ default:
+ return false;
+ }
}
+ return false;
}
--
--
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