This prevents code motion from hoisting map-checks across such stores
which may result in unnecessary deoptimizations.
In the following example program we would move a map-check from the inner loop out before the outer loop which is not desirable:
function f() {
var o = {};
var j = 0;
o.a = 1;
do {
o.b = 6; // Map transition
for (var i=0; i<10; i++) {
o.a = o.b + i;
}
} while(++j < 1) {}
}
for (var i = 0; i < 1000000; i++) f();
Review URL: http://codereview.chromium.org/5991001
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6071 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
When running with 10 stress runs we get polymorphic stores. This revealed
an incorrect bailout ID for the state following a polymorphic store. The ID
should be the internal ID of the assignment side-effect, not the ID of the
end of the expression.
Review URL: http://codereview.chromium.org/5885003
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6051 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Before, when we deoptimized after a branch we jumped to before the branch
was taken in the unoptimized code with a token value that indicated when
edge to take. There was a lot of machinery to track this value through the
short-circuit logical operations and logical negation, and to handle it
properly at inline function return sites. There was also machinery to
prevent incorrectly seeing this environment with the extra value never
actually materialized in the unoptimized code.
Instead, now we deoptimize directly to one of the targets of the branch.
Much but not yet all of the extra machinery has been removed or simplified.
The cost is that branching control structures (the looping statements, if
statements, conditional expressions, and the short-circuit binary logical
operations) need extra AST IDs to identify the branch targets.
Review URL: http://codereview.chromium.org/5908001
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6049 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The issue is caused when deoptimizing to an internal AST ID in a
postfix increment or decrement operation on variable. This could
happen for a global variable. In that case, the optimized code was
not properly simulating an extra stack slot in the unoptimized code to
hold the original value.
Review URL: http://codereview.chromium.org/5871002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6025 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This fixes V8 issue 989.
Before, assignments used the AST ID of the assignment expression to
mark the side effect of the store, which became a target for
deoptimization bailout for code after the assignment. In effect
contexts this environment included the value of the assignment, which
was unexpected by the unoptimized code.
Now we introduce a new assignment ID for AST node types that include
an assignment (Assignment, CountOperation, and ForInStatement) and use
it for the side effect of the store.
Review URL: http://codereview.chromium.org/5682010
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5990 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
When falling off the end of a function inlined in a test context, we cannot
constant fold the test of undefined away. The graph builder assumes that
control flow always reaches both branches of a test.
Instead, explicitly test and branch on "undefined". Introduce a pair of
empty blocks to hold the necessary LeaveInlined instructions.
Review URL: http://codereview.chromium.org/5566005
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5927 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
