We iteratively remove all dead Hydrogen instruction until we reach a fixed point. We consider an instruction dead if it is unused, has no observable side effects and is deletable. The last part of the condition is currently not very nice: We basically have to whitelist "safe" instructions, because we are missing more detailed dependencies and/or more detailed tracking of side effects.
We disable dead code elimination for now in our test runners, because we have tons of poorly written tests which wouldn't test anymore what they are supposed to test with this phase enabled. To get test coverage for dead code elimination itself, we should enable it on a few build bots. This is not really a perfect state, but the best we can do for now.
This patch includes a few const-correctness fixes, most of them were necessary for this CL.
Review URL: https://codereview.chromium.org/11088027
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12697 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This fixes materialization of arguments objects for strict mode functions during
deoptimization. We materialize arguments from the stack area where optimized
code pushes the arguments when entering the inlined environment. For adapted
invocations we use the arguments adaptor frame for materialization.
R=svenpanne@chromium.org
BUG=v8:2261
TEST=mjsunit/regress/regress-2261,mjsunit/compiler/inline-arguments
Review URL: https://chromiumcodereview.appspot.com/10908194
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12489 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Safe operations are those that either do not observe unsignedness or have special support for uint32 values:
- all binary bitwise operations: they perform ToInt32 on inputs;
- >> and << shifts: they perform ToInt32 on left hand side and ToUint32 on right hand side;
- >>> shift: it performs ToUint32 on both inputs;
- stores to integer external arrays (not pixel, float or double ones): these stores are "bitwise";
- HChange: special support added for conversions of uint32 values to double and tagged values;
- HSimulate: special support added for deoptimization with uint32 values in registers and stack slots;
- HPhi: phis that have only safe uses and only uint32 operands are uint32 themselves.
BUG=v8:2097
TEST=test/mjsunit/compiler/uint32.js
Review URL: https://chromiumcodereview.appspot.com/10778029
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12367 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Currently only simple setter calls are handled (i.e. no calls in count
operations or compound assignments), and deoptimization in the setter is not
handled at all. Because of the latter, we temporarily hide this feature behind
the --inline-accessors flag, just like inlining getters.
We now use an enum everywhere we depend on the handling of a return value,
passing around several boolean would be more confusing.
Made VisitReturnStatement and the final parts of TryInline more similar, so
matching them visually is a bit easier now.
Simplified the signature of AddLeaveInlined, the target of the HGoto can simply
be retrieved from the function state.
Review URL: https://chromiumcodereview.appspot.com/10836133
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12286 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
When inlining is being done, it is crucial to use the correct type feedback
oracle with a given type feedback ID. To ensure this, TestContext now carries an
oracle which is associated with the context's condition, and these are both used
together in TestContext::BuildBranch.
Note that in VisitReturnStatement and TryInline we are currently lucky that the
oracles don't go out of sync in an observable way, but this will change when we
inline setters. Therefore, there is no separate test case...
Review URL: https://chromiumcodereview.appspot.com/10834247
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12284 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Currently only simple getter calls are handled (i.e. no calls in count
operations or compound assignments), and deoptimization in the getter is not
handled at all. Because of the latter, we temporarily hide this feature behind a
new flag --inline-accessors, which is false by default.
Review URL: https://chromiumcodereview.appspot.com/10828066
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12223 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This is a refactoring-only CL and the third one in a series for enabling
inlining of accessors. The goal of this CL is to move the builders for accessors
to the places where we might be able to inline them later, i.e. the VisitFoo and
HandleBar member functions of HGraphBuilder.
Extracted duplicate code into LookupAccessorPair.
Review URL: https://chromiumcodereview.appspot.com/10831047
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12209 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This is a refactoring-only CL and the first one in a series for enabling
inlining of accessors. The naming and argument order has been unified a bit, and
some tests have been pushed to the caller in order to get a simpler
signature. Note that the latter temporarily introduces some code redundancy, but
this will be cleaned up in one of the next CLs.
Review URL: https://chromiumcodereview.appspot.com/10826028
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12198 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The CompilationInfo record now saves a Zone, and the compiler pipeline
allocates memory from the Zone in the CompilationInfo. Before
compiling a function, we create a Zone on the stack and save a pointer
to that Zone to the CompilationInfo; which then gets picked up and
allocated from.
BUG=
TEST=
Review URL: https://chromiumcodereview.appspot.com/10534139
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11877 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
When an array index (in an array access) is a simple "expression + constant", just embed the constant in the array access operation so that the full index expression is (potentially) no longer used and its live range can be much shorter.
This is effective in conjunction with array bounds check removal (otherwise the index is anyway used in the check).
Review URL: https://chromiumcodereview.appspot.com/10382055
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11596 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
As a special case, for checks on index expressions with the form (expr + constant) if a smaller constant is checked later in the DT also eliminate the check.
Finally, if a larger constant is checked later in the same BB do the more general check (larger constant) earlier instead of the less general one.
This will not cause useless deoptimizations because, since we are in the same BB, all the checks would have been executed anyway.
BUG=
TEST=
Review URL: https://chromiumcodereview.appspot.com/10032029
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11437 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Do proper dispatch on declaration type instead of mingling together
different code generation paths. Once we add more declaration forms,
this is more scalable.
In separate steps, I'd like to (1) clean up the logic for DeclareGlobal,
and (2) try to reduce the special handling of the name function var if
possible.
R=fschneider@chromium.org
BUG=
TEST=
Review URL: https://chromiumcodereview.appspot.com/9704054
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11331 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
