As part of aggressive dead code elimination, we initially assume all
flow-graph instructions are not live. We mark those that are critical
and recursively all their children. The children of variable
references (VariableProxies occurring as rvalues) include all their
reaching definitions.
Review URL: http://codereview.chromium.org/1159005
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4246 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This change adds a data-flow pass to statically determine
if a variable contains a primitive type.
It requires building the flow graph and computing reaching
definitions as pre-requisites. The analysis annotates all
VariableProxy nodes with the result.
Review URL: http://codereview.chromium.org/1132005
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4224 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This change adds the option to peel off the first iteration of inner loops.
Loop peeling is off by default and can enabled by a flag. It also requires building a flow graph.
As part of this I added the possibility to clone AST nodes.
Review URL: http://codereview.chromium.org/998001
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4205 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Reaching definitions in (RD_in) is initially empty for all nodes. Gen
and kill sets are computed. AST node numbers are used for nodes to
refer to their definition number.
Also: two small changes to flow graph printing. Children of branch
nodes are visited in right-to-left order when performing depth first
search. Instructions are numbered locally within blocks so as to not
destroy AST node number before printing (it's useful to print the
definition).
Review URL: http://codereview.chromium.org/876001
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4107 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This change adds a pass over the AST that computes the
set of assigned variables for locals and parameters for each expression.
The result of this analysis is used to for two purposes:
1. Recognize variables that are trivial subexpressions. A left sub-expression
of a binary operation is trivial if it is a local variable or a parameter
and it is not assigned in the right sub-expression. In the case of a
trivial left sub-expression we evaluate the right first.
Currently only binary operations and compare operations are considered
when finding trivial left sub-expressions.
2. Recogize certain simple for-loops with a constant trip count where the loop
variable is always within smi range. If the loop count variable is not
assigned in the body of the loop (except in the update expression the
for-loop). This allows omitting smi checks on operation using the loop
count variable.
Review URL: http://codereview.chromium.org/669155
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4087 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Visitor stack overflow is used to signal an unsupported construct in
the flow graph. Check for it in more places. Make the utility
functions for appending to graphs handle more cases if they can be
handled correctly.
Remove the entry node in favor of a block with a NULL predecessor as
single entry. Represent the empty flow graph as a single empty block.
Add empty blocks lazily where needed to preserve edge-split form.
Review URL: http://codereview.chromium.org/804003
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4086 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
A variable usage analysis pass was run on toplevel and lazily-compiled
code but never used. Remove this pass and the data structures it
builds.
The representation of variable usage for Variables has been changed
from a struct containing a (weighted) count of reads and writes to a
simple flag. VariableProxies are always used, as before. The unused
"object uses" is removed.
Review URL: http://codereview.chromium.org/669270
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4052 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The flow graph is built by walking the AST. Edges are labeled with
instructions (AST nodes). Normal nodes have a single predecessor edge and a
single (labeled) successor edge. Branch nodes are explicit, they have a
single predecessor edge and a pair of (unlabeled) successor edges. Merge
nodes are explicit, they have a pair of predecessor edges and a single
(unlabeled) successor edge.
There is a distinguished (normal) entry node and a distinguished (special)
exit node with arbitrarily many predecessor edges and no successor edges.
The graph is intended to support graph-based analysis and transformation.
Review URL: http://codereview.chromium.org/660449
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4051 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This change adds a post-order numbering to AST nodes that
are relevant for the fast code generator. It is only invoked
together with the fast compiler.
Also changed the ast printer to print the numbering for
testing purposes if it is present.
Review URL: http://codereview.chromium.org/553134
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3738 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
non-optimizing compiler can cope with. By default it bails out
to the old compiler on encountering a for loop (for performance)
but with this change the --always-fast-compiler flag will enable
functions with for loops to be compiled in the non-optimizing
compiler. Also enables the non-optimizing compiler on functions
that can be lazily compiled (again only with the flag).
Review URL: http://codereview.chromium.org/552065
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3667 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
generator.
Contexts are no longer stored in the AST but in the code generator's
state. This means that the running the code generator selector is not
required to use the toplevel code generator (for instance, if we
already know that we can and should use it).
Review URL: http://codereview.chromium.org/546075
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3645 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
When initializing the special local variable containing the reference to the enclosing
function in named functions we now (correctly) emit an INIT_CONST instead of INIT_VAR,
and we correctly bail out in the top-level code generator.
Also part of this change is adding missing statement position information
for some statements in the top-level code generator.
Review URL: http://codereview.chromium.org/536029
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3587 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
* Rename the operation of filling a context with a value. Formerly it
was 'Move', now it's 'Apply' so as to avoid confusion with various
other Moves (eg, in the toplevel codegen, in the macro assemblers).
* Use the abstraction Drop rather than math on the stack pointer.
* Add a predicate on AST expression nodes to abstract a repeated test
whether we should us a regular (named) IC or a keyed IC.
Review URL: http://codereview.chromium.org/546006
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3580 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Until now we only supported postfix operations on global variables.
This change add generic count operations to the top-level compiler.
I tried to re-use code from the code generator used for assignment expressions
where possible.
Review URL: http://codereview.chromium.org/496009
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3530 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
1. Refactor the structure of VisitAssignment: The existing code is not ideal
to be extended with support for compound assignments.
2. Reuse common code for keyed property assigments: Now variables rewritten
to a property (.arguments access) are treated like normal keyed property
assignments. This allows us to remove some code duplication.
Review URL: http://codereview.chromium.org/456024
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3425 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
