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
When entering a finally block in unoptimized code, we unconditionally
save the accumulator register in the stack in case it holds a return
value or an exception. In the case of a break, continue, or falling
off the end of the try or catch block, this value is unpredictable and
not necessarily safe for GC.
Review URL: http://codereview.chromium.org/5883003
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6035 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
In the FullCodeGenerator, we compile the true subexpression of a
conditional (ternary) expression in the inherited context of the
entire expression. This is correct for effect and value contexts, but
not for test contexts where the context includes a possible
fall-through label.
Review URL: http://codereview.chromium.org/3621013
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5607 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Change more functions used by the Compiler class to have a uniform
interface: they get passed as argument an input/output pointer to a
CompilationInfo that they mutate if they succeed, and they return a
flag telling whether they succeeded.
Also, remove some unnecessary timers.
Review URL: http://codereview.chromium.org/3561012
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5583 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
For some reason, the scope's arguments and arguments shadow were
variable proxies, which resulted in all references to the arguments
shadow being shared in the AST. This makes it hard to put per-node
state on the AST nodes.
I took the opportunity to remove Variable::AsVariable which has
confused people in the past, and to rename Variable::slot to the more
accurate Variable::AsSlot.
Review URL: http://codereview.chromium.org/3432022
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5517 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This adds a check to the fast case string add to ensure that the String object still have the default valueOf function. The default valueOf is sitting on a hidden prototype of String.prototype.
Before using the fast case valueOf the object is checked for a local valueOf property. For slow case objects this check always reports true (the dictionary is not probed, so valueOf might be there) and for fast case objects the descriptor array is checked for the valueOf symbol (just liniar scan). After that the prototype is checked for beeing the initial value of String.prototype. If this all pass (that is the default valueOf is still in place) this result is cached on the map making the check fast the next time.
This is only implemented in the optimizing compiler, as the two usages of %_IsStringWrapperSafeForDefaultValueOf is never hit by the full compiler.
I will port to x64 and ARM when this has been reviewed for ia32.
I will remove the performance counters prior to final commit.
BUG=http://code.google.com/p/v8/issues/detail?id=760
TEST=test/mjsunit/regress/regress-760-1.js
TEST=test/mjsunit/regress/regress-760-2.js
Review URL: http://codereview.chromium.org/3117006
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5252 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This includes adding a new inline IsSpecObject method to the code
generator. The old approach was somehow ineffecient since we would
call both IsObject, IsUndetectable and IsFunction to determine if
something was an object according to the spec. This change introduces
a new macro that determines if something is an object according to the
spec (and this does not include null).
This change also corrects a few places where undetectable objects was
not allowed even when they should be (priorly they would use only
IS_SPEC_OBJECT_OR_NULL, which would return false on an undetectable
object, the new IS_SPEC_OBJECT returns true on an undetectable object.
Review URL: http://codereview.chromium.org/2877018
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5087 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
With the change in r4820 all return statements are now breakable like any statement, so stepping will stop before the return statement actually returning from a function. With this change the position when breaking in the function return (after executing the return statement) will be the actual end of the function. At this point the return value is available as it saved to the stack by the debug break at return handling. Added information on the actual value returned from the function to the debugger.
Review URL: http://codereview.chromium.org/2783002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4835 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Added support for more precise break points when debugging and stepping. To achieve that additional nop instructions are inserted where breaking would otherwise be impossible. The number of nop instructions inserted are sufficient to make place for patching with a call to a debug break code stub. On Intel that is 5 nop's for 32-bit and 13 for 64-bit. Om ARM 3 nop instructions (12 bytes) are required.
In order to avoid inserting nop's in to many places a simple ast checker have been added to check whether there are breakable code in a statement or expression. If it is possible to break in an expression no additional break enabeling code is inserted.
Added break locations to the true and false part of a conditional expression.
Added stepping tests to cover more constructs.
These changes are only in the full compiler.
Changed the default value for the option --debugger in teh d8 shell from true to false. The reason for this is that with --debugger turned on the full compiler will be used for all code in when running d8, which can be unexpeceted.
Review URL: http://codereview.chromium.org/2693002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4820 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
These string methods can be composed from two basic blocks: charCodeAt
and fromCharCode, both of which have fast cases for certain types of
inputs. In this patch these two blocks are refactored to allow
generating the fast cases without having to jump around the slow
cases. In the slow cases since they can now be invoked both from
inline runtime functions and from IC stubs we either have to
save/restore state of the current frame or enter/leave a new internal
frame. This is handled by new RuntimeCallHelper interface. Its
implementation for virtual frame is based on FrameRegisterState class
extracted from DeferredCode class.
Review URL: http://codereview.chromium.org/2087009
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4733 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This makes the full compiler handle all constructs on ia32. However the syntax checker for the full compiler is still the same so for both normal operation and with the flag --always-full-compiler the coverage of the full compiler will be the same.
This is on preparation for improving the debugger break point experience where the plan is to only use code from full code generator when debugging JavaScript.
Runs all tests on all three platforms in release and debug mode. The tests also run with both the following flags to the test runner
--special-command="@ --nofull-compiler"
--special-command="@ --always-full-compiler"
The changes to the x64 and ARM architectures are mainly structural due to the change to EmitVariableAssignment to handle initialization of const variables.
Review URL: http://codereview.chromium.org/1989012
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4676 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Introducing a virtual-frame-inl.h file containing some platform-independent
virtual frame function which are small enough to be inlined.
Removed unnecessary #include of virtual-frame.h from register-allocator-inl.h
and added the necessary explicit includes in a number of files.
Review URL: http://codereview.chromium.org/660104
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3962 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
