Change the ARM exit frame to have the same layout as the IA32 exit frame. This basically re-arranges the order of fp and sp and changes the sp location of the entry frame to hold the sp used by the gc and not the sp for popping the arguments. This removes the option of tearing down the frame and returning using one ldm instruction.
The main motivation for this is to avoid pushing an alignment word before generating the entry frame. The GC handling of optimized frames process the registers pushed as part of a safepoint and asumes that these are at the top of the frame, so if an alignment word is pushed this processing will be one off.
The alignment handling in the C entry stub have also been simplified. Now the value of lr is stored to a stack slot already reserved avoiding pushing it and keeping track of "frame skew".
This does result in more instructions in the exit frame on ARM, but we can look into improving this later.
Review URL: http://codereview.chromium.org/6247019
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6448 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This is svn r6415 with a bugfix.
The bug was that we can have scopes with 0 heap slots (functions with
such scopes do not need a local context) and scopes with at least
Context::MIN_CONTEXT_SLOTS. The code generator only allocated a local
context if there were strictly more than Context::MIN_CONTEXT_SLOTS.
Before the change to with/arguments, it was impossible to actually get
a function scope with exactly Context::MIN_CONTEXT_SLOTS because every
such scope included a heap-allocated arguments (and arguments shadow)
slot.
Review URL: http://codereview.chromium.org/6248014
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6426 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This change introduces near labels in the assembler, allowing us to
uptimize forward jumps (conditional and unconditional) if we can
guarantee that the jump is witin range -128 to +127.
I changed a large fractions of the existing Labels to NearLabels, and
left out cases where it was not immediately clear if it could be used
or not (not immediately clear means labels covering a large code
block, or used in function calls which we could potentially change to
accept near labels).
Review URL: http://codereview.chromium.org/3388004
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5460 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The live registers are now only stored to the expression stack with the non pointer values being stored as smis (on the 32-bit platforms these values are assumed to be 31-bit max).
This makes the CEntryStub entry/exit code much simpler, and there is no longer any need for a mode (debug or normal) on it.
Fix a missing live register when breaking at ARM keyed load.
Review URL: http://codereview.chromium.org/3141047
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5358 ce2b1a6d-e550-0410-aec6-3dcde31c8c00