The problem appeared due to a fact that stubs doesn't create a stack
frame, reusing the stack frame of the caller function. When building
stack traces, the current function is retrieved from PC, and its
callees are retrieved by traversing the stack backwards. Thus, for
stubs, the stub itself was discovered via PC, and then stub's caller's
caller was retrieved from stack.
To fix this problem, a pointer to JSFunction object is now captured
from the topmost stack frame, and is saved into stack trace log
record. Then a simple heuristics is applied whether a referred
function should be added to decoded stack, or not, to avoid reporting
the same function twice (from PC and from the pointer.)
BUG=553
TEST=added to mjsunit/tools/tickprocessor
Review URL: http://codereview.chromium.org/546089
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3673 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
As this is only needed for internal profiling (not for DevTools),
the following approach had been chosen:
- during snapshot creation, positions of serialized objects inside
a snapshot are logged;
- then during V8 initialization, positions of deserealized objects
are logged;
- those positions are used for retrieving code objects names from
snapshot creation log, which needs to be supplied to tick processor
script.
Positions logging is controlled with the new flag: --log_snapshot_positions.
This flag is turned off by default, and this adds no startup penalty.
To plug this fix to Golem, the following actions are needed:
- logs created using 'mksnapshot' need to be stored along with VM images;
- tick processor script needs to be run with '--snapshot-log=...' cmdline
argument.
BUG=571
Review URL: http://codereview.chromium.org/551062
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3635 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
it in regular flat strings that are part of the snapshot.
After this change we don't need libraries-empty.cc any more. In
this change libraries-empty.cc is just a the same as libraries.cc
and the scons build builds it but does not use it. We can move
in stages to a situation where it is not generated at all for all
the build systems that we have.
Review URL: http://codereview.chromium.org/360050
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3238 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
fast-mode code generator.
AST expression nodes are annotated with a location when doing the
initial syntactic check of the AST. In the current implementation,
expression locations are 'temporary' (ie, allocated to the stack) or
'nowhere' (ie, the expression's value is not needed though it must be
evaluated for side effects).
For the assignment '.result = true' on IA32, we had before (with the
true value already on top of the stack):
32 mov eax,[esp]
35 mov [ebp+0xf4],eax
38 pop eax
Now:
32 pop [ebp+0xf4]
======== On x64, before:
37 movq rax,[rsp]
41 movq [rbp-0x18],rax
45 pop rax
Now:
37 pop [rbp-0x18]
======== On ARM, before (with the true value in register ip):
36 str ip, [sp, #-4]!
40 ldr ip, [sp, #+0]
44 str ip, [fp, #-12]
48 add sp, sp, #4
Now:
36 str ip, [fp, #-12]
Review URL: http://codereview.chromium.org/267118
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3076 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Turned on with '--log-producers' flag, also needs '--noinline-new' (this is temporarily), '--log-code', '--log-gc'. Not all allocations are traced (I'm investigating.)
Stacks are stored using weak handles. Thus, when an object is collected, its allocation stack is deleted.
Review URL: http://codereview.chromium.org/267077
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3069 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
fast code generator is optimized for compilation time and code size.
Currently it is only implemented on IA32. It is potentially triggered
for any code in the global scope (including code eval'd in the global
scope). It performs a syntactic check and chooses to compile in fast
mode if the AST contains only supported constructs and matches some
other constraints.
Initially supported constructs are
* ExpressionStatement,
* ReturnStatement,
* VariableProxy (variable references) to parameters and
stack-allocated locals,
* Assignment with lhs a parameter or stack-allocated local, and
* Literal
This allows compilation of literals at the top level and not much
else.
All intermediate values are allocated to temporaries and the stack is
used for all temporaries. The extra memory traffic is a known issue.
The code generated for 'true' is:
0 push ebp
1 mov ebp,esp
3 push esi
4 push edi
5 push 0xf5cca135 ;; object: 0xf5cca135 <undefined>
10 cmp esp,[0x8277efc]
16 jnc 27 (0xf5cbbb1b)
22 call 0xf5cac960 ;; code: STUB, StackCheck, minor: 0
27 push 0xf5cca161 ;; object: 0xf5cca161 <true>
32 mov eax,[esp]
35 mov [ebp+0xf4],eax
38 pop eax
39 mov eax,[ebp+0xf4]
42 mov esp,ebp ;; js return
44 pop ebp
45 ret 0x4
48 mov eax,0xf5cca135 ;; object: 0xf5cca135 <undefined>
53 mov esp,ebp ;; js return
55 pop ebp
56 ret 0x4
Review URL: http://codereview.chromium.org/273050
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3067 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The profile is taken together with constructors profile. In theory, it
should represent a complete heap graph. However, this takes a lot of memory,
so it is reduced to a more compact, but still useful form. Namely:
- objects are aggregated by their constructors, except for Array and Object
instances, that are too hetereogeneous;
- for Arrays and Objects, initially every instance is concerned, but then
they are grouped together based on their retainer graph paths similarity (e.g.
if two objects has the same retainer, they are considered equal);
Review URL: http://codereview.chromium.org/200132
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2903 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The SCons build now has the options profilingsupport and debuggersupport for controlling the setting of the defines ENABLE_LOGGIGN_AND_PROFILING and ENABLE_DEBUGGER_SUPPORT. By default both are set to true.
The changes to the XCode project have not been tested.
Review URL: http://codereview.chromium.org/195061
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2875 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-fstrict-aliasing is enabled by mainline gcc at -O2 and higher, but in Apple
gcc, it must be enabled explicitly. This results in a 1.5% improvement in V8
benchmark scores.
This also removes the -fno-exceptions and -fno-rtti settings from v8.gyp for
the Mac, and removes -fno-rtti from v8.gyp for Linux, because these settings
have become part of Chromium's common.gypi, included here, as of r23304 at the
latest. The settings in v8.gyp have become redundant.
Review URL: http://codereview.chromium.org/174154
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2734 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
system can't currently process stacks produced by gcc -fomit-frame-pointer
properly. The drawback outweighs the 2% performance improvement. Once
the crash reporting system is able to handle this optimization, it should be
revisited.
Review URL: http://codereview.chromium.org/173123
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2733 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
