Depending on what we know about the right operand, we basically do 3
different things (and the code is actually structured this way):
* If we statically know that the right operand is a power of 2, we do
some bit fiddling instead of doing a "real" modulus calculation.
This should actually be done on the Hydrogen level, not on the
Lithium level, but this will be a separate CL.
* If type feedback tells us that the right operand is a power of 2, we
do the same as above, but guarded by conditional deoptimization to
make sure that the assumption is still valid. In the long run, we
should make this guard visible on the Hydrogen level to make it
visible for GVN and other optimizations.
* In the general case we only do the minimum steps necessary and don't
try to be too clever, because cleverness actually slows us down on
real-world code.
If we look at the code gerators for LModI, we actually see that we
basically have 3 (4 on ARM) fundamentally different translations. I
don't really like lumping them together, they should probably be
different Lithium instructions. For the time being, I restructured the
generators to make this crystal-clear, at the cost of some duplication
regarding the power-of-2 cases. This will go away when we do the
strength reduction on the Hydrogen level, so I'd like to keep it as it
is for now.
Note that the MIPS part was only slightly restructured, there is still
some work to do there.
R=jkummerow@chromium.org
Review URL: https://codereview.chromium.org/15769010
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15034 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
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 shaves 416+ KB, just under 1% off the size of the debug d8 executable
on Linux (mostly because the CheckHelper functions for assertions were
getting separate copies for each compilation unit). The difference in
release builds is negligible---a size reduction of 0.1%.
Also, change namespace-level 'static const' variables to remove the static
storage class as it's the default.
R=danno@chromium.org
BUG=
TEST=
Review URL: http://codereview.chromium.org/8680013
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10083 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This implementation extends the internal ObjectHashTable to be able to
hold arbitrary objects (e.g. Smis, Strings, ...) as keys by applying
specialized hashing functions to primitive types. Equality of keys is
defined using the internal SameValue function.
R=rossberg@chromium.org
BUG=v8:1622
TEST=mjsunit/harmony/collections
Review URL: http://codereview.chromium.org/8372027
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9777 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This is reapplying r9501 with this single change which seemed to be causing most (all) of the failures for r9501.
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -2230,6 +2230,7 @@ Debugger::Debugger(Isolate* isolate)
compiling_natives_(false),
is_loading_debugger_(false),
never_unload_debugger_(false),
+ force_debugger_active_(true),
message_handler_(NULL),
debugger_unload_pending_(false),
host_dispatch_handler_(NULL),
R=kmillikin@chromium.org
BUG=
TEST=
Review URL: http://codereview.chromium.org//8337009
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9684 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This change will ensure that full code with debug break slots is compiled and activated for all functions which already have activation frames.
This additional handling is only for functions which have activations on the stack, and that activation is of the full code compiled without debug break slots. In that case the full code is recompiled with debug break slots. It is ensured that the full code is compiled generating the exact same instructions - except for the additional debug break slots - as before. The return address on the stack is then patched to continue execution in the new code.
Also fixed SortedListBSearch to actually use the passed comparision function.
R=svenpanne@chromium.org, kmillikin@chromium.org
BUG=
TEST=
Review URL: http://codereview.chromium.org//8050010
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9489 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Use the BitField helper class for the code flags, so that we do not have to
define both a shift and a mask explicitly. This makes changing the flags
layout simpler.
Also, make the 'mask' and 'max' members of BitField into constants, because
they are constant and so that they can be used as constant expressions.
E.g., so they can be used in declaring other const members or in static
asserts.
R=fschneider@chromium.org
BUG=
TEST=
Review URL: http://codereview.chromium.org/7787028
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9232 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Duplicate identifier detection must be an early syntax error in strict code,
so errors in otherwise lazily compiled functions must be caught in the
preparser.
Originally introduced in r8541 and reverted in r8542.
Now really compiles on Windows.
Review URL: http://codereview.chromium.org/7782023
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9172 ce2b1a6d-e550-0410-aec6-3dcde31c8c00