Hydrogen attempts to force representation changes on certain operations in order
to deoptimise on the change rather than the operation. However, these forced
changes are often unnecessary on 64-bit platforms, and cause poor code
generation, so this patch makes some of them conditional on whether it's
possible for deoptimisation to occur in the change.
On ARM64, this prevents sequences like:
;;; <@46,#89> smi-tag
0x7ff282c7f050 144 lsl x4, x4, #32
;;; <@48,#90> smi-untag
0x7ff282c7f054 148 asr x5, x4, #32
;;; <@50,#31> mul-const-i-s
0x7ff282c7f058 152 lsl w6, w5, #3
BUG=
R=jkummerow@chromium.org
Review URL: https://codereview.chromium.org/303263010
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21818 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Instead of tracking simple absolute offset from the start of the script like other places do, track a pair of (inlining id, offset from the start of inlined function).
This enables us to pinpoint with inlining path an instruction came from. Previously in multi-script environments we emitted positions that made very little sense because inside a single optimized function they would point to different scripts without a way to distinguish them.
Start dumping the source of every inlined function to make possible IR viewing tools with integrated source views as there was previously no way to acquire this information from IR dumps. We also dump source position at which each inlining occured.
Tracked positions are written into hydrogen.cfg as pos:<inlining-id>_<offset>.
Flag --emit-opt-code-positions is renamed by this change into --hydrogen-track-positions to better convey it's meaning.
In addition this change assigned global unique identifier to each optimization performed inside isolate. This allows to precisely match compilation artifacts (e.g. IR and disassembly) and deoptimizations.
BUG=
R=yangguo@chromium.org
Review URL: https://codereview.chromium.org/140683011
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19360 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Add static_cast<int> in HPositionInfo::position to please Win64 build.
Improvements in positions handling in optimizing compiler.
- When building binary arithmetic op and comparison restore source position of the operation itself before building operation itself after it was changed by building operands. This ensures that position recorded for operation points to the operation token instead of pointing to the rightmost operand;
- Add support for recording operands' positions and use these positions when inserting HChange instructions;
- When generating hydrogen.cfg emit H-instruction position as BCI (previously 0 was emitted), additionally on every lithium instruction emit annotation pointing to corresponding hydrogen-instruction. This allows to easily reach from deopt_id to lithium instruction and from it to hydrogen instruction and source position.
R=danno@chromium.org
Review URL: https://codereview.chromium.org/59703011
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17848 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
- When building binary arithmetic op and comparison restore source position of the operation itself before building operation itself after it was changed by building operands. This ensures that position recorded for operation points to the operation token instead of pointing to the rightmost operand;
- Add support for recording operands' positions and use these positions when inserting HChange instructions;
- When generating hydrogen.cfg emit H-instruction position as BCI (previously 0 was emitted), additionally on every lithium instruction emit annotation pointing to corresponding hydrogen-instruction. This allows to easily reach from deopt_id to lithium instruction and from it to hydrogen instruction and source position.
BUG=
R=danno@chromium.org
Review URL: https://codereview.chromium.org/49203002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17765 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
In the process:
- Add a command-line flag --opt-code-positions to track source position information throughout optimized code.
- Add a subclass of the hydrogen graph builder to ensure that the source position is properly set on the graph builder for all generated hydrogen code.
- Overhaul handling of source positions in hydrogen to ensure they are passed through to generated code consistently and in most cases transparently.
Originally reviewed in this CL: https://codereview.chromium.org/24957003/
Review URL: https://codereview.chromium.org/29123008
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17295 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
If not all uses of arithmetic binary operation can be truncated to Smi, check if they can be truncated to Int32 which could avoid minus zero check
Fixed DoMulI on X64 to adopt correct operand size when the representation is Smi
Fixed DoMulI on ARM. Constant right operand optimization is based on Integer 32 instead of its representation.
BUG=
R=verwaest@chromium.org
Review URL: https://chromiumcodereview.appspot.com/22600005
Patch from Weiliang Lin <weiliang.lin2@gmail.com>.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16361 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
