Commit Graph

11 Commits

Author SHA1 Message Date
Jaebaek Seo
df4198e50e
Add DebugValue for DebugDecl invisible to value assignment (#3973)
For some cases, we have DebugDecl invisible to a value assignment, but
the value assignment information is important i.e., debugger cannot inspect
the variable without the information. For example, a parameter of an inlined
function must have its value assignment i.e., argument passing out of its
function scope. If we simply remove DebugDecl because it is invisible to the
argument passing, we cannot inspec the variable.

This PR
- Adds DebugValue for DebugDecl invisible to a value assignment. We use
the value of the variable in the basic block that contains DebugDecl, which is
found by ssa-rewrite. If the value instruction does not dominate DebugDecl,
we use the value of the variable in the immediate dominator of the basic block.
- Checks the visibility of DebugDecl for Phi value assignment based on the
all value operands of the Phi. Since Phi just references multiple values from
multiple basic blocks, scopes of value operands must be regarded as the scope
of the Phi.
2020-10-27 15:10:08 -04:00
Jaebaek Seo
d4b9f576eb
[spirv-opt] debug info preservation in ssa-rewrite (#3356)
Add OpenCL.DebugInfo.100 `DebugValue` instructions for store
and phi instructions of local variables to provide the debugger with
the updated values of local variables correctly.
2020-06-19 14:57:43 -04:00
Steven Perron
35c9518c4e
Handle id overflow in the ssa rewriter. (#2845)
* Handle id overflow in the ssa rewriter.

Remove LocalSSAElim pass at the same time.  It does the same thing as the SSARewrite pass. Then even share almost all of the same code.

Fixes crbug.com/997246
2019-09-10 09:38:23 -04:00
Steven Perron
c9190a54da
SSA rewriter: Don't use trivial phis (#2757)
When a phi candidate is marked as trivial, we are suppose to update all
of its uses to the reference the value that it is being folded to.
However, the code updates the uses misses `defs_at_block_`.  So at a
later time, the id for the trivial phi can reemerge.

Fixes #2744
2019-07-23 17:59:30 -04:00
dan sinclair
eda2cfbe12
Cleanup includes. (#1795)
This Cl cleans up the include paths to be relative to the top level
directory. Various include-what-you-use fixes have been added.
2018-08-03 15:06:09 -04:00
dan sinclair
58a6876cee
Rewrite include guards (#1793)
This CL rewrites the include guards to make PRESUBMIT.py include guard
check happy.
2018-08-03 08:05:33 -04:00
dan sinclair
c7da51a085
Cleanup extraneous namespace qualifies in source/opt. (#1716)
This CL follows up on the opt namespacing CLs by removing the
unnecessary opt:: and opt::analysis:: namespace prefixes.
2018-07-12 15:14:43 -04:00
dan sinclair
f96b7f1cb9
use Pass::Run to set the context on each pass. (#1708)
Currently the IRContext is passed into the Pass::Process method. It is
then up to the individual pass to store the context into the context_
variable. This CL changes the Run method to store the context before
calling Process which no-longer receives the context as a parameter.
2018-07-12 09:08:45 -04:00
dan sinclair
e6b953361d
Move the ir namespace to opt. (#1680)
This CL moves the files in opt/ to consistenly be under the opt::
namespace. This frees up the ir:: namespace so it can be used to make a
shared ir represenation.
2018-07-09 11:32:29 -04:00
Diego Novillo
2e644e4578 Fix VS2013 build failures. 2018-03-20 21:44:17 -04:00
Diego Novillo
735d8a579e SSA rewrite pass.
This pass replaces the load/store elimination passes.  It implements the
SSA re-writing algorithm proposed in

     Simple and Efficient Construction of Static Single Assignment Form.
     Braun M., Buchwald S., Hack S., Leißa R., Mallon C., Zwinkau A. (2013)
     In: Jhala R., De Bosschere K. (eds)
     Compiler Construction. CC 2013.
     Lecture Notes in Computer Science, vol 7791.
     Springer, Berlin, Heidelberg

     https://link.springer.com/chapter/10.1007/978-3-642-37051-9_6

In contrast to common eager algorithms based on dominance and dominance
frontier information, this algorithm works backwards from load operations.

When a target variable is loaded, it queries the variable's reaching
definition.  If the reaching definition is unknown at the current location,
it searches backwards in the CFG, inserting Phi instructions at join points
in the CFG along the way until it finds the desired store instruction.

The algorithm avoids repeated lookups using memoization.

For reducible CFGs, which are a superset of the structured CFGs in SPIRV,
this algorithm is proven to produce minimal SSA.  That is, it inserts the
minimal number of Phi instructions required to ensure the SSA property, but
some Phi instructions may be dead
(https://en.wikipedia.org/wiki/Static_single_assignment_form).
2018-03-20 20:56:55 -04:00