Commit Graph

8 Commits

Author SHA1 Message Date
Shahbaz Youssefi
5760114d77
spirv-diff: Fix OpTypeFunction matching w.r.t operand count (#4771)
The code accidentally expected OpTypeFunction operand count to match.
This is fixed so that OpTypeFunction instructions with different operand
counts are considered not matching.
2022-04-01 09:04:26 -04:00
Shahbaz Youssefi
bd325d2984
spirv-diff: Basic support for OpTypeForwardPointer (#4761)
Currently, the diff tool matches types bottom up, so on every
instruction it expects to know if its operands are already matched or
not.  With cyclical references, it cannot know that.  Type matching
would need significant rework to be able to support such a use case; for
example, it may need to maintain a set of plausable matches between type
pointers that are forward-referenced, and potentially back track when
later the types turn out to be incompatible.

In this change, OpTypeForwardPointer is supported in the more common and
trivial case.  Firstly, forwarded type pointers are only matched if they
have they have the same storage class and point to the same type opcode:

- In the presence of debug info, matching is done only if the names are
  unique in both src and dst.
- In the absence of debug info, matching is done only if there is only
  one possible matching.

Fixes: #4754
2022-03-28 17:01:07 +00:00
Shahbaz Youssefi
40cd21839c
spirv-diff: Use GetSingleWord*Operand (#4768) 2022-03-28 14:42:47 +00:00
Shahbaz Youssefi
48c8363f0a
spirv-diff: Refactor instruction grouping and matching (#4760)
In preparation for supporting OpTypeForwardPointer, which adds more
usages like this.  This change refactors common code used to group
instructions and match the groups.
2022-03-24 18:04:48 +00:00
Shahbaz Youssefi
0ad83f9139
spirv-diff: Match OpSpecConstantComposite correctly (#4704)
OpSpecConstantComposite is not decorated with SpecId, and so is matched
similarly to OpConstantComposite.
2022-02-11 15:29:42 +00:00
Shahbaz Youssefi
332475dbc9
spirv-diff: Handle OpSpecConstant array sizes (#4700)
Previously, array sizes were presumed to be OpConstant, which is not
necessarily true.  This change ensures OpSpecConstant array sizes as
matched exactly, instead of taken as OpConstant and matched by value.
2022-02-09 09:06:46 -05:00
Shahbaz Youssefi
9beb54513c
Stabilize the output of spirv-diff (#4698)
* Reimplement LCS used by spirv-diff

Two improvements are made to the LCS algorithm:

- The LCS algorithm is reimplemented to use a std::stack instead of
  being recursive.  This prevents stack overflow in the LCSTest.Large
  test.
- The LCS algorithm uses an NxM table.  Previously, entries of this
  table were {size_t, bool, bool}, which is now packed in 32 bits.  The
  first entry can assume a maximum value of min(N, M), which
  realistically for SPIR-V diff will not be larger than 1 billion
  instructions.  This reduces memory usage of LCS by 75%.

This partially reverts 845f3efb8a and
enables LCS tests.

* Stabilize the output of spirv-diff

std::map is used instead of std::unordered_map to ensure the output of
spirv-diff is identical everywhere.

This partially reverts 845f3efb8a and
enables spirv-diff tests.
2022-02-07 09:37:04 -05:00
Shahbaz Youssefi
7fa9e746ef
Introduce spirv-diff (#4611)
spirv-diff is a new tool that produces diff-style output comparing two
SPIR-V modules.  The instructions between the src and dst modules are
matched as best as the tool can, and output is produced (in src
id-space) that shows which instructions are removed in src, added in dst
or modified between them.  The order of instructions are not retained.

Matching instructions between two SPIR-V modules is not trivial, and
thus a number of heuristics are applied in this tool.  In particular,
without debug information, it's hard to match functions as they can be
reordered.  As such, this tool is primarily useful to produce the diff
of two SPIR-V modules derived from the same source.

This tool can be useful in a number of scenarios:

- Compare the SPIR-V before and after modifying a shader
- Compare the SPIR-V produced from a shader before and after compiler
  codegen changes.
- Compare the SPIR-V produced from a shader before and after some
  transformation or optimization.
- Compare the SPIR-V produced from a shader with different compilers.
2022-02-02 10:33:18 -05:00