- Find unreachable continue targets. Look for back edges
with a DFS traversal separate from the dominance traversals,
where we count the OpLoopMerge from the header to the continue
target as an edge in the graph.
- It's ok for a loop to have multiple back edges, provided
they are all from the same block, and we call that the latch block.
This may require a clarification/fix in the SPIR-V spec.
- Compute postdominance correctly for infinite loop:
Bias *predecessor* traversal root finding so that you use
a later block in the original list. This ensures that
for certain simple infinite loops in the CFG where neither
block branches to a node without successors, that we'll
compute the loop header as dominating the latch block, and the
latch block as postdominating the loop header.
Fixes dominance calculation when there is a forward arc from an
unreachable block A to a reachable block B. Before this fix, we would
say that B is not dominated by the graph entry node, and instead say
that the immediate dominator of B is the psuedo-entry node of the
augmented CFG.
The fix:
- Dominance is defined in terms of a traversal from the entry block
of the CFG. So the forward DFS should start from the function
entry block, not the pseudo-entry-block.
- When following edges backward during dominance calculations, only go to
nodes that are actually reachable in the forward traversal.
Important: the sense of reachability flips around when computing
post-dominance.
Fixes https://github.com/KhronosGroup/SPIRV-Tools/issues/297
AssemblyBuilder contains boilplates.
Adds OpName instructions for all added defining instructions.
Adds OpDecorate SpecId for all spec constants added with OpSpecConstant,
OpSpecConstantTrue and OpSpecConstantFalse instructions.
The def-use dominance checker doesn't have enough info to know
that a particular use is in an OpPhi, so skip tracking those uses
for now. Add a TODO to do a proper OpPhi variable-argument check
in the future.
Fixes https://github.com/KhronosGroup/SPIRV-Tools/issues/286
Ensure the dominance calculation visits all nodes in the CFG.
The successor list of the pseudo-entry node is augmented with
a single node in each cycle that otherwise would not be visited.
Similarly, the predecssors list of the pseduo-exit node is augmented
with the a single node in each cycle that otherwise would not
be visited.
Pulls DepthFirstSearch out so it's accessible outside of the dominator
calculation.
Fixes https://github.com/KhronosGroup/SPIRV-Tools/issues/279
Add a pass to freeze spec constants to their default values. This pass does
not fold the frozen spec constants and does not handle SpecConstantOp
instructions and SpecConstantComposite instructions.
* Creates an ID class which manages definition and use of IDs
* Moved tracking code from validate.cpp to validate_id.cpp
* Rename and combine SsaPass and ProcessIds into IdPass
* Remove module dependency in Function
* The `Input` StorageClass doesn't require the `Shader` capability
anymore.
* The `Sampled1D` and `SampledBuffer` capabilities don't require
the `Shader` capability anymore. So they do not indirectly
depend on the `Matrix` capability. So are the `Image1D` and
`ImageBuffer` capabilities, which depend on `Sampled1D` and
`SampledBuffer`.
A new GLSL grammar file is uploaded for SPIR-V 1.1, but it's the
same as the existing one for SPIR-V 1.0.
Now tracking commit 3814effb879ab5a98a7b9288a4b4c7849d2bc8ac in
SPIRV-Headers.
For DependencyInfinite and DependencyLength, test
that they don't require a capability to be turned on.
Also, that they are assembled, binary parsed, and disassembled
correctly.
Works around issue 248 by weakening the test:
https://github.com/KhronosGroup/SPIRV-Tools/issues/248
The validator should try to track (32-bit) constant values, and then
for capability checks on IDs, check the referenced value, not the
raw ID number.
For dominance calculations we use an "augmented" CFG
where we always add a pseudo-entry node that is the predecessor
in the augmented CFG to any nodes that have no predecessors in the
regular CFG. Similarly, we add a pseudo-exit node that is the
predecessor in the augmented CFG that is a successor to any
node that has no successors in the regular CFG.
Pseudo entry and exit blocks live in the Function object.
Fixes a subtle problem where we were implicitly creating
the block_details for the pseudo-exit node since it didn't
appear in the idoms map, and yet we referenced it. In such a case the
contents of the block details could be garbage, or zero-initialized.
That sometimes caused incorrect calculation of immediate dominators
and post-dominators. For example, on a debug build where the details
could be zero-initialized, the dominator of an unreachable block would
be given as the pseudo-exit node. Bizarre.
Also, enforce the rule that you must have an OpFunctionEnd to close off
the last function.
