llvm-project/llvm/test/DebugInfo/Generic/assignment-tracking/parse-and-verify
OCHyams 26382a4412 Reapply [Assignment Tracking][5/*] Add core infrastructure for instruction reference
Previously reverted in 41f5a0004e. Fold in
D133576 previously reverted in d29d5ffb63.

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The Assignment Tracking debug-info feature is outlined in this RFC:

https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir

Overview
It's possible to find intrinsics linked to an instruction by looking at the
MetadataAsValue uses of the attached DIAssignID. That covers instruction ->
intrinsic(s) lookup. Add a global DIAssignID -> instruction(s) map which gives
us the ability to perform intrinsic -> instruction(s) lookup. Add plumbing to
keep the map up to date through optimisations and add utility functions
including two that perform those lookups. Finally, add a unittest.

Details
In llvm/lib/IR/LLVMContextImpl.h add AssignmentIDToInstrs which maps DIAssignID
* attachments to Instruction *s. Because the DIAssignID * is the key we can't
use a TrackingMDNodeRef for it, and therefore cannot easily update the mapping
when a temporary DIAssignID is replaced.

Temporary DIAssignID's are only used in IR parsing to deal with metadata
forward references. Update llvm/lib/AsmParser/LLParser.cpp to avoid using
temporary DIAssignID's for attachments.

In llvm/lib/IR/Metadata.cpp add Instruction::updateDIAssignIDMapping which is
called to remove or add an entry (or both) to AssignmentIDToInstrs. Call this
from Instruction::setMetadata and add a call to setMetadata in Intruction's
dtor that explicitly unsets the DIAssignID so that the mappging gets updated.

In llvm/lib/IR/DebugInfo.cpp and DebugInfo.h add utility functions:

    getAssignmentInsts(const DbgAssignIntrinsic *DAI)
    getAssignmentMarkers(const Instruction *Inst)
    RAUW(DIAssignID *Old, DIAssignID *New)
    deleteAll(Function *F)
    deleteAssignmentMarkers(const Instruction *Inst)

These core utils are tested in llvm/unittests/IR/DebugInfoTest.cpp.

Reviewed By: jmorse

Differential Revision: https://reviews.llvm.org/D132224
2022-11-08 14:56:23 +00:00
..
distinct.ll [Assignment Tracking][3/*] Add DIAssignID metadata boilerplate 2022-11-07 09:05:56 +00:00
instruction-type.ll [Assignment Tracking][3/*] Add DIAssignID metadata boilerplate 2022-11-07 09:05:56 +00:00
operands.ll [Assignment Tracking][3/*] Add DIAssignID metadata boilerplate 2022-11-07 09:05:56 +00:00
roundtrip.ll [Assignment Tracking][4/*] Add llvm.dbg.assign intrinsic boilerplate 2022-11-07 10:09:22 +00:00
verify.ll Reapply [Assignment Tracking][5/*] Add core infrastructure for instruction reference 2022-11-08 14:56:23 +00:00