Commit Graph

7 Commits

Author SHA1 Message Date
OCHyams 26382a4412 Reapply [Assignment Tracking][5/*] Add core infrastructure for instruction reference
Previously reverted in 41f5a0004e. Fold in
D133576 previously reverted in d29d5ffb63.

---

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
Shubham Sandeep Rastogi 41f5a0004e Revert "[Assignment Tracking][5/*] Add core infrastructure for instruction reference"
This reverts commit 171f7024cc.

Reverting this patch because it causes a cyclic dependency in the module build

https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/48197/consoleFull#-69937453049ba4694-19c4-4d7e-bec5-911270d8a58c

In file included from <module-includes>:1:
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/IR/Argument.h:18:10: fatal error: cyclic dependency in module 'LLVM_IR': LLVM_IR -> LLVM_intrinsic_gen -> LLVM_IR
         ^
While building module 'LLVM_MC' imported from /Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/lib/MC/MCAsmInfoCOFF.cpp:14:
While building module 'LLVM_IR' imported from /Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/MC/MCPseudoProbe.h:57:
In file included from <module-includes>:12:
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/IR/DebugInfo.h:24:10: fatal error: could not build module 'LLVM_intrinsic_gen'
 ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
While building module 'LLVM_MC' imported from /Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/lib/MC/MCAsmInfoCOFF.cpp:14:
In file included from <module-includes>:15:
In file included from /Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/MC/MCContext.h:23:
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/MC/MCPseudoProbe.h:57:10: fatal error: could not build module 'LLVM_IR'
 ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/lib/MC/MCAsmInfoCOFF.cpp:14:10: fatal error: could not build module 'LLVM_MC'
 ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
4 errors generated.
2022-11-07 15:09:05 -08:00
OCHyams 171f7024cc [Assignment Tracking][5/*] Add core infrastructure for instruction reference
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)

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

Reviewed By: jmorse

Differential Revision: https://reviews.llvm.org/D132224
2022-11-07 12:03:02 +00:00
OCHyams c37f29c49e [Assignment Tracking][4/*] Add llvm.dbg.assign intrinsic boilerplate
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

Add the llvm.dbg.assign intrinsic boilerplate. This updates the textual-bitcode
roundtrip test to also check that round-tripping with the intrinsic works.

The intrinsic marks the position of a source level assignment.

The llvm.dbg.assign interface looks like this (each parameter is wrapped in
MetadataAsValue, and Value * type parameters are first wrapped in
ValueAsMetadata):

    void @llvm.dbg.assign(Value *Value,
                          DIExpression *ValueExpression,
                          DILocalVariable *Variable,
                          DIAssignID *ID,
                          Value *Address,
                          DIExpression *AddressExpression)

The first three parameters look and behave like an llvm.dbg.value. ID is a
reference to a store. The intrinsic is "linked to" instructions in the same
function that use the same ID as an attachment. That is mostly conceptual at
this point; the two-way link infrastructure will come in another patch. Address
is the destination address of the store and it is modified by
AddressExpression. LLVM currently encodes variable fragment information in
DIExpressions, so as an implementation quirk the FragmentInfo for Variable is
contained within ValueExpression only.

Reviewed By: jmorse

Differential Revision: https://reviews.llvm.org/D132223
2022-11-07 10:09:22 +00:00
OCHyams a2620e00ff [Assignment Tracking][3/*] Add DIAssignID metadata boilerplate
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

Add the DIAssignID metadata attachment boilerplate. Includes a textual-bitcode
roundtrip test and tests that the verifier and parser catch badly formed IR.

This piece of metadata links together stores (used as an attachment) and the
yet-to-be-added llvm.dbg.assign debug intrinsic (used as an operand).

Reviewed By: jmorse

Differential Revision: https://reviews.llvm.org/D132222
2022-11-07 09:05:56 +00:00
OCHyams fac26edae5 Revert "[Assignment Tracking][3/*] Add DIAssignID metadata boilerplate"
This reverts commit c285df77e9b78f971f9cd9d025248c20b030cc2a.

A sanitizer bot found an issue:
https://lab.llvm.org/buildbot/#/builders/5/builds/28809/steps/13/logs/stdio
2022-11-03 13:46:00 +00:00
OCHyams e53c4c6d86 [Assignment Tracking][3/*] Add DIAssignID metadata boilerplate
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

Add the DIAssignID metadata attachment boilerplate. Includes a textual-bitcode
roundtrip test and tests that the verifier and parser catch badly formed IR.

This piece of metadata links together stores (used as an attachment) and the
yet-to-be-added llvm.dbg.assign debug intrinsic (used as an operand).

Reviewed By: jmorse

Differential Revision: https://reviews.llvm.org/D132222
2022-11-03 11:24:18 +00:00