Since the migration from `@llvm.dbg.value` intrinsic to `#dbg_value`
records, there is no way to retrieve the debug records for an
`Instruction` in LLVM-C API.
Previously, with debug info intrinsics, retrieving debug info for an
`Instruction` could be done with `LLVMGetNextInstructions`, because the
intrinsic call was also an instruction.
However, to be able to retrieve debug info with the current LLVM, where
debug records are used, the `getDbgRecordRange()` iterator needs to be
exposed.
Add new functions for DbgRecord sequence traversal:
LLVMGetFirstDbgRecord
LLVMGetLastDbgRecord
LLVMGetNextDbgRecord
LLVMGetPreviousDbgRecord
See llvm/docs/RemoveDIsDebugInfo.md and release notes.
Related review: https://github.com/llvm/llvm-project/pull/91724
This patch updates the RemoveDIs migration document to include details
on the textual IR changes, including steps to update any downstream lit
tests accordingly. These steps are the same as those used to update the
lit tests in the LLVM/Clang lit tests, as detailed in the review linked
above.
Add `LLVMPositionBuilderBeforeDbgRecords` and
`LLVMPositionBuilderBeforeInstrAndDbgRecords` to `llvm/include/llvm-c/Core.h`
which behave the same as `LLVMPositionBuilder` and `LVMPositionBuilderBefore`
except that the position is set before debug records attached to the target
instruction (the existing functions set the insertion point to after any
attached debug records).
More info on debug records and the migration towards using them can be found
here: https://llvm.org/docs/RemoveDIsDebugInfo.html
The distinction is important in some situations. An important example is when
inserting a phi before another instruction which has debug records attached to
it (these come "before" the instruction). Inserting before the instruction but
after the debug records would result in having debug records before a phi, which
is illegal. That results in an assertion failure:
`llvm/lib/IR/Instruction.cpp:166: Assertion '!isa<PHINode>(this) && "Inserting
PHI after debug-records!"' failed.`
In llvm (C++) we've added bit to instruction iterators that carries around the
extra information. Adding dedicated functions seemed like the least invasive and
least suprising way to update the C API.
Update llvm/tools/llvm-c-test/debuginfo.c to test this functionality.
Update the OCaml bindings, the migration docs and release notes.
Although the patch that enables debug records by default has been
temporarily reverted, it will (eventually) be reverted and everyone's
code will be subjected to the new debug info format. Although this is
broadly a good thing, it is important that the documentation has enough
information to guide users through the update; this patch adds what
should hopefully be enough detail for most users to either find the
answers, or find out how to find those answers.
Follow on from #84915 which adds the DbgRecord function variants. The C API
changes were reviewed in #85657.
# C API
Update the LLVMDIBuilderInsert... functions to insert DbgRecords instead
of debug intrinsics.
LLVMDIBuilderInsertDeclareBefore
LLVMDIBuilderInsertDeclareAtEnd
LLVMDIBuilderInsertDbgValueBefore
LLVMDIBuilderInsertDbgValueAtEnd
Calling these functions will now cause an assertion if the module is in the
wrong debug info format. They should only be used when the module is in "new
debug format".
Use LLVMIsNewDbgInfoFormat to query and LLVMSetIsNewDbgInfoFormat to change the
debug info format of a module.
Please see https://llvm.org/docs/RemoveDIsDebugInfo.html#c-api-change
(RemoveDIsDebugInfo.md) for more info.
# OCaml bindings
Add set_is_new_dbg_info_format and is_new_dbg_info_format to the OCaml bindings.
These can be used to set and query the current debug info mode. These will
eventually be removed, but are useful while we're transitioning between old and
new debug info formats.
Add string_of_lldbgrecord, like string_of_llvalue but prints DbgRecords.
In test dbginfo.ml, unconditionally set the module debug info to the new mode
and update CHECK lines to check for DbgRecords. Without this change the test
crashes because it attempts to insert DbgRecords (new default behaviour of
llvm_dibuild_insert_declare_...) into a module that is in the old debug info
mode.
Follow on from #84915 which adds the DbgRecord function variants.
Update the LLVMDIBuilderInsert... functions to insert DbgRecords instead
of debug intrinsics.
LLVMDIBuilderInsertDeclareBefore
LLVMDIBuilderInsertDeclareAtEnd
LLVMDIBuilderInsertDbgValueBefore
LLVMDIBuilderInsertDbgValueAtEnd
Calling these functions will now cause an assertion if the module is in the
wrong debug info format. They should only be used when the module is in "new
debug format".
Use LLVMIsNewDbgInfoFormat to query and LLVMSetIsNewDbgInfoFormat to change the
debug info format of a module.
Please see https://llvm.org/docs/RemoveDIsDebugInfo.html#c-api-change
(RemoveDIsDebugInfo.md) for more info.
Another trivial rename patch, the last big one for now, which renamed
DPMarkers to DbgMarkers. This required the field `DbgMarker` in
`Instruction` to be renamed to `DebugMarker` to avoid a clash, but
otherwise was a simple string substitution of `s/DPMarker/DbgMarker` and
a manual renaming of `DPM` to `DM` in the few places where that acronym
was used for debug markers.
This patch renames DPLabel to DbgLabelRecord, in accordance with the
ongoing DbgRecord rename. This rename was fairly trivial, since DPLabel
isn't as widely used as DPValue and has no real conflicts in either its
full or abbreviated name. As usual, the entire replacement was done
automatically, with `s/DPLabel/DbgLabelRecord/` and `s/DPL/DLR/`.
This is the major rename patch that prior patches have built towards.
The DPValue class is being renamed to DbgVariableRecord, which reflects
the updated terminology for the "final" implementation of the RemoveDI
feature. This is a pure string substitution + clang-format patch. The
only manual component of this patch was determining where to perform
these string substitutions: `DPValue` and `DPV` are almost exclusively
used for DbgRecords, *except* for:
- llvm/lib/target, where 'DP' is used to mean double-precision, and so
appears as part of .td files and in variable names. NB: There is a
single existing use of `DPValue` here that refers to debug info, which
I've manually updated.
- llvm/tools/gold, where 'LDPV' is used as a prefix for symbol
visibility enums.
Outside of these places, I've applied several basic string
substitutions, with the intent that they only affect DbgRecord-related
identifiers; I've checked them as I went through to verify this, with
reasonable confidence that there are no unintended changes that slipped
through the cracks. The substitutions applied are all case-sensitive,
and are applied in the order shown:
```
DPValue -> DbgVariableRecord
DPVal -> DbgVarRec
DPV -> DVR
```
Following the previous rename patches, it should be the case that there
are no instances of any of these strings that are meant to refer to the
general case of DbgRecords, or anything other than the DPValue class.
The idea behind this patch is therefore that pure string substitution is
correct in all cases as long as these assumptions hold.
Follow on from #84739, which updates the DIBuilder class.
All the functions that have been added are temporary and will be
deprecated in the future. The intention is that they'll help downstream
projects adapt during the transition period.
```
New functions (all to be deprecated)
------------------------------------
LLVMIsNewDbgInfoFormat # Returns true if the module is in the new non-instruction mode.
LLVMSetIsNewDbgInfoFormat # Convert to the requested debug info format.
LLVMDIBuilderInsertDeclareIntrinsicBefore # Insert a debug intrinsic (old debug info format).
LLVMDIBuilderInsertDeclareIntrinsicAtEnd # Same as above.
LLVMDIBuilderInsertDbgValueIntrinsicBefore # Same as above.
LLVMDIBuilderInsertDbgValueIntrinsicAtEnd # Same as above.
LLVMDIBuilderInsertDeclareRecordBefore # Insert a debug record (new debug info format).
LLVMDIBuilderInsertDeclareRecordAtEnd # Same as above.
LLVMDIBuilderInsertDbgValueRecordBefore # Same as above.
LLVMDIBuilderInsertDbgValueRecordAtEnd # Same as above.
```
The existing `LLVMDIBuilderInsert...` functions call through to the
intrinsic versions (old debug info format) currently.
In the next patch, I'll swap them to call the debug records versions
(new debug info format). Downstream users of this API can query and
change the current format using the first two functions above, or can
instead opt to temporarily use intrinsics or records explicitly.
This patch adds some small updates to the LLVM documentation regarding
DbgRecords to accurately describe the current class structure. There are
some more refactorings to come, so this isn't intended to be the final
document update, but it covers the immediate task of updating references
to DPValue that really refer to DbgRecord.
As part of the effort to rename the DbgRecord classes, this patch
renames the widely-used functions that operate on DbgRecords but refer
to DbgValues or DPValues in their names to refer to DbgRecords instead;
all such functions are defined in one of `BasicBlock.h`,
`Instruction.h`, and `DebugProgramInstruction.h`.
This patch explicitly does not change the names of any comments or
variables, except for where they use the exact name of one of the
renamed functions. The reason for this is reviewability; this patch can
be trivially examined to determine that the only changes are direct
string substitutions and any results from clang-format responding to the
changed line lengths. Future patches will cover renaming variables and
comments, and then renaming the classes themselves.
This is a high level description and FAQ for what we're doing in
RemoveDIs, and how old code should be behave with new debug-info
(exactly the same 99% of the time).
