When processing coverage generated from branch coverage mode, some
functions can reach findMainViewFileID with an empty CountedRegions
list. In that case the current logic still proceeds to infer the main
view file, even though there is no regular counted region available to
do so.
Return std::nullopt early when CountedRegions is empty.
This was observed when reproducing issue #189169 with:
cargo llvm-cov --lib --branch
The issue appears related to branch-only coverage information being
recorded separately in CountedBranchRegions, while
findMainViewFileID currently only consults CountedRegions.
This patch is a defensive fix for the empty-region case; further
investigation may still be needed to determine whether branch regions
should participate in main view file selection.
Co-authored-by: Zile Xiong <xiongzile99@gmail.com>
CoverageMappingWriter reorders `Region`s by `endLoc DESC` to prioritize
wider `Decision` with the same `startLoc`.
In `llvm-cov`, tweak seeking Decisions by reversal order to find smaller
Decision first.
Since #119952, `getCoverageForFile` and `getCoverageForFunction` have
similar structure each other. Ther merged method `addFunctionRegions`
has two lambda subfunctions.
* `getCoverageForFile`
- `MainFileID` may be `nullopt`.
- `shouldProcess` picks up relevant records along `FileIDs` that is
scanned based on `MainFileID`. They may have expanded source files.
- `shouldExpand` takes the presense of `MainFileID` into account.
* `getCoverageForFunction`
- This assumes the presense of `MainFileID`.
- `shouldProcess` picks up records that belong only to `MainFileID`.
- `shouldExpand` assumes the presense of `MainFileID`.
This change introduces a wrapper class `MergeableCoverageData` for
further merging instances. At the moment, this returns `CoverageData`
including `buildSegments()`.
This change itself is NFC.
`getBranchCounterPair()` allocates an additional Counter to SkipPath in
`SingleByteCoverage`.
`IsCounterEqual()` calculates the comparison with rewinding counter
replacements.
`NumRegionCounters` is updated to take additional counters in account.
`incrementProfileCounter()` has a few additiona arguments.
- `UseSkipPath=true`, to specify setting counters for SkipPath. It
assumes `UseSkipPath=false` is used together.
- `UseBoth` may be specified for marking another path. It introduces the
same effect as issueing `markStmtAsUsed(!SkipPath, S)`.
`llvm-cov` discovers counters in `FalseCount` to allocate `MaxCounterID`
for empty profile data.
https://discourse.llvm.org/t/rfc-integrating-singlebytecoverage-with-branch-coverage/82492
Resumes: #112730
Depends on: #112698#112702#112724
When no profile is provided, but the new --empty-profile option is
specified, the export/report/show commands now emit coverage data
equivalent to that obtained from a profile with all zero counters
("baseline coverage").
This is useful for build systems (e.g. Bazel) that can track coverage
information for each build target, even those that are never linked into
tests and thus don't have runtime coverage data recorded. By merging in
baseline coverage, lines in files that aren't linked into tests are
correctly reported as uncovered.
Reland with fixes to `CoverageMappingTest.cpp`.
Reverts llvm/llvm-project#144121
Reverts llvm/llvm-project#117910
```
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/unittests/ProfileData/CoverageMappingTest.cpp
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/unittests/ProfileData/CoverageMappingTest.cpp:281:28: error: 'std::reference_wrapper' may not intend to support class template argument deduction [-Werror,-Wctad-maybe-unsupported]
281 | std::make_optional(std::reference_wrapper(*ProfileReader));
| ^
/usr/lib/gcc/ppc64le-redhat-linux/8/../../../../include/c++/8/bits/refwrap.h:289:11: note: add a deduction guide to suppress this warning
289 | class reference_wrapper
| ^
```
When no profile is provided, but the new --empty-profile option is
specifed, the export/report/show commands now emit coverage data
equivalent to that obtained from a profile with all zero counters
("baseline coverage").
This is useful for build systems (e.g. Bazel) that can track coverage
information for each build target, even those that are never linked into
tests and thus don't have runtime coverage data recorded. By merging in
baseline coverage, lines in files that aren't linked into tests are
correctly reported as uncovered.
When iterating over function records, filtered by file name, currently,
the iteration goes over all the function records, repeatedly for each
source file, essentially giving quadratic behavior.
413647d730972eac9675f695c2ea63fb393a5531 sped up some cases by keeping
track of the indices of the function records corresponding to each file
name. This change expands the use of that map to FunctionRecordIterator.
On a test case with Firefox's libxul.so and a 2.5MB profile, this brings
down the runtime of `llvm-cov export $lib --instr-profile $prof -t lcov`
from 12 minutes with 90% spent in skipOtherFiles to 19 seconds with no
samples in skipOtherFiles at all under a sampling profiler (with a
sampling interval of 1ms).
Fixes#62079
The result of "Independence pairs" is not mergeable. This change makes
defers re-calculation of "Independence pairs" after merging test
vectors.
No apparent behavior changes.
Currently both True/False counts were folded. It lost the information,
"It is True or False before folding." It prevented recalling branch
counts in merging template instantiations.
In `llvm-cov`, a folded branch is shown as:
- `[True: n, Folded]`
- `[Folded, False n]`
In the case If `n` is zero, a branch is reported as "uncovered". This is
distinguished from "folded" branch. When folded branches are merged,
`Folded` may be dissolved.
In the coverage map, either `Counter` is `Zero`. Currently both were
`Zero`.
Since "partial fold" has been introduced, either case in `switch` is
omitted as `Folded`.
Each `case:` in `switch` is reported as `[True: n, Folded]`, since
`False` count doesn't show meaningful value.
When `switch` doesn't have `default:`, `switch (Cond)` is reported as
`[Folded, False: n]`, since `True` count was just the sum of `case`(s).
`switch` with `default` can be considered as "the statement that doesn't
have any `False`(s)".
By storing possible test vectors instead of combinations of conditions,
the restriction is dramatically relaxed.
This introduces two options to `cc1`:
* `-fmcdc-max-conditions=32767`
* `-fmcdc-max-test-vectors=2147483646`
This change makes coverage mapping, profraw, and profdata incompatible
with Clang-18.
- Bitmap semantics changed. It is incompatible with previous format.
- `BitmapIdx` in `Decision` points to the end of the bitmap.
- Bitmap is packed per function.
- `llvm-cov` can understand `profdata` generated by `llvm-profdata-18`.
RFC:
https://discourse.llvm.org/t/rfc-coverage-new-algorithm-and-file-format-for-mc-dc/76798
--
Change(s) since llvmorg-19-init-14288-g7ead2d8c7e91
- Update compiler-rt/test/profile/ContinuousSyncMode/image-with-mcdc.c
This broke the lit tests on Mac:
https://green.lab.llvm.org/job/llvm.org/job/clang-stage1-RA/1096/
> By storing possible test vectors instead of combinations of conditions,
> the restriction is dramatically relaxed.
>
> This introduces two options to `cc1`:
>
> * `-fmcdc-max-conditions=32767`
> * `-fmcdc-max-test-vectors=2147483646`
>
> This change makes coverage mapping, profraw, and profdata incompatible
> with Clang-18.
>
> - Bitmap semantics changed. It is incompatible with previous format.
> - `BitmapIdx` in `Decision` points to the end of the bitmap.
> - Bitmap is packed per function.
> - `llvm-cov` can understand `profdata` generated by `llvm-profdata-18`.
>
> RFC:
> https://discourse.llvm.org/t/rfc-coverage-new-algorithm-and-file-format-for-mc-dc/76798
This reverts commit 7ead2d8c7e9114b3f23666209a1654939987cb30.
By storing possible test vectors instead of combinations of conditions,
the restriction is dramatically relaxed.
This introduces two options to `cc1`:
* `-fmcdc-max-conditions=32767`
* `-fmcdc-max-test-vectors=2147483646`
This change makes coverage mapping, profraw, and profdata incompatible
with Clang-18.
- Bitmap semantics changed. It is incompatible with previous format.
- `BitmapIdx` in `Decision` points to the end of the bitmap.
- Bitmap is packed per function.
- `llvm-cov` can understand `profdata` generated by `llvm-profdata-18`.
RFC:
https://discourse.llvm.org/t/rfc-coverage-new-algorithm-and-file-format-for-mc-dc/76798
This replaces `SmallVector<CondState>` and emulates it.
- -------- True False DontCare
- Values: True False False
- Visited: True True False
`findIndependencePairs()` can be optimized with logical ops.
FIXME: Specialize `findIndependencePairs()` for the single word.
To reduce conditional judges in the loop in `findIndependencePairs()`, I
have tried a couple of tweaks.
* Isolate the final result in `TestVectors`
`using TestVectors = llvm::SmallVector<std::pair<TestVector,
CondState>>;`
The final result was just piggybacked on `TestVector`, so it has been
isolated.
* Filter out and sort `ExecVectors` by the final result
It will cost more in constructing `ExecVectors`, but it can reduce at
least one conditional judgement in the loop.
This patch inserts 1-byte counters instead of an 8-byte counters into
llvm profiles for source-based code coverage. The origial idea was
proposed as block-cov for PGO, and this patch repurposes that idea for
coverage: https://groups.google.com/g/llvm-dev/c/r03Z6JoN7d4
The current 8-byte counters mechanism add counters to minimal regions,
and infer the counters in the remaining regions via adding or
subtracting counters. For example, it infers the counter in the if.else
region by subtracting the counters between if.entry and if.then regions
in an if statement. Whenever there is a control-flow merge, it adds the
counters from all the incoming regions. However, we are not going to be
able to infer counters by subtracting two execution counts when using
single-byte counters. Therefore, this patch conservatively inserts
additional counters for the cases where we need to add or subtract
counters.
RFC:
https://discourse.llvm.org/t/rfc-single-byte-counters-for-source-based-code-coverage/75685
This is a preparation of incoming Clang changes (#82448) and just checks
`TVIdx` is calculated correctly. NFC.
`TVIdxBuilder` calculates deterministic Indices for each Condition Node.
It is used for `clang` to emit `TestVector` indices (aka ID) and for
`llvm-cov` to reconstruct `TestVectors`.
This includes the unittest `CoverageMappingTest.TVIdxBuilder`.
See also
https://discourse.llvm.org/t/rfc-coverage-new-algorithm-and-file-format-for-mc-dc/76798
- Prune `RegionMCDCBitmapMap` and `RegionCondIDMap`. They are handled
by `MCDCState`.
- Rename `s/BitmapMap/DecisionByStmt/`. It can handle Decision stuff.
- Rename `s/CondIDMap/BranchByStmt/`. It can be handle Branch stuff.
- `MCDCRecordProcessor`: Use `DecisionParams.BitmapIdx` directly.
Also, Let `NumConditions` `uint16_t`.
It is smarter to handle the ID as signed.
Narrowing to `int16_t` will reduce costs of handling byvalue. (See also
#81221 and #81227)
External behavior doesn't change. They below handle values as internal
values plus 1.
* `-dump-coverage-mapping`
* `CoverageMappingReader.cpp`
* `CoverageMappingWriter.cpp`
Introduce `mcdc::DecisionParameters` and `mcdc::BranchParameters` and make
sure them not initialized as zero.
FIXME: Could we make `CoverageMappingRegion` as a smart tagged union?
They can be also used in `clang`.
Introduce the lightweight header instead of `CoverageMapping.h`.
This includes for now:
* `mcdc::ConditionID`
* `mcdc::Parameters`
Deprecate `TestVectors`, since no one uses it.
This affects the output order of ExecVectors.
The current impl emits sorted by binary value of ExecVector. This impl
emits along the traversal of `buildTestVector()`.
* `getFunctionBitmap()` stores not `std::vector<uint8_t>` but
`BitVector`.
* `CounterMappingContext` holds `Bitmap` (instead of the ref of bytes)
* `Bitmap` and `BitmapIdx` are used instead of `evaluateBitmap()`.
FIXME: `InstrProfRecord` itself should handle `Bitmap` as `BitVector`.
The current implementation (D138849) assumes `Branch`(es) would follow
after the corresponding `Decision`. It is not true if `Branch`(es) are
forwarded to expanded file ID. As a result, consecutive `Decision`(s)
would be confused with insufficient number of `Branch`(es).
`Expansion` will point `Branch`(es) in other file IDs if `Expansion` is
included in the range of `Decision`.
Fixes#77871
---------
Co-authored-by: Alan Phipps <a-phipps@ti.com>
Update code from https://reviews.llvm.org/D138847
`buildTestVector` is a standard DFS (walking a reduced ordered binary
decision diagram). Avoid shouldCopyOffTestVectorFor{True,False}Path
complexity and redundant `Map[ID]` lookups.
`findIndependencePairs` unnecessarily uses four nested loops (n<=6) to
find independence pairs. Instead, enumerate the two execution vectors
and find the number of mismatches. This algorithm can be optimized using
the marking function technique described in _Efficient Test Coverage
Measurement for MC/DC, 2013_, but this may be overkill.
In `CoverageMapping.cpp:getMaxBitmapSize()`,
this assumed that the last `Decision` has the maxmum `BitmapIdx`.
Let it scan `max(BitmapIdx)`.
Note that `<=` is used insted of `<`, because `BitmapIdx == 0` is valid
and `MaxBitmapID` is `unsigned`. `BitmapIdx` is unique in the record.
Fixes#78922
The life of `MCDCRecordProcessor`'s instance is short. It may accept
`const` objects to process.
On the other hand, the life of `MCDCBranches` is shorter than `Record`.
It may be rewritten with reference, rather than copying.
`if constexpr` and `if consteval` conditional statements code coverage
should behave more like a preprocesor `#if`-s than normal
ConditionalStmt. This PR should fix that.
---------
Co-authored-by: cor3ntin <corentinjabot@gmail.com>
Fixes a build failure introduced by
commit 8ecbb0404d74 ("Reland [Coverage][llvm-cov]
Enable MC/DC Support in LLVM Source-based Code Coverage (2/3)")
Use of pow() is not necessary.
