-
Notifications
You must be signed in to change notification settings - Fork 14.6k
[Coverage] Handles macros from system headers and nested macros in scratch space #94438
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Closed
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
- Introduce `LeafExprSet`, - Suppress traversing LAnd and LOr expr under system headers. - Handle LAnd and LOr as instrumented leaves to override `!isInstrumentedCondition(C)`. - Replace Loc with FileLoc if it is expanded with system headers. Fixes llvm#78920 llvmorg-19-init-11775-g702a2b627ff4
This amends 702a2b6 to hopefully get the test passing for Windows again. llvmorg-19-init-11817-g3591da9f1ccb
The problematic program is as follows: ```shell void f(void) { PRE(a) && 0; } int main(void) { return 0; } ``` in which after token concatenation (`##`), there's another nested macro `pre_a`. Currently only the outer expansion region will be produced. ([compiler explorer link](https://godbolt.org/#g:!((g:!((g:!((h:codeEditor,i:(filename:'1',fontScale:14,fontUsePx:'0',j:1,lang:___c,selection:(endColumn:29,endLineNumber:8,positionColumn:29,positionLineNumber:8,selectionStartColumn:29,selectionStartLineNumber:8,startColumn:29,startLineNumber:8),source:'%23define+pre_a+0%0A%23define+PRE(x)+pre_%23%23x%0A%0Avoid+f(void)+%7B%0A++++PRE(a)+%26%26+0%3B%0A%7D%0A%0Aint+main(void)+%7B+return+0%3B+%7D'),l:'5',n:'0',o:'C+source+%231',t:'0')),k:51.69491525423727,l:'4',n:'0',o:'',s:0,t:'0'),(g:!((g:!((h:compiler,i:(compiler:cclang_assertions_trunk,filters:(b:'0',binary:'1',binaryObject:'1',commentOnly:'0',debugCalls:'1',demangle:'0',directives:'0',execute:'0',intel:'0',libraryCode:'1',trim:'1',verboseDemangling:'0'),flagsViewOpen:'1',fontScale:14,fontUsePx:'0',j:2,lang:___c,libs:!(),options:'-fprofile-instr-generate+-fcoverage-mapping+-fcoverage-mcdc+-Xclang+-dump-coverage-mapping+',overrides:!(),selection:(endColumn:1,endLineNumber:1,positionColumn:1,positionLineNumber:1,selectionStartColumn:1,selectionStartLineNumber:1,startColumn:1,startLineNumber:1),source:1),l:'5',n:'0',o:'+x86-64+clang+(assertions+trunk)+(Editor+%231)',t:'0')),k:34.5741843594503,l:'4',m:28.903654485049834,n:'0',o:'',s:0,t:'0'),(g:!((h:output,i:(compilerName:'x86-64+clang+(trunk)',editorid:1,fontScale:14,fontUsePx:'0',j:2,wrap:'1'),l:'5',n:'0',o:'Output+of+x86-64+clang+(assertions+trunk)+(Compiler+%232)',t:'0')),header:(),l:'4',m:71.09634551495017,n:'0',o:'',s:0,t:'0')),k:48.30508474576271,l:'3',n:'0',o:'',t:'0')),l:'2',m:100,n:'0',o:'',t:'0')),version:4)) ```text f: File 0, 4:14 -> 6:2 = #0 Decision,File 0, 5:5 -> 5:16 = M:0, C:2 Expansion,File 0, 5:5 -> 5:8 = #0 (Expanded file = 1) File 0, 5:15 -> 5:16 = llvm#1 Branch,File 0, 5:15 -> 5:16 = 0, 0 [2,0,0] File 1, 2:16 -> 2:23 = #0 File 2, 1:15 -> 1:16 = #0 File 2, 1:15 -> 1:16 = #0 Branch,File 2, 1:15 -> 1:16 = 0, 0 [1,2,0] ``` The inner expansion region isn't produced because: 1. In the range-based for loop quoted below, each sloc is processed and possibly emit a corresponding expansion region. 2. For our sloc in question, its direct parent returned by `getIncludeOrExpansionLoc()` is a `<scratch space>`, because that's how `##` is processed. https://github.com/llvm/llvm-project/blob/88b6186af3908c55b357858eb348b5143f21c289/clang/lib/CodeGen/CoverageMappingGen.cpp#L518-L520 3. This `<scratch space>` cannot be found in the FileID mapping so `ParentFileID` will be assigned an `std::nullopt` https://github.com/llvm/llvm-project/blob/88b6186af3908c55b357858eb348b5143f21c289/clang/lib/CodeGen/CoverageMappingGen.cpp#L521-L526 4. As a result this iteration of for loop finishes early and no expansion region is added for the sloc. This problem gets worse with MC/DC: as the example shows, there's a branch from File 2 but File 2 itself is missing. This will trigger assertion failures. The fix is more or less a workaround and takes a similar approach as ~~Depends on llvm#89573.~~ This includes llvm#89573. Kudos to @chapuni! This and llvm#89573 together fix llvm#87000: I tested locally, both the reduced program and my original use case (fwiw, Linux kernel) can run successfully. --------- Co-authored-by: NAKAMURA Takumi <[email protected]> llvmorg-19-init-12274-gf9e9e599c013
@llvm/pr-subscribers-clang-codegen @llvm/pr-subscribers-clang Author: Wentao Zhang (whentojump) ChangesBackports #89869 and #91446 (and associated tests in 3591da9) that fixes missing code regions and With them, we are able to measure MC/DC of large C/C++ projects like LLVM itself and Linux kernel. Full diff: https://github.com/llvm/llvm-project/pull/94438.diff 5 Files Affected:
|
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Labels
clang:codegen
IR generation bugs: mangling, exceptions, etc.
clang
Clang issues not falling into any other category
coverage
release:backport
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Backports #89869 and #91446 (and associated tests in 3591da9) that fixes missing code regions and
llvm-cov
crashes.With them, we are able to measure MC/DC of large C/C++ projects like LLVM itself and Linux kernel.