[llvm-cov] Export decision coverage to output json

[uthmanna]

This commit adds decision coverage to the JSON output of llvm-cov, as discussed here: Missing Decision Coverage (DC) in output json with @evodius96

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[llvmbot]

@llvm/pr-subscribers-pgo

Author: None (uthmanna)

Changes

This commit adds decision coverage to the JSON output of llvm-cov, as discussed here: Missing Decision Coverage (DC) in output json with @evodius96

---

Full diff: https://github.com/llvm/llvm-project/pull/144335.diff

2 Files Affected:

• (modified) llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h (+3)
• (modified) llvm/tools/llvm-cov/CoverageExporterJson.cpp (+14-2)

diff --git a/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h b/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h
index d1230b0ba7c58..c9854e08a38e8 100644
--- a/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h
+++ b/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h
@@ -494,6 +494,9 @@ struct MCDCRecord {
     return TV[TestVectorIndex].first[PosToID[Condition]];
   }
 
+  /// Return the executed test vectors.
+  const TestVectors &getTV() const { return TV; }
+
   /// Return the Result evaluation for an executed test vector.
   /// See MCDCRecordProcessor::RecordTestVector().
   CondState getTVResult(unsigned TestVectorIndex) {
diff --git a/llvm/tools/llvm-cov/CoverageExporterJson.cpp b/llvm/tools/llvm-cov/CoverageExporterJson.cpp
index 4088c1b053aa8..cae7b86bc6b0c 100644
--- a/llvm/tools/llvm-cov/CoverageExporterJson.cpp
+++ b/llvm/tools/llvm-cov/CoverageExporterJson.cpp
@@ -62,7 +62,7 @@
 #include <utility>
 
 /// The semantic version combined as a string.
-#define LLVM_COVERAGE_EXPORT_JSON_STR "2.0.1"
+#define LLVM_COVERAGE_EXPORT_JSON_STR "3.0.0"
 
 /// Unique type identifier for JSON coverage export.
 #define LLVM_COVERAGE_EXPORT_JSON_TYPE_STR "llvm.coverage.json.export"
@@ -108,10 +108,22 @@ json::Array gatherConditions(const coverage::MCDCRecord &Record) {
   return Conditions;
 }
 
+std::pair<unsigned, unsigned> getDecisions(const coverage::MCDCRecord &Record) {
+  const coverage::MCDCRecord::TestVectors &TestVectors = Record.getTV();
+  const unsigned TrueConditions =
+      std::count_if(TestVectors.begin(), TestVectors.end(), [](const auto &TV) {
+        return TV.second == coverage::MCDCRecord::CondState::MCDC_True;
+      });
+
+  return {TrueConditions, TestVectors.size() - TrueConditions};
+}
+
 json::Array renderMCDCRecord(const coverage::MCDCRecord &Record) {
   const llvm::coverage::CounterMappingRegion &CMR = Record.getDecisionRegion();
+  const auto [TrueConditions, FalseConditions] = getDecisions(Record);
   return json::Array({CMR.LineStart, CMR.ColumnStart, CMR.LineEnd,
-                      CMR.ColumnEnd, CMR.ExpandedFileID, int64_t(CMR.Kind),
+                      CMR.ColumnEnd, TrueConditions, FalseConditions,
+                      CMR.ExpandedFileID, int64_t(CMR.Kind),
                       gatherConditions(Record)});
 }
 

[evodius96]

Thank you for updating this. We have not been good about moving the version forward.

[uthmanna]

This is actually very important to me, as I check this value to see whether the subsequent processing is still correct.

[evodius96]

As a design consideration, I'm reluctant to bring knowledge of test vectors into the Exporter and would favor encapsulating the calculation of the number of True and False test vectors within coverage::MCDCRecord. Basically, move getDecisions() into coverage::MCDCRecord. That routine can still return a pair of numbers.

[uthmanna]

Sounds reasonable, I've moved it, hope it's OK.

[evodius96]

LGTM. Do you have access to merge it? If not, I can attempt to merge it on your behalf.

[uthmanna]

@evodius96 It doesn't look like it, or I can't find it. Feel free to merge them. Thank you!