[llvm] [clang] [coverage] skipping code coverage for 'if constexpr' and 'if consteval' (PR #78033)

[Hana Dusíková via cfe-commits]

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@@ -1251,6 +1264,69 @@ struct CounterCoverageMappingBuilder
     popRegions(Index);
   }
 
+  /// Find a valid range starting with \p StartingLoc and ending before \p
+  /// BeforeLoc.
+  std::optional<SourceRange> findAreaStartingFromTo(SourceLocation StartingLoc,
+                                                    SourceLocation BeforeLoc) {
+    // If StartingLoc is in function-like macro, use its start location.
+    if (StartingLoc.isMacroID()) {
+      FileID FID = SM.getFileID(StartingLoc);
+      const SrcMgr::ExpansionInfo *EI = &SM.getSLocEntry(FID).getExpansion();
+      if (EI->isFunctionMacroExpansion())
+        StartingLoc = EI->getExpansionLocStart();
+    }
+
+    size_t StartDepth = locationDepth(StartingLoc);
+    size_t EndDepth = locationDepth(BeforeLoc);
+    while (!SM.isWrittenInSameFile(StartingLoc, BeforeLoc)) {
+      bool UnnestStart = StartDepth >= EndDepth;
+      bool UnnestEnd = EndDepth >= StartDepth;
+      if (UnnestEnd) {
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hanickadot wrote:

it's a pattern used thru whole `CoverageMappingGen.cpp` file, it's copied and modified existing functions for calculating Gap regions, so I would rather not

https://github.com/llvm/llvm-project/pull/78033