From 2b9475136a86dbdd27a1005cf5c9a7fd6887a511 Mon Sep 17 00:00:00 2001
From: Tom Stellard <tstellar@redhat.com>
Date: Wed, 28 Nov 2018 20:04:13 +0000
Subject: Merging r347262:

------------------------------------------------------------------------
r347262 | vedantk | 2018-11-19 12:10:22 -0800 (Mon, 19 Nov 2018) | 8 lines

[Coverage] Fix PR39258: support coverage regions that start deeper than they end

popRegions used to assume that the start location of a region can't be
nested deeper than the end location, which is not always true.

Patch by Orivej Desh!

Differential Revision: https://reviews.llvm.org/D53244
------------------------------------------------------------------------
---
 clang/lib/CodeGen/CoverageMappingGen.cpp | 53 +++++++++++++++++++++++++-------
 clang/test/CoverageMapping/macros.c      | 10 ++++++
 2 files changed, 52 insertions(+), 11 deletions(-)

diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp
index 389d29e467b..45a260b41d4 100644
--- a/clang/lib/CodeGen/CoverageMappingGen.cpp
+++ b/clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -553,6 +553,15 @@ struct CounterCoverageMappingBuilder
     completeDeferred(Count, DeferredEndLoc);
   }
 
+  size_t locationDepth(SourceLocation Loc) {
+    size_t Depth = 0;
+    while (Loc.isValid()) {
+      Loc = getIncludeOrExpansionLoc(Loc);
+      Depth++;
+    }
+    return Depth;
+  }
+
   /// Pop regions from the stack into the function's list of regions.
   ///
   /// Adds all regions from \c ParentIndex to the top of the stack to the
@@ -567,19 +576,41 @@ struct CounterCoverageMappingBuilder
         SourceLocation EndLoc = Region.hasEndLoc()
                                     ? Region.getEndLoc()
                                     : RegionStack[ParentIndex].getEndLoc();
+        size_t StartDepth = locationDepth(StartLoc);
+        size_t EndDepth = locationDepth(EndLoc);
         while (!SM.isWrittenInSameFile(StartLoc, EndLoc)) {
-          // The region ends in a nested file or macro expansion. Create a
-          // separate region for each expansion.
-          SourceLocation NestedLoc = getStartOfFileOrMacro(EndLoc);
-          assert(SM.isWrittenInSameFile(NestedLoc, EndLoc));
-
-          if (!isRegionAlreadyAdded(NestedLoc, EndLoc))
-            SourceRegions.emplace_back(Region.getCounter(), NestedLoc, EndLoc);
-
-          EndLoc = getPreciseTokenLocEnd(getIncludeOrExpansionLoc(EndLoc));
-          if (EndLoc.isInvalid())
-            llvm::report_fatal_error("File exit not handled before popRegions");
+          bool UnnestStart = StartDepth >= EndDepth;
+          bool UnnestEnd = EndDepth >= StartDepth;
+          if (UnnestEnd) {
+            // The region ends in a nested file or macro expansion. Create a
+            // separate region for each expansion.
+            SourceLocation NestedLoc = getStartOfFileOrMacro(EndLoc);
+            assert(SM.isWrittenInSameFile(NestedLoc, EndLoc));
+
+            if (!isRegionAlreadyAdded(NestedLoc, EndLoc))
+              SourceRegions.emplace_back(Region.getCounter(), NestedLoc, EndLoc);
+
+            EndLoc = getPreciseTokenLocEnd(getIncludeOrExpansionLoc(EndLoc));
+            if (EndLoc.isInvalid())
+              llvm::report_fatal_error("File exit not handled before popRegions");
+            EndDepth--;
+          }
+          if (UnnestStart) {
+            // The region begins in a nested file or macro expansion. Create a
+            // separate region for each expansion.
+            SourceLocation NestedLoc = getEndOfFileOrMacro(StartLoc);
+            assert(SM.isWrittenInSameFile(StartLoc, NestedLoc));
+
+            if (!isRegionAlreadyAdded(StartLoc, NestedLoc))
+              SourceRegions.emplace_back(Region.getCounter(), StartLoc, NestedLoc);
+
+            StartLoc = getIncludeOrExpansionLoc(StartLoc);
+            if (StartLoc.isInvalid())
+              llvm::report_fatal_error("File exit not handled before popRegions");
+            StartDepth--;
+          }
         }
+        Region.setStartLoc(StartLoc);
         Region.setEndLoc(EndLoc);
 
         MostRecentLocation = EndLoc;
diff --git a/clang/test/CoverageMapping/macros.c b/clang/test/CoverageMapping/macros.c
index 95fe37ed7e8..39cd190b2a8 100644
--- a/clang/test/CoverageMapping/macros.c
+++ b/clang/test/CoverageMapping/macros.c
@@ -4,6 +4,7 @@
 #define MACRO_2 bar()
 #define MACRO_1 return; MACRO_2
 #define MACRO_3 MACRO_2
+#define GOTO goto
 
 void bar() {}
 
@@ -56,6 +57,15 @@ void func5() { // CHECK-NEXT: File 0, [[@LINE]]:14 -> [[@LINE+4]]:2 = #0
 // CHECK-NEXT: Expansion,File 1, 6:17 -> 6:24 = #1
 // CHECK-NEXT: File 2, 4:17 -> 4:22 = #1
 
+// CHECK-NEXT: func6
+void func6(unsigned count) { // CHECK-NEXT: File 0, [[@LINE]]:28 -> [[@LINE+4]]:2 = #0
+begin:                       // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+3]]:2 = #1
+    if (count--)             // CHECK-NEXT: File 0, [[@LINE]]:9 -> [[@LINE]]:16 = #1
+        GOTO begin;          // CHECK-NEXT: File 0, [[@LINE]]:9 -> [[@LINE]]:19 = #2
+}
+// CHECK-NEXT: Expansion,File 0, [[@LINE-2]]:9 -> [[@LINE-2]]:13 = #2
+// CHECK-NEXT: File 1, 7:14 -> 7:18 = #2
+
 int main(int argc, const char *argv[]) {
   func();
   func2();
-- 
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