[Coverage] Push a region and propagate counts through try blocks

[vsk]

Summary

This lets us handle expansions in the try block properly. Here's how the final report changes:

Before:

       |   20|// CHECK: Z3fn4v:
      1|   21|#define TRY2 try { // CHECK-DAG: File 1, [[@LINE]]:18 -> [[@LINE]]:19 = #1
      1|   22|void fn4() TRY2 // CHECK-DAG: Expansion,File 0, [[@LINE]]:12 -> [[@LINE]]:16 = #1 (Expanded file = 1)
                         ^1  ^1
      1|   23|  for (;;)
      1|   24|    return;
      1|   25|}
      0|   26|catch (...) {}
       |   27|
       |   28|// CHECK: Z3fn5v:
       |   29|#define TRY3 try { return; } catch (...) // CHECK-DAG: File 2, [[@LINE]]:18 -> [[@LINE]]:29 = #1
      0|   30|#define TRY4 try { TRY3 { return; } } catch (...) // CHECK-DAG: Expansion,File 1, [[@LINE]]:20 -> [[@LINE]]:24 = #1 (Expanded file = 2)
      1|   31|void fn5() {
      1|   32|  for (;;) {
      0|   33|    TRY4 { return; } // CHECK-DAG: Expansion,File 0, [[@LINE]]:5 -> [[@LINE]]:9 = #1 (Expanded file = 1)
                  ^0   ^0
      1|   34|  }                  // CHECK-DAG: File 0, [[@LINE-1]]:10 -> [[@LINE-1]]:21 = #5
      1|   35|}


After:

       |   20|// CHECK: Z3fn4v:
      1|   21|#define TRY2 try { // CHECK-DAG: File 1, [[@LINE]]:18 -> [[@LINE]]:19 = #1
                           ^1  ^1
      1|   22|void fn4() TRY2 // CHECK-DAG: Expansion,File 0, [[@LINE]]:12 -> [[@LINE]]:16 = #1 (Expanded file = 1)
                         ^1  ^1
      1|   23|  for (;;)
      1|   24|    return;
      1|   25|}
      0|   26|catch (...) {}
       |   27|
       |   28|// CHECK: Z3fn5v:
      1|   29|#define TRY3 try { return; } catch (...) // CHECK-DAG: File 2, [[@LINE]]:18 -> [[@LINE]]:29 = #1
      1|   30|#define TRY4 try { TRY3 { return; } } catch (...) // CHECK-DAG: Expansion,File 1, [[@LINE]]:20 -> [[@LINE]]:24 = #1 (Expanded file = 2)
                               ^1^1   ^0
      1|   31|void fn5() {
      1|   32|  for (;;) {
      1|   33|    TRY4 { return; } // CHECK-DAG: Expansion,File 0, [[@LINE]]:5 -> [[@LINE]]:9 = #1 (Expanded file = 1)
                  ^1   ^0
      1|   34|  }                  // CHECK-DAG: File 0, [[@LINE-1]]:10 -> [[@LINE-1]]:21 = #5
      1|   35|}

[vsk]

Ping.

[vsk]

This change is probably too minor for pre-commit review. I rebased the patch and committed r273463: I'd be happy to make any changes to it if requested.

lib/CodeGen/CoverageMappingGen.cpp

       OutCount = addCounters(OutCount, ElseCount);
 
     if (OutCount != ParentCount)
       pushRegion(OutCount);
   }
 
   void VisitCXXTryStmt(const CXXTryStmt *S) {
     extendRegion(S);
-    Visit(S->getTryBlock());
+    // Handle macros that generate the "try" but not the rest.
+    extendRegion(S->getTryBlock());
+
+    Counter ParentCount = getRegion().getCounter();
+    propagateCounts(ParentCount, S->getTryBlock());
+
     for (unsigned I = 0, E = S->getNumHandlers(); I < E; ++I)
       Visit(S->getHandler(I));
   }
 
   void VisitCXXCatchStmt(const CXXCatchStmt *S) {
     propagateCounts(getRegionCounter(S), S->getHandlerBlock());
   }
 

test/CoverageMapping/trycatch.cpp

int j = 0;                        // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE+2]]:4 = 0
                                       // CHECK-NEXT: File 0, [[@LINE+1]]:10 -> [[@LINE+2]]:27 = (#0 - #1)
   } else if(i == 8)                   // CHECK-NEXT: File 0, [[@LINE]]:13 -> [[@LINE]]:19 = (#0 - #1)
     throw ImportantError();           // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE]]:27 = #2
 }
 
                                       // CHECK-NEXT: main
 int main() {                          // CHECK-NEXT: File 0, [[@LINE]]:12 -> [[@LINE+13]]:2 = #0
   int j = 1;
-  try {
+  try {                               // CHECK-NEXT: File 0, [[@LINE]]:7 -> [[@LINE+2]]:4 = #0
     func(j);
   } catch(const Error &e) {           // CHECK-NEXT: File 0, [[@LINE]]:27 -> [[@LINE+2]]:4 = #2
     j = 1;
   } catch(const ImportantError &e) {  // CHECK-NEXT: File 0, [[@LINE]]:36 -> [[@LINE+2]]:4 = #3
     j = 11;
   }
   catch(const Warning &w) {           // CHECK-NEXT: File 0, [[@LINE]]:27 -> [[@LINE+2]]:4 = #4
     j = 0;
   }
   return 0;
 }

test/CoverageMapping/trymacro.cpp

 
 #define TRY try
 #define CATCH(x) catch (x)
 
 // CHECK: Z3fn3v:
 void fn3() TRY { return; } // CHECK: [[@LINE]]:15 -> [[@LINE+1]]:14 = #1
 CATCH(...) {}              // CHECK: [[@LINE]]:12 -> [[@LINE]]:14 = #2
 
+// CHECK: Z3fn4v:
+#define TRY2 try { // CHECK-DAG: File 1, [[@LINE]]:18 -> [[@LINE]]:19 = #1
+void fn4() TRY2 // CHECK-DAG: Expansion,File 0, [[@LINE]]:12 -> [[@LINE]]:16 = #1 (Expanded file = 1)
+  for (;;)
+    return;
+}
+catch (...) {}
+
+// CHECK: Z3fn5v:
+#define TRY3 try { return; } catch (...) // CHECK-DAG: File 2, [[@LINE]]:18 -> [[@LINE]]:29 = #1
+#define TRY4 try { TRY3 { return; } } catch (...) // CHECK-DAG: Expansion,File 1, [[@LINE]]:20 -> [[@LINE]]:24 = #1 (Expanded file = 2)
+void fn5() {
+  for (;;) {
+    TRY4 { return; } // CHECK-DAG: Expansion,File 0, [[@LINE]]:5 -> [[@LINE]]:9 = #1 (Expanded file = 1)
+  }                  // CHECK-DAG: File 0, [[@LINE-1]]:10 -> [[@LINE-1]]:21 = #5
+}
+
 int main() {
   fn1();
   fn2();
   fn3();
+  fn4();
+  fn5();
 }