[Coverage] Emit deferred regions in headers

There are some limitations with emitting regions in macro expansions
because we don't gather file IDs within the expansions. Fix the check
that prevents us from emitting deferred regions in expansions to make an
exception for headers, which is something we can handle.

rdar://35373009

llvm-svn: 317760

3 files changed, 22 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp
index 26236b72ff7..6e0099bc201 100644
--- a/clang/lib/CodeGen/CoverageMappingGen.cpp
+++ b/clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -496,12 +496,14 @@ struct CounterCoverageMappingBuilder
     DeferredRegion = None;
 
     // If the region ends in an expansion, find the expansion site.
-    if (SM.getFileID(DeferredEndLoc) != SM.getMainFileID()) {
-      FileID StartFile = SM.getFileID(DR.getStartLoc());
+    FileID StartFile = SM.getFileID(DR.getStartLoc());
+    if (SM.getFileID(DeferredEndLoc) != StartFile) {
       if (isNestedIn(DeferredEndLoc, StartFile)) {
         do {
           DeferredEndLoc = getIncludeOrExpansionLoc(DeferredEndLoc);
         } while (StartFile != SM.getFileID(DeferredEndLoc));
+      } else {
+        return Index;
       }
     }
 
@@ -591,7 +593,7 @@ struct CounterCoverageMappingBuilder
           if (!DeferredRegion.hasValue() &&
               // File IDs aren't gathered within macro expansions, so it isn't
               // useful to try and create a deferred region inside of one.
-              (SM.getFileID(EndLoc) == SM.getMainFileID()))
+              !EndLoc.isMacroID())
             DeferredRegion =
                 SourceMappingRegion(Counter::getZero(), EndLoc, None);
         }
diff --git a/clang/test/CoverageMapping/Inputs/deferred-region-helper.h b/clang/test/CoverageMapping/Inputs/deferred-region-helper.h
new file mode 100644
index 00000000000..c3e5c16e32a
--- /dev/null
+++ b/clang/test/CoverageMapping/Inputs/deferred-region-helper.h
@@ -0,0 +1,5 @@
+void included_func() {
+  if (false)
+    return;
+  return;
+}
diff --git a/clang/test/CoverageMapping/deferred-region.cpp b/clang/test/CoverageMapping/deferred-region.cpp
index 3504588a6c3..5a104f77897 100644
--- a/clang/test/CoverageMapping/deferred-region.cpp
+++ b/clang/test/CoverageMapping/deferred-region.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -std=c++11 -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -fexceptions -fcxx-exceptions -emit-llvm-only -triple %itanium_abi_triple -main-file-name deferred-region.cpp %s | FileCheck %s
+// RUN: %clang_cc1 -std=c++11 -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -fexceptions -fcxx-exceptions -emit-llvm-only -triple %itanium_abi_triple -main-file-name deferred-region.cpp -I %S/Inputs %s | FileCheck %s
 
 #define IF if
 #define STMT(S) S
@@ -170,6 +170,16 @@ out:
 	return; // CHECK: Gap,File 0, [[@LINE]]:8 -> [[@LINE+1]]:2 = 0
 }
 
+#include "deferred-region-helper.h"
+// CHECK-LABEL: _Z13included_funcv:
+// CHECK:  Gap,File 0, 2:13 -> 3:5 = #1
+// CHECK:  Gap,File 0, 3:11 -> 4:3 = (#0 - #1)
+
+// CHECK-LABEL: _Z7includev:
+void include() {
+  included_func();
+}
+
 int main() {
   foo(0);
   foo(1);
@@ -189,5 +199,6 @@ int main() {
   for_loop();
   while_loop();
   gotos();
+  include();
   return 0;
 }