[Coverage] Precise region termination with deferred regions (reapply)

The current coverage implementation doesn't handle region termination
very precisely. Take for example an `if' statement with a `return':

  void f() {
    if (true) {
      return; // The `if' body's region is terminated here.
    }
    // This line gets the same coverage as the `if' condition.
  }

If the function `f' is called, the line containing the comment will be
marked as having executed once, which is not correct.

The solution here is to create a deferred region after terminating a
region. The deferred region is completed once the start location of the
next statement is known, and is then pushed onto the region stack.
In the cases where it's not possible to complete a deferred region, it
can safely be dropped.

Testing: lit test updates, a stage2 coverage-enabled build of clang

This is a reapplication but there are no changes from the original commit.
With D36813, the segment builder in llvm will be able to handle deferred
regions correctly.

llvm-svn: 312818

7 files changed, 190 insertions, 17 deletions

diff --git a/clang/test/CoverageMapping/deferred-region.cpp b/clang/test/CoverageMapping/deferred-region.cpp
new file mode 100644
index 00000000000..282b6a15630
--- /dev/null
+++ b/clang/test/CoverageMapping/deferred-region.cpp
@@ -0,0 +1,165 @@
+// 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
+
+#define IF if
+#define STMT(S) S
+
+// CHECK-LABEL: _Z3fooi:
+void foo(int x) {
+  if (x == 0) {
+    return;
+  } // CHECK: [[@LINE]]:4 -> [[@LINE+2]]:2 = (#0 - #1)
+
+}
+
+// CHECK-NEXT: _Z4foooi:
+void fooo(int x) {
+  if (x == 0) {
+    return;
+  } // CHECK: [[@LINE]]:4 -> [[@LINE+2]]:3 = (#0 - #1)
+
+  if (x == 1) {
+    return;
+  } // CHECK: [[@LINE]]:4 -> [[@LINE+2]]:2 = ((#0 - #1) - #2)
+
+}
+
+// CHECK-LABEL: _Z3bazv:
+void baz() { // CHECK: [[@LINE]]:12 -> [[@LINE+2]]:2
+  return;    // CHECK-NOT: File
+}
+
+// CHECK-LABEL: _Z3bari:
+void bar(int x) {
+  IF (x)
+    return; // CHECK: [[@LINE]]:11 -> [[@LINE+2]]:3 = (#0 - #1)
+
+  IF (!x)
+    return; // CHECK: [[@LINE]]:11 -> [[@LINE+2]]:3 = ((#0 - #1) - #2)
+
+  foo(x);
+}
+
+// CHECK-LABEL: _Z4quuxi:
+// Deferred regions are not emitted within macro expansions.
+void quux(int x) {
+  STMT(
+  if (x == 0)
+    return;)
+
+  // CHECK-NOT: [[@LINE-2]]:{{.*}} -> [[@LINE+2]]
+
+  if (x == 1)
+    STMT(return;)
+
+  // CHECK-NOT: [[@LINE-2]]:{{.*}} -> [[@LINE+3]]
+
+  STMT(
+  if (x == 2)
+    return;
+
+  // CHECK-NOT: [[@LINE-2]]:{{.*}} -> [[@LINE+2]]
+
+  if (x == 3)
+    return;
+  )
+}
+
+// CHECK-LABEL: _Z8weird_ifv:
+void weird_if() {
+  int i = 0;
+
+  if (false)
+    return; // CHECK: [[@LINE]]:11 -> [[@LINE+2]]:3 = (#0 - #1)
+
+  if (false)
+    i++;
+
+  if (i + 100 > 0) { // CHECK: [[@LINE]]:20 -> [[@LINE+6]]:4 = #3
+    if (false)       // CHECK: [[@LINE+1]]:7 -> [[@LINE+1]]:13 = #4
+      return;        // CHECK: [[@LINE]]:13 -> [[@LINE+2]]:5 = (#3 - #4)
+                     // CHECK: [[@LINE+1]]:5 -> [[@LINE+3]]:4 = (#3 - #4)
+    return;          // CHECK: [[@LINE]]:5 -> [[@LINE+4]]:3 = ((#0 - #1) - #3)
+
+  }
+
+  if (false)
+    return;
+}
+
+// CHECK-LABEL: _Z8for_loopv:
+void for_loop() {
+  if (false)
+    return; // CHECK: [[@LINE]]:11 -> [[@LINE+2]]:3 = (#0 - #1)
+
+  for (int i = 0; i < 10; ++i) {
+    if (i % 2 == 0)
+      continue; // CHECK: [[@LINE]]:15 -> [[@LINE+2]]:5 = (#2 - #3)
+
+    if (i % 5 == 0)
+      break; // CHECK: [[@LINE]]:12 -> [[@LINE+2]]:5 = ((#2 - #3) - #4)
+
+    int x = i; // CHECK: [[@LINE]]:5 -> [[@LINE+3]]:4 = ((#2 - #3) - #4)
+    return; // CHECK-NOT: [[@LINE]]:11 -> [[@LINE+2]]
+
+  }
+}
+
+struct Error {};
+
+// CHECK-LABEL: _Z10while_loopv:
+void while_loop() {
+  if (false)
+    return; // CHECK: [[@LINE]]:11 -> [[@LINE+2]]:3 = (#0 - #1)
+
+  int x = 0;
+  while (++x < 10) {
+    if (x == 1)
+      continue; // CHECK: [[@LINE]]:15 -> [[@LINE+2]]:5 = (#2 - #3)
+
+    while (++x < 4) {
+      if (x == 3)
+        break; // CHECK: [[@LINE]]:14 -> [[@LINE+2]]:7 = (#4 - #5)
+
+      while (++x < 5) {}
+    }
+
+    if (x == 0)
+      throw Error(); // CHECK: [[@LINE]]:20 -> [[@LINE+2]]:5 = ((#2 - #3) - #7)
+
+    while (++x < 9) {
+      if (x == 0)
+        break; // CHECK-NOT: [[@LINE]]:14 -> [[@LINE+2]]
+
+    }
+  }
+}
+
+// CHECK-LABEL: _Z5gotosv:
+void gotos() {
+  if (false)
+    goto out; // CHECK: [[@LINE]]:13 -> [[@LINE+2]]:3 = (#0 - #1)
+
+  return; // CHECK: [[@LINE]]:3 -> [[@LINE+4]]:2 = (#0 - #1)
+
+out:
+	return; // CHECK: [[@LINE]]:8 -> [[@LINE+1]]:2 = 0
+}
+
+int main() {
+  foo(0);
+  foo(1);
+  fooo(0);
+  fooo(1);
+  baz();
+  bar(0);
+  bar(1);
+  quux(0);
+  quux(1);
+  quux(2);
+  quux(3);
+  weird_if();
+  for_loop();
+  while_loop();
+  gotos();
+  return 0;
+}
diff --git a/clang/test/CoverageMapping/label.cpp b/clang/test/CoverageMapping/label.cpp
index 1c5111a675a..aec5e4f7ebf 100644
--- a/clang/test/CoverageMapping/label.cpp
+++ b/clang/test/CoverageMapping/label.cpp
@@ -14,19 +14,22 @@ void func() {                // CHECK-NEXT: File 0, [[@LINE]]:13 -> {{[0-9]+}}:2
       int m = 2;
     } else
       goto x;                // CHECK-NEXT: File 0, [[@LINE]]:7 -> [[@LINE]]:13 = (#1 - #2)
-    int k = 3;               // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE+1]]:4 = #3
-  }
-  static int j = 0;          // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+4]]:2 = ((#0 + #3) - #1)
+    int k = 3;               // CHECK-NEXT: File 0, [[@LINE-1]]:13 -> [[@LINE]]:5 = #3
+  }                          // CHECK-NEXT: File 0, [[@LINE-1]]:5 -> [[@LINE]]:4 = #3
+  static int j = 0;          // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+5]]:2 = ((#0 + #3) - #1)
   ++j;
   if(j == 1)                 // CHECK-NEXT: File 0, [[@LINE]]:6 -> [[@LINE]]:12 = ((#0 + #3) - #1)
     goto x;                  // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE]]:11 = #4
+                             // CHECK-NEXT: File 0, [[@LINE-1]]:11 -> [[@LINE+1]]:2 = (((#0 + #3) - #1) - #4)
 }
 
                              // CHECK-NEXT: test1
 void test1(int x) {          // CHECK-NEXT: File 0, [[@LINE]]:19 -> {{[0-9]+}}:2 = #0
   if(x == 0)                 // CHECK-NEXT: File 0, [[@LINE]]:6 -> [[@LINE]]:12 = #0
     goto a;                  // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE]]:11 = #1
-  goto b;                    // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE]]:9 = (#0 - #1)
+                             // CHECK-NEXT: File 0, [[@LINE-1]]:11 -> [[@LINE+1]]:3 = (#0 - #1)
+  goto b;                    // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+5]]:2 = (#0 - #1)
+                             // CHECK-NEXT: File 0, [[@LINE-1]]:3 -> [[@LINE+4]]:2 = #3
 a:                           // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+3]]:2 = #2
 b:                           // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+2]]:2 = #3
   x = x + 1;
@@ -36,9 +39,11 @@ b:                           // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+2]]:2
 void test2(int x) {          // CHECK-NEXT: File 0, [[@LINE]]:19 -> {{[0-9]+}}:2 = #0
   if(x == 0)                 // CHECK-NEXT: File 0, [[@LINE]]:6 -> [[@LINE]]:12 = #0
     goto a;                  // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE]]:11 = #1
-                             // CHECK-NEXT: File 0, [[@LINE+2]]:8 -> [[@LINE+2]]:25 = (#0 - #1)
+                             // CHECK-NEXT: File 0, [[@LINE-1]]:11 -> [[@LINE+3]]:8 = #0
+                             // CHECK-NEXT: File 0, [[@LINE+2]]:8 -> [[@LINE+3]]:11 = (#0 - #1)
                              // CHECK-NEXT: File 0, [[@LINE+1]]:11 -> [[@LINE+1]]:17 = (#0 - #1)
-  else if(x == 1) goto b;    // CHECK-NEXT: File 0, [[@LINE]]:19 -> [[@LINE]]:25 = #2
+  else if(x == 1)            // CHECK-NEXT: File 0, [[@LINE+1]]:5 -> [[@LINE+1]]:11 = #2
+    goto b;                  // CHECK-NEXT: File 0, [[@LINE]]:11 -> [[@LINE+1]]:1 = #3
 a:                           // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+3]]:2 = #3
 b:                           // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+2]]:2 = #4
   x = x + 1;
@@ -47,11 +52,13 @@ b:                           // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+2]]:2
                              // CHECK-NEXT: main
 int main() {                 // CHECK-NEXT: File 0, [[@LINE]]:12 -> {{[0-9]+}}:2 = #0
   int j = 0;
-  for(int i = 0; i < 10; ++i) { // CHECK: File 0, [[@LINE]]:31 -> [[@LINE+11]]:4 = #1
-  a:                         // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+10]]:4 = #2
+  for(int i = 0; i < 10; ++i) { // CHECK: File 0, [[@LINE]]:31 -> [[@LINE+13]]:4 = #1
+  a:                         // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+12]]:4 = #2
     if(i < 3)                // CHECK-NEXT: File 0, [[@LINE]]:8 -> [[@LINE]]:13 = #2
       goto e;                // CHECK-NEXT: File 0, [[@LINE]]:7 -> [[@LINE]]:13 = #3
-    goto c;                  // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE]]:11 = (#2 - #3)
+                             // CHECK-NEXT: File 0, [[@LINE-1]]:13 -> [[@LINE+1]]:5 = (#2 - #3)
+    goto c;                  // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE+8]]:4 = (#2 - #3)
+
   b:                         // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+6]]:4 = #4
     j = 2;
   c:                         // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+4]]:4 = #5
diff --git a/clang/test/CoverageMapping/moremacros.c b/clang/test/CoverageMapping/moremacros.c
index 56662270d07..630b75d855e 100644
--- a/clang/test/CoverageMapping/moremacros.c
+++ b/clang/test/CoverageMapping/moremacros.c
@@ -15,7 +15,7 @@ int main(int argc, const char *argv[]) {
   if (!argc) LBRAC
     return 0;
   // CHECK-NEXT: Expansion,File 0, [[@LINE+1]]:3 -> [[@LINE+1]]:8 = #2
-  RBRAC
+  RBRAC // CHECK-NEXT: [[@LINE]]:8 -> [[@LINE+6]]:3 = (#0 - #2)
 
   // CHECK-NEXT: File 0, [[@LINE+4]]:3 -> [[@LINE+15]]:2 = (#0 - #2)
   // CHECK-NEXT: File 0, [[@LINE+3]]:7 -> [[@LINE+3]]:12 = (#0 - #2)
@@ -23,7 +23,7 @@ int main(int argc, const char *argv[]) {
   // CHECK-NEXT: File 0, [[@LINE+1]]:19 -> [[@LINE+3]]:4 = #3
   if (!argc) LBRAC
     return 0;
-  }
+  } // CHECK-NEXT: [[@LINE]]:4 -> [[@LINE+5]]:3 = ((#0 - #2) - #3)
 
   // CHECK-NEXT: File 0, [[@LINE+3]]:3 -> [[@LINE+7]]:2 = ((#0 - #2) - #3)
   // CHECK-NEXT: File 0, [[@LINE+2]]:7 -> [[@LINE+2]]:12 = ((#0 - #2) - #3)
@@ -31,7 +31,7 @@ int main(int argc, const char *argv[]) {
   if (!argc) {
     return 0;
   // CHECK-NEXT: Expansion,File 0, [[@LINE+1]]:3 -> [[@LINE+1]]:8 = #4
-  RBRAC
+  RBRAC // CHECK-NEXT: [[@LINE]]:8 -> [[@LINE+1]]:2 = (((#0 - #2) - #3) - #4)
 }
 
 // CHECK-NEXT: File 1, 3:15 -> 3:16 = #2
diff --git a/clang/test/CoverageMapping/return.c b/clang/test/CoverageMapping/return.c
index 1b190b0eb73..3cc271b7ca3 100644
--- a/clang/test/CoverageMapping/return.c
+++ b/clang/test/CoverageMapping/return.c
@@ -13,7 +13,7 @@ void func2() {                  // CHECK-NEXT: File 0, [[@LINE]]:14 -> {{[0-9]+}
   for(int i = 0; i < 10; ++i) { // CHECK-NEXT: File 0, [[@LINE]]:31 -> {{[0-9]+}}:4 = #1
                                 // CHECK-NEXT: File 0, [[@LINE+1]]:8 -> [[@LINE+1]]:13 = #1
     if(i > 2) {                 // CHECK-NEXT: File 0, [[@LINE]]:15 -> [[@LINE+2]]:6 = #2
-      return;
+      return;                   // CHECK-NEXT: File 0, [[@LINE+1]]:6 -> [[@LINE+3]]:5 = (#1 - #2)
     }                           // CHECK-NEXT: File 0, [[@LINE+2]]:5 -> {{[0-9]+}}:4 = (#1 - #2)
                                 // CHECK-NEXT: File 0, [[@LINE+1]]:8 -> [[@LINE+1]]:14 = (#1 - #2)
     if(i == 3) {                // CHECK-NEXT: File 0, [[@LINE]]:16 -> [[@LINE+2]]:6 = #3
diff --git a/clang/test/CoverageMapping/switch.cpp b/clang/test/CoverageMapping/switch.cpp
index 52f22e8eda1..d347e663d10 100644
--- a/clang/test/CoverageMapping/switch.cpp
+++ b/clang/test/CoverageMapping/switch.cpp
@@ -6,7 +6,7 @@ void foo(int i) {   // CHECK-NEXT: File 0, [[@LINE]]:17 -> [[@LINE+8]]:2 = #0
   case 1:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:11 = #2
     return;
   case 2:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:10 = #3
-    break;
+    break;          // CHECK-NEXT: File 0, [[@LINE]]:10 -> [[@LINE+2]]:3 = #1
   }
   int x = 0;        // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:2 = #1
 }
@@ -55,7 +55,7 @@ int main() {        // CHECK-NEXT: File 0, [[@LINE]]:12 -> [[@LINE+35]]:2 = #0
     i = 2;
     break;
   default:          // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:10 = #4
-    break;
+    break;          // CHECK-NEXT: File 0, [[@LINE]]:10 -> [[@LINE+2]]:3 = #1
   }
   switch(i) {       // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+23]]:2 = #1
   case 0:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+2]]:10 = #6
@@ -64,7 +64,7 @@ int main() {        // CHECK-NEXT: File 0, [[@LINE]]:12 -> [[@LINE+35]]:2 = #0
   case 1:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+3]]:10 = #7
     i = 2;
   default:          // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:10 = (#7 + #8)
-    break;
+    break;          // CHECK-NEXT: File 0, [[@LINE]]:10 -> [[@LINE+3]]:3 = #5
   }
 
   switch(i) {       // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+13]]:2 = #5
diff --git a/clang/test/CoverageMapping/switchmacro.c b/clang/test/CoverageMapping/switchmacro.c
index 55f93d8f60c..8fb1b83d711 100644
--- a/clang/test/CoverageMapping/switchmacro.c
+++ b/clang/test/CoverageMapping/switchmacro.c
@@ -8,6 +8,7 @@ int foo(int i) { // CHECK-NEXT: File 0, [[@LINE]]:16 -> {{[0-9]+}}:2 = #0
   default:       // CHECK-NEXT: File 0, [[@LINE]]:3 -> {{[0-9]+}}:11 = #2
     if (i == 1)  // CHECK-NEXT: File 0, [[@LINE]]:9 -> [[@LINE]]:15 = #2
       return 0;  // CHECK-NEXT: File 0, [[@LINE]]:7 -> [[@LINE]]:15 = #3
+                 // CHECK-NEXT: File 0, [[@LINE-1]]:15 -> [[@LINE+3]]:5 = (#2 - #3)
     // CHECK-NEXT: Expansion,File 0, [[@LINE+2]]:5 -> [[@LINE+2]]:8 = (#2 - #3) (Expanded file = 1)
     // CHECK-NEXT: File 0, [[@LINE+1]]:8 -> {{[0-9]+}}:11 = (#2 - #3)
     FOO(1);
diff --git a/clang/test/CoverageMapping/trycatch.cpp b/clang/test/CoverageMapping/trycatch.cpp
index 01d8fb93074..37b35d30987 100644
--- a/clang/test/CoverageMapping/trycatch.cpp
+++ b/clang/test/CoverageMapping/trycatch.cpp
@@ -18,7 +18,7 @@ void func(int i) {                    // CHECK-NEXT: File 0, [[@LINE]]:18 -> {{[
                                       // 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: File 0, [[@LINE-1]]:27 -> [[@LINE]]:2 = ((#0 - #1) - #2)
 
                                       // CHECK-NEXT: main
 int main() {                          // CHECK-NEXT: File 0, [[@LINE]]:12 -> [[@LINE+13]]:2 = #0