[coverage] Fix coverage with default arguments

In the presence of default arguments, the body of the function gets
wrapped into another block. This caused our trailing-range-after-return
optimization to not apply, because the wrapper block had no source
range assigned. This CL correctly assignes a source range to that block,
which allows already present code to handle it correctly.

Note that this is not a real coverage bug; we've just been reporting
whitespace as uncovered. We're fixing it for consistency.

Originally reported on github.com/bcoe/c8/issues/66

Bug: v8:9952
Change-Id: Iab3905f558eb99126e0dad8072d03d0a312fdcd3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1903430
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64836}

src/parsing/parser-base.h

@@ -4114,6 +4114,7 @@ void ParserBase<Impl>::ParseFunctionBody(
       inner_body.Rewind();
       inner_body.Add(inner_block);
       inner_block->set_scope(inner_scope);
+      impl()->RecordBlockSourceRange(inner_block, scope()->end_position());
       if (!impl()->HasCheckedSyntax()) {
         const AstRawString* conflict = inner_scope->FindVariableDeclaredIn(
             function_scope, VariableMode::kLastLexicalVariableMode);

test/mjsunit/code-coverage-block-async.js

@@ -119,4 +119,21 @@ new Foo().timeout().next();               // 0400
   {"start":184,"end":302,"count":0},
   {"start":158,"end":182,"count":1}] );
 
+TestCoverage(
+"https://crbug.com/v8/9952",
+`
+async function test(foo) {                // 0000
+  return {bar};                           // 0050
+                                          // 0100
+  function bar() {                        // 0150
+    console.log("test");                  // 0200
+  }                                       // 0250
+}                                         // 0300
+test().then(r => r.bar());                // 0350
+%PerformMicrotaskCheckpoint();            // 0400`,
+[{"start":0,"end":449,"count":1},
+ {"start":0,"end":301,"count":1},
+ {"start":152,"end":253,"count":1},
+ {"start":362,"end":374,"count":1}]);
+
 %DebugToggleBlockCoverage(false);

test/mjsunit/code-coverage-block.js

@@ -1083,4 +1083,33 @@ TestCoverage(
  {"start":16,"end":33,"count":0}]
 );
 
+TestCoverage(
+"https://crbug.com/v8/9952",
+`
+function test(foo = "foodef") {           // 0000
+  return {bar};                           // 0050
+                                          // 0100
+  function bar() {                        // 0150
+    console.log("test");                  // 0200
+  }                                       // 0250
+}                                         // 0300
+test().bar();                             // 0350`,
+[{"start":0,"end":399,"count":1},
+ {"start":0,"end":301,"count":1},
+ {"start":152,"end":253,"count":1}]);
+
+TestCoverage(
+"https://crbug.com/v8/9952",
+`
+function test(foo = (()=>{})) {           // 0000
+  return {foo};                           // 0050
+}                                         // 0100
+                                          // 0150
+test(()=>{}).foo();                       // 0200`,
+[{"start":0,"end":249,"count":1},
+ {"start":0,"end":101,"count":1},
+ {"start":21,"end":27,"count":0},
+ {"start":205,"end":211,"count":1}]
+);
+
 %DebugToggleBlockCoverage(false);