[coverage] Support conditional expressions

Bug: v8:6000
Change-Id: I8c068383300ba869a87f836504c84ea08fcff87e
Reviewed-on: https://chromium-review.googlesource.com/568307
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46675}

src/ast/ast-source-ranges.h

@@ -31,6 +31,7 @@ struct SourceRange {
 #define AST_SOURCE_RANGE_LIST(V) \
   V(Block)                       \
   V(CaseClause)                  \
+  V(Conditional)                 \
   V(IfStatement)                 \
   V(IterationStatement)          \
   V(JumpStatement)               \
@@ -88,6 +89,28 @@ class CaseClauseSourceRanges final : public AstNodeSourceRanges {
   SourceRange body_range_;
 };
 
+class ConditionalSourceRanges final : public AstNodeSourceRanges {
+ public:
+  explicit ConditionalSourceRanges(const SourceRange& then_range,
+                                   const SourceRange& else_range)
+      : then_range_(then_range), else_range_(else_range) {}
+
+  SourceRange GetRange(SourceRangeKind kind) {
+    switch (kind) {
+      case SourceRangeKind::kThen:
+        return then_range_;
+      case SourceRangeKind::kElse:
+        return else_range_;
+      default:
+        UNREACHABLE();
+    }
+  }
+
+ private:
+  SourceRange then_range_;
+  SourceRange else_range_;
+};
+
 class IfStatementSourceRanges final : public AstNodeSourceRanges {
  public:
   explicit IfStatementSourceRanges(const SourceRange& then_range,

src/interpreter/bytecode-generator.cc

@@ -1851,12 +1851,19 @@ void BytecodeGenerator::VisitDoExpression(DoExpression* expr) {
 }
 
 void BytecodeGenerator::VisitConditional(Conditional* expr) {
+  int then_slot =
+      AllocateBlockCoverageSlotIfEnabled(expr, SourceRangeKind::kThen);
+  int else_slot =
+      AllocateBlockCoverageSlotIfEnabled(expr, SourceRangeKind::kElse);
+
   if (expr->condition()->ToBooleanIsTrue()) {
     // Generate then block unconditionally as always true.
     VisitForAccumulatorValue(expr->then_expression());
+    BuildIncrementBlockCoverageCounterIfEnabled(then_slot);
   } else if (expr->condition()->ToBooleanIsFalse()) {
     // Generate else block unconditionally if it exists.
     VisitForAccumulatorValue(expr->else_expression());
+    BuildIncrementBlockCoverageCounterIfEnabled(else_slot);
   } else {
     BytecodeLabel end_label;
     BytecodeLabels then_labels(zone()), else_labels(zone());
@@ -1865,10 +1872,12 @@ void BytecodeGenerator::VisitConditional(Conditional* expr) {
                  TestFallthrough::kThen);
 
     then_labels.Bind(builder());
+    BuildIncrementBlockCoverageCounterIfEnabled(then_slot);
     VisitForAccumulatorValue(expr->then_expression());
     builder()->Jump(&end_label);
 
     else_labels.Bind(builder());
+    BuildIncrementBlockCoverageCounterIfEnabled(else_slot);
     VisitForAccumulatorValue(expr->else_expression());
     builder()->Bind(&end_label);
   }

src/parsing/parser-base.h

@@ -2953,6 +2953,7 @@ ParserBase<Impl>::ParseConditionalExpression(bool accept_IN,
   //   LogicalOrExpression
   //   LogicalOrExpression '?' AssignmentExpression ':' AssignmentExpression
 
+  SourceRange then_range, else_range;
   int pos = peek_position();
   // We start using the binary expression parser for prec >= 4 only!
   ExpressionT expression = ParseBinaryExpression(4, accept_IN, CHECK_OK);
@@ -2964,6 +2965,7 @@ ParserBase<Impl>::ParseConditionalExpression(bool accept_IN,
 
   ExpressionT left;
   {
+    SourceRangeScope range_scope(scanner(), &then_range);
     ExpressionClassifier classifier(this);
     // In parsing the first assignment expression in conditional
     // expressions we always accept the 'in' keyword; see ECMA-262,
@@ -2975,12 +2977,15 @@ ParserBase<Impl>::ParseConditionalExpression(bool accept_IN,
   Expect(Token::COLON, CHECK_OK);
   ExpressionT right;
   {
+    SourceRangeScope range_scope(scanner(), &else_range);
     ExpressionClassifier classifier(this);
     right = ParseAssignmentExpression(accept_IN, CHECK_OK);
     AccumulateNonBindingPatternErrors();
   }
   impl()->RewriteNonPattern(CHECK_OK);
-  return factory()->NewConditional(expression, left, right, pos);
+  ExpressionT expr = factory()->NewConditional(expression, left, right, pos);
+  impl()->RecordConditionalSourceRange(expr, then_range, else_range);
+  return expr;
 }
 
 

src/parsing/parser.h

@@ -1157,6 +1157,15 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
                               new (zone()) CaseClauseSourceRanges(body_range));
   }
 
+  V8_INLINE void RecordConditionalSourceRange(Expression* node,
+                                              const SourceRange& then_range,
+                                              const SourceRange& else_range) {
+    if (source_range_map_ == nullptr) return;
+    source_range_map_->Insert(
+        node->AsConditional(),
+        new (zone()) ConditionalSourceRanges(then_range, else_range));
+  }
+
   V8_INLINE void RecordJumpStatementSourceRange(Statement* node,
                                                 int32_t continuation_position) {
     if (source_range_map_ == nullptr) return;

src/parsing/preparser.h

@@ -1748,6 +1748,9 @@ class PreParser : public ParserBase<PreParser> {
                                         int32_t continuation_position) {}
   V8_INLINE void RecordCaseClauseSourceRange(PreParserStatement node,
                                              const SourceRange& body_range) {}
+  V8_INLINE void RecordConditionalSourceRange(PreParserExpression node,
+                                              const SourceRange& then_range,
+                                              const SourceRange& else_range) {}
   V8_INLINE void RecordIfStatementSourceRange(PreParserStatement node,
                                               const SourceRange& then_range,
                                               const SourceRange& else_range) {}

test/inspector/cpu-profiler/coverage-block-expected.txt

@@ -304,6 +304,11 @@ Running test: testPreciseCountCoverageIncremental
                                 startOffset : 74
                             }
                             [1] : {
+                                count : 0
+                                endOffset : 156
+                                startOffset : 145
+                            }
+                            [2] : {
                                 count : 0
                                 endOffset : 175
                                 startOffset : 173

test/mjsunit/code-coverage-block.js

@@ -504,4 +504,38 @@ TestCoverage(
  {"start":621,"end":653,"count":0}]
 );
 
+TestCoverage(
+"conditional expressions",
+`
+var TRUE = true;                          // 0000
+var FALSE = false;                        // 0050
+!function() {                             // 0100
+  TRUE ? nop() : nop();                   // 0150
+  true ? nop() : nop();                   // 0200
+  false ? nop() : nop();                  // 0250
+  FALSE ? TRUE ? nop()                    // 0300
+               : nop()                    // 0350
+        : nop();                          // 0400
+  TRUE ? FALSE ? nop()                    // 0450
+               : nop()                    // 0500
+       : nop();                           // 0550
+  TRUE ? nop() : FALSE ? nop()            // 0600
+                       : nop();           // 0650
+  FALSE ? nop() : TRUE ? nop()            // 0700
+                       : nop();           // 0750
+}();                                      // 0800
+`,
+[{"start":0,"end":849,"count":1},
+ {"start":101,"end":801,"count":1},
+ {"start":167,"end":172,"count":0},
+ {"start":217,"end":222,"count":0},
+ {"start":260,"end":265,"count":0},
+ {"start":310,"end":372,"count":0},
+ {"start":467,"end":472,"count":0},
+ {"start":559,"end":564,"count":0},
+ {"start":617,"end":680,"count":0},
+ {"start":710,"end":715,"count":0},
+ {"start":775,"end":780,"count":0}]
+);
+
 %DebugToggleBlockCoverage(false);