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deps: v8, cherry-pick 9365d09, aac2f8c, 47d34a3
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  Original commit message 9365d09:

      [coverage] Rework continuation counter handling

      This changes a few bits about how continuation counters are handled.

      It introduces a new mechanism that allows removal of a continuation
      range after it has been created. If coverage is enabled, we run a first
      post-processing pass on the AST immediately after parsing, which
      removes problematic continuation ranges in two situations:

      1. nested continuation counters - only the outermost stays alive.
      2. trailing continuation counters within a block-like structure are
         removed if the containing structure itself has a continuation.

      [email protected], [email protected], [email protected]

      Bug: v8:8381, v8:8539
      Change-Id: I6bcaea5060d8c481d7bae099f6db9f993cc30ee3
      Reviewed-on: https://chromium-review.googlesource.com/c/1339119
      Reviewed-by: Yang Guo <[email protected]>
      Reviewed-by: Leszek Swirski <[email protected]>
      Reviewed-by: Georg Neis <[email protected]>
      Commit-Queue: Jakob Gruber <[email protected]>
      Cr-Commit-Position: refs/heads/master@{#58443}

  Refs: v8/v8@9365d09

  Original commit message aac2f8c:

      [coverage] Filter out singleton ranges that alias full ranges

      Block coverage is based on a system of ranges that can either have
      both a start and end position, or only a start position (so-called
      singleton ranges). When formatting coverage information, singletons
      are expanded until the end of the immediate full parent range. E.g.
      in:

      {0, 10}  // Full range.
      {5, -1}  // Singleton range.

      the singleton range is expanded to {5, 10}.

      Singletons are produced mostly for continuation counters that track
      whether we execute past a specific language construct.

      Unfortunately, continuation counters can turn up in spots that confuse
      our post-processing. For example:

      if (true) { ... block1 ... } else { ... block2 ... }

      If block1 produces a continuation counter, it could end up with the
      same start position as the else-branch counter. Since we merge
      identical blocks, the else-branch could incorrectly end up with an
      execution count of one.

      We need to avoid merging such cases. A full range should always take
      precedence over a singleton range; a singleton range should never
      expand to completely fill a full range. An additional post-processing
      pass ensures this.

      Bug: v8:8237
      Change-Id: Idb3ec7b2feddc0585313810b9c8be1e9f4ec64bf
      Reviewed-on: https://chromium-review.googlesource.com/c/1273095
      Reviewed-by: Georg Neis <[email protected]>
      Reviewed-by: Yang Guo <[email protected]>
      Commit-Queue: Jakob Gruber <[email protected]>
      Cr-Commit-Position: refs/heads/master@{#56531}

  Refs: v8/v8@aac2f8c

  deps: V8: backport 47d34a3

  Original commit message:

      Revert "[coverage] change block range to avoid ambiguity."

      This reverts commit 471fef0469d04d7c487f3a08e81f3d77566a2f50.

      Reason for revert: A more general fix incoming at https://crrev.com/c/1273095.

      Original change's description:
      > [coverage] change block range to avoid ambiguity.
      >
      > By moving the block range end to left of closing bracket,
      > we can avoid ambiguity where an open-ended singleton range
      > could be both interpreted as inside the parent range, or
      > next to it.
      >
      > R=<U+200B>[email protected]
      >
      > Bug: v8:8237
      > Change-Id: Ibc9412b31efe900b6d8bff0d8fa8c52ddfbf460a
      > Reviewed-on: https://chromium-review.googlesource.com/1254127
      > Reviewed-by: Georg Neis <[email protected]>
      > Commit-Queue: Yang Guo <[email protected]>
      > Cr-Commit-Position: refs/heads/master@{#56347}

      [email protected],[email protected],[email protected]

      # Not skipping CQ checks because original CL landed > 1 day ago.

      Bug: v8:8237
      Change-Id: I39310cf3c2f06a0d98ff314740aaeefbfffc0834
      Reviewed-on: https://chromium-review.googlesource.com/c/1273096
      Reviewed-by: Jakob Gruber <[email protected]>
      Reviewed-by: Toon Verwaest <[email protected]>
      Reviewed-by: Yang Guo <[email protected]>
      Commit-Queue: Jakob Gruber <[email protected]>
      Cr-Commit-Position: refs/heads/master@{#56513}

  Refs: v8/v8@47d34a3

PR-URL: #25429
Backport-PR-URL: #25728
Reviewed-By: Yang Guo <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>

Reviewed-By: Anna Henningsen <[email protected]>
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@bcoe @addaleax
bcoe authored and addaleax committed Feb 1, 2019
1 parent 411f6fe commit 673e434
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Showing 13 changed files with 392 additions and 166 deletions.
2 changes: 2 additions & 0 deletions deps/v8/BUILD.gn
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Original file line number Diff line number Diff line change
Expand Up @@ -1570,6 +1570,8 @@ v8_source_set("v8_base") {
"src/ast/prettyprinter.h",
"src/ast/scopes.cc",
"src/ast/scopes.h",
"src/ast/source-range-ast-visitor.cc",
"src/ast/source-range-ast-visitor.h",
"src/ast/variables.cc",
"src/ast/variables.h",
"src/bailout-reason.cc",
Expand Down
2 changes: 2 additions & 0 deletions deps/v8/gypfiles/v8.gyp
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Original file line number Diff line number Diff line change
Expand Up @@ -548,6 +548,8 @@
'../src/ast/prettyprinter.h',
'../src/ast/scopes.cc',
'../src/ast/scopes.h',
'../src/ast/source-range-ast-visitor.cc',
'../src/ast/source-range-ast-visitor.h',
'../src/ast/variables.cc',
'../src/ast/variables.h',
'../src/bailout-reason.cc',
Expand Down
88 changes: 80 additions & 8 deletions deps/v8/src/ast/ast-source-ranges.h
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Original file line number Diff line number Diff line change
Expand Up @@ -58,18 +58,24 @@ class AstNodeSourceRanges : public ZoneObject {
public:
virtual ~AstNodeSourceRanges() {}
virtual SourceRange GetRange(SourceRangeKind kind) = 0;
virtual bool HasRange(SourceRangeKind kind) = 0;
virtual void RemoveContinuationRange() { UNREACHABLE(); }
};

class BinaryOperationSourceRanges final : public AstNodeSourceRanges {
public:
explicit BinaryOperationSourceRanges(const SourceRange& right_range)
: right_range_(right_range) {}

SourceRange GetRange(SourceRangeKind kind) {
SourceRange GetRange(SourceRangeKind kind) override {
DCHECK_EQ(kind, SourceRangeKind::kRight);
return right_range_;
}

bool HasRange(SourceRangeKind kind) override {
return kind == SourceRangeKind::kRight;
}

private:
SourceRange right_range_;
};
Expand All @@ -79,11 +85,20 @@ class ContinuationSourceRanges : public AstNodeSourceRanges {
explicit ContinuationSourceRanges(int32_t continuation_position)
: continuation_position_(continuation_position) {}

SourceRange GetRange(SourceRangeKind kind) {
SourceRange GetRange(SourceRangeKind kind) override {
DCHECK_EQ(kind, SourceRangeKind::kContinuation);
return SourceRange::OpenEnded(continuation_position_);
}

bool HasRange(SourceRangeKind kind) override {
return kind == SourceRangeKind::kContinuation;
}

void RemoveContinuationRange() override {
DCHECK(HasRange(SourceRangeKind::kContinuation));
continuation_position_ = kNoSourcePosition;
}

private:
int32_t continuation_position_;
};
Expand All @@ -99,11 +114,15 @@ class CaseClauseSourceRanges final : public AstNodeSourceRanges {
explicit CaseClauseSourceRanges(const SourceRange& body_range)
: body_range_(body_range) {}

SourceRange GetRange(SourceRangeKind kind) {
SourceRange GetRange(SourceRangeKind kind) override {
DCHECK_EQ(kind, SourceRangeKind::kBody);
return body_range_;
}

bool HasRange(SourceRangeKind kind) override {
return kind == SourceRangeKind::kBody;
}

private:
SourceRange body_range_;
};
Expand All @@ -114,7 +133,7 @@ class ConditionalSourceRanges final : public AstNodeSourceRanges {
const SourceRange& else_range)
: then_range_(then_range), else_range_(else_range) {}

SourceRange GetRange(SourceRangeKind kind) {
SourceRange GetRange(SourceRangeKind kind) override {
switch (kind) {
case SourceRangeKind::kThen:
return then_range_;
Expand All @@ -125,6 +144,10 @@ class ConditionalSourceRanges final : public AstNodeSourceRanges {
}
}

bool HasRange(SourceRangeKind kind) override {
return kind == SourceRangeKind::kThen || kind == SourceRangeKind::kElse;
}

private:
SourceRange then_range_;
SourceRange else_range_;
Expand All @@ -136,13 +159,14 @@ class IfStatementSourceRanges final : public AstNodeSourceRanges {
const SourceRange& else_range)
: then_range_(then_range), else_range_(else_range) {}

SourceRange GetRange(SourceRangeKind kind) {
SourceRange GetRange(SourceRangeKind kind) override {
switch (kind) {
case SourceRangeKind::kElse:
return else_range_;
case SourceRangeKind::kThen:
return then_range_;
case SourceRangeKind::kContinuation: {
if (!has_continuation_) return SourceRange::Empty();
const SourceRange& trailing_range =
else_range_.IsEmpty() ? then_range_ : else_range_;
return SourceRange::ContinuationOf(trailing_range);
Expand All @@ -152,29 +176,52 @@ class IfStatementSourceRanges final : public AstNodeSourceRanges {
}
}

bool HasRange(SourceRangeKind kind) override {
return kind == SourceRangeKind::kThen || kind == SourceRangeKind::kElse ||
kind == SourceRangeKind::kContinuation;
}

void RemoveContinuationRange() override {
DCHECK(HasRange(SourceRangeKind::kContinuation));
has_continuation_ = false;
}

private:
SourceRange then_range_;
SourceRange else_range_;
bool has_continuation_ = true;
};

class IterationStatementSourceRanges final : public AstNodeSourceRanges {
public:
explicit IterationStatementSourceRanges(const SourceRange& body_range)
: body_range_(body_range) {}

SourceRange GetRange(SourceRangeKind kind) {
SourceRange GetRange(SourceRangeKind kind) override {
switch (kind) {
case SourceRangeKind::kBody:
return body_range_;
case SourceRangeKind::kContinuation:
if (!has_continuation_) return SourceRange::Empty();
return SourceRange::ContinuationOf(body_range_);
default:
UNREACHABLE();
}
}

bool HasRange(SourceRangeKind kind) override {
return kind == SourceRangeKind::kBody ||
kind == SourceRangeKind::kContinuation;
}

void RemoveContinuationRange() override {
DCHECK(HasRange(SourceRangeKind::kContinuation));
has_continuation_ = false;
}

private:
SourceRange body_range_;
bool has_continuation_ = true;
};

class JumpStatementSourceRanges final : public ContinuationSourceRanges {
Expand All @@ -199,6 +246,7 @@ class NaryOperationSourceRanges final : public AstNodeSourceRanges {
size_t RangeCount() const { return ranges_.size(); }

SourceRange GetRange(SourceRangeKind kind) { UNREACHABLE(); }
bool HasRange(SourceRangeKind kind) { return false; }

private:
ZoneVector<SourceRange> ranges_;
Expand Down Expand Up @@ -227,39 +275,63 @@ class TryCatchStatementSourceRanges final : public AstNodeSourceRanges {
explicit TryCatchStatementSourceRanges(const SourceRange& catch_range)
: catch_range_(catch_range) {}

SourceRange GetRange(SourceRangeKind kind) {
SourceRange GetRange(SourceRangeKind kind) override {
switch (kind) {
case SourceRangeKind::kCatch:
return catch_range_;
case SourceRangeKind::kContinuation:
if (!has_continuation_) return SourceRange::Empty();
return SourceRange::ContinuationOf(catch_range_);
default:
UNREACHABLE();
}
}

bool HasRange(SourceRangeKind kind) override {
return kind == SourceRangeKind::kCatch ||
kind == SourceRangeKind::kContinuation;
}

void RemoveContinuationRange() override {
DCHECK(HasRange(SourceRangeKind::kContinuation));
has_continuation_ = false;
}

private:
SourceRange catch_range_;
bool has_continuation_ = true;
};

class TryFinallyStatementSourceRanges final : public AstNodeSourceRanges {
public:
explicit TryFinallyStatementSourceRanges(const SourceRange& finally_range)
: finally_range_(finally_range) {}

SourceRange GetRange(SourceRangeKind kind) {
SourceRange GetRange(SourceRangeKind kind) override {
switch (kind) {
case SourceRangeKind::kFinally:
return finally_range_;
case SourceRangeKind::kContinuation:
if (!has_continuation_) return SourceRange::Empty();
return SourceRange::ContinuationOf(finally_range_);
default:
UNREACHABLE();
}
}

bool HasRange(SourceRangeKind kind) override {
return kind == SourceRangeKind::kFinally ||
kind == SourceRangeKind::kContinuation;
}

void RemoveContinuationRange() override {
DCHECK(HasRange(SourceRangeKind::kContinuation));
has_continuation_ = false;
}

private:
SourceRange finally_range_;
bool has_continuation_ = true;
};

// Maps ast node pointers to associated source ranges. The parser creates these
Expand Down
68 changes: 68 additions & 0 deletions deps/v8/src/ast/source-range-ast-visitor.cc
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Original file line number Diff line number Diff line change
@@ -0,0 +1,68 @@
// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/ast/source-range-ast-visitor.h"

#include "src/ast/ast-source-ranges.h"

namespace v8 {
namespace internal {

SourceRangeAstVisitor::SourceRangeAstVisitor(uintptr_t stack_limit,
Expression* root,
SourceRangeMap* source_range_map)
: AstTraversalVisitor(stack_limit, root),
source_range_map_(source_range_map) {}

void SourceRangeAstVisitor::VisitBlock(Block* stmt) {
AstTraversalVisitor::VisitBlock(stmt);
ZonePtrList<Statement>* stmts = stmt->statements();
AstNodeSourceRanges* enclosingSourceRanges = source_range_map_->Find(stmt);
if (enclosingSourceRanges != nullptr) {
CHECK(enclosingSourceRanges->HasRange(SourceRangeKind::kContinuation));
MaybeRemoveLastContinuationRange(stmts);
}
}

void SourceRangeAstVisitor::VisitFunctionLiteral(FunctionLiteral* expr) {
AstTraversalVisitor::VisitFunctionLiteral(expr);
ZonePtrList<Statement>* stmts = expr->body();
MaybeRemoveLastContinuationRange(stmts);
}

bool SourceRangeAstVisitor::VisitNode(AstNode* node) {
AstNodeSourceRanges* range = source_range_map_->Find(node);

if (range == nullptr) return true;
if (!range->HasRange(SourceRangeKind::kContinuation)) return true;

// Called in pre-order. In case of conflicting continuation ranges, only the
// outermost range may survive.

SourceRange continuation = range->GetRange(SourceRangeKind::kContinuation);
if (continuation_positions_.find(continuation.start) !=
continuation_positions_.end()) {
range->RemoveContinuationRange();
} else {
continuation_positions_.emplace(continuation.start);
}

return true;
}

void SourceRangeAstVisitor::MaybeRemoveLastContinuationRange(
ZonePtrList<Statement>* statements) {
if (statements == nullptr || statements->is_empty()) return;

Statement* last_statement = statements->last();
AstNodeSourceRanges* last_range = source_range_map_->Find(last_statement);
if (last_range == nullptr) return;

if (last_range->HasRange(SourceRangeKind::kContinuation)) {
last_range->RemoveContinuationRange();
}
}

} // namespace internal
} // namespace v8
49 changes: 49 additions & 0 deletions deps/v8/src/ast/source-range-ast-visitor.h
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@@ -0,0 +1,49 @@
// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_AST_SOURCE_RANGE_AST_VISITOR_H_
#define V8_AST_SOURCE_RANGE_AST_VISITOR_H_

#include <unordered_set>

#include "src/ast/ast-traversal-visitor.h"

namespace v8 {
namespace internal {

class SourceRangeMap;

// Post-processes generated source ranges while the AST structure still exists.
//
// In particular, SourceRangeAstVisitor
//
// 1. deduplicates continuation source ranges, only keeping the outermost one.
// See also: https://crbug.com/v8/8539.
//
// 2. removes the source range associated with the final statement in a block
// or function body if the parent itself has a source range associated with it.
// See also: https://crbug.com/v8/8381.
class SourceRangeAstVisitor final
: public AstTraversalVisitor<SourceRangeAstVisitor> {
public:
SourceRangeAstVisitor(uintptr_t stack_limit, Expression* root,
SourceRangeMap* source_range_map);

private:
friend class AstTraversalVisitor<SourceRangeAstVisitor>;

void VisitBlock(Block* stmt);
void VisitFunctionLiteral(FunctionLiteral* expr);
bool VisitNode(AstNode* node);

void MaybeRemoveLastContinuationRange(ZonePtrList<Statement>* stmts);

SourceRangeMap* source_range_map_ = nullptr;
std::unordered_set<int> continuation_positions_;
};

} // namespace internal
} // namespace v8

#endif // V8_AST_SOURCE_RANGE_AST_VISITOR_H_
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