runtime/vm/token_position.h - sdk.git - Git at Google

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

 #ifndef RUNTIME_VM_TOKEN_POSITION_H_
 #define RUNTIME_VM_TOKEN_POSITION_H_

 #include "platform/utils.h"
 #include "vm/allocation.h"

 namespace dart {

 // The token space is organized as follows:
 //
 // Sentinel values start at -1 and move towards negative infinity:
 // kNoSourcePos                -> -1
 // ClassifyingTokenPositions 1 -> -1 - 1
 // ClassifyingTokenPositions N -> -1 - N
 //
 // Real token positions represent source offsets in some script, and are encoded
 // as non-negative values which are equal to that offset.
 //
 // Synthetically created functions that correspond to user code are given
 // starting token positions unique from other synthetic functions. The value for
 // these token positions encode a unique non-negative value as a negative number
 // within [kSmiMin32, -1 - N).
 //
 // For example:
 // A synthetic token with value 0 is encoded as ((-1 - N) - (0 + 1)) = -2 - N.
 // A synthetic token with value 1 is encoded as ((-1 - N) - (1 + 1)) = -3 - N.
 //
 // Note that the encoded value is _not_ related to any possible real token
 // position, as two real token positions for different scripts can have the same
 // value and thus cannot serve as a unique nonce for a synthetic node.
 //
 // All other nodes read from user code, such as non-synthetic functions, fields,
 // etc., are given real starting token positions. All nodes coming from user
 // code, both real or synthetic, with ending token positions have real ending
 // token positions.
 //
 // This organization allows for ~1 billion token positions.

 #define SENTINEL_TOKEN_DESCRIPTORS(V)                                          \
   V(NoSource, -1)                                                              \
   V(Box, -2)                                                                   \
   V(ParallelMove, -3)                                                          \
   V(TempMove, -4)                                                              \
   V(Constant, -5)                                                              \
   V(MoveArgument, -6)                                                          \
   V(ControlFlow, -7)                                                           \
   V(Context, -8)                                                               \
   V(MethodExtractor, -9)                                                       \
   V(DeferredSlowPath, -10)                                                     \
   V(DeferredDeoptInfo, -11)                                                    \
   V(DartCodePrologue, -12)                                                     \
   V(DartCodeEpilogue, -13)                                                     \
   V(Last, -14)  // Always keep this at the end.

 // A token position represents either a debug safe source (real) position,
 // non-debug safe unique (synthetic) position, or a classifying value used
 // by the profiler.
 class TokenPosition {
  public:
   uword Hash() const;

   // Returns whether the token positions are equal.  Defined for all token
   // positions.
   bool operator==(const TokenPosition& b) const { return value() == b.value(); }

   // Returns whether the token positions are not equal. Defined for all token
   // positions.
   bool operator!=(const TokenPosition& b) const { return !(*this == b); }

   // Returns whether the token position is less than [b]. Only defined for
   // real token positions.
   inline bool operator<(const TokenPosition& b) const {
     return Pos() < b.Pos();
   }

   // Returns whether the token position is greater than [b]. Only defined for
   // real token positions.
   inline bool operator>(const TokenPosition& b) const { return b < *this; }

   // Returns whether the token position is less than or equal to [b]. Only
   // defined for real token positions.
   inline bool operator<=(const TokenPosition& b) const { return !(*this > b); }

   // Returns whether the token position is greater than or equal to [b].  Only
   // defined for real token positions.
   inline bool operator>=(const TokenPosition& b) const { return !(*this < b); }

   // For real token positions, returns whether this is between [a] and [b],
   // inclusive. If [a] or [b] is non-real, they are treated as less than
   // any real token position.
   //
   // For synthetic token positions, returns whether [a] or [b] equals this.
   //
   // For other token positions, always returns false.
   bool IsWithin(const TokenPosition& a, const TokenPosition& b) const {
     if (IsReal()) return (a.value() <= value()) && (value() <= b.value());
     if (IsSynthetic()) return (a == *this) || (b == *this);
     return false;
   }

   // Returns [a] if both positions are not real, the real position if only one
   // of [a] and [b] is real, or the minimum position of [a] and [b].
   static const TokenPosition& Min(const TokenPosition& a,
                                   const TokenPosition& b) {
     if (!b.IsReal()) return a;
     if (!a.IsReal()) return b;
     return b.value() < a.value() ? b : a;
   }
   // Returns [a] if both positions are not real, the real position if only one
   // of [a] and [b] is real, or the maximum position of [a] and [b].
   static const TokenPosition& Max(const TokenPosition& a,
                                   const TokenPosition& b) {
     if (!b.IsReal()) return a;
     if (!a.IsReal()) return b;
     return b.value() > a.value() ? b : a;
   }

   // Compares two arbitrary source positions for use in sorting, where a
   // negative return means [a] sorts before [b], a return of 0 means [a] is the
   // same as [b], and a positive return means [a] sorts after [b].
   //
   // Does _not_ correspond to the relational operators on token positions, as
   // this also allows comparison of kNoSource, classifying, and synthetic token
   // positions to each other.
   static intptr_t CompareForSorting(const TokenPosition& a,
                                     const TokenPosition& b) {
     return a.value() - b.value();
   }

   static constexpr int32_t kMaxSentinelDescriptors = 64;

 #define DECLARE_VALUES(name, value)                                            \
   static constexpr int32_t k##name##Pos = value;                               \
   static const TokenPosition k##name;
   SENTINEL_TOKEN_DESCRIPTORS(DECLARE_VALUES);
 #undef DECLARE_VALUES
   // Check assumptions used in Is<X> methods below.
 #define CHECK_VALUES(name, value)                                              \
   static_assert(k##name##Pos < 0, "Non-negative sentinel descriptor");         \
   static_assert(                                                               \
       k##name##Pos == kNoSourcePos || k##name##Pos <= kBoxPos,                 \
       "Box sentinel descriptor is not greatest classifying sentinel value");   \
   static_assert(kLastPos <= k##name##Pos,                                      \
                 "Last sentinel descriptor is not least sentinel valu");        \
   SENTINEL_TOKEN_DESCRIPTORS(CHECK_VALUES);
 #undef CHECK_VALUES
   static_assert(kLastPos > -kMaxSentinelDescriptors,
                 "More sentinel descriptors than expected");

   static constexpr int32_t kMinSourcePos = 0;
   static const TokenPosition kMinSource;
   static constexpr int32_t kMaxSourcePos =
       kSmiMax32 - kMaxSentinelDescriptors - 2;
   static const TokenPosition kMaxSource;

   // Decode from a serialized form.
   static TokenPosition Deserialize(int32_t value);

   // Encode into a serialized form.
   int32_t Serialize() const;

   // Given a real token position, returns the next real token position.
   TokenPosition Next() {
     ASSERT(IsReal());
     return TokenPosition(value_ + 1);
   }

   // Return the source position for real token positions.
   inline intptr_t Pos() const {
     ASSERT(IsReal());
     return value_;
   }

   // Is |this| a classifying sentinel source position?
   // Classifying positions are used by the profiler to group instructions whose
   // cost isn't naturally attributable to a source location.
   inline bool IsClassifying() const {
     return (value_ >= kBox.value()) && (value_ <= kLast.value());
   }

   // Is |this| the no source position sentinel?
   inline bool IsNoSource() const { return value_ == kNoSourcePos; }

   // Is |this| a synthetic source position?
   // Synthetic source positions are used by the profiler to attribute ticks to a
   // pieces of source, but ignored by the debugger as potential breakpoints.
   inline bool IsSynthetic() const { return value_ < kLastPos; }

   // Is |this| a real source position?
   inline bool IsReal() const { return value_ >= kMinSourcePos; }

   // Is |this| a debug pause source position?
   inline bool IsDebugPause() const { return IsReal(); }

   // Creates a synthetic source position from a non-negative value.
   static TokenPosition Synthetic(intptr_t value) {
     ASSERT(value >= 0 && value <= kMaxSourcePos);
     return TokenPosition((kLastPos - 1) - value);
   }

   // Encode the token position for storage in the coverage array.
   intptr_t EncodeCoveragePosition(bool is_branch_coverage);

   // Decode a token position that was stored in the coverage array.
   static TokenPosition DecodeCoveragePosition(intptr_t encoded_position,
                                               bool* is_branch_coverage);

   const char* ToCString() const;

  private:
   explicit TokenPosition(intptr_t value) : value_(value) {}

   // The raw value of this TokenPosition.
   intptr_t value() const { return value_; }

   int32_t value_;

   DISALLOW_ALLOCATION();
 };

 }  // namespace dart

 #endif  // RUNTIME_VM_TOKEN_POSITION_H_
	// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
	// for details. All rights reserved. Use of this source code is governed by a
	// BSD-style license that can be found in the LICENSE file.

	#ifndef RUNTIME_VM_TOKEN_POSITION_H_
	#define RUNTIME_VM_TOKEN_POSITION_H_

	#include "platform/utils.h"
	#include "vm/allocation.h"

	namespace dart {

	// The token space is organized as follows:
	//
	// Sentinel values start at -1 and move towards negative infinity:
	// kNoSourcePos -> -1
	// ClassifyingTokenPositions 1 -> -1 - 1
	// ClassifyingTokenPositions N -> -1 - N
	//
	// Real token positions represent source offsets in some script, and are encoded
	// as non-negative values which are equal to that offset.
	//
	// Synthetically created functions that correspond to user code are given
	// starting token positions unique from other synthetic functions. The value for
	// these token positions encode a unique non-negative value as a negative number
	// within [kSmiMin32, -1 - N).
	//
	// For example:
	// A synthetic token with value 0 is encoded as ((-1 - N) - (0 + 1)) = -2 - N.
	// A synthetic token with value 1 is encoded as ((-1 - N) - (1 + 1)) = -3 - N.
	//
	// Note that the encoded value is _not_ related to any possible real token
	// position, as two real token positions for different scripts can have the same
	// value and thus cannot serve as a unique nonce for a synthetic node.
	//
	// All other nodes read from user code, such as non-synthetic functions, fields,
	// etc., are given real starting token positions. All nodes coming from user
	// code, both real or synthetic, with ending token positions have real ending
	// token positions.
	//
	// This organization allows for ~1 billion token positions.

	#define SENTINEL_TOKEN_DESCRIPTORS(V) \
	V(NoSource, -1) \
	V(Box, -2) \
	V(ParallelMove, -3) \
	V(TempMove, -4) \
	V(Constant, -5) \
	V(MoveArgument, -6) \
	V(ControlFlow, -7) \
	V(Context, -8) \
	V(MethodExtractor, -9) \
	V(DeferredSlowPath, -10) \
	V(DeferredDeoptInfo, -11) \
	V(DartCodePrologue, -12) \
	V(DartCodeEpilogue, -13) \
	V(Last, -14) // Always keep this at the end.

	// A token position represents either a debug safe source (real) position,
	// non-debug safe unique (synthetic) position, or a classifying value used
	// by the profiler.
	class TokenPosition {
	public:
	uword Hash() const;

	// Returns whether the token positions are equal. Defined for all token
	// positions.
	bool operator==(const TokenPosition& b) const { return value() == b.value(); }

	// Returns whether the token positions are not equal. Defined for all token
	// positions.
	bool operator!=(const TokenPosition& b) const { return !(*this == b); }

	// Returns whether the token position is less than [b]. Only defined for
	// real token positions.
	inline bool operator<(const TokenPosition& b) const {
	return Pos() < b.Pos();
	}

	// Returns whether the token position is greater than [b]. Only defined for
	// real token positions.
	inline bool operator>(const TokenPosition& b) const { return b < *this; }

	// Returns whether the token position is less than or equal to [b]. Only
	// defined for real token positions.
	inline bool operator<=(const TokenPosition& b) const { return !(*this > b); }

	// Returns whether the token position is greater than or equal to [b]. Only
	// defined for real token positions.
	inline bool operator>=(const TokenPosition& b) const { return !(*this < b); }

	// For real token positions, returns whether this is between [a] and [b],
	// inclusive. If [a] or [b] is non-real, they are treated as less than
	// any real token position.
	//
	// For synthetic token positions, returns whether [a] or [b] equals this.
	//
	// For other token positions, always returns false.
	bool IsWithin(const TokenPosition& a, const TokenPosition& b) const {
	if (IsReal()) return (a.value() <= value()) && (value() <= b.value());
	if (IsSynthetic()) return (a == this) \|\| (b == this);
	return false;
	}

	// Returns [a] if both positions are not real, the real position if only one
	// of [a] and [b] is real, or the minimum position of [a] and [b].
	static const TokenPosition& Min(const TokenPosition& a,
	const TokenPosition& b) {
	if (!b.IsReal()) return a;
	if (!a.IsReal()) return b;
	return b.value() < a.value() ? b : a;
	}
	// Returns [a] if both positions are not real, the real position if only one
	// of [a] and [b] is real, or the maximum position of [a] and [b].
	static const TokenPosition& Max(const TokenPosition& a,
	const TokenPosition& b) {
	if (!b.IsReal()) return a;
	if (!a.IsReal()) return b;
	return b.value() > a.value() ? b : a;
	}

	// Compares two arbitrary source positions for use in sorting, where a
	// negative return means [a] sorts before [b], a return of 0 means [a] is the
	// same as [b], and a positive return means [a] sorts after [b].
	//
	// Does _not_ correspond to the relational operators on token positions, as
	// this also allows comparison of kNoSource, classifying, and synthetic token
	// positions to each other.
	static intptr_t CompareForSorting(const TokenPosition& a,
	const TokenPosition& b) {
	return a.value() - b.value();
	}

	static constexpr int32_t kMaxSentinelDescriptors = 64;

	#define DECLARE_VALUES(name, value) \
	static constexpr int32_t k##name##Pos = value; \
	static const TokenPosition k##name;
	SENTINEL_TOKEN_DESCRIPTORS(DECLARE_VALUES);
	#undef DECLARE_VALUES
	// Check assumptions used in Is<X> methods below.
	#define CHECK_VALUES(name, value) \
	static_assert(k##name##Pos < 0, "Non-negative sentinel descriptor"); \
	static_assert( \
	k##name##Pos == kNoSourcePos \|\| k##name##Pos <= kBoxPos, \
	"Box sentinel descriptor is not greatest classifying sentinel value"); \
	static_assert(kLastPos <= k##name##Pos, \
	"Last sentinel descriptor is not least sentinel valu"); \
	SENTINEL_TOKEN_DESCRIPTORS(CHECK_VALUES);
	#undef CHECK_VALUES
	static_assert(kLastPos > -kMaxSentinelDescriptors,
	"More sentinel descriptors than expected");

	static constexpr int32_t kMinSourcePos = 0;
	static const TokenPosition kMinSource;
	static constexpr int32_t kMaxSourcePos =
	kSmiMax32 - kMaxSentinelDescriptors - 2;
	static const TokenPosition kMaxSource;

	// Decode from a serialized form.
	static TokenPosition Deserialize(int32_t value);

	// Encode into a serialized form.
	int32_t Serialize() const;

	// Given a real token position, returns the next real token position.
	TokenPosition Next() {
	ASSERT(IsReal());
	return TokenPosition(value_ + 1);
	}

	// Return the source position for real token positions.
	inline intptr_t Pos() const {
	ASSERT(IsReal());
	return value_;
	}

	// Is \|this\| a classifying sentinel source position?
	// Classifying positions are used by the profiler to group instructions whose
	// cost isn't naturally attributable to a source location.
	inline bool IsClassifying() const {
	return (value_ >= kBox.value()) && (value_ <= kLast.value());
	}

	// Is \|this\| the no source position sentinel?
	inline bool IsNoSource() const { return value_ == kNoSourcePos; }

	// Is \|this\| a synthetic source position?
	// Synthetic source positions are used by the profiler to attribute ticks to a
	// pieces of source, but ignored by the debugger as potential breakpoints.
	inline bool IsSynthetic() const { return value_ < kLastPos; }

	// Is \|this\| a real source position?
	inline bool IsReal() const { return value_ >= kMinSourcePos; }

	// Is \|this\| a debug pause source position?
	inline bool IsDebugPause() const { return IsReal(); }

	// Creates a synthetic source position from a non-negative value.
	static TokenPosition Synthetic(intptr_t value) {
	ASSERT(value >= 0 && value <= kMaxSourcePos);
	return TokenPosition((kLastPos - 1) - value);
	}

	// Encode the token position for storage in the coverage array.
	intptr_t EncodeCoveragePosition(bool is_branch_coverage);

	// Decode a token position that was stored in the coverage array.
	static TokenPosition DecodeCoveragePosition(intptr_t encoded_position,
	bool* is_branch_coverage);

	const char* ToCString() const;

	private:
	explicit TokenPosition(intptr_t value) : value_(value) {}

	// The raw value of this TokenPosition.
	intptr_t value() const { return value_; }

	int32_t value_;

	DISALLOW_ALLOCATION();
	};

	} // namespace dart

	#endif // RUNTIME_VM_TOKEN_POSITION_H_