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Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue Class Referenceabstract

Description

Base class for semantic values.

A semantic value represents a datum from the specimen being analyzed. The datum could be from memory, it could be something stored in a register, it could be the result of some computation, etc. The datum in the specimen has a datum type that might be only partially known; the datum value could, for instance, be 32-bits but unknown whether it is integer or floating point.

The various semantic domains will define SValue subclasses that are appropriate for that domain–a concrete domain will define an SValue that specimen data in a concrete form, an interval domain will define an SValue that represents specimen data in intervals, etc.

Semantics value objects are allocated on the heap and reference counted. The BaseSemantics::SValue is an abstract class that defines the interface. See the Rose::BinaryAnalysis::InstructionSemantics2 namespace for an overview of how the parts fit together.

Definition at line 46 of file SValue.h.

#include <SValue.h>

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Classes

class  WithFormatter
 SValue with formatter. More...
 

Public Types

using Ptr = SValuePtr
 Shared-ownership pointer for an SValue object. More...
 

Public Member Functions

virtual SValuePtr undefined_ (size_t nbits) const =0
 Create a new undefined semantic value. More...
 
virtual SValuePtr unspecified_ (size_t nbits) const =0
 Create a new unspecified semantic value. More...
 
virtual SValuePtr bottom_ (size_t nBits) const =0
 Data-flow bottom value. More...
 
virtual SValuePtr number_ (size_t nbits, uint64_t number) const =0
 Create a new concrete semantic value. More...
 
virtual SValuePtr boolean_ (bool value) const
 Create a new, Boolean value. More...
 
virtual SValuePtr copy (size_t new_width=0) const =0
 Create a new value from an existing value, changing the width if new_width is non-zero. More...
 
virtual Sawyer::Optional< SValuePtrcreateOptionalMerge (const SValuePtr &other, const MergerPtr &merger, const SmtSolverPtr &solver) const =0
 Possibly create a new value by merging two existing values. More...
 
SValuePtr createMerged (const SValuePtr &other, const MergerPtr &merger, const SmtSolverPtr &solver) const
 Create a new value by merging two existing values. More...
 
size_t nBits () const
 Property: value width. More...
 
virtual bool isBottom () const =0
 Determines whether a value is a data-flow bottom. More...
 
bool isConcrete () const
 Determines if the value is a concrete number. More...
 
Sawyer::Optional< uint64_t > toUnsigned () const
 Converts a concrete value to a native unsigned integer. More...
 
Sawyer::Optional< int64_t > toSigned () const
 Converts a concrete value to a native signed integer. More...
 
bool mustEqual (const SValuePtr &other, const SmtSolverPtr &solver=SmtSolverPtr()) const
 Tests two values for equality. More...
 
bool mayEqual (const SValuePtr &other, const SmtSolverPtr &solver=SmtSolverPtr()) const
 Tests two values for possible equality. More...
 
bool isTrue () const
 Returns true if concrete non-zero. More...
 
bool isFalse () const
 Returns true if concrete zero. More...
 
virtual void hash (Combinatorics::Hasher &) const =0
 Hash this semantic value. More...
 
virtual bool is_number () const =0
 Virtual API. More...
 
virtual uint64_t get_number () const =0
 Virtual API. More...
 
virtual bool must_equal (const SValuePtr &other, const SmtSolverPtr &solver=SmtSolverPtr()) const =0
 Virtual API. More...
 
virtual bool may_equal (const SValuePtr &other, const SmtSolverPtr &solver=SmtSolverPtr()) const =0
 Virtual API. More...
 
std::string comment () const
 Property: Comment. More...
 
void comment (const std::string &) const
 Property: Comment. More...
 
void print (std::ostream &) const
 Print a value to a stream using default format. More...
 
virtual void print (std::ostream &, Formatter &) const =0
 Print a value to a stream using default format. More...
 
WithFormatter with_format (Formatter &fmt)
 Used for printing values with formatting. More...
 
WithFormatter operator+ (Formatter &fmt)
 Used for printing values with formatting. More...
 
WithFormatter operator+ (const std::string &linePrefix)
 Used for printing values with formatting. More...
 
virtual size_t get_width () const
 Virtual API. More...
 
virtual void set_width (size_t nbits)
 Virtual API. More...
 
virtual std::string get_comment () const
 Some subclasses support the ability to add comments to values. More...
 
virtual void set_comment (const std::string &) const
 Some subclasses support the ability to add comments to values. More...
 
- Public Member Functions inherited from Sawyer::SharedObject
 SharedObject ()
 Default constructor. More...
 
 SharedObject (const SharedObject &)
 Copy constructor. More...
 
virtual ~SharedObject ()
 Virtual destructor. More...
 
SharedObjectoperator= (const SharedObject &)
 Assignment. More...
 
- Public Member Functions inherited from Sawyer::SharedFromThis< SValue >
SharedPointer< SValue > sharedFromThis ()
 Create a shared pointer from this. More...
 
SharedPointer< const SValue > sharedFromThis () const
 Create a shared pointer from this. More...
 

Static Public Member Functions

static SValuePtr promote (const SValuePtr &x)
 
- Static Public Member Functions inherited from Sawyer::SmallObject
static SynchronizedPoolAllocatorpoolAllocator ()
 Return the pool allocator for this class. More...
 
static void * operator new (size_t size)
 
static void operator delete (void *ptr, size_t size)
 

Protected Member Functions

 SValue (size_t nbits)
 
 SValue (const SValue &other)
 

Protected Attributes

size_t width
 

Member Typedef Documentation

Shared-ownership pointer for an SValue object.

See Shared ownership.

Definition at line 49 of file SValue.h.

Member Function Documentation

virtual SValuePtr Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::undefined_ ( size_t  nbits) const
pure virtual
virtual SValuePtr Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::unspecified_ ( size_t  nbits) const
pure virtual

Create a new unspecified semantic value.

The new semantic value will have the same dynamic type as the value on which this virtual method is called. Undefined (undefined_) and unspecified are closely related. Unspecified values are the same as undefined values except they're instantiated as the result of some machine instruction where the ISA documentation indicates that the value is unspecified (e.g., status flags for x86 shift and rotate instructions).

Most semantic domains make no distinction between undefined and unspecified.

See also
undefined_

Implemented in Rose::BinaryAnalysis::InstructionSemantics2::SymbolicSemantics::SValue, Rose::BinaryAnalysis::ModelChecker::P2Model::SValue, Rose::BinaryAnalysis::InstructionSemantics2::StaticSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::PartialSymbolicSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::IntervalSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::MultiSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::SourceAstSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::ConcreteSemantics::SValue, and Rose::BinaryAnalysis::InstructionSemantics2::NullSemantics::SValue.

virtual SValuePtr Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::bottom_ ( size_t  nBits) const
pure virtual
virtual SValuePtr Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::number_ ( size_t  nbits,
uint64_t  number 
) const
pure virtual
virtual SValuePtr Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::boolean_ ( bool  value) const
inlinevirtual

Create a new, Boolean value.

The new semantic value will have the same dynamic type as the value on which this virtual method is called. This is how 1-bit flag register values (among others) are created. The base implementation uses number_() to construct a 1-bit value whose bit is zero (false) or one (true).

Reimplemented in Rose::BinaryAnalysis::InstructionSemantics2::SymbolicSemantics::SValue, Rose::BinaryAnalysis::ModelChecker::P2Model::SValue, Rose::BinaryAnalysis::InstructionSemantics2::StaticSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::SourceAstSemantics::SValue, and Rose::BinaryAnalysis::InstructionSemantics2::ConcreteSemantics::SValue.

Definition at line 121 of file SValue.h.

References number_().

virtual SValuePtr Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::copy ( size_t  new_width = 0) const
pure virtual
virtual Sawyer::Optional<SValuePtr> Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::createOptionalMerge ( const SValuePtr other,
const MergerPtr merger,
const SmtSolverPtr solver 
) const
pure virtual

Possibly create a new value by merging two existing values.

This method optionally returns a new semantic value as the data-flow merge of this and other. If the two inputs are "equal" in some sense of the dataflow implementation then nothing is returned, otherwise a new value is returned. Typical usage is like this:

if (SValuePtr merged = v1->createOptionalMerge(v2).orDefault()) {
std::cout <<"v1 and v2 were merged to " <<*merged <<"\n";
} else {
std::cout <<"no merge is necessary\n";
}
or
@code
SValuePtr merge;
if (v1->createOptionalMerge(v2).assignTo(merged)) {
std::cout <<"v1 and v2 were merged to " <<*merged <<"\n";
} else {
std::cout <<"v1 and v2 are equal in some sense (no merge necessary)\n";
}

If you always want a copy regardless of whether the merge is necessary, then use the createMerged convenience function instead.

Implemented in Rose::BinaryAnalysis::InstructionSemantics2::SymbolicSemantics::SValue, Rose::BinaryAnalysis::ModelChecker::P2Model::SValue, Rose::BinaryAnalysis::InstructionSemantics2::StaticSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::PartialSymbolicSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::IntervalSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::MultiSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::SourceAstSemantics::SValue, Rose::BinaryAnalysis::InstructionSemantics2::ConcreteSemantics::SValue, and Rose::BinaryAnalysis::InstructionSemantics2::NullSemantics::SValue.

Referenced by createMerged().

SValuePtr Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::createMerged ( const SValuePtr other,
const MergerPtr merger,
const SmtSolverPtr solver 
) const
inline

Create a new value by merging two existing values.

This is a convenience wrapper around createOptionalMerge. It always returns a newly constructed semantic value regardless of whether a merge was necessary. In order to determine if a merge was necessary one can compare the return value to this using must_equal, although doing so is more expensive than calling createOptionalMerge.

Definition at line 163 of file SValue.h.

References copy(), and createOptionalMerge().

size_t Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::nBits ( ) const
virtual bool Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::isBottom ( ) const
pure virtual
bool Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::isConcrete ( ) const

Determines if the value is a concrete number.

Concrete numbers can be created with the number_ and boolean_ methods, virtual constructors, or other means. Some semantic domains have only concrete numbers.

This function should not be overridden by subclasses. Instead, it calls the virtual is_number method to do its work.

Sawyer::Optional<uint64_t> Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::toUnsigned ( ) const

Converts a concrete value to a native unsigned integer.

If this is a concrete value (see isConcrete) and an unsigned integer interpretation of the bits fits in a 64-bit unsigned integer (uint64_t) then that interpretation is returned, otherwise nothing is returned.

This function should not be overridden by subclasses. Instead, it calls get_number to do its work.

Sawyer::Optional<int64_t> Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::toSigned ( ) const

Converts a concrete value to a native signed integer.

If this is a concrete value (see isConcrete) and a signed integer interpretation of the bits fits in a 64-bit signed integer (int64_t) then that interpretation is returned, otherwise nothing is returned.

This function should not be overridden by subclasses. Instead, it calls get_number to do its work.

bool Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::mustEqual ( const SValuePtr other,
const SmtSolverPtr solver = SmtSolverPtr() 
) const

Tests two values for equality.

Returns true if this value and the other value must be equal, and false if they might not be equal.

This function should not be overridden by subclasses. Instead, it calls must_equal to do its work.

bool Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::mayEqual ( const SValuePtr other,
const SmtSolverPtr solver = SmtSolverPtr() 
) const

Tests two values for possible equality.

Returns true if this value and the other value might be equal, and false if they cannot be equal.

This function should not be overridden by subclasses. Instead, it calls may_equal to do its work.

bool Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::isTrue ( ) const

Returns true if concrete non-zero.

This is not virtual since it can be implemented in terms of other functions.

bool Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::isFalse ( ) const

Returns true if concrete zero.

This is not virtual since it can be implemented in terms of other functions.

std::string Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::comment ( ) const

Property: Comment.

Some subclasses support associating a string comment with a value. If the class does not support comments, then this property will always have an empty value regardless of what's assigned. Since comments do not affect computation, their value is allowed to be changed even for const objects.

This function should not be overridden by subclasses. Instead, it calls get_comment and set_comment to do its work.

void Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::comment ( const std::string &  ) const

Property: Comment.

Some subclasses support associating a string comment with a value. If the class does not support comments, then this property will always have an empty value regardless of what's assigned. Since comments do not affect computation, their value is allowed to be changed even for const objects.

This function should not be overridden by subclasses. Instead, it calls get_comment and set_comment to do its work.

virtual void Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::hash ( Combinatorics::Hasher ) const
pure virtual
void Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::print ( std::ostream &  ) const

Print a value to a stream using default format.

The value will normally occupy a single line and not contain leading space or line termination. See also, with_format().

virtual void Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::print ( std::ostream &  ,
Formatter  
) const
pure virtual
WithFormatter Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::with_format ( Formatter fmt)
inline

Used for printing values with formatting.

The usual way to use this is:

SValuePtr val = ...;
Formatter fmt = ...;
std::cout <<"The value is: " <<(*val+fmt) <<"\n";

Definition at line 283 of file SValue.h.

Referenced by operator+().

WithFormatter Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::operator+ ( Formatter fmt)
inline

Used for printing values with formatting.

The usual way to use this is:

SValuePtr val = ...;
Formatter fmt = ...;
std::cout <<"The value is: " <<(*val+fmt) <<"\n";

Definition at line 284 of file SValue.h.

References with_format().

WithFormatter Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::operator+ ( const std::string &  linePrefix)

Used for printing values with formatting.

The usual way to use this is:

SValuePtr val = ...;
Formatter fmt = ...;
std::cout <<"The value is: " <<(*val+fmt) <<"\n";
virtual bool Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::is_number ( ) const
pure virtual
virtual uint64_t Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::get_number ( ) const
pure virtual
virtual size_t Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::get_width ( ) const
inlinevirtual

Virtual API.

See nBits.

Definition at line 302 of file SValue.h.

virtual void Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::set_width ( size_t  nbits)
inlinevirtual
virtual bool Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::must_equal ( const SValuePtr other,
const SmtSolverPtr solver = SmtSolverPtr() 
) const
pure virtual
virtual bool Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::may_equal ( const SValuePtr other,
const SmtSolverPtr solver = SmtSolverPtr() 
) const
pure virtual
virtual std::string Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::get_comment ( ) const
inlinevirtual

Some subclasses support the ability to add comments to values.

We define no-op versions of these methods here because it makes things easier. The base class tries to be as small as possible by not storing comments at all. Comments should not affect any computation (comparisons, hash values, etc), and therefore are allowed to be modified even for const objects.

Reimplemented in Rose::BinaryAnalysis::InstructionSemantics2::SymbolicSemantics::SValue.

Definition at line 317 of file SValue.h.

virtual void Rose::BinaryAnalysis::InstructionSemantics2::BaseSemantics::SValue::set_comment ( const std::string &  ) const
inlinevirtual

Some subclasses support the ability to add comments to values.

We define no-op versions of these methods here because it makes things easier. The base class tries to be as small as possible by not storing comments at all. Comments should not affect any computation (comparisons, hash values, etc), and therefore are allowed to be modified even for const objects.

Reimplemented in Rose::BinaryAnalysis::InstructionSemantics2::SymbolicSemantics::SValue.

Definition at line 318 of file SValue.h.


The documentation for this class was generated from the following file: