Class AssemblyResolvedPatterns
- All Implemented Interfaces:
Comparable<AssemblyResolution>
AssemblyResolution
indicating successful application of a constructor
This is almost analogous to DisjointPattern
, in that is joins an instruction AssemblyPatternBlock
with a
corresponding context AssemblyPatternBlock
. However, this object is mutable, and it
collects backfill records, as well as forbidden patterns.
When the applied constructor is from the "instruction" subtable, this represents a fully-
constructed instruction with required context. All backfill records ought to be resolved and
applied before the final result is given to the user, i.e., passed into the
AssemblySelector
. If at any time during the resolution or backfill process, the result
becomes confined to one of the forbidden patterns, it must be dropped, since the encoding will
actually invoke a more specific SLEIGH constructor.
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected final Set<AssemblyResolvedBackfill>
protected final Constructor
protected final AssemblyPatternBlock
protected static final String
protected final Set<AssemblyResolvedPatterns>
protected final AssemblyPatternBlock
protected static final String
protected static final Pattern
protected static final String
Fields inherited from class ghidra.app.plugin.assembler.sleigh.sem.AssemblyResolution
children, description, right
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Method Summary
Modifier and TypeMethodDescriptionbackfill
(RecursiveDescentSolver solver, Map<String, Long> vals) Apply as many backfill records as possibleprotected boolean
Check if this and another resolution have equal encodingsCheck if the current encoding is forbidden by one of the attached patternsprotected String
childrenToString
(String indent) Get the child portion ofAssemblyResolution.toString()
Combine the given backfill record into this resolutionCombine the encodings and backfills of the given resolution into this oneprotected AssemblyResolvedPatterns
Combine a backfill resultprotected int
copyAppendDescription
(String append) Duplicate this resolution, with additional description text appendedUsed for testing and diagnostics: list the constructor line numbers used to resolve this encodingboolean
boolean
static AssemblyResolvedPatterns
fromString
(String str, String description, List<AssemblyResolution> children) Build a new successful SLEIGH constructor resolution from a string representationGet the context blockint
Get the length of the instruction encoding, excluding trailing undefined bytesGet the instruction blockint
Get the length of the instruction encodingprotected static int
getOpIndex
(String piece) protected static ConstructState
getPureRecursion
(ConstructState state) If the construct state is a^instruction
or other purely-recursive constructor, get its single child.int
Count the number of bits specified in the resolution patternsboolean
Check if this resolution has pending backfills to applyboolean
Check if this record has childrenboolean
Check if this record describes a backfillboolean
isError()
Check if this record describes an errorDisplay the resolution result in one line (omitting child details)Set all bits read by a given context operation to unknownGet this same resolution, pushing its right siblings down to its childrenIterable<byte[]>
possibleInsVals
(AssemblyPatternBlock forCtx) Get an iterable over all the possible fillings of the instruction pattern given a contextreadContext
(int start, int len) Decode a portion of the context blockreadContextOp
(ContextOp cop) Decode the value from the context located where the given context operation would writereadInstruction
(int start, int len) Decode a portion of the instruction blockshift
(int amt) Shift the resolution's instruction pattern to the right, if applicableSolve and apply context changes in reverse to forbidden patternstruncate
(int amt) Truncate (unshift) the resolved instruction pattern from the left NOTE: This drops all backfill and forbidden pattern records, since this method is typically used to read token fields rather than passed around for resolution.withConstructor
(Constructor cons) Create a copy of this resolution with a replaced constructorwithDescription
(String desc) Create a copy of this resolution with a new descriptionCreate a new resolution from this one with the given forbidden patterns recordedwithRight
(AssemblyResolution right) Get this same resolution, but with the given right siblingwriteContextOp
(ContextOp cop, MaskedLong val) Encode the given value into the context block as specified by an operationMethods inherited from class ghidra.app.plugin.assembler.sleigh.sem.AssemblyResolution
backfill, collectAllRight, compareTo, contextOnly, error, error, error, fromPattern, getAllRight, hashCode, instrOnly, nop, nop, resolved, toString, toString, withoutRight
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Field Details
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INS
- See Also:
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CTX
- See Also:
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SEP
- See Also:
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cons
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ins
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ctx
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backfills
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forbids
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pat
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Method Details
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computeHash
protected int computeHash()- Specified by:
computeHash
in classAssemblyResolution
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equals
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fromString
public static AssemblyResolvedPatterns fromString(String str, String description, List<AssemblyResolution> children) Build a new successful SLEIGH constructor resolution from a string representationThis was used primarily in testing, to specify expected results.
- Parameters:
str
- the string representation: "ins:[pattern],ctx:[pattern]
"description
- a description of the resolutionchildren
- any children involved in the resolution- Returns:
- the decoded resolution
- See Also:
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shift
Description copied from class:AssemblyResolution
Shift the resolution's instruction pattern to the right, if applicableThis also shifts any backfill and forbidden pattern records.
- Specified by:
shift
in classAssemblyResolution
- Parameters:
amt
- the number of bytes to shift.- Returns:
- the result
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truncate
Truncate (unshift) the resolved instruction pattern from the left NOTE: This drops all backfill and forbidden pattern records, since this method is typically used to read token fields rather than passed around for resolution.- Parameters:
amt
- the number of bytes to remove from the left- Returns:
- the result
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checkNotForbidden
Check if the current encoding is forbidden by one of the attached patternsThe pattern becomes forbidden if this encoding's known bits are an overset of any forbidden pattern's known bits.
- Returns:
- false if the pattern is forbidden (and thus in error), true if permitted
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bitsEqual
Check if this and another resolution have equal encodingsThis is like
equals(Object)
, but it ignores backfill records and forbidden patterns.- Parameters:
that
- the other resolution- Returns:
- true if both have equal encodings
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combine
Combine the encodings and backfills of the given resolution into this oneThis combines corresponding pattern blocks (assuming they agree), collects backfill records, and collects forbidden patterns.
- Parameters:
that
- the other resolution- Returns:
- the result if successful, or null
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combineLessBackfill
protected AssemblyResolvedPatterns combineLessBackfill(AssemblyResolvedPatterns that, AssemblyResolvedBackfill bf) Combine a backfill resultWhen a backfill is successful, the result should be combined with the owning resolution. In addition, for bookkeeping's sake, the resolved record should be removed from the list of backfills.
- Parameters:
that
- the result from backfillingbf
- the resolved backfilled record- Returns:
- the result if successful, or null
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combine
Combine the given backfill record into this resolution- Parameters:
bf
- the backfill record- Returns:
- the result
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withForbids
Create a new resolution from this one with the given forbidden patterns recorded- Parameters:
more
- the additional forbidden patterns to record- Returns:
- the new resolution
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withDescription
Create a copy of this resolution with a new description- Parameters:
desc
- the new description- Returns:
- the copy
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withConstructor
Create a copy of this resolution with a replaced constructor- Parameters:
cons
- the new constructor- Returns:
- the copy
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writeContextOp
Encode the given value into the context block as specified by an operation- Parameters:
cop
- the context operation specifying the location of the value to encodeval
- the masked value to encode- Returns:
- the result This is the forward (as in disassembly) direction of applying context operations. The pattern expression is evaluated, and the result is written as specified.
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readContextOp
Decode the value from the context located where the given context operation would writeThis is used to read the value from the left-hand-side "variable" of a context operation. It seems backward, because it is. When assembling, the right-hand-side expression of a context operation must be solved. This means the "variable" is known from the context(s) of the resolved children constructors. The value read is then used as the goal in solving the expression.
- Parameters:
cop
- the context operation whose "variable" to read.- Returns:
- the masked result.
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copyAppendDescription
Duplicate this resolution, with additional description text appended- Parameters:
append
- the text to append- Returns:
- the duplicate NOTE: An additional separator
": "
is inserted
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withRight
Description copied from class:AssemblyResolution
Get this same resolution, but with the given right sibling- Specified by:
withRight
in classAssemblyResolution
- Returns:
- the resolution
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nopLeftSibling
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parent
Description copied from class:AssemblyResolution
Get this same resolution, pushing its right siblings down to its children- Specified by:
parent
in classAssemblyResolution
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maskOut
Set all bits read by a given context operation to unknown- Parameters:
cop
- the context operation- Returns:
- the result
- See Also:
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backfill
Apply as many backfill records as possibleEach backfill record is resolved in turn, if the record cannot be resolved, it remains listed. If the record can be resolved, but it conflicts, an error record is returned. Each time a record is resolved and combined successfully, all remaining records are tried again. The result is the combined resolved backfills, with only the unresolved backfill records listed.
- Parameters:
solver
- the solver, usually the same as the original attempt to solve.vals
- the values.- Returns:
- the result, or an error.
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lineToString
Description copied from class:AssemblyResolution
Display the resolution result in one line (omitting child details)- Specified by:
lineToString
in classAssemblyResolution
- Returns:
- the display description
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hasBackfills
public boolean hasBackfills()Check if this resolution has pending backfills to apply- Returns:
- true if there are backfills
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solveContextChangesForForbids
public AssemblyResolvedPatterns solveContextChangesForForbids(AssemblyConstructorSemantic sem, Map<String, Long> vals) Solve and apply context changes in reverse to forbidden patternsTo avoid circumstances where a context change during disassembly would invoke a more specific sub-constructor than was used to assembly the instruction, we must solve the forbidden patterns in tandem with the overall resolution. If the context of any forbidden pattern cannot be solved, we simply drop the forbidden pattern -- the lack of a solution implies there is no way the context change could produce the forbidden pattern.
- Parameters:
sem
- the constructor whose context changes to solvevals
- any defined symbols- Returns:
- the result
- See Also:
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getInstructionLength
public int getInstructionLength()Get the length of the instruction encodingThis is used to ensure each operand is encoded at the correct offset
NOTE: this DOES include the offset
NOTE: this DOES include pending backfills- Returns:
- the length of the instruction block
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getDefinedInstructionLength
public int getDefinedInstructionLength()Get the length of the instruction encoding, excluding trailing undefined bytesNOTE: this DOES include the offset
NOTE: this DOES NOT include pending backfills- Returns:
- the length of the defined bytes in the instruction block
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getInstruction
Get the instruction block- Returns:
- the instruction block
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getContext
Get the context block- Returns:
- the context block
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readInstruction
Decode a portion of the instruction block- Parameters:
start
- the first byte to decodelen
- the number of bytes to decode- Returns:
- the read masked value
- See Also:
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readContext
Decode a portion of the context block- Parameters:
start
- the first byte to decodelen
- the number of bytes to decode- Returns:
- the read masked value
- See Also:
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isError
public boolean isError()Description copied from class:AssemblyResolution
Check if this record describes an error- Specified by:
isError
in classAssemblyResolution
- Returns:
- true if the record is an error
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isBackfill
public boolean isBackfill()Description copied from class:AssemblyResolution
Check if this record describes a backfill- Specified by:
isBackfill
in classAssemblyResolution
- Returns:
- true if the record is a backfill
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hasChildren
public boolean hasChildren()Description copied from class:AssemblyResolution
Check if this record has childrenIf a subclass has another, possibly additional, notion of children that it would like to include in
AssemblyResolution.toString()
, it must override this method to return true when such children are present.- Overrides:
hasChildren
in classAssemblyResolution
- Returns:
- true if this record has children
- See Also:
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childrenToString
Description copied from class:AssemblyResolution
Get the child portion ofAssemblyResolution.toString()
If a subclass has another, possible additional, notion of children that it would like to include in
AssemblyResolution.toString()
, it must override this method.- Overrides:
childrenToString
in classAssemblyResolution
- Parameters:
indent
- the current indentation- Returns:
- the indented description for each child on its own line
- See Also:
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dumpConstructorTree
Used for testing and diagnostics: list the constructor line numbers used to resolve this encodingThis includes braces to describe the tree structure
- Returns:
- the constructor tree
- See Also:
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getSpecificity
public int getSpecificity()Count the number of bits specified in the resolution patternsTotals the specificity of the instruction and context pattern blocks.
- Returns:
- the number of bits in the resulting patterns
- See Also:
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possibleInsVals
Get an iterable over all the possible fillings of the instruction pattern given a contextThis is meant to be used idiomatically, as in an enhanced for loop:
for (byte[] ins : rcon.possibleInsVals(ctx)) { System.out.println(format(ins)); }
This is similar to calling
getInstruction()
.AssemblyPatternBlock.possibleVals()
, but with forbidden patterns removed. A context is required so that only those forbidden patterns matching the given context are actually removed. This method should always be preferred to the sequence mentioned above, sinceAssemblyPatternBlock.possibleVals()
on its own may yield bytes that do not produce the desired instruction.NOTE: The implementation is based on
AssemblyPatternBlock.possibleVals()
, so be aware that a single array is reused for each iterate. You should not retain a pointer to the array, but rather make a copy.- Parameters:
forCtx
- the context at the assembly address- Returns:
- the iterable
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getOpIndex
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getPureRecursion
If the construct state is a^instruction
or other purely-recursive constructor, get its single child.- Parameters:
state
- the parent state- Returns:
- the child state if recursive, or null
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equivalentConstructState
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