Package ghidra.app.plugin.assembler.sleigh.sem

Interface AssemblyResolvedPatterns

All Superinterfaces:
AssemblyResolution, Comparable<AssemblyResolution>
All Known Implementing Classes:
DefaultAssemblyResolvedPatterns
public interface AssemblyResolvedPatterns extends AssemblyResolution

  • Method Details

    • getInstruction

      AssemblyPatternBlock getInstruction()
      Get the instruction block
      Returns:
      the instruction block

    • getContext

      AssemblyPatternBlock getContext()
      Get the context block
      Returns:
      the context block

    • getInstructionLength

      int getInstructionLength()
      Get the length of the instruction encoding

      This 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

    • getDefinedInstructionLength

      int getDefinedInstructionLength()
      Get the length of the instruction encoding, excluding trailing undefined bytes

      NOTE: this DOES include the offset
      NOTE: this DOES NOT include pending backfills

      Returns:
      the length of the defined bytes in the instruction block

    • getBackfills

      Collection<AssemblyResolvedBackfill> getBackfills()
      Get the backfill records for this resolution, if any
      Returns:
      the backfills

    • hasBackfills

      boolean hasBackfills()
      Check if this resolution has pending backfills to apply
      Returns:
      true if there are backfills

    • getForbids

      Collection<AssemblyResolvedPatterns> getForbids()
      Get the forbidden patterns for this resolution

      These represent patterns included in the current resolution that would actually get matched by a more specific constructor somewhere in the resolved tree, and thus are subtracted.

      Returns:
      the forbidden patterns

    • readInstruction

      MaskedLong readInstruction(int byteStart, int size)
      Decode a portion of the instruction block
      Parameters:
      byteStart - the first byte to decode
      size - the number of bytes to decode
      Returns:
      the read masked value
      See Also:

    • readContext

      MaskedLong readContext(int start, int len)
      Decode a portion of the context block
      Parameters:
      start - the first byte to decode
      len - the number of bytes to decode
      Returns:
      the read masked value
      See Also:

    • readContextOp

      MaskedLong readContextOp(ContextOp cop)
      Decode the value from the context located where the given context operation would write

      This 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.

    • bitsEqual

      boolean bitsEqual(AssemblyResolvedPatterns that)
      Check if this and another resolution have equal encodings

      This is like Object.equals(Object), but it ignores backfill records and forbidden patterns.

      Parameters:
      that - the other resolution
      Returns:
      true if both have equal encodings

    • equivalentConstructState

      boolean equivalentConstructState(ConstructState state)
      Check if this assembled construct state is the same as the given dis-assembled construct state.

    • shift

      AssemblyResolvedPatterns shift(int shamt)
      Description copied from interface: AssemblyResolution
      Shift the resolution's instruction pattern to the right, if applicable

      This also shifts any backfill and forbidden pattern records.

      Specified by:
      shift in interface AssemblyResolution
      Parameters:
      shamt - the number of bytes to shift.
      Returns:
      the result

    • withDescription

      AssemblyResolvedPatterns withDescription(String description)
      Create a copy of this resolution with a new description
      Parameters:
      description - the new description
      Returns:
      the copy

    • withRight

      AssemblyResolvedPatterns withRight(AssemblyResolution right)
      Create a copy of this resolution with a sibling to the right

      The right sibling is a mechanism for collecting children of a parent yet to be created. See parent(String, int).

      Parameters:
      right - the right sibling
      Returns:
      the new resolution

    • withConstructor

      AssemblyResolvedPatterns withConstructor(Constructor cons)
      Create a copy of this resolution with a replaced constructor
      Parameters:
      cons - the new constructor
      Returns:
      the copy

    • combine

      AssemblyResolvedPatterns combine(AssemblyResolvedPatterns pat)
      Combine the encodings and backfills of the given resolution into this one

      This combines corresponding pattern blocks (assuming they agree), collects backfill records, and collects forbidden patterns.

      Parameters:
      pat - the other resolution
      Returns:
      the result if successful, or null

    • combine

      AssemblyResolvedPatterns combine(AssemblyResolvedBackfill bf)
      Combine the given backfill record into this resolution
      Parameters:
      bf - the backfill record
      Returns:
      the result

    • combineLessBackfill

      AssemblyResolvedPatterns combineLessBackfill(AssemblyResolvedPatterns that, AssemblyResolvedBackfill bf)
      Combine a backfill result

      When 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 backfilling
      bf - the resolved backfilled record
      Returns:
      the result if successful, or null

    • parent

      AssemblyResolvedPatterns parent(String description, int opCount)
      Description copied from interface: AssemblyResolution
      Get this same resolution, pushing its right siblings down to its children
      Specified by:
      parent in interface AssemblyResolution

    • backfill

      AssemblyResolution backfill(RecursiveDescentSolver solver, Map<String,Long> vals)
      Apply as many backfill records as possible

      Each 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.

    • checkNotForbidden

      AssemblyResolution checkNotForbidden()
      Check if the current encoding is forbidden by one of the attached patterns

      The 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

    • nopLeftSibling

      AssemblyResolvedPatterns nopLeftSibling()
      Generate a new nop right this resolution to its right.

      Alternatively phrased: append a nop to the left of this list of siblings, returning the new head.

      Returns:
      the nop resolution

    • solveContextChangesForForbids

      AssemblyResolvedPatterns solveContextChangesForForbids(AssemblyConstructorSemantic sem, Map<String,Long> vals)
      Solve and apply context changes in reverse to forbidden patterns

      To 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 solve
      vals - any defined symbols
      Returns:
      the result
      See Also:

    • possibleInsVals

      Iterable<byte[]> possibleInsVals(AssemblyPatternBlock forCtx)
      Get an iterable over all the possible fillings of the instruction pattern given a context

      This 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, since AssemblyPatternBlock.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

    • dumpConstructorTree

      String dumpConstructorTree()
      Used for testing and diagnostics: list the constructor line numbers used to resolve this encoding

      This includes braces to describe the tree structure

      Returns:
      the constructor tree
      See Also:

    • truncate

      AssemblyResolvedPatterns truncate(int shamt)
      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:
      shamt - the number of bytes to remove from the left
      Returns:
      the result

    • withForbids

      AssemblyResolvedPatterns withForbids(Set<AssemblyResolvedPatterns> more)
      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

    • maskOut

      AssemblyResolvedPatterns maskOut(ContextOp cop)
      Set all bits read by a given context operation to unknown
      Parameters:
      cop - the context operation
      Returns:
      the result
      See Also:

    • writeContextOp

      AssemblyResolvedPatterns writeContextOp(ContextOp cop, MaskedLong val)
      Encode the given value into the context block as specified by an operation

      This is the forward (as in disassembly) direction of applying context operations. The pattern expression is evaluated, and the result is written as specified.

      Parameters:
      cop - the context operation specifying the location of the value to encode
      val - the masked value to encode
      Returns:
      the result