org.graalvm.compiler.asm.aarch64

Class AArch64Assembler.PatcherUtil

java.lang.Object

org.graalvm.compiler.asm.aarch64.AArch64Assembler.PatcherUtil

Enclosing class:

AArch64Assembler

public static class AArch64Assembler.PatcherUtil
extends Object

Contains methods for patching instructions within AArch64.

Constructor Summary

Constructors

Constructor and Description
PatcherUtil()

Method Summary

Modifier and Type	Method and Description
static int	computeRelativePageDifference(long target, long curPos, int pageSize) Computes the page-relative difference between two addresses.
static int	patchAddLo12(int original, int imm12) Patches add with provided imm12 value.
static int	patchAdrpHi21(int original, int imm21) Patches adrp instruction with provided imm21 value.
static int	patchBitSequence(int original, int value, int[] bitsUsed, int[] offsets) Method to patch a series a bytes within an instruction.
static int	patchLdrLo12(int original, int imm12, int srcSize) Patches lar (unsigned, scaled) with provided imm12 value.
static int	patchMov(int original, int imm16) Patches mov instruction with provided imm16 value.
static int	readInstruction(byte[] code, int pos) Convert byte array instruction into an int.
static void	writeInstruction(byte[] code, int pos, int val) Write int representation of instruction to byte array.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PatcherUtil

public PatcherUtil()

Method Detail

readInstruction

public static int readInstruction(byte[] code,
                                  int pos)

Convert byte array instruction into an int.

writeInstruction

public static void writeInstruction(byte[] code,
                                    int pos,
                                    int val)

Write int representation of instruction to byte array.

patchBitSequence

public static int patchBitSequence(int original,
                                   int value,
                                   int[] bitsUsed,
                                   int[] offsets)

Method to patch a series a bytes within an instruction.

Parameters:

original - Initial instruction value.

value - The value to be given to the series of bytes.

bitsUsed - The number of bits to patch within each byte.

offsets - Where within the bytes the value should be added.

Returns:

New patched instruction value.

patchAdrpHi21

public static int patchAdrpHi21(int original,
                                int imm21)

Patches adrp instruction with provided imm21 value.

Parameters:

original - Original instruction value.

imm21 - The value to patch.

Returns:

New patched instruction value.

patchAddLo12

public static int patchAddLo12(int original,
                               int imm12)

Patches add with provided imm12 value. Note this is expected to be used in conjunction with an adrp to form a 33-bit pc-relative address.

Parameters:

original - Original instruction value.

imm12 - The value to patch.

Returns:

New patched instruction value.

patchLdrLo12

public static int patchLdrLo12(int original,
                               int imm12,
                               int srcSize)

Patches lar (unsigned, scaled) with provided imm12 value. Note this is expected to be used in conjunction with an adrp to perform a 33-bit pc-relative load.

Parameters:

original - Original instruction value.

imm12 - The *unscaled* value to patch. The method performs all necessary shifting.

srcSize - The memory operation size. This determines the scaling factor.

Returns:

New patched instruction value.

patchMov

public static int patchMov(int original,
                           int imm16)

Patches mov instruction with provided imm16 value.

Parameters:

original - Original instruction value.

imm16 - The value to patch.

Returns:

New patched instruction value.

computeRelativePageDifference

public static int computeRelativePageDifference(long target,
                                                long curPos,
                                                int pageSize)

Computes the page-relative difference between two addresses.