diff options
Diffstat (limited to '3rdparty/asmjit/src/asmjit/core/codewriter.cpp')
-rw-r--r-- | 3rdparty/asmjit/src/asmjit/core/codewriter.cpp | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/3rdparty/asmjit/src/asmjit/core/codewriter.cpp b/3rdparty/asmjit/src/asmjit/core/codewriter.cpp new file mode 100644 index 00000000000..2ee5b38cda5 --- /dev/null +++ b/3rdparty/asmjit/src/asmjit/core/codewriter.cpp @@ -0,0 +1,278 @@ +// This file is part of AsmJit project <https://asmjit.com> +// +// See asmjit.h or LICENSE.md for license and copyright information +// SPDX-License-Identifier: Zlib + +#include "../core/api-build_p.h" +#include "../core/codeholder.h" +#include "../core/codewriter_p.h" +#include "../arm/armutils.h" + +ASMJIT_BEGIN_NAMESPACE + +bool CodeWriterUtils::encodeOffset32(uint32_t* dst, int64_t offset64, const OffsetFormat& format) noexcept { + uint32_t bitCount = format.immBitCount(); + uint32_t bitShift = format.immBitShift(); + uint32_t discardLsb = format.immDiscardLsb(); + + // Invalid offset (should not happen). + if (!bitCount || bitCount > format.valueSize() * 8u) + return false; + + uint32_t value; + uint32_t u = 0; + bool unsignedLogic = format.type() == OffsetType::kUnsignedOffset; + + // First handle all offsets that use additional field for their sign and the offset is encoded as its + // absolute value. + if (format.hasSignBit()) { + u = uint32_t(offset64 >= 0); + if (u == 0) + offset64 = -offset64; + unsignedLogic = true; + } + + // First handle all unsigned offset types. + if (unsignedLogic) { + if (discardLsb) { + ASMJIT_ASSERT(discardLsb <= 32); + if ((offset64 & Support::lsbMask<uint32_t>(discardLsb)) != 0) + return false; + offset64 = int64_t(uint64_t(offset64) >> discardLsb); + } + + value = uint32_t(offset64 & Support::lsbMask<uint32_t>(bitCount)); + if (value != offset64) + return false; + } + else { + // The rest of OffsetType options are all signed. + if (discardLsb) { + ASMJIT_ASSERT(discardLsb <= 32); + if ((offset64 & Support::lsbMask<uint32_t>(discardLsb)) != 0) + return false; + offset64 >>= discardLsb; + } + + if (!Support::isInt32(offset64)) + return false; + + value = uint32_t(int32_t(offset64)); + if (!Support::isEncodableOffset32(int32_t(value), bitCount)) + return false; + } + + switch (format.type()) { + case OffsetType::kSignedOffset: + case OffsetType::kUnsignedOffset: { + *dst = (value & Support::lsbMask<uint32_t>(bitCount)) << bitShift; + return true; + } + + // Opcode: {.....|imm:1|..N.N|......|imm:3|....|imm:8} + case OffsetType::kThumb32_ADR: { + // Sanity checks. + if (format.valueSize() != 4 || bitCount != 12 || bitShift != 0) + return false; + + uint32_t imm8 = (value & 0x00FFu); + uint32_t imm3 = (value & 0x0700u) << (12 - 8); + uint32_t imm1 = (value & 0x0800u) << (26 - 11); + uint32_t n = u ^ 1u; + + *dst = imm8 | imm3 | imm1 | (n << 21) | (n << 23); + return true; + } + + // Opcode: {....|.|imm[22]|imm[19:10]|..|ja|.|jb|imm[9:0]|.} + case OffsetType::kThumb32_BLX: + // The calculation is the same as `B`, but the first LSB bit must be zero, so account for that. + value <<= 1; + ASMJIT_FALLTHROUGH; + + // Opcode: {....|.|imm[23]|imm[20:11]|..|ja|.|jb|imm[10:0]} + case OffsetType::kThumb32_B: { + // Sanity checks. + if (format.valueSize() != 4) + return false; + + uint32_t ia = (value & 0x0007FFu); + uint32_t ib = (value & 0x1FF800u) << (16 - 11); + uint32_t ic = (value & 0x800000u) << (26 - 23); + uint32_t ja = ((~value >> 23) ^ (value >> 22)) & 1u; + uint32_t jb = ((~value >> 23) ^ (value >> 21)) & 1u; + + *dst = ia | ib | ic | (ja << 14) | (jb << 11); + return true; + } + + // Opcode: {....|.|imm[19]|....|imm[16:11]|..|ja|.|jb|imm[10:0]} + case OffsetType::kThumb32_BCond: { + // Sanity checks. + if (format.valueSize() != 4 || bitCount != 20 || bitShift != 0) + return false; + + uint32_t ia = (value & 0x0007FFu); + uint32_t ib = (value & 0x01F800u) << (16 - 11); + uint32_t ic = (value & 0x080000u) << (26 - 19); + uint32_t ja = ((~value >> 19) ^ (value >> 22)) & 1u; + uint32_t jb = ((~value >> 19) ^ (value >> 21)) & 1u; + + *dst = ia | ib | ic | (ja << 14) | (jb << 11); + return true; + } + + case OffsetType::kAArch32_ADR: { + uint32_t encodedImm; + if (!arm::Utils::encodeAArch32Imm(value, &encodedImm)) + return false; + + *dst = (Support::bitMask(22) << u) | (encodedImm << bitShift); + return true; + } + + case OffsetType::kAArch32_U23_SignedOffset: { + *dst = (value << bitShift) | (u << 23); + return true; + } + + case OffsetType::kAArch32_U23_0To3At0_4To7At8: { + // Sanity checks. + if (format.valueSize() != 4 || bitCount != 8 || bitShift != 0) + return false; + + uint32_t immLo = (value & 0x0Fu); + uint32_t immHi = (value & 0xF0u) << (8 - 4); + + *dst = immLo | immHi | (u << 23); + return true; + } + + case OffsetType::kAArch32_1To24At0_0At24: { + // Sanity checks. + if (format.valueSize() != 4 || bitCount != 25 || bitShift != 0) + return false; + + uint32_t immLo = (value & 0x0000001u) << 24; + uint32_t immHi = (value & 0x1FFFFFEu) >> 1; + + *dst = immLo | immHi; + return true; + } + + case OffsetType::kAArch64_ADR: + case OffsetType::kAArch64_ADRP: { + // Sanity checks. + if (format.valueSize() != 4 || bitCount != 21 || bitShift != 5) + return false; + + uint32_t immLo = value & 0x3u; + uint32_t immHi = (value >> 2) & Support::lsbMask<uint32_t>(19); + + *dst = (immLo << 29) | (immHi << 5); + return true; + } + + default: + return false; + } +} + +bool CodeWriterUtils::encodeOffset64(uint64_t* dst, int64_t offset64, const OffsetFormat& format) noexcept { + uint32_t bitCount = format.immBitCount(); + uint32_t discardLsb = format.immDiscardLsb(); + + if (!bitCount || bitCount > format.valueSize() * 8u) + return false; + + uint64_t value; + + // First handle all unsigned offset types. + if (format.type() == OffsetType::kUnsignedOffset) { + if (discardLsb) { + ASMJIT_ASSERT(discardLsb <= 32); + if ((offset64 & Support::lsbMask<uint32_t>(discardLsb)) != 0) + return false; + offset64 = int64_t(uint64_t(offset64) >> discardLsb); + } + + value = uint64_t(offset64) & Support::lsbMask<uint64_t>(bitCount); + if (value != uint64_t(offset64)) + return false; + } + else { + // The rest of OffsetType options are all signed. + if (discardLsb) { + ASMJIT_ASSERT(discardLsb <= 32); + if ((offset64 & Support::lsbMask<uint32_t>(discardLsb)) != 0) + return false; + offset64 >>= discardLsb; + } + + if (!Support::isEncodableOffset64(offset64, bitCount)) + return false; + + value = uint64_t(offset64); + } + + switch (format.type()) { + case OffsetType::kSignedOffset: + case OffsetType::kUnsignedOffset: { + *dst = (value & Support::lsbMask<uint64_t>(bitCount)) << format.immBitShift(); + return true; + } + + default: + return false; + } +} + +bool CodeWriterUtils::writeOffset(void* dst, int64_t offset64, const OffsetFormat& format) noexcept { + // Offset the destination by ValueOffset so the `dst` points to the + // patched word instead of the beginning of the patched region. + dst = static_cast<char*>(dst) + format.valueOffset(); + + switch (format.valueSize()) { + case 1: { + uint32_t mask; + if (!encodeOffset32(&mask, offset64, format)) + return false; + + Support::writeU8(dst, uint8_t(Support::readU8(dst) | mask)); + return true; + } + + case 2: { + uint32_t mask; + if (!encodeOffset32(&mask, offset64, format)) + return false; + + Support::writeU16uLE(dst, uint16_t(Support::readU16uLE(dst) | mask)); + return true; + } + + case 4: { + uint32_t mask; + if (!encodeOffset32(&mask, offset64, format)) { + return false; + } + + Support::writeU32uLE(dst, Support::readU32uLE(dst) | mask); + return true; + } + + case 8: { + uint64_t mask; + if (!encodeOffset64(&mask, offset64, format)) + return false; + + Support::writeU64uLE(dst, Support::readU64uLE(dst) | mask); + return true; + } + + default: + return false; + } +} + +ASMJIT_END_NAMESPACE |