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Diffstat (limited to 'include/llvm/Support/ARMWinEH.h')
| -rw-r--r-- | include/llvm/Support/ARMWinEH.h | 384 |
1 files changed, 384 insertions, 0 deletions
diff --git a/include/llvm/Support/ARMWinEH.h b/include/llvm/Support/ARMWinEH.h new file mode 100644 index 0000000..78deb8d --- /dev/null +++ b/include/llvm/Support/ARMWinEH.h @@ -0,0 +1,384 @@ +//===-- llvm/Support/WinARMEH.h - Windows on ARM EH Constants ---*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_SUPPORT_WINARMEH_H +#define LLVM_SUPPORT_WINARMEH_H + +#include "llvm/ADT/ArrayRef.h" +#include "llvm/Support/Endian.h" + +namespace llvm { +namespace ARM { +namespace WinEH { +enum class RuntimeFunctionFlag { + RFF_Unpacked, /// unpacked entry + RFF_Packed, /// packed entry + RFF_PackedFragment, /// packed entry representing a fragment + RFF_Reserved, /// reserved +}; + +enum class ReturnType { + RT_POP, /// return via pop {pc} (L flag must be set) + RT_B, /// 16-bit branch + RT_BW, /// 32-bit branch + RT_NoEpilogue, /// no epilogue (fragment) +}; + +/// RuntimeFunction - An entry in the table of procedure data (.pdata) +/// +/// 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 +/// 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 +/// +---------------------------------------------------------------+ +/// | Function Start RVA | +/// +-------------------+-+-+-+-----+-+---+---------------------+---+ +/// | Stack Adjust |C|L|R| Reg |H|Ret| Function Length |Flg| +/// +-------------------+-+-+-+-----+-+---+---------------------+---+ +/// +/// Flag : 2-bit field with the following meanings: +/// - 00 = packed unwind data not used; reamining bits point to .xdata record +/// - 01 = packed unwind data +/// - 10 = packed unwind data, function assumed to have no prologue; useful +/// for function fragments that are discontiguous with the start of the +/// function +/// - 11 = reserved +/// Function Length : 11-bit field providing the length of the entire function +/// in bytes, divided by 2; if the function is greater than +/// 4KB, a full .xdata record must be used instead +/// Ret : 2-bit field indicating how the function returns +/// - 00 = return via pop {pc} (the L bit must be set) +/// - 01 = return via 16-bit branch +/// - 10 = return via 32-bit branch +/// - 11 = no epilogue; useful for function fragments that may only contain a +/// prologue but the epilogue is elsewhere +/// H : 1-bit flag indicating whether the function "homes" the integer parameter +/// registers (r0-r3), allocating 16-bytes on the stack +/// Reg : 3-bit field indicating the index of the last saved non-volatile +/// register. If the R bit is set to 0, then only integer registers are +/// saved (r4-rN, where N is 4 + Reg). If the R bit is set to 1, then +/// only floating-point registers are being saved (d8-dN, where N is +/// 8 + Reg). The special case of the R bit being set to 1 and Reg equal +/// to 7 indicates that no registers are saved. +/// R : 1-bit flag indicating whether the non-volatile registers are integer or +/// floating-point. 0 indicates integer, 1 indicates floating-point. The +/// special case of the R-flag being set and Reg being set to 7 indicates +/// that no non-volatile registers are saved. +/// L : 1-bit flag indicating whether the function saves/restores the link +/// register (LR) +/// C : 1-bit flag indicating whether the function includes extra instructions +/// to setup a frame chain for fast walking. If this flag is set, r11 is +/// implicitly added to the list of saved non-volatile integer registers. +/// Stack Adjust : 10-bit field indicating the number of bytes of stack that are +/// allocated for this function. Only values between 0x000 and +/// 0x3f3 can be directly encoded. If the value is 0x3f4 or +/// greater, then the low 4 bits have special meaning as follows: +/// - Bit 0-1 +/// indicate the number of words' of adjustment (1-4), minus 1 +/// - Bit 2 +/// indicates if the prologue combined adjustment into push +/// - Bit 3 +/// indicates if the epilogue combined adjustment into pop +/// +/// RESTRICTIONS: +/// - IF C is SET: +/// + L flag must be set since frame chaining requires r11 and lr +/// + r11 must NOT be included in the set of registers described by Reg +/// - IF Ret is 0: +/// + L flag must be set + +// NOTE: RuntimeFunction is meant to be a simple class that provides raw access +// to all fields in the structure. The accessor methods reflect the names of +// the bitfields that they correspond to. Although some obvious simplifications +// are possible via merging of methods, it would prevent the use of this class +// to fully inspect the contents of the data structure which is particularly +// useful for scenarios such as llvm-readobj to aid in testing. + +class RuntimeFunction { +public: + const support::ulittle32_t BeginAddress; + const support::ulittle32_t UnwindData; + + RuntimeFunction(const support::ulittle32_t *Data) + : BeginAddress(Data[0]), UnwindData(Data[1]) {} + + RuntimeFunction(const support::ulittle32_t BeginAddress, + const support::ulittle32_t UnwindData) + : BeginAddress(BeginAddress), UnwindData(UnwindData) {} + + RuntimeFunctionFlag Flag() const { + return RuntimeFunctionFlag(UnwindData & 0x3); + } + + uint32_t ExceptionInformationRVA() const { + assert(Flag() == RuntimeFunctionFlag::RFF_Unpacked && + "unpacked form required for this operation"); + return (UnwindData & ~0x3); + } + + uint32_t PackedUnwindData() const { + assert((Flag() == RuntimeFunctionFlag::RFF_Packed || + Flag() == RuntimeFunctionFlag::RFF_PackedFragment) && + "packed form required for this operation"); + return (UnwindData & ~0x3); + } + uint32_t FunctionLength() const { + assert((Flag() == RuntimeFunctionFlag::RFF_Packed || + Flag() == RuntimeFunctionFlag::RFF_PackedFragment) && + "packed form required for this operation"); + return (((UnwindData & 0x00001ffc) >> 2) << 1); + } + ReturnType Ret() const { + assert((Flag() == RuntimeFunctionFlag::RFF_Packed || + Flag() == RuntimeFunctionFlag::RFF_PackedFragment) && + "packed form required for this operation"); + assert(((UnwindData & 0x00006000) || L()) && "L must be set to 1"); + return ReturnType((UnwindData & 0x00006000) >> 13); + } + bool H() const { + assert((Flag() == RuntimeFunctionFlag::RFF_Packed || + Flag() == RuntimeFunctionFlag::RFF_PackedFragment) && + "packed form required for this operation"); + return ((UnwindData & 0x00008000) >> 15); + } + uint8_t Reg() const { + assert((Flag() == RuntimeFunctionFlag::RFF_Packed || + Flag() == RuntimeFunctionFlag::RFF_PackedFragment) && + "packed form required for this operation"); + return ((UnwindData & 0x00070000) >> 16); + } + bool R() const { + assert((Flag() == RuntimeFunctionFlag::RFF_Packed || + Flag() == RuntimeFunctionFlag::RFF_PackedFragment) && + "packed form required for this operation"); + return ((UnwindData & 0x00080000) >> 19); + } + bool L() const { + assert((Flag() == RuntimeFunctionFlag::RFF_Packed || + Flag() == RuntimeFunctionFlag::RFF_PackedFragment) && + "packed form required for this operation"); + return ((UnwindData & 0x00100000) >> 20); + } + bool C() const { + assert((Flag() == RuntimeFunctionFlag::RFF_Packed || + Flag() == RuntimeFunctionFlag::RFF_PackedFragment) && + "packed form required for this operation"); + assert(((~UnwindData & 0x00200000) || L()) && + "L flag must be set, chaining requires r11 and LR"); + assert(((~UnwindData & 0x00200000) || (Reg() < 7) || R()) && + "r11 must not be included in Reg; C implies r11"); + return ((UnwindData & 0x00200000) >> 21); + } + uint16_t StackAdjust() const { + assert((Flag() == RuntimeFunctionFlag::RFF_Packed || + Flag() == RuntimeFunctionFlag::RFF_PackedFragment) && + "packed form required for this operation"); + return ((UnwindData & 0xffc00000) >> 22); + } +}; + +/// PrologueFolding - pseudo-flag derived from Stack Adjust indicating that the +/// prologue has stack adjustment combined into the push +inline bool PrologueFolding(const RuntimeFunction &RF) { + return RF.StackAdjust() >= 0x3f4 && (RF.StackAdjust() & 0x4); +} +/// Epilogue - pseudo-flag derived from Stack Adjust indicating that the +/// epilogue has stack adjustment combined into the pop +inline bool EpilogueFolding(const RuntimeFunction &RF) { + return RF.StackAdjust() >= 0x3f4 && (RF.StackAdjust() & 0x8); +} +/// StackAdjustment - calculated stack adjustment in words. The stack +/// adjustment should be determined via this function to account for the special +/// handling the special encoding when the value is >= 0x3f4. +inline uint16_t StackAdjustment(const RuntimeFunction &RF) { + uint16_t Adjustment = RF.StackAdjust(); + if (Adjustment >= 0x3f4) + return (Adjustment & 0x3) ? ((Adjustment & 0x3) << 2) - 1 : 0; + return Adjustment; +} + +/// SavedRegisterMask - Utility function to calculate the set of saved general +/// purpose (r0-r15) and VFP (d0-d31) registers. +std::pair<uint16_t, uint32_t> SavedRegisterMask(const RuntimeFunction &RF); + +/// ExceptionDataRecord - An entry in the table of exception data (.xdata) +/// +/// 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 +/// 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 +/// +-------+---------+-+-+-+---+-----------------------------------+ +/// | C Wrd | Epi Cnt |F|E|X|Ver| Function Length | +/// +-------+--------+'-'-'-'---'---+-------------------------------+ +/// | Reserved |Ex. Code Words| (Extended Epilogue Count) | +/// +-------+--------+--------------+-------------------------------+ +/// +/// Function Length : 18-bit field indicating the total length of the function +/// in bytes divided by 2. If a function is larger than +/// 512KB, then multiple pdata and xdata records must be used. +/// Vers : 2-bit field describing the version of the remaining structure. Only +/// version 0 is currently defined (values 1-3 are not permitted). +/// X : 1-bit field indicating the presence of exception data +/// E : 1-bit field indicating that the single epilogue is packed into the +/// header +/// F : 1-bit field indicating that the record describes a function fragment +/// (implies that no prologue is present, and prologue processing should be +/// skipped) +/// Epilogue Count : 5-bit field that differs in meaning based on the E field. +/// +/// If E is set, then this field specifies the index of the +/// first unwind code describing the (only) epilogue. +/// +/// Otherwise, this field indicates the number of exception +/// scopes. If more than 31 scopes exist, then this field and +/// the Code Words field must both be set to 0 to indicate that +/// an extension word is required. +/// Code Words : 4-bit field that species the number of 32-bit words needed to +/// contain all the unwind codes. If more than 15 words (63 code +/// bytes) are required, then this field and the Epilogue Count +/// field must both be set to 0 to indicate that an extension word +/// is required. +/// Extended Epilogue Count, Extended Code Words : +/// Valid only if Epilog Count and Code Words are both +/// set to 0. Provides an 8-bit extended code word +/// count and 16-bits for epilogue count +/// +/// 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 +/// 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 +/// +----------------+------+---+---+-------------------------------+ +/// | Ep Start Idx | Cond |Res| Epilogue Start Offset | +/// +----------------+------+---+-----------------------------------+ +/// +/// If the E bit is unset in the header, the header is followed by a series of +/// epilogue scopes, which are sorted by their offset. +/// +/// Epilogue Start Offset: 18-bit field encoding the offset of epilogue relative +/// to the start of the function in bytes divided by two +/// Res : 2-bit field reserved for future expansion (must be set to 0) +/// Condition : 4-bit field providing the condition under which the epilogue is +/// executed. Unconditional epilogues should set this field to 0xe. +/// Epilogues must be entirely conditional or unconditional, and in +/// Thumb-2 mode. The epilogue beings with the first instruction +/// after the IT opcode. +/// Epilogue Start Index : 8-bit field indicating the byte index of the first +/// unwind code describing the epilogue +/// +/// 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 +/// 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 +/// +---------------+---------------+---------------+---------------+ +/// | Unwind Code 3 | Unwind Code 2 | Unwind Code 1 | Unwind Code 0 | +/// +---------------+---------------+---------------+---------------+ +/// +/// Following the epilogue scopes, the byte code describing the unwinding +/// follows. This is padded to align up to word alignment. Bytes are stored in +/// little endian. +/// +/// 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 +/// 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 +/// +---------------------------------------------------------------+ +/// | Exception Handler RVA (requires X = 1) | +/// +---------------------------------------------------------------+ +/// | (possibly followed by data required for exception handler) | +/// +---------------------------------------------------------------+ +/// +/// If the X bit is set in the header, the unwind byte code is followed by the +/// exception handler information. This constants of one Exception Handler RVA +/// which is the address to the exception handler, followed immediately by the +/// variable length data associated with the exception handler. +/// + +struct EpilogueScope { + const support::ulittle32_t ES; + + EpilogueScope(const support::ulittle32_t Data) : ES(Data) {} + uint32_t EpilogueStartOffset() const { + return (ES & 0x0003ffff); + } + uint8_t Res() const { + return ((ES & 0x000c0000) >> 18); + } + uint8_t Condition() const { + return ((ES & 0x00f00000) >> 20); + } + uint8_t EpilogueStartIndex() const { + return ((ES & 0xff000000) >> 24); + } +}; + +struct ExceptionDataRecord; +inline size_t HeaderWords(const ExceptionDataRecord &XR); + +struct ExceptionDataRecord { + const support::ulittle32_t *Data; + + ExceptionDataRecord(const support::ulittle32_t *Data) : Data(Data) {} + + uint32_t FunctionLength() const { + return (Data[0] & 0x0003ffff); + } + + uint8_t Vers() const { + return (Data[0] & 0x000C0000) >> 18; + } + + bool X() const { + return ((Data[0] & 0x00100000) >> 20); + } + + bool E() const { + return ((Data[0] & 0x00200000) >> 21); + } + + bool F() const { + return ((Data[0] & 0x00400000) >> 22); + } + + uint8_t EpilogueCount() const { + if (HeaderWords(*this) == 1) + return (Data[0] & 0x0f800000) >> 23; + return Data[1] & 0x0000ffff; + } + + uint8_t CodeWords() const { + if (HeaderWords(*this) == 1) + return (Data[0] & 0xf0000000) >> 28; + return (Data[1] & 0x00ff0000) >> 16; + } + + ArrayRef<support::ulittle32_t> EpilogueScopes() const { + assert(E() == 0 && "epilogue scopes are only present when the E bit is 0"); + size_t Offset = HeaderWords(*this); + return ArrayRef<support::ulittle32_t>(&Data[Offset], EpilogueCount()); + } + + ArrayRef<support::ulittle8_t> UnwindByteCode() const { + const size_t Offset = HeaderWords(*this) + + (E() ? 0 : EpilogueCount()); + const support::ulittle8_t *ByteCode = + reinterpret_cast<const support::ulittle8_t *>(&Data[Offset]); + return ArrayRef<support::ulittle8_t>(ByteCode, + CodeWords() * sizeof(uint32_t)); + } + + uint32_t ExceptionHandlerRVA() const { + assert(X() && "Exception Handler RVA is only valid if the X bit is set"); + return Data[HeaderWords(*this) + EpilogueCount() + CodeWords()]; + } + + uint32_t ExceptionHandlerParameter() const { + assert(X() && "Exception Handler RVA is only valid if the X bit is set"); + return Data[HeaderWords(*this) + EpilogueCount() + CodeWords() + 1]; + } +}; + +inline size_t HeaderWords(const ExceptionDataRecord &XR) { + return (XR.Data[0] & 0xff800000) ? 1 : 2; +} +} +} +} + +#endif + |