| Index: third_party/libc++abi/include/mach-o/compact_unwind_encoding.h
|
| ===================================================================
|
| --- third_party/libc++abi/include/mach-o/compact_unwind_encoding.h (revision 0)
|
| +++ third_party/libc++abi/include/mach-o/compact_unwind_encoding.h (revision 0)
|
| @@ -0,0 +1,487 @@
|
| +//===------------------ mach-o/compact_unwind_encoding.h ------------------===//
|
| +//
|
| +// The LLVM Compiler Infrastructure
|
| +//
|
| +// This file is dual licensed under the MIT and the University of Illinois Open
|
| +// Source Licenses. See LICENSE.TXT for details.
|
| +//
|
| +//
|
| +// Darwin's alternative to dwarf based unwind encodings.
|
| +//
|
| +//===----------------------------------------------------------------------===//
|
| +
|
| +
|
| +#ifndef __COMPACT_UNWIND_ENCODING__
|
| +#define __COMPACT_UNWIND_ENCODING__
|
| +
|
| +#include <stdint.h>
|
| +
|
| +//
|
| +// Compilers can emit standard Dwarf FDEs in the __TEXT,__eh_frame section
|
| +// of object files. Or compilers can emit compact unwind information in
|
| +// the __LD,__compact_unwind section.
|
| +//
|
| +// When the linker creates a final linked image, it will create a
|
| +// __TEXT,__unwind_info section. This section is a small and fast way for the
|
| +// runtime to access unwind info for any given function. If the compiler
|
| +// emitted compact unwind info for the function, that compact unwind info will
|
| +// be encoded in the __TEXT,__unwind_info section. If the compiler emitted
|
| +// dwarf unwind info, the __TEXT,__unwind_info section will contain the offset
|
| +// of the FDE in the __TEXT,__eh_frame section in the final linked image.
|
| +//
|
| +// Note: Previously, the linker would transform some dwarf unwind infos into
|
| +// compact unwind info. But that is fragile and no longer done.
|
| +
|
| +
|
| +//
|
| +// The compact unwind endoding is a 32-bit value which encoded in an
|
| +// architecture specific way, which registers to restore from where, and how
|
| +// to unwind out of the function.
|
| +//
|
| +typedef uint32_t compact_unwind_encoding_t;
|
| +
|
| +
|
| +// architecture independent bits
|
| +enum {
|
| + UNWIND_IS_NOT_FUNCTION_START = 0x80000000,
|
| + UNWIND_HAS_LSDA = 0x40000000,
|
| + UNWIND_PERSONALITY_MASK = 0x30000000,
|
| +};
|
| +
|
| +
|
| +
|
| +
|
| +//
|
| +// x86
|
| +//
|
| +// 1-bit: start
|
| +// 1-bit: has lsda
|
| +// 2-bit: personality index
|
| +//
|
| +// 4-bits: 0=old, 1=ebp based, 2=stack-imm, 3=stack-ind, 4=dwarf
|
| +// ebp based:
|
| +// 15-bits (5*3-bits per reg) register permutation
|
| +// 8-bits for stack offset
|
| +// frameless:
|
| +// 8-bits stack size
|
| +// 3-bits stack adjust
|
| +// 3-bits register count
|
| +// 10-bits register permutation
|
| +//
|
| +enum {
|
| + UNWIND_X86_MODE_MASK = 0x0F000000,
|
| + UNWIND_X86_MODE_EBP_FRAME = 0x01000000,
|
| + UNWIND_X86_MODE_STACK_IMMD = 0x02000000,
|
| + UNWIND_X86_MODE_STACK_IND = 0x03000000,
|
| + UNWIND_X86_MODE_DWARF = 0x04000000,
|
| +
|
| + UNWIND_X86_EBP_FRAME_REGISTERS = 0x00007FFF,
|
| + UNWIND_X86_EBP_FRAME_OFFSET = 0x00FF0000,
|
| +
|
| + UNWIND_X86_FRAMELESS_STACK_SIZE = 0x00FF0000,
|
| + UNWIND_X86_FRAMELESS_STACK_ADJUST = 0x0000E000,
|
| + UNWIND_X86_FRAMELESS_STACK_REG_COUNT = 0x00001C00,
|
| + UNWIND_X86_FRAMELESS_STACK_REG_PERMUTATION = 0x000003FF,
|
| +
|
| + UNWIND_X86_DWARF_SECTION_OFFSET = 0x00FFFFFF,
|
| +};
|
| +
|
| +enum {
|
| + UNWIND_X86_REG_NONE = 0,
|
| + UNWIND_X86_REG_EBX = 1,
|
| + UNWIND_X86_REG_ECX = 2,
|
| + UNWIND_X86_REG_EDX = 3,
|
| + UNWIND_X86_REG_EDI = 4,
|
| + UNWIND_X86_REG_ESI = 5,
|
| + UNWIND_X86_REG_EBP = 6,
|
| +};
|
| +
|
| +//
|
| +// For x86 there are four modes for the compact unwind encoding:
|
| +// UNWIND_X86_MODE_EBP_FRAME:
|
| +// EBP based frame where EBP is push on stack immediately after return address,
|
| +// then ESP is moved to EBP. Thus, to unwind ESP is restored with the current
|
| +// EPB value, then EBP is restored by popping off the stack, and the return
|
| +// is done by popping the stack once more into the pc.
|
| +// All non-volatile registers that need to be restored must have been saved
|
| +// in a small range in the stack that starts EBP-4 to EBP-1020. The offset/4
|
| +// is encoded in the UNWIND_X86_EBP_FRAME_OFFSET bits. The registers saved
|
| +// are encoded in the UNWIND_X86_EBP_FRAME_REGISTERS bits as five 3-bit entries.
|
| +// Each entry contains which register to restore.
|
| +// UNWIND_X86_MODE_STACK_IMMD:
|
| +// A "frameless" (EBP not used as frame pointer) function with a small
|
| +// constant stack size. To return, a constant (encoded in the compact
|
| +// unwind encoding) is added to the ESP. Then the return is done by
|
| +// popping the stack into the pc.
|
| +// All non-volatile registers that need to be restored must have been saved
|
| +// on the stack immediately after the return address. The stack_size/4 is
|
| +// encoded in the UNWIND_X86_FRAMELESS_STACK_SIZE (max stack size is 1024).
|
| +// The number of registers saved is encoded in UNWIND_X86_FRAMELESS_STACK_REG_COUNT.
|
| +// UNWIND_X86_FRAMELESS_STACK_REG_PERMUTATION constains which registers were
|
| +// saved and their order.
|
| +// UNWIND_X86_MODE_STACK_IND:
|
| +// A "frameless" (EBP not used as frame pointer) function large constant
|
| +// stack size. This case is like the previous, except the stack size is too
|
| +// large to encode in the compact unwind encoding. Instead it requires that
|
| +// the function contains "subl $nnnnnnnn,ESP" in its prolog. The compact
|
| +// encoding contains the offset to the nnnnnnnn value in the function in
|
| +// UNWIND_X86_FRAMELESS_STACK_SIZE.
|
| +// UNWIND_X86_MODE_DWARF:
|
| +// No compact unwind encoding is available. Instead the low 24-bits of the
|
| +// compact encoding is the offset of the dwarf FDE in the __eh_frame section.
|
| +// This mode is never used in object files. It is only generated by the
|
| +// linker in final linked images which have only dwarf unwind info for a
|
| +// function.
|
| +//
|
| +// The following is the algorithm used to create the permutation encoding used
|
| +// with frameless stacks. It is passed the number of registers to be saved and
|
| +// an array of the register numbers saved.
|
| +//
|
| +//uint32_t permute_encode(uint32_t registerCount, const uint32_t registers[6])
|
| +//{
|
| +// uint32_t renumregs[6];
|
| +// for (int i=6-registerCount; i < 6; ++i) {
|
| +// int countless = 0;
|
| +// for (int j=6-registerCount; j < i; ++j) {
|
| +// if ( registers[j] < registers[i] )
|
| +// ++countless;
|
| +// }
|
| +// renumregs[i] = registers[i] - countless -1;
|
| +// }
|
| +// uint32_t permutationEncoding = 0;
|
| +// switch ( registerCount ) {
|
| +// case 6:
|
| +// permutationEncoding |= (120*renumregs[0] + 24*renumregs[1]
|
| +// + 6*renumregs[2] + 2*renumregs[3]
|
| +// + renumregs[4]);
|
| +// break;
|
| +// case 5:
|
| +// permutationEncoding |= (120*renumregs[1] + 24*renumregs[2]
|
| +// + 6*renumregs[3] + 2*renumregs[4]
|
| +// + renumregs[5]);
|
| +// break;
|
| +// case 4:
|
| +// permutationEncoding |= (60*renumregs[2] + 12*renumregs[3]
|
| +// + 3*renumregs[4] + renumregs[5]);
|
| +// break;
|
| +// case 3:
|
| +// permutationEncoding |= (20*renumregs[3] + 4*renumregs[4]
|
| +// + renumregs[5]);
|
| +// break;
|
| +// case 2:
|
| +// permutationEncoding |= (5*renumregs[4] + renumregs[5]);
|
| +// break;
|
| +// case 1:
|
| +// permutationEncoding |= (renumregs[5]);
|
| +// break;
|
| +// }
|
| +// return permutationEncoding;
|
| +//}
|
| +//
|
| +
|
| +
|
| +
|
| +
|
| +//
|
| +// x86_64
|
| +//
|
| +// 1-bit: start
|
| +// 1-bit: has lsda
|
| +// 2-bit: personality index
|
| +//
|
| +// 4-bits: 0=old, 1=rbp based, 2=stack-imm, 3=stack-ind, 4=dwarf
|
| +// rbp based:
|
| +// 15-bits (5*3-bits per reg) register permutation
|
| +// 8-bits for stack offset
|
| +// frameless:
|
| +// 8-bits stack size
|
| +// 3-bits stack adjust
|
| +// 3-bits register count
|
| +// 10-bits register permutation
|
| +//
|
| +enum {
|
| + UNWIND_X86_64_MODE_MASK = 0x0F000000,
|
| + UNWIND_X86_64_MODE_RBP_FRAME = 0x01000000,
|
| + UNWIND_X86_64_MODE_STACK_IMMD = 0x02000000,
|
| + UNWIND_X86_64_MODE_STACK_IND = 0x03000000,
|
| + UNWIND_X86_64_MODE_DWARF = 0x04000000,
|
| +
|
| + UNWIND_X86_64_RBP_FRAME_REGISTERS = 0x00007FFF,
|
| + UNWIND_X86_64_RBP_FRAME_OFFSET = 0x00FF0000,
|
| +
|
| + UNWIND_X86_64_FRAMELESS_STACK_SIZE = 0x00FF0000,
|
| + UNWIND_X86_64_FRAMELESS_STACK_ADJUST = 0x0000E000,
|
| + UNWIND_X86_64_FRAMELESS_STACK_REG_COUNT = 0x00001C00,
|
| + UNWIND_X86_64_FRAMELESS_STACK_REG_PERMUTATION = 0x000003FF,
|
| +
|
| + UNWIND_X86_64_DWARF_SECTION_OFFSET = 0x00FFFFFF,
|
| +};
|
| +
|
| +enum {
|
| + UNWIND_X86_64_REG_NONE = 0,
|
| + UNWIND_X86_64_REG_RBX = 1,
|
| + UNWIND_X86_64_REG_R12 = 2,
|
| + UNWIND_X86_64_REG_R13 = 3,
|
| + UNWIND_X86_64_REG_R14 = 4,
|
| + UNWIND_X86_64_REG_R15 = 5,
|
| + UNWIND_X86_64_REG_RBP = 6,
|
| +};
|
| +//
|
| +// For x86_64 there are four modes for the compact unwind encoding:
|
| +// UNWIND_X86_64_MODE_RBP_FRAME:
|
| +// RBP based frame where RBP is push on stack immediately after return address,
|
| +// then RSP is moved to RBP. Thus, to unwind RSP is restored with the current
|
| +// EPB value, then RBP is restored by popping off the stack, and the return
|
| +// is done by popping the stack once more into the pc.
|
| +// All non-volatile registers that need to be restored must have been saved
|
| +// in a small range in the stack that starts RBP-8 to RBP-1020. The offset/4
|
| +// is encoded in the UNWIND_X86_64_RBP_FRAME_OFFSET bits. The registers saved
|
| +// are encoded in the UNWIND_X86_64_RBP_FRAME_REGISTERS bits as five 3-bit entries.
|
| +// Each entry contains which register to restore.
|
| +// UNWIND_X86_64_MODE_STACK_IMMD:
|
| +// A "frameless" (RBP not used as frame pointer) function with a small
|
| +// constant stack size. To return, a constant (encoded in the compact
|
| +// unwind encoding) is added to the RSP. Then the return is done by
|
| +// popping the stack into the pc.
|
| +// All non-volatile registers that need to be restored must have been saved
|
| +// on the stack immediately after the return address. The stack_size/4 is
|
| +// encoded in the UNWIND_X86_64_FRAMELESS_STACK_SIZE (max stack size is 1024).
|
| +// The number of registers saved is encoded in UNWIND_X86_64_FRAMELESS_STACK_REG_COUNT.
|
| +// UNWIND_X86_64_FRAMELESS_STACK_REG_PERMUTATION constains which registers were
|
| +// saved and their order.
|
| +// UNWIND_X86_64_MODE_STACK_IND:
|
| +// A "frameless" (RBP not used as frame pointer) function large constant
|
| +// stack size. This case is like the previous, except the stack size is too
|
| +// large to encode in the compact unwind encoding. Instead it requires that
|
| +// the function contains "subq $nnnnnnnn,RSP" in its prolog. The compact
|
| +// encoding contains the offset to the nnnnnnnn value in the function in
|
| +// UNWIND_X86_64_FRAMELESS_STACK_SIZE.
|
| +// UNWIND_X86_64_MODE_DWARF:
|
| +// No compact unwind encoding is available. Instead the low 24-bits of the
|
| +// compact encoding is the offset of the dwarf FDE in the __eh_frame section.
|
| +// This mode is never used in object files. It is only generated by the
|
| +// linker in final linked images which have only dwarf unwind info for a
|
| +// function.
|
| +//
|
| +
|
| +
|
| +#ifndef __OPEN_SOURCE__
|
| +
|
| +// ARM64
|
| +//
|
| +// 1-bit: start
|
| +// 1-bit: has lsda
|
| +// 2-bit: personality index
|
| +//
|
| +// 4-bits: 4=frame-based, 2=frameless, 3=dwarf
|
| +// frameless:
|
| +// 12-bits of stack size
|
| +// frame-based:
|
| +// 4-bits D reg pairs saved
|
| +// 5-bits X reg pairs saved
|
| +// dwarf:
|
| +// 24-bits offset of dwarf FDE in __eh_frame section
|
| +//
|
| +enum {
|
| + UNWIND_ARM64_MODE_MASK = 0x0F000000,
|
| + UNWIND_ARM64_MODE_FRAMELESS = 0x02000000,
|
| + UNWIND_ARM64_MODE_DWARF = 0x03000000,
|
| + UNWIND_ARM64_MODE_FRAME = 0x04000000,
|
| +
|
| + UNWIND_ARM64_FRAME_X19_X20_PAIR = 0x00000001,
|
| + UNWIND_ARM64_FRAME_X21_X22_PAIR = 0x00000002,
|
| + UNWIND_ARM64_FRAME_X23_X24_PAIR = 0x00000004,
|
| + UNWIND_ARM64_FRAME_X25_X26_PAIR = 0x00000008,
|
| + UNWIND_ARM64_FRAME_X27_X28_PAIR = 0x00000010,
|
| + UNWIND_ARM64_FRAME_D8_D9_PAIR = 0x00000100,
|
| + UNWIND_ARM64_FRAME_D10_D11_PAIR = 0x00000200,
|
| + UNWIND_ARM64_FRAME_D12_D13_PAIR = 0x00000400,
|
| + UNWIND_ARM64_FRAME_D14_D15_PAIR = 0x00000800,
|
| +
|
| + UNWIND_ARM64_FRAME_X21_X22_PAIR_OLD = 0x00000001,
|
| + UNWIND_ARM64_FRAME_X23_X24_PAIR_OLD = 0x00000002,
|
| + UNWIND_ARM64_FRAME_X25_X26_PAIR_OLD = 0x00000004,
|
| + UNWIND_ARM64_FRAME_X27_X28_PAIR_OLD = 0x00000008,
|
| + UNWIND_ARM64_FRAME_D8_D9_PAIR_OLD = 0x00000010,
|
| + UNWIND_ARM64_FRAME_D10_D11_PAIR_OLD = 0x00000020,
|
| + UNWIND_ARM64_FRAME_D12_D13_PAIR_OLD = 0x00000040,
|
| + UNWIND_ARM64_FRAME_D14_D15_PAIR_OLD = 0x00000080,
|
| +
|
| + UNWIND_ARM64_FRAMELESS_STACK_SIZE_MASK = 0x00FFF000,
|
| + UNWIND_ARM64_DWARF_SECTION_OFFSET = 0x00FFFFFF,
|
| +};
|
| +// For arm64 there are three modes for the compact unwind encoding:
|
| +// UNWIND_ARM64_MODE_FRAME:
|
| +// This is a standard arm64 prolog where FP/LR are immediately pushed on the
|
| +// stack, then SP is copied to FP. If there are any non-volatile registers
|
| +// saved, then are copied into the stack frame in pairs in a contiguous
|
| +// range right below the saved FP/LR pair. Any subset of the five X pairs
|
| +// and four D pairs can be saved, but the memory layout must be in register
|
| +// number order.
|
| +// UNWIND_ARM64_MODE_FRAMELESS:
|
| +// A "frameless" leaf function, where FP/LR are not saved. The return address
|
| +// remains in LR throughout the function. If any non-volatile registers
|
| +// are saved, they must be pushed onto the stack before any stack space is
|
| +// allocated for local variables. The stack sized (including any saved
|
| +// non-volatile registers) divided by 16 is encoded in the bits
|
| +// UNWIND_ARM64_FRAMELESS_STACK_SIZE_MASK.
|
| +// UNWIND_ARM64_MODE_DWARF:
|
| +// No compact unwind encoding is available. Instead the low 24-bits of the
|
| +// compact encoding is the offset of the dwarf FDE in the __eh_frame section.
|
| +// This mode is never used in object files. It is only generated by the
|
| +// linker in final linked images which have only dwarf unwind info for a
|
| +// function.
|
| +//
|
| +
|
| +#endif // __OPEN_SOURCE__
|
| +
|
| +
|
| +
|
| +
|
| +
|
| +////////////////////////////////////////////////////////////////////////////////
|
| +//
|
| +// Relocatable Object Files: __LD,__compact_unwind
|
| +//
|
| +////////////////////////////////////////////////////////////////////////////////
|
| +
|
| +//
|
| +// A compiler can generated compact unwind information for a function by adding
|
| +// a "row" to the __LD,__compact_unwind section. This section has the
|
| +// S_ATTR_DEBUG bit set, so the section will be ignored by older linkers.
|
| +// It is removed by the new linker, so never ends up in final executables.
|
| +// This section is a table, initially with one row per function (that needs
|
| +// unwind info). The table columns and some conceptual entries are:
|
| +//
|
| +// range-start pointer to start of function/range
|
| +// range-length
|
| +// compact-unwind-encoding 32-bit encoding
|
| +// personality-function or zero if no personality function
|
| +// lsda or zero if no LSDA data
|
| +//
|
| +// The length and encoding fields are 32-bits. The other are all pointer sized.
|
| +//
|
| +// In x86_64 assembly, these entry would look like:
|
| +//
|
| +// .section __LD,__compact_unwind,regular,debug
|
| +//
|
| +// #compact unwind for _foo
|
| +// .quad _foo
|
| +// .set L1,LfooEnd-_foo
|
| +// .long L1
|
| +// .long 0x01010001
|
| +// .quad 0
|
| +// .quad 0
|
| +//
|
| +// #compact unwind for _bar
|
| +// .quad _bar
|
| +// .set L2,LbarEnd-_bar
|
| +// .long L2
|
| +// .long 0x01020011
|
| +// .quad __gxx_personality
|
| +// .quad except_tab1
|
| +//
|
| +//
|
| +// Notes: There is no need for any labels in the the __compact_unwind section.
|
| +// The use of the .set directive is to force the evaluation of the
|
| +// range-length at assembly time, instead of generating relocations.
|
| +//
|
| +// To support future compiler optimizations where which non-volatile registers
|
| +// are saved changes within a function (e.g. delay saving non-volatiles until
|
| +// necessary), there can by multiple lines in the __compact_unwind table for one
|
| +// function, each with a different (non-overlapping) range and each with
|
| +// different compact unwind encodings that correspond to the non-volatiles
|
| +// saved at that range of the function.
|
| +//
|
| +// If a particular function is so wacky that there is no compact unwind way
|
| +// to encode it, then the compiler can emit traditional dwarf unwind info.
|
| +// The runtime will use which ever is available.
|
| +//
|
| +// Runtime support for compact unwind encodings are only available on 10.6
|
| +// and later. So, the compiler should not generate it when targeting pre-10.6.
|
| +
|
| +
|
| +
|
| +
|
| +////////////////////////////////////////////////////////////////////////////////
|
| +//
|
| +// Final Linked Images: __TEXT,__unwind_info
|
| +//
|
| +////////////////////////////////////////////////////////////////////////////////
|
| +
|
| +//
|
| +// The __TEXT,__unwind_info section is laid out for an efficient two level lookup.
|
| +// The header of the section contains a coarse index that maps function address
|
| +// to the page (4096 byte block) containing the unwind info for that function.
|
| +//
|
| +
|
| +#define UNWIND_SECTION_VERSION 1
|
| +struct unwind_info_section_header
|
| +{
|
| + uint32_t version; // UNWIND_SECTION_VERSION
|
| + uint32_t commonEncodingsArraySectionOffset;
|
| + uint32_t commonEncodingsArrayCount;
|
| + uint32_t personalityArraySectionOffset;
|
| + uint32_t personalityArrayCount;
|
| + uint32_t indexSectionOffset;
|
| + uint32_t indexCount;
|
| + // compact_unwind_encoding_t[]
|
| + // uintptr_t personalities[]
|
| + // unwind_info_section_header_index_entry[]
|
| + // unwind_info_section_header_lsda_index_entry[]
|
| +};
|
| +
|
| +struct unwind_info_section_header_index_entry
|
| +{
|
| + uint32_t functionOffset;
|
| + uint32_t secondLevelPagesSectionOffset; // section offset to start of regular or compress page
|
| + uint32_t lsdaIndexArraySectionOffset; // section offset to start of lsda_index array for this range
|
| +};
|
| +
|
| +struct unwind_info_section_header_lsda_index_entry
|
| +{
|
| + uint32_t functionOffset;
|
| + uint32_t lsdaOffset;
|
| +};
|
| +
|
| +//
|
| +// There are two kinds of second level index pages: regular and compressed.
|
| +// A compressed page can hold up to 1021 entries, but it cannot be used
|
| +// if too many different encoding types are used. The regular page holds
|
| +// 511 entries.
|
| +//
|
| +
|
| +struct unwind_info_regular_second_level_entry
|
| +{
|
| + uint32_t functionOffset;
|
| + compact_unwind_encoding_t encoding;
|
| +};
|
| +
|
| +#define UNWIND_SECOND_LEVEL_REGULAR 2
|
| +struct unwind_info_regular_second_level_page_header
|
| +{
|
| + uint32_t kind; // UNWIND_SECOND_LEVEL_REGULAR
|
| + uint16_t entryPageOffset;
|
| + uint16_t entryCount;
|
| + // entry array
|
| +};
|
| +
|
| +#define UNWIND_SECOND_LEVEL_COMPRESSED 3
|
| +struct unwind_info_compressed_second_level_page_header
|
| +{
|
| + uint32_t kind; // UNWIND_SECOND_LEVEL_COMPRESSED
|
| + uint16_t entryPageOffset;
|
| + uint16_t entryCount;
|
| + uint16_t encodingsPageOffset;
|
| + uint16_t encodingsCount;
|
| + // 32-bit entry array
|
| + // encodings array
|
| +};
|
| +
|
| +#define UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET(entry) (entry & 0x00FFFFFF)
|
| +#define UNWIND_INFO_COMPRESSED_ENTRY_ENCODING_INDEX(entry) ((entry >> 24) & 0xFF)
|
| +
|
| +
|
| +
|
| +#endif
|
| +
|
|
|
| Property changes on: third_party/libc++abi/include/mach-o/compact_unwind_encoding.h
|
| ___________________________________________________________________
|
| Added: svn:eol-style
|
| + LF
|
|
|
|
|