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#pragma once
#if defined(OBJFORMAT_MACHO)
#include "ghcplatform.h"
#include <mach-o/loader.h>
#if defined(x86_64_HOST_ARCH) || defined(powerpc64_HOST_ARCH) \
|| defined(aarch64_HOST_ARCH) || defined(arm64_HOST_ARCH)
typedef struct mach_header_64 MachOHeader;
typedef struct segment_command_64 MachOSegmentCommand;
typedef struct section_64 MachOSection;
typedef struct nlist_64 MachONList;
#elif defined(i386_HOST_ARCH) || defined(powerpc_HOST_ARCH) \
|| defined(arm_HOST_ARCH)
typedef struct mach_header MachOHeader;
typedef struct segment_command MachOSegmentCommand;
typedef struct section MachOSection;
typedef struct nlist MachONList;
#else
#error Unknown Darwin architecture
#endif
typedef struct load_command MachOLoadCommand;
typedef struct symtab_command MachOSymtabCommand;
typedef struct dysymtab_command MachODsymtabCommand;
typedef struct relocation_info MachORelocationInfo;
typedef struct scattered_relocation_info MachOScatteredRelocationInfo;
/* Dealing with nlist symbol entries can become
* painful. We'll have our own Symbol struct that
* mirrors the symbol from the nlist and can carry
* some more information (like addr).
*/
typedef struct _MachOSymbol {
SymbolName * name; /* the name of the symbol. */
SymbolAddr * addr; /* the final resting place of the symbol */
void * got_addr; /* address of the got slot for this symbol, if any */
MachONList * nlist; /* the nlist symbol entry */
} MachOSymbol;
struct ObjectCodeFormatInfo {
// while we have the image
// we can store some pointers
// into it, so we don't have
// recompute them each time.
/* the object header */
MachOHeader *header;
MachOSymtabCommand *symCmd;
MachOSegmentCommand *segCmd;
MachODsymtabCommand *dsymCmd;
/* points to the first nlist in the image */
MachONList *nlist;
/* points to the names offset in the image */
char *names;
/* points to the start of the sections */
MachOSection *macho_sections;
/* A richer nlist type */
MachOSymbol *macho_symbols;
size_t n_macho_symbols;
/* pointer to the global offset table */
void *got_start;
size_t got_size;
};
/* When loading sections of the macho
* into different pages, such that the
* pages can be marked r+x for text and
* r+w for data, relocation may need
* to be done indirectly, as the symbol
* is not within reach of the of the
* call site. E.g. B/BL instructions on
* aarch64 have +-128mb relative
* range. When pages are mmap'd they
* may end up at random positions.
*
* Hence we reserve space for the stub
* slots right after the text section
*
* .----------. - page start
* | |
* | __TEXT |
* | |
* |----------|
* | Stubs |
* '----------'
*
* Therefore, unless the __TEXT section
* grows beyond 128mb-|Stubs|, we can
* always reach the corresponding stub
* for a symbol.
*
* Stubs will be rendered as
* - 8 bytes: target address
* - 4 bytes: relative load at -8bytes
instruction
* - 4 bytes: branch instruction
*
* These are very similar to the SymbolExtras
* below. However the SymbolExtras are allocated
* per ObjectCode and not per Section.
*
* TODO: Merge SymbolExtras and Stubs.
*/
typedef
struct _Stub {
void * addr;
void * target;
struct _Stub * next;
}
Stub;
struct SectionFormatInfo {
/*
* The following fields are relevant for stubs next to sections only.
*/
void * stub_offset;
size_t stub_size;
size_t nstubs;
Stub * stubs;
/*
* The following fields make working with mach-o objects much easier.
*/
MachOSection * macho_section;
MachORelocationInfo * relocation_info;
};
#endif /* OBJECTFORMAT_MACHO */
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