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tinycc/x86_64-link.c

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Fix relocs_info declaration in tcc.h C standard specifies that array should be declared with a non null size or with * for standard array. Declaration of relocs_info in tcc.h was not respecting this rule. This commit add a R_NUM macro that maps to the R_<ARCH>_NUM macros and declare relocs_info using it. This commit also moves all linker-related macros from <arch>-gen.c files to <arch>-link.c ones.
2016-12-06 04:40:59 +08:00
#ifdef TARGET_DEFS_ONLY
#define EM_TCC_TARGET EM_X86_64
/* relocation type for 32 bit data relocation */
#define R_DATA_32 R_X86_64_32
#define R_DATA_PTR R_X86_64_64
#define R_JMP_SLOT R_X86_64_JUMP_SLOT
#define R_GLOB_DAT R_X86_64_GLOB_DAT
#define R_COPY R_X86_64_COPY
#define R_NUM R_X86_64_NUM
#define ELF_START_ADDR 0x400000
#define ELF_PAGE_SIZE 0x200000
Do section relocation in architecture backend
2016-11-12 23:16:06 +08:00
#define HAVE_SECTION_RELOC
Fix PLT creation for i386 i386 target does not have PC relative loads. Its ABI therefore require ebx register to points to the GOT when executing a PLT entry. This means that PLT entry cannot be used transparently, the compiler needs to expect execution of a PLT entry to be able to use one, that is a PLT entry should only be created if the relocation explicitely asks for it (eg. R_386_PLT32). This patch creates a new target macro PCRELATIVE_DLLPLT to indicate whether a target can do a PC relative load in PLT entry when building a dynamic library. Executable do not normally pose a problem because they are loaded at a fixed address and thus the absolute address of GOT can be used. Note that in such a case, if the compiler does not use a PLT aware relocation for external access then the code relocation will fall on the dynamic loader since there is no PLT entry to relocate too.
2016-12-10 17:14:29 +08:00
#define PCRELATIVE_DLLPLT 1
Do section relocation in architecture backend
2016-11-12 23:16:06 +08:00
Fix relocs_info declaration in tcc.h C standard specifies that array should be declared with a non null size or with * for standard array. Declaration of relocs_info in tcc.h was not respecting this rule. This commit add a R_NUM macro that maps to the R_<ARCH>_NUM macros and declare relocs_info using it. This commit also moves all linker-related macros from <arch>-gen.c files to <arch>-link.c ones.
2016-12-06 04:40:59 +08:00
#else /* !TARGET_DEFS_ONLY */
#include "tcc.h"
Use functions to get relocation info MSVC does not support array designator so cannot compile source using relocs_info. This commit replace the relocs_info array into a set of functions, each returning the value given by a given field of the struct reloc_info.
2016-12-11 01:22:08 +08:00
/* Returns 1 for a code relocation, 0 for a data relocation. For unknown
relocations, returns -1. */
int code_reloc (int reloc_type)
{
switch (reloc_type) {
case R_X86_64_32:
case R_X86_64_32S:
case R_X86_64_64:
case R_X86_64_GOTPCREL:
case R_X86_64_GOTPCRELX:
case R_X86_64_REX_GOTPCRELX:
case R_X86_64_GOTTPOFF:
case R_X86_64_GOT32:
case R_X86_64_GLOB_DAT:
case R_X86_64_COPY:
return 0;
case R_X86_64_PC32:
case R_X86_64_PLT32:
case R_X86_64_JUMP_SLOT:
return 1;
}
tcc_error ("Unknown relocation type: %d", reloc_type);
return -1;
}
/* Returns an enumerator to describe wether and when the relocation needs a
GOT and/or PLT entry to be created. See tcc.h for a description of the
different values. */
int gotplt_entry_type (int reloc_type)
{
switch (reloc_type) {
case R_X86_64_GLOB_DAT:
case R_X86_64_JUMP_SLOT:
case R_X86_64_COPY:
return NO_GOTPLT_ENTRY;
case R_X86_64_32:
case R_X86_64_32S:
case R_X86_64_64:
case R_X86_64_PC32:
return AUTO_GOTPLT_ENTRY;
case R_X86_64_GOTTPOFF:
return BUILD_GOT_ONLY;
case R_X86_64_GOT32:
case R_X86_64_GOTPCREL:
case R_X86_64_GOTPCRELX:
case R_X86_64_REX_GOTPCRELX:
case R_X86_64_PLT32:
return ALWAYS_GOTPLT_ENTRY;
}
tcc_error ("Unknown relocation type: %d", reloc_type);
return -1;
}
Do section relocation in architecture backend
2016-11-12 23:16:06 +08:00
static ElfW_Rel *qrel; /* ptr to next reloc entry reused */
void relocate_init(Section *sr)
{
qrel = (ElfW_Rel *) sr->data;
}
void relocate(TCCState *s1, ElfW_Rel *rel, int type, char *ptr, addr_t addr, addr_t val)
{
int sym_index, esym_index;
sym_index = ELFW(R_SYM)(rel->r_info);
switch (type) {
case R_X86_64_64:
if (s1->output_type == TCC_OUTPUT_DLL) {
esym_index = s1->symtab_to_dynsym[sym_index];
qrel->r_offset = rel->r_offset;
if (esym_index) {
qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_64);
qrel->r_addend = rel->r_addend;
qrel++;
break;
} else {
qrel->r_info = ELFW(R_INFO)(0, R_X86_64_RELATIVE);
qrel->r_addend = read64le(ptr) + val;
qrel++;
}
}
add64le(ptr, val);
break;
case R_X86_64_32:
case R_X86_64_32S:
if (s1->output_type == TCC_OUTPUT_DLL) {
/* XXX: this logic may depend on TCC's codegen
now TCC uses R_X86_64_32 even for a 64bit pointer */
qrel->r_info = ELFW(R_INFO)(0, R_X86_64_RELATIVE);
/* Use sign extension! */
qrel->r_addend = (int)read32le(ptr) + val;
qrel++;
}
add32le(ptr, val);
break;
case R_X86_64_PC32:
if (s1->output_type == TCC_OUTPUT_DLL) {
/* DLL relocation */
esym_index = s1->symtab_to_dynsym[sym_index];
if (esym_index) {
qrel->r_offset = rel->r_offset;
qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_PC32);
/* Use sign extension! */
qrel->r_addend = (int)read32le(ptr) + rel->r_addend;
qrel++;
break;
}
}
goto plt32pc32;
case R_X86_64_PLT32:
Consolidate all relocations in relocate_section Static relocation of functions in dynamic libraries must use the PLT entry as the target. Before this commit, it used to be done in 2 parts for ARM, with the offset of the PLT entry from the beginning of the PLT being put in the relocated place in build_got_entries () and then the address of the PLT being added in relocate_section. This led to code dealing with reading the offset of a bl instruction in build_got_entries. Furthermore, the addition of the address of the start of the PLT was done based on the relocation type which does not convey whether a PLT entry should be used to reach the symbol. This commit moves the decision to use the PLT as the target in relocate_section, therefore having the instruction aware code contained to the target-specific bit of that function (in <target>-link.c). Note that relocate_syms is *not* the right place to do this because two different relocations for the same symbol can make different decision. This is the case in tcc -run mode where the static and dynamic relocation are done by tcc. Storing the PLT entry address in the symbol's st_value field and relying on the specific relocation type being used for dynamic relocation would work but the PLT entry address would then appear in the static symbol table (symtab). This would also make the static symbol table entry differ from the dynamic symbol table entry.
2016-11-12 23:16:08 +08:00
/* fallthrough: val already holds the PLT slot address */
Do section relocation in architecture backend
2016-11-12 23:16:06 +08:00
plt32pc32:
{
long long diff;
diff = (long long)val - addr;
if (diff < -2147483648LL || diff > 2147483647LL) {
tcc_error("internal error: relocation failed");
}
add32le(ptr, diff);
}
break;
case R_X86_64_GLOB_DAT:
case R_X86_64_JUMP_SLOT:
/* They don't need addend */
write64le(ptr, val - rel->r_addend);
break;
case R_X86_64_GOTPCREL:
case R_X86_64_GOTPCRELX:
case R_X86_64_REX_GOTPCRELX:
add32le(ptr, s1->got->sh_addr - addr +
s1->sym_attrs[sym_index].got_offset - 4);
break;
case R_X86_64_GOTTPOFF:
add32le(ptr, val - s1->got->sh_addr);
break;
case R_X86_64_GOT32:
/* we load the got offset */
add32le(ptr, s1->sym_attrs[sym_index].got_offset);
break;
}
}
Fix relocs_info declaration in tcc.h C standard specifies that array should be declared with a non null size or with * for standard array. Declaration of relocs_info in tcc.h was not respecting this rule. This commit add a R_NUM macro that maps to the R_<ARCH>_NUM macros and declare relocs_info using it. This commit also moves all linker-related macros from <arch>-gen.c files to <arch>-link.c ones.
2016-12-06 04:40:59 +08:00
#endif /* !TARGET_DEFS_ONLY */
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