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50b4f320dc
tinycc/arm-link.c
herman ten brugge 50b4f320dc lazy binding 
Currently tcc does not use lazy binding. It puts all relocations in the RELX
section and solve them all at startup.
This was not working on bsd.

tcc.h:
- New RELPLT_SECTION_FMT for plt relocations
- New entry relocplt in struct Section

tccelf.c:
- put_elf_reloca: put R_JMP_SLOT in relocplt section
- build_got_entries*: Use two passes because R_JMP_SLOT and R_GLOB_DAT
                      can not be intermixed on some targets (arm, arm64)
- layout_sections: Calculate correct size relocplt section for DT_ values.
                   Make sure relocplt is last
- fill_dynamic: Add DT_ values when got is filled
                move DT_VERSYM because dynamic linker cannot handle it standone
- Add note section for NetBSD

arm-link.c/arm64-link.c/i386-link.c/riscv64-link.c/x86_64-link.c:
- fill got table with pointer to plt section or symbol value in case
  of TCC_OUTPUT_MEMORY

arm-link.c/arm64-link.c:
- fix offset first plt entry

i386-link.c/x86_64-link.c:
- use correct reloc entry
- use relofs - sizeof (ElfW_Rel) because the reloc is already done

lib/bcheck.c:
- no __libc_freeres on FreeBSD and NetBSD

tests/Makefile:
- Add -fno-stack-protector for OpenBSD

tests/tests2/Makefile:
- disable 106_pthread/114_bound_signal
2020-12-18 15:24:32 +01:00

416 lines
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#ifdef TARGET_DEFS_ONLY
#define EM_TCC_TARGET EM_ARM
/* relocation type for 32 bit data relocation */
#define R_DATA_32 R_ARM_ABS32
#define R_DATA_PTR R_ARM_ABS32
#define R_JMP_SLOT R_ARM_JUMP_SLOT
#define R_GLOB_DAT R_ARM_GLOB_DAT
#define R_COPY R_ARM_COPY
#define R_RELATIVE R_ARM_RELATIVE
#define R_NUM R_ARM_NUM
#define ELF_START_ADDR 0x00008000
#define ELF_PAGE_SIZE 0x1000
#define PCRELATIVE_DLLPLT 1
#define RELOCATE_DLLPLT 1
enum float_abi {
ARM_SOFTFP_FLOAT,
ARM_HARD_FLOAT,
};
#else /* !TARGET_DEFS_ONLY */
#include "tcc.h"
/* 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_ARM_MOVT_ABS:
case R_ARM_MOVW_ABS_NC:
case R_ARM_THM_MOVT_ABS:
case R_ARM_THM_MOVW_ABS_NC:
case R_ARM_ABS32:
case R_ARM_REL32:
case R_ARM_GOTPC:
case R_ARM_GOTOFF:
case R_ARM_GOT32:
case R_ARM_COPY:
case R_ARM_GLOB_DAT:
case R_ARM_NONE:
return 0;
case R_ARM_PC24:
case R_ARM_CALL:
case R_ARM_JUMP24:
case R_ARM_PLT32:
case R_ARM_THM_PC22:
case R_ARM_THM_JUMP24:
case R_ARM_PREL31:
case R_ARM_V4BX:
case R_ARM_JUMP_SLOT:
return 1;
}
return -1;
}
/* Returns an enumerator to describe whether 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_ARM_NONE:
case R_ARM_COPY:
case R_ARM_GLOB_DAT:
case R_ARM_JUMP_SLOT:
return NO_GOTPLT_ENTRY;
case R_ARM_PC24:
case R_ARM_CALL:
case R_ARM_JUMP24:
case R_ARM_PLT32:
case R_ARM_THM_PC22:
case R_ARM_THM_JUMP24:
case R_ARM_MOVT_ABS:
case R_ARM_MOVW_ABS_NC:
case R_ARM_THM_MOVT_ABS:
case R_ARM_THM_MOVW_ABS_NC:
case R_ARM_PREL31:
case R_ARM_ABS32:
case R_ARM_REL32:
case R_ARM_V4BX:
return AUTO_GOTPLT_ENTRY;
case R_ARM_GOTPC:
case R_ARM_GOTOFF:
return BUILD_GOT_ONLY;
case R_ARM_GOT32:
return ALWAYS_GOTPLT_ENTRY;
}
return -1;
}
#ifndef TCC_TARGET_PE
ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
{
Section *plt = s1->plt;
uint8_t *p;
unsigned plt_offset;
/* when building a DLL, GOT entry accesses must be done relative to
start of GOT (see x86_64 example above) */
/* empty PLT: create PLT0 entry that push address of call site and
jump to ld.so resolution routine (GOT + 8) */
if (plt->data_offset == 0) {
p = section_ptr_add(plt, 20);
write32le(p, 0xe52de004); /* push {lr} */
write32le(p+4, 0xe59fe004); /* ldr lr, [pc, #4] */
write32le(p+8, 0xe08fe00e); /* add lr, pc, lr */
write32le(p+12, 0xe5bef008); /* ldr pc, [lr, #8]! */
/* p+16 is set in relocate_plt */
}
plt_offset = plt->data_offset;
if (attr->plt_thumb_stub) {
p = section_ptr_add(plt, 4);
write32le(p, 0x4778); /* bx pc */
write32le(p+2, 0x46c0); /* nop */
}
p = section_ptr_add(plt, 12);
/* save GOT offset for relocate_plt */
write32le(p + 4, got_offset);
return plt_offset;
}
/* relocate the PLT: compute addresses and offsets in the PLT now that final
address for PLT and GOT are known (see fill_program_header) */
ST_FUNC void relocate_plt(TCCState *s1)
{
uint8_t *p, *p_end;
if (!s1->plt)
return;
p = s1->plt->data;
p_end = p + s1->plt->data_offset;
if (p < p_end) {
int x = s1->got->sh_addr - s1->plt->sh_addr - 12;
write32le(s1->plt->data + 16, x - 4);
p += 20;
while (p < p_end) {
unsigned off = x + read32le(p + 4) + (s1->plt->data - p) + 4;
if (read32le(p) == 0x46c04778) /* PLT Thumb stub present */
p += 4;
write32le(p, 0xe28fc600 | ((off >> 20) & 0xff)); // add ip, pc, #0xNN00000
write32le(p + 4, 0xe28cca00 | ((off >> 12) & 0xff)); // add ip, ip, #0xNN000
write32le(p + 8, 0xe5bcf000 | (off & 0xfff)); // ldr pc, [ip, #0xNNN]!
p += 12;
}
}
if (s1->got->relocplt) {
int mem = s1->output_type == TCC_OUTPUT_MEMORY;
ElfW_Rel *rel;
p = s1->got->data;
for_each_elem(s1->got->relocplt, 0, rel, ElfW_Rel) {
int sym_index = ELFW(R_SYM)(rel->r_info);
ElfW(Sym) *sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
write32le(p + rel->r_offset, mem ? sym->st_value : s1->plt->sh_addr);
}
}
}
#endif
void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val)
{
ElfW(Sym) *sym;
int sym_index, esym_index;
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
switch(type) {
case R_ARM_PC24:
case R_ARM_CALL:
case R_ARM_JUMP24:
case R_ARM_PLT32:
{
int x, is_thumb, is_call, h, blx_avail, is_bl, th_ko;
x = (*(int *) ptr) & 0xffffff;
#ifdef DEBUG_RELOC
printf ("reloc %d: x=0x%x val=0x%x ", type, x, val);
#endif
(*(int *)ptr) &= 0xff000000;
if (x & 0x800000)
x -= 0x1000000;
x <<= 2;
blx_avail = (TCC_CPU_VERSION >= 5);
is_thumb = val & 1;
is_bl = (*(unsigned *) ptr) >> 24 == 0xeb;
is_call = (type == R_ARM_CALL || (type == R_ARM_PC24 && is_bl));
x += val - addr;
#ifdef DEBUG_RELOC
printf (" newx=0x%x name=%s\n", x,
(char *) symtab_section->link->data + sym->st_name);
#endif
h = x & 2;
th_ko = (x & 3) && (!blx_avail || !is_call);
if (th_ko || x >= 0x2000000 || x < -0x2000000)
tcc_error("can't relocate value at %x,%d",addr, type);
x >>= 2;
x &= 0xffffff;
/* Only reached if blx is avail and it is a call */
if (is_thumb) {
x |= h << 24;
(*(int *)ptr) = 0xfa << 24; /* bl -> blx */
}
(*(int *) ptr) |= x;
}
return;
/* Since these relocations only concern Thumb-2 and blx instruction was
introduced before Thumb-2, we can assume blx is available and not
guard its use */
case R_ARM_THM_PC22:
case R_ARM_THM_JUMP24:
{
int x, hi, lo, s, j1, j2, i1, i2, imm10, imm11;
int to_thumb, is_call, to_plt, blx_bit = 1 << 12;
Section *plt;
/* weak reference */
if (sym->st_shndx == SHN_UNDEF &&
ELFW(ST_BIND)(sym->st_info) == STB_WEAK)
return;
/* Get initial offset */
hi = (*(uint16_t *)ptr);
lo = (*(uint16_t *)(ptr+2));
s = (hi >> 10) & 1;
j1 = (lo >> 13) & 1;
j2 = (lo >> 11) & 1;
i1 = (j1 ^ s) ^ 1;
i2 = (j2 ^ s) ^ 1;
imm10 = hi & 0x3ff;
imm11 = lo & 0x7ff;
x = (s << 24) | (i1 << 23) | (i2 << 22) |
(imm10 << 12) | (imm11 << 1);
if (x & 0x01000000)
x -= 0x02000000;
/* Relocation infos */
to_thumb = val & 1;
plt = s1->plt;
to_plt = (val >= plt->sh_addr) &&
(val < plt->sh_addr + plt->data_offset);
is_call = (type == R_ARM_THM_PC22);
if (!to_thumb && !to_plt && !is_call) {
int index;
uint8_t *p;
char *name, buf[1024];
Section *text;
name = (char *) symtab_section->link->data + sym->st_name;
text = s1->sections[sym->st_shndx];
/* Modify reloc to target a thumb stub to switch to ARM */
snprintf(buf, sizeof(buf), "%s_from_thumb", name);
index = put_elf_sym(symtab_section,
text->data_offset + 1,
sym->st_size, sym->st_info, 0,
sym->st_shndx, buf);
to_thumb = 1;
val = text->data_offset + 1;
rel->r_info = ELFW(R_INFO)(index, type);
/* Create a thumb stub function to switch to ARM mode */
put_elf_reloc(symtab_section, text,
text->data_offset + 4, R_ARM_JUMP24,
sym_index);
p = section_ptr_add(text, 8);
write32le(p, 0x4778); /* bx pc */
write32le(p+2, 0x46c0); /* nop */
write32le(p+4, 0xeafffffe); /* b $sym */
}
/* Compute final offset */
x += val - addr;
if (!to_thumb && is_call) {
blx_bit = 0; /* bl -> blx */
x = (x + 3) & -4; /* Compute offset from aligned PC */
}
/* Check that relocation is possible
* offset must not be out of range
* if target is to be entered in arm mode:
- bit 1 must not set
- instruction must be a call (bl) or a jump to PLT */
if (!to_thumb || x >= 0x1000000 || x < -0x1000000)
if (to_thumb || (val & 2) || (!is_call && !to_plt))
tcc_error("can't relocate value at %x,%d",addr, type);
/* Compute and store final offset */
s = (x >> 24) & 1;
i1 = (x >> 23) & 1;
i2 = (x >> 22) & 1;
j1 = s ^ (i1 ^ 1);
j2 = s ^ (i2 ^ 1);
imm10 = (x >> 12) & 0x3ff;
imm11 = (x >> 1) & 0x7ff;
(*(uint16_t *)ptr) = (uint16_t) ((hi & 0xf800) |
(s << 10) | imm10);
(*(uint16_t *)(ptr+2)) = (uint16_t) ((lo & 0xc000) |
(j1 << 13) | blx_bit | (j2 << 11) |
imm11);
}
return;
case R_ARM_MOVT_ABS:
case R_ARM_MOVW_ABS_NC:
{
int x, imm4, imm12;
if (type == R_ARM_MOVT_ABS)
val >>= 16;
imm12 = val & 0xfff;
imm4 = (val >> 12) & 0xf;
x = (imm4 << 16) | imm12;
if (type == R_ARM_THM_MOVT_ABS)
*(int *)ptr |= x;
else
*(int *)ptr += x;
}
return;
case R_ARM_THM_MOVT_ABS:
case R_ARM_THM_MOVW_ABS_NC:
{
int x, i, imm4, imm3, imm8;
if (type == R_ARM_THM_MOVT_ABS)
val >>= 16;
imm8 = val & 0xff;
imm3 = (val >> 8) & 0x7;
i = (val >> 11) & 1;
imm4 = (val >> 12) & 0xf;
x = (imm3 << 28) | (imm8 << 16) | (i << 10) | imm4;
if (type == R_ARM_THM_MOVT_ABS)
*(int *)ptr |= x;
else
*(int *)ptr += x;
}
return;
case R_ARM_PREL31:
{
int x;
x = (*(int *)ptr) & 0x7fffffff;
(*(int *)ptr) &= 0x80000000;
x = (x * 2) / 2;
x += val - addr;
if((x^(x>>1))&0x40000000)
tcc_error("can't relocate value at %x,%d",addr, type);
(*(int *)ptr) |= x & 0x7fffffff;
}
case R_ARM_ABS32:
if (s1->output_type == TCC_OUTPUT_DLL) {
esym_index = get_sym_attr(s1, sym_index, 0)->dyn_index;
qrel->r_offset = rel->r_offset;
if (esym_index) {
qrel->r_info = ELFW(R_INFO)(esym_index, R_ARM_ABS32);
qrel++;
return;
} else {
qrel->r_info = ELFW(R_INFO)(0, R_ARM_RELATIVE);
qrel++;
}
}
*(int *)ptr += val;
return;
case R_ARM_REL32:
*(int *)ptr += val - addr;
return;
case R_ARM_GOTPC:
*(int *)ptr += s1->got->sh_addr - addr;
return;
case R_ARM_GOTOFF:
*(int *)ptr += val - s1->got->sh_addr;
return;
case R_ARM_GOT32:
/* we load the got offset */
*(int *)ptr += get_sym_attr(s1, sym_index, 0)->got_offset;
return;
case R_ARM_COPY:
return;
case R_ARM_V4BX:
/* trade Thumb support for ARMv4 support */
if ((0x0ffffff0 & *(int*)ptr) == 0x012FFF10)
*(int*)ptr ^= 0xE12FFF10 ^ 0xE1A0F000; /* BX Rm -> MOV PC, Rm */
return;
case R_ARM_GLOB_DAT:
case R_ARM_JUMP_SLOT:
*(addr_t *)ptr = val;
return;
case R_ARM_NONE:
/* Nothing to do. Normally used to indicate a dependency
on a certain symbol (like for exception handling under EABI). */
return;
case R_ARM_RELATIVE:
#ifdef TCC_TARGET_PE
add32le(ptr, val - s1->pe_imagebase);
#endif
/* do nothing */
return;
default:
fprintf(stderr,"FIXME: handle reloc type %x at %x [%p] to %x\n",
type, (unsigned)addr, ptr, (unsigned)val);
return;
}
}
#endif /* !TARGET_DEFS_ONLY */
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