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update arm text relocations

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Avoid absolute text relocations and use relative/got addressing.
This makes code work on netbsd where this is required. (No DT_TEXTREL)
This commit is contained in:
herman ten brugge 2021-01-06 09:48:15 +01:00
parent cb788d72c7
commit f44332c891
1 changed files with 31 additions and 58 deletions
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87
arm-gen.c
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@ -536,6 +536,32 @@ static int negcc(int cc)
return TOK_NE; return TOK_NE;
} }
/* Load value into register r.
Use relative/got addressing to avoid setting DT_TEXTREL */
static void load_value(SValue *sv, int fr, int r)
{
o(0xE59F0000|(intr(r)<<12));
o(0xEA000000);
if(fr & VT_SYM) {
if (sv->sym->type.t & VT_STATIC) {
greloc(cur_text_section, sv->sym, ind, R_ARM_REL32);
o(sv->c.i - 12);
o(0xe080000f | (intr(r)<<12) | (intr(r)<<16)); // add rx,rx,pc
}
else {
greloc(cur_text_section, sv->sym, ind, R_ARM_GOT_PREL);
o(-12);
o(0xe080000f | (intr(r)<<12) | (intr(r)<<16)); // add rx,rx,pc
o(0xe5900000 | (intr(r)<<12) | (intr(r)<<16)); // ldr rx,[rx]
if (sv->c.i)
stuff_const_harder(0xe2800000 | (intr(r)<<12) | (intr(r)<<16),
sv->c.i);
}
}
else
o(sv->c.i);
}
/* load 'r' from value 'sv' */ /* load 'r' from value 'sv' */
void load(int r, SValue *sv) void load(int r, SValue *sv)
{ {
@ -629,53 +655,15 @@ void load(int r, SValue *sv)
} else { } else {
if (v == VT_CONST) { if (v == VT_CONST) {
op=stuff_const(0xE3A00000|(intr(r)<<12),sv->c.i); op=stuff_const(0xE3A00000|(intr(r)<<12),sv->c.i);
if (fr & VT_SYM || !op) { if (fr & VT_SYM || !op)
o(0xE59F0000|(intr(r)<<12)); load_value(sv, fr, r);
o(0xEA000000);
if(fr & VT_SYM) {
if (sv->sym->type.t & VT_STATIC) {
greloc(cur_text_section, sv->sym, ind, R_ARM_REL32);
o(sv->c.i - 12);
o(0xe080000f | (intr(r)<<12) | (intr(r)<<16)); // add rx,rx,pc
}
else {
greloc(cur_text_section, sv->sym, ind, R_ARM_GOT_PREL);
o(-12);
o(0xe080000f | (intr(r)<<12) | (intr(r)<<16)); // add rx,rx,pc
o(0xe5900000 | (intr(r)<<12) | (intr(r)<<16)); // ldr rx,[rx]
if (sv->c.i)
stuff_const_harder(0xe2800000 | (intr(r)<<12) | (intr(r)<<16),
sv->c.i);
}
}
else else
o(sv->c.i);
} else
o(op); o(op);
return; return;
} else if (v == VT_LOCAL) { } else if (v == VT_LOCAL) {
op=stuff_const(0xE28B0000|(intr(r)<<12),sv->c.i); op=stuff_const(0xE28B0000|(intr(r)<<12),sv->c.i);
if (fr & VT_SYM || !op) { if (fr & VT_SYM || !op) {
o(0xE59F0000|(intr(r)<<12)); load_value(sv, fr, r);
o(0xEA000000);
if(fr & VT_SYM) {
if (sv->sym->type.t & VT_STATIC) {
greloc(cur_text_section, sv->sym, ind, R_ARM_REL32);
o(sv->c.i - 12);
o(0xe080000f | (intr(r)<<12) | (intr(r)<<16)); // add rx,rx,pc
}
else {
greloc(cur_text_section, sv->sym, ind, R_ARM_GOT_PREL);
o(-12);
o(0xe080000f | (intr(r)<<12) | (intr(r)<<16)); // add rx,rx,pc
o(0xe5900000 | (intr(r)<<12) | (intr(r)<<16)); // ldr rx,[rx]
if (sv->c.i)
stuff_const_harder(0xe2800000 | (intr(r)<<12) | (intr(r)<<16),
sv->c.i);
}
}
else
o(sv->c.i);
o(0xE08B0000|(intr(r)<<12)|intr(r)); o(0xE08B0000|(intr(r)<<12)|intr(r));
} else } else
o(op); o(op);
@ -809,22 +797,7 @@ static void gcall_or_jmp(int is_jmp)
o(x|(is_jmp?0xE0000000:0xE1000000)); o(x|(is_jmp?0xE0000000:0xE1000000));
} else { } else {
r = TREG_LR; r = TREG_LR;
o(0xE59F0000|(intr(r)<<12)); // ldr r,[pc] load_value(vtop, vtop->r, r);
o(0xEA000000); // b $+4
if (vtop->sym->type.t & VT_STATIC) {
greloc(cur_text_section, vtop->sym, ind, R_ARM_REL32);
o(vtop->c.i - 12);
o(0xe080000f | (intr(r)<<12) | (intr(r)<<16)); // add rx,rx,pc
}
else {
greloc(cur_text_section, vtop->sym, ind, R_ARM_GOT_PREL);
o(-12);
o(0xe080000f | (intr(r)<<12) | (intr(r)<<16)); // add r,r,pc
o(0xe5900000 | (intr(r)<<12) | (intr(r)<<16)); // ldr r,[r]
if (vtop->c.i)
stuff_const_harder(0xe2800000 | (intr(r)<<12) | (intr(r)<<16),
vtop->c.i);
}
if(is_jmp) if(is_jmp)
o(0xE1A0F000 | intr(r)); // mov pc, r o(0xE1A0F000 | intr(r)); // mov pc, r
else else