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src/x86_64-gen.c  view on Meta::CPAN

        addr += 8;
    }

    /* define parameters */
    while ((sym = sym->next) != NULL) {
        type = &sym->type;
        bt = type->t & VT_BTYPE;
        size = gfunc_arg_size(type);
        if (size > 8) {
            if (reg_param_index < REGN) {
                gen_modrm64(0x89, arg_regs[reg_param_index], VT_LOCAL, NULL, addr);
            }
            sym_push(sym->v & ~SYM_FIELD, type, VT_LOCAL | VT_LVAL | VT_REF, addr);
        } else {
            if (reg_param_index < REGN) {
                /* save arguments passed by register */
                if ((bt == VT_FLOAT) || (bt == VT_DOUBLE)) {
                    o(0xd60f66); /* movq */
                    gen_modrm(reg_param_index, VT_LOCAL, NULL, addr);
                } else {
                    gen_modrm64(0x89, arg_regs[reg_param_index], VT_LOCAL, NULL, addr);
                }
            }
            sym_push(sym->v & ~SYM_FIELD, type, VT_LOCAL | VT_LVAL, addr);
        }
        addr += 8;
        reg_param_index++;
    }

    while (reg_param_index < REGN) {
        if (func_type->ref->c == FUNC_ELLIPSIS) {
            gen_modrm64(0x89, arg_regs[reg_param_index], VT_LOCAL, NULL, addr);
            addr += 8;
        }
        reg_param_index++;
    }
}

/* generate function epilog */
void gfunc_epilog(void)
{
    int v, saved_ind;

    o(0xc9); /* leave */
    if (func_ret_sub == 0) {
        o(0xc3); /* ret */
    } else {
        o(0xc2); /* ret n */
        g(func_ret_sub);
        g(func_ret_sub >> 8);
    }

    saved_ind = ind;
    ind = func_sub_sp_offset - FUNC_PROLOG_SIZE;
    /* align local size to word & save local variables */
    v = (func_scratch + -loc + 15) & -16;

    if (v >= 4096) {
        Sym *sym = external_global_sym(TOK___chkstk, &func_old_type, 0);
        oad(0xb8, v); /* mov stacksize, %eax */
        oad(0xe8, -4); /* call __chkstk, (does the stackframe too) */
        greloc(cur_text_section, sym, ind-4, R_X86_64_PC32);
        o(0x90); /* fill for FUNC_PROLOG_SIZE = 11 bytes */
    } else {
        o(0xe5894855);  /* push %rbp, mov %rsp, %rbp */
        o(0xec8148);  /* sub rsp, stacksize */
        gen_le32(v);
    }

    cur_text_section->data_offset = saved_ind;
    pe_add_unwind_data(ind, saved_ind, v);
    ind = cur_text_section->data_offset;
}

#else

static void gadd_sp(int val)
{
    if (val == (char)val) {
        o(0xc48348);
        g(val);
    } else {
        oad(0xc48148, val); /* add $xxx, %rsp */
    }
}

typedef enum X86_64_Mode {
  x86_64_mode_none,
  x86_64_mode_memory,
  x86_64_mode_integer,
  x86_64_mode_sse,
  x86_64_mode_x87
} X86_64_Mode;

static X86_64_Mode classify_x86_64_merge(X86_64_Mode a, X86_64_Mode b) {
    if (a == b)
        return a;
    else if (a == x86_64_mode_none)
        return b;
    else if (b == x86_64_mode_none)
        return a;
    else if ((a == x86_64_mode_memory) || (b == x86_64_mode_memory))
        return x86_64_mode_memory;
    else if ((a == x86_64_mode_integer) || (b == x86_64_mode_integer))
        return x86_64_mode_integer;
    else if ((a == x86_64_mode_x87) || (b == x86_64_mode_x87))
        return x86_64_mode_memory;
    else
        return x86_64_mode_sse;
}

static X86_64_Mode classify_x86_64_inner(CType *ty) {
    X86_64_Mode mode;
    Sym *f;
    
    switch (ty->t & VT_BTYPE) {
    case VT_VOID: return x86_64_mode_none;
    
    case VT_INT:
    case VT_BYTE:
    case VT_SHORT:

src/x86_64-gen.c  view on Meta::CPAN

            o(0xc0 + REG_VALUE(r) * 8 + REG_VALUE(d));
            if (reg_count == 2) {
                d = arg_prepare_reg(gen_reg+1);
                orex(1,d,vtop->r2,0x89); /* mov */
                o(0xc0 + REG_VALUE(vtop->r2) * 8 + REG_VALUE(d));
            }
        }
        vtop--;
    }
    assert(gen_reg == 0);
    assert(sse_reg == 0);

    /* We shouldn't have many operands on the stack anymore, but the
       call address itself is still there, and it might be in %eax
       (or edx/ecx) currently, which the below writes would clobber.
       So evict all remaining operands here.  */
    save_regs(0);

    /* Copy R10 and R11 into RDX and RCX, respectively */
    if (nb_reg_args > 2) {
        o(0xd2894c); /* mov %r10, %rdx */
        if (nb_reg_args > 3) {
            o(0xd9894c); /* mov %r11, %rcx */
        }
    }

    oad(0xb8, nb_sse_args < 8 ? nb_sse_args : 8); /* mov nb_sse_args, %eax */
    gcall_or_jmp(0);
    if (args_size)
        gadd_sp(args_size);
    vtop--;
}


#define FUNC_PROLOG_SIZE 11

static void push_arg_reg(int i) {
    loc -= 8;
    gen_modrm64(0x89, arg_regs[i], VT_LOCAL, NULL, loc);
}

/* generate function prolog of type 't' */
void gfunc_prolog(CType *func_type)
{
    X86_64_Mode mode;
    int i, addr, align, size, reg_count;
    int param_addr = 0, reg_param_index, sse_param_index;
    Sym *sym;
    CType *type;

    sym = func_type->ref;
    addr = PTR_SIZE * 2;
    loc = 0;
    ind += FUNC_PROLOG_SIZE;
    func_sub_sp_offset = ind;
    func_ret_sub = 0;

    if (func_type->ref->c == FUNC_ELLIPSIS) {
        int seen_reg_num, seen_sse_num, seen_stack_size;
        seen_reg_num = seen_sse_num = 0;
        /* frame pointer and return address */
        seen_stack_size = PTR_SIZE * 2;
        /* count the number of seen parameters */
        sym = func_type->ref;
        while ((sym = sym->next) != NULL) {
            type = &sym->type;
            mode = classify_x86_64_arg(type, NULL, &size, &align, &reg_count);
            switch (mode) {
            default:
            stack_arg:
                seen_stack_size = ((seen_stack_size + align - 1) & -align) + size;
                break;
                
            case x86_64_mode_integer:
                if (seen_reg_num + reg_count <= 8) {
                    seen_reg_num += reg_count;
                } else {
                    seen_reg_num = 8;
                    goto stack_arg;
                }
                break;
                
            case x86_64_mode_sse:
                if (seen_sse_num + reg_count <= 8) {
                    seen_sse_num += reg_count;
                } else {
                    seen_sse_num = 8;
                    goto stack_arg;
                }
                break;
            }
        }

        loc -= 16;
        /* movl $0x????????, -0x10(%rbp) */
        o(0xf045c7);
        gen_le32(seen_reg_num * 8);
        /* movl $0x????????, -0xc(%rbp) */
        o(0xf445c7);
        gen_le32(seen_sse_num * 16 + 48);
        /* movl $0x????????, -0x8(%rbp) */
        o(0xf845c7);
        gen_le32(seen_stack_size);

        /* save all register passing arguments */
        for (i = 0; i < 8; i++) {
            loc -= 16;
            o(0xd60f66); /* movq */
            gen_modrm(7 - i, VT_LOCAL, NULL, loc);
            /* movq $0, loc+8(%rbp) */
            o(0x85c748);
            gen_le32(loc + 8);
            gen_le32(0);
        }
        for (i = 0; i < REGN; i++) {
            push_arg_reg(REGN-1-i);
        }
    }

    sym = func_type->ref;
    reg_param_index = 0;