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codegen.c
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#include "slimcc.h"
#define GP_MAX 6
#define FP_MAX 8
#define GP_SLOTS 6
#define FP_SLOTS 6
#define STRBUF_SZ 192
#define STRBUF_SZ2 208
typedef enum {
REG_NULL = 0,
REG_AX,
REG_CX,
REG_DX,
REG_SI,
REG_DI,
REG_R8,
REG_R9,
REG_R10,
REG_R11,
REG_R12,
REG_R13,
REG_R14,
REG_R15,
REG_BX,
REG_BP,
REG_SP,
REG_XMM0,
REG_XMM1,
REG_XMM2,
REG_XMM3,
REG_XMM4,
REG_XMM5,
REG_XMM6,
REG_XMM7,
REG_XMM8,
REG_XMM9,
REG_XMM10,
REG_XMM11,
REG_XMM12,
REG_XMM13,
REG_XMM14,
REG_XMM15,
REG_X87_ST0,
REG_X87_ST1,
REG_X87_ST2,
REG_X87_ST3,
REG_X87_ST4,
REG_X87_ST5,
REG_X87_ST6,
REG_X87_ST7,
REG_END
} Reg;
static char *regs[REG_XMM0][4] = {
[REG_NULL] = {"null", "null", "null", "null"},
[REG_SP] = {"%spl", "%sp", "%esp", "%rsp"},
[REG_BP] = {"%bpl", "%bp", "%ebp", "%rbp"},
[REG_AX] = {"%al", "%ax", "%eax", "%rax"},
[REG_BX] = {"%bl", "%bx", "%ebx", "%rbx"},
[REG_CX] = {"%cl", "%cx", "%ecx", "%rcx"},
[REG_DX] = {"%dl", "%dx", "%edx", "%rdx"},
[REG_SI] = {"%sil", "%si", "%esi", "%rsi"},
[REG_DI] = {"%dil", "%di", "%edi", "%rdi"},
[REG_R8] = {"%r8b", "%r8w", "%r8d", "%r8"},
[REG_R9] = {"%r9b", "%r9w", "%r9d", "%r9"},
[REG_R10] = {"%r10b", "%r10w", "%r10d", "%r10"},
[REG_R11] = {"%r11b", "%r11w", "%r11d", "%r11"},
[REG_R12] = {"%r12b", "%r12w", "%r12d", "%r12"},
[REG_R13] = {"%r13b", "%r13w", "%r13d", "%r13"},
[REG_R14] = {"%r14b", "%r14w", "%r14d", "%r14"},
[REG_R15] = {"%r15b", "%r15w", "%r15d", "%r15"},
};
static FILE *output_file;
static char *argreg8[] = {"%dil", "%sil", "%dl", "%cl", "%r8b", "%r9b"};
static char *argreg16[] = {"%di", "%si", "%dx", "%cx", "%r8w", "%r9w"};
static char *argreg32[] = {"%edi", "%esi", "%edx", "%ecx", "%r8d", "%r9d"};
static char *argreg64[] = {"%rdi", "%rsi", "%rdx", "%rcx", "%r8", "%r9"};
static char *tmpreg32[] = {"%edi", "%esi", "%r8d", "%r9d", "%r10d", "%r11d"};
static char *tmpreg64[] = {"%rdi", "%rsi", "%r8", "%r9", "%r10", "%r11"};
static Obj *current_fn;
static char *lvar_ptr;
static int va_gp_start;
static int va_fp_start;
static int va_st_start;
static int vla_base_ofs;
static int rtn_ptr_ofs;
static int lvar_stk_sz;
static int peak_stk_usage;
static char *rtn_label;
bool dont_reuse_stack;
static struct {
bool in[REG_END];
bool out[REG_END];
} asm_use;
static struct {
AsmParam **data;
int capacity;
int cnt;
} asm_ops;
static struct {
char *rbp;
char *rbx;
} asm_alt_ptr;
typedef enum {
SL_GP,
SL_FP,
SL_ST,
} SlotKind;
typedef struct {
SlotKind kind;
int gp_depth;
int fp_depth;
int st_depth;
int st_ofs;
char *push_reg;
long loc;
} Slot;
static struct {
Slot *data;
int capacity;
int depth;
} tmp_stack;
static void load2(Type *ty, int sofs, char *sptr);
static void store2(Type *ty, int dofs, char *dptr);
static void store_gp2(char **reg, int sz, int ofs, char *ptr);
static void gen_asm(Node *node);
static void gen_expr(Node *node);
static void gen_stmt(Node *node);
static void gen_void_expr(Node *node);
static void gen_void_assign(Node *node);
static bool gen_expr_opt(Node *node);
static bool gen_addr_opt(Node *node);
static bool gen_cmp_opt_gp(Node *node, NodeKind *kind);
static bool has_load_opt_gp(Node *node);
static bool gen_load_opt_gp(Node *node, char *reg32, char *reg64);
static Node *bool_expr_opt(Node *node, bool *flip);
static void imm_add(char *op, char *tmp, int64_t val);
static void imm_sub(char *op, char *tmp, int64_t val);
static void imm_and(char *op, char *tmp, int64_t val);
static void imm_cmp(char *op, char *tmp, int64_t val);
static char *arith_ins(NodeKind kind);
#define Printstr(str) fprintf(output_file, str)
#define Printstrf(fmt, ...) fprintf(output_file, fmt, __VA_ARGS__)
FMTCHK(1,2)
static void println(char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
vfprintf(output_file, fmt, ap);
va_end(ap);
fprintf(output_file, "\n");
}
static long resrvln(void) {
long loc = ftell(output_file);
fprintf(output_file, " \n");
return loc;
}
FMTCHK(1,3)
static void insrtln(char *fmt, long loc, ...) {
long cur_loc = ftell(output_file);
fseek(output_file, loc, SEEK_SET);
va_list ap;
va_start(ap, loc);
vfprintf(output_file, fmt, ap);
va_end(ap);
fseek(output_file, cur_loc, SEEK_SET);
}
static char *asm_name(Obj *var) {
return var->asm_name ? var->asm_name : var->name;
}
static int count(void) {
static int i = 1;
return i++;
}
static bool is_gp_ty(Type *ty) {
return is_integer(ty) || ty->kind == TY_PTR;
}
static bool is_scalar(Type *ty) {
return is_numeric(ty) || ty->kind == TY_PTR;
}
static bool is_pow_of_two(uint64_t val) {
return !(val & (val - 1));
}
static bool in_imm_range (int64_t val) {
return val == (int32_t)val;
}
static Node *skip_gp_cast(Node *node) {
while (node->kind == ND_CAST && node->ty->size == node->lhs->ty->size &&
node->ty->kind != TY_BOOL && is_gp_ty(node->ty) && is_gp_ty(node->lhs->ty))
node = node->lhs;
return node;
}
static bool eval_memop(Node *node, char *ofs, char **ptr, bool let_subarray, bool let_atomic) {
int offset;
Obj *var = eval_var_opt(node, &offset, let_subarray, let_atomic);
if (var) {
if (var->is_local) {
snprintf(ofs, STRBUF_SZ, "%d", offset + var->ofs);
*ptr = var->ptr;
return true;
} else if (!var->is_tls && (!opt_fpic || var->is_static)) {
snprintf(ofs, STRBUF_SZ, "%d+\"%s\"", offset, asm_name(var));
*ptr = "%rip";
return true;
}
}
return false;
}
static bool is_memop_ptr(Node *node, char *ofs, char **ptr) {
node = skip_gp_cast(node);
if (node->kind == ND_ADDR)
return eval_memop(node->lhs, ofs, ptr, true, true);
if (node->kind == ND_CAST && node->ty->kind == TY_PTR)
node = node->lhs;
if (node->ty->kind == TY_ARRAY || node->ty->kind == TY_FUNC)
return eval_memop(node, ofs, ptr, true, true);
return false;
}
static bool is_memop(Node *node, char *ofs, char **ptr, bool let_atomic) {
node = skip_gp_cast(node);
if (is_bitfield(node))
return false;
return eval_memop(node, ofs, ptr, false, let_atomic);
}
static bool has_memop(Node *node) {
char ofs[STRBUF_SZ], *ptr;
return is_memop(node, ofs, &ptr, true);
}
static bool is_int_to_int_cast(Node *node) {
return node->kind == ND_CAST && is_integer(node->ty) && is_integer(node->lhs->ty);
}
static bool has_defr(Node *node) {
return node->defr_start != node->defr_end;
}
static Type *bitwidth_to_ty(int width, bool is_unsigned) {
switch (width) {
case 64: return is_unsigned ? ty_ullong : ty_llong;
case 32: return is_unsigned ? ty_uint : ty_int;
case 16: return is_unsigned ? ty_ushort : ty_short;
case 8: return is_unsigned ? ty_uchar : ty_char;
}
return NULL;
}
static int write_size(Node *node) {
if (node->ty->kind == TY_LDOUBLE)
return 10;
return node->ty->size;
}
static int64_t limit_imm(int64_t val, int sz) {
switch (sz) {
case 4: return (int32_t)val;
case 2: return (int16_t)val;
case 1: return (int8_t)val;
}
return val;
}
static char *size_suffix(int sz) {
switch (sz) {
case 8: return "q";
case 4: return "l";
case 2: return "w";
case 1: return "b";
}
internal_error();
}
static void clobber_all_regs(void) {
for (int i = 0; i < tmp_stack.depth; i++)
tmp_stack.data[i].kind = SL_ST;
}
static void clobber_gp(int i) {
if (tmp_stack.depth > 0) {
Slot *sl = &tmp_stack.data[tmp_stack.depth - 1];
sl->gp_depth = MAX(sl->gp_depth, i);
}
}
static Slot *push_tmpstack(SlotKind kind) {
if (tmp_stack.depth == tmp_stack.capacity) {
tmp_stack.capacity += 4;
tmp_stack.data = realloc(tmp_stack.data, sizeof(Slot) * tmp_stack.capacity);
}
long loc = resrvln();
Slot *sl = &tmp_stack.data[tmp_stack.depth++];
*sl = (Slot){.kind = kind, .loc = loc};
return sl;
}
static Slot *pop_tmpstack(int sz) {
tmp_stack.depth--;
assert(tmp_stack.depth >= 0);
Slot *sl = &tmp_stack.data[tmp_stack.depth];
if ((sl->kind == SL_GP && sl->gp_depth >= GP_SLOTS) ||
(sl->kind == SL_FP && sl->fp_depth >= FP_SLOTS))
sl->kind = SL_ST;
if (tmp_stack.depth > 0) {
Slot *sl2 = &tmp_stack.data[tmp_stack.depth - 1];
sl2->gp_depth = MAX(sl2->gp_depth, sl->gp_depth + (sl->kind == SL_GP));
sl2->fp_depth = MAX(sl2->fp_depth, sl->fp_depth + (sl->kind == SL_FP));
sl2->st_depth = MAX(sl2->st_depth, sl->st_depth + (sl->kind == SL_ST) * sz);
}
if (sl->kind == SL_ST) {
if (dont_reuse_stack) {
peak_stk_usage += sz * 8;
sl->st_ofs = -peak_stk_usage;
} else {
int bottom = lvar_stk_sz + (sl->st_depth + sz) * 8;
peak_stk_usage = MAX(peak_stk_usage, bottom);
sl->st_ofs = -bottom;
}
}
return sl;
}
static void push(void) {
push_tmpstack(SL_GP);
}
static void push_from(char *reg) {
Slot *sl = push_tmpstack(SL_GP);
sl->push_reg = reg;
}
static char *pop_gp(bool is_r64, char *dest_reg, bool must_be_dest) {
Slot *sl = pop_tmpstack(1);
char *push_reg;
if (sl->push_reg)
push_reg = sl->push_reg;
else
push_reg = is_r64 ? "%rax" : "%eax";
if (sl->kind == SL_GP) {
char *pop_reg = (is_r64 ? tmpreg64 : tmpreg32)[sl->gp_depth];
insrtln(" mov %s, %s", sl->loc, push_reg, pop_reg);
if (!must_be_dest)
return pop_reg;
println(" mov %s, %s", pop_reg, dest_reg);
return dest_reg;
}
insrtln(" mov %s, %d(%s)", sl->loc, push_reg, sl->st_ofs, lvar_ptr);
println(" mov %d(%s), %s", sl->st_ofs, lvar_ptr, dest_reg);
return dest_reg;
}
static char *pop_inreg2(bool is_r64, char *fallback_reg) {
return pop_gp(is_r64, fallback_reg, false);
}
static char *pop_inreg(char *fallback_reg) {
return pop_inreg2(true, fallback_reg);
}
static void pop2(bool is_r64, char *arg) {
pop_gp(is_r64, arg, true);
}
static void pop(char *arg) {
pop2(true, arg);
}
static void pushf(void) {
push_tmpstack(SL_FP);
}
static int pop_fp(bool is_xmm64, int dest_reg, bool must_be_dest) {
Slot *sl = pop_tmpstack(1);
char *mv = is_xmm64 ? "movsd" : "movss";
if (sl->kind == SL_FP) {
int pop_reg = sl->fp_depth + 2;
insrtln(" %s %%xmm0, %%xmm%d", sl->loc, mv, pop_reg);
if (!must_be_dest)
return pop_reg;
println(" %s %%xmm%d, %%xmm%d", mv, pop_reg, dest_reg);
return dest_reg;
}
insrtln(" %s %%xmm0, %d(%s)", sl->loc, mv, sl->st_ofs, lvar_ptr);
println(" %s %d(%s), %%xmm%d", mv, sl->st_ofs, lvar_ptr, dest_reg);
return dest_reg;
}
static int popf_inreg(bool is_xmm64, int reg) {
return pop_fp(is_xmm64, reg, false);
}
static int popf(int reg) {
return pop_fp(true, reg, true);
}
static void push_x87(void) {
push_tmpstack(SL_ST);
}
static bool pop_x87(void) {
Slot *sl = pop_tmpstack(2);
insrtln(" fstpt %d(%s)", sl->loc, sl->st_ofs, lvar_ptr);
println(" fldt %d(%s)", sl->st_ofs, lvar_ptr);
return true;
}
static void push_by_ty(Type *ty) {
switch (ty->kind) {
case TY_LDOUBLE: push_x87(); return;
case TY_DOUBLE:
case TY_FLOAT: pushf(); return;
default: push(); return;
}
}
static void pop_by_ty(Type *ty) {
switch (ty->kind) {
case TY_LDOUBLE: pop_x87(); return;
case TY_DOUBLE:
case TY_FLOAT: popf(0); return;
default: pop("%rax"); return;
}
}
static void push_copy(int sz) {
assert(sz > 0);
for (int ofs = ((sz - 1) / 8 * 8); ofs >= 0; ofs -= 8)
push_tmpstack(SL_ST);
}
static void pop_copy(int sz, char *sptr) {
assert(sz > 0);
int pos;
for (int ofs = ((sz - 1) / 8 * 8); ofs >= 0; ofs -= 8) {
Slot *sl = pop_tmpstack(1);
pos = sl->st_ofs;
insrtln(" mov %d(%s), %%rdx; mov %%rdx, %d(%s)", sl->loc, ofs, sptr, sl->st_ofs, lvar_ptr);
}
println(" lea %d(%s), %s", pos, lvar_ptr, sptr);
}
// When we load a char or a short value to a register, we always
// extend them to the size of int, so we can assume the lower half of
// a register always contains a valid value.
static void load_extend_int(Type *ty, char *ofs, char *ptr, char *reg) {
char *insn = ty->is_unsigned ? "movz" : "movs";
switch (ty->size) {
case 1: println(" %sbl %s(%s), %s", insn, ofs, ptr, reg); return;
case 2: println(" %swl %s(%s), %s", insn, ofs, ptr, reg); return;
case 4: println(" movl %s(%s), %s", ofs, ptr, reg); return;
case 8: println(" mov %s(%s), %s", ofs, ptr, reg); return;
}
internal_error();
}
static void load_extend_int64(Type *ty, char *ofs, char *ptr, char *reg) {
switch (ty->size) {
case 4: println(" movslq %s(%s), %s", ofs, ptr, reg); return;
case 2: println(" movswq %s(%s), %s", ofs, ptr, reg); return;
case 1: println(" movsbq %s(%s), %s", ofs, ptr, reg); return;
}
internal_error();
}
// Round up `n` to the nearest multiple of `align`. For instance,
// align_to(5, 8) returns 8 and align_to(11, 8) returns 16.
int align_to(int n, int align) {
return (n + align - 1) / align * align;
}
static char *reg_dx(int sz) {
switch (sz) {
case 1: return "%dl";
case 2: return "%dx";
case 4: return "%edx";
case 8: return "%rdx";
}
internal_error();
}
static char *reg_ax(int sz) {
switch (sz) {
case 1: return "%al";
case 2: return "%ax";
case 4: return "%eax";
case 8: return "%rax";
}
internal_error();
}
static char *regop_ax(Type *ty) {
switch (ty->size) {
case 1:
case 2:
case 4: return "%eax";
case 8: return "%rax";
}
internal_error();
}
static void gen_mem_copy2(char *sofs, char *sptr, char *dofs, char *dptr, int sz) {
for (int i = 0; i < sz;) {
int rem = sz - i;
if (rem >= 16) {
println(" movups %d+%s(%s), %%xmm0", i, sofs, sptr);
println(" movups %%xmm0, %d+%s(%s)", i, dofs, dptr);
i += 16;
continue;
}
int p2 = (rem >= 8) ? 8 : (rem >= 4) ? 4 : (rem >= 2) ? 2 : 1;
println(" mov %d+%s(%s), %s", i, sofs, sptr, reg_dx(p2));
println(" mov %s, %d+%s(%s)", reg_dx(p2), i, dofs, dptr);
i += p2;
}
}
static void gen_mem_copy(int sofs, char *sptr, int dofs, char *dptr, int sz) {
char sofs_buf[STRBUF_SZ];
snprintf(sofs_buf, STRBUF_SZ, "%d", sofs);
char dofs_buf[STRBUF_SZ];
snprintf(dofs_buf, STRBUF_SZ, "%d", dofs);
gen_mem_copy2(sofs_buf, sptr, dofs_buf, dptr, sz);
}
static void gen_mem_zero(int dofs, char *dptr, int sz) {
if (sz >= 16) {
println(" xorps %%xmm0, %%xmm0");
for (int i = 0; i < sz;) {
if (sz < i + 16)
i = sz - 16;
println(" movups %%xmm0, %d(%s)", i + dofs, dptr);
i += 16;
}
return;
}
println(" xor %%eax, %%eax");
for (int i = 0; i < sz;) {
int rem = sz - i;
int p2 = (rem >= 8) ? 8 : (rem >= 4) ? 4 : (rem >= 2) ? 2 : 1;
println(" mov %s, %d(%s)", reg_ax(p2), i + dofs, dptr);
i += p2;
}
}
static bool is_cmp(Node *node) {
switch (node->kind) {
case ND_EQ:
case ND_NE:
case ND_LT:
case ND_LE:
case ND_GT:
case ND_GE:
return true;
}
return false;
}
static void flip_cmp(NodeKind *kind, bool flip) {
if (!flip)
return;
switch (*kind) {
case ND_EQ: *kind = ND_NE; return;
case ND_NE: *kind = ND_EQ; return;
case ND_LT: *kind = ND_GE; return;
case ND_LE: *kind = ND_GT; return;
case ND_GT: *kind = ND_LE; return;
case ND_GE: *kind = ND_LT; return;
}
internal_error();
}
static char *cmp_cc(NodeKind kind, bool is_unsigned) {
switch (kind) {
case ND_EQ: return "e";
case ND_NE: return "ne";
case ND_LT: return is_unsigned ? "b" : "l";
case ND_LE: return is_unsigned ? "be" : "le";
case ND_GT: return is_unsigned ? "a" : "g";
case ND_GE: return is_unsigned ? "ae" : "ge";
}
internal_error();
}
static void gen_cmp_setcc(NodeKind kind, bool is_unsigned) {
println(" set%s %%al", cmp_cc(kind, is_unsigned));
println(" movzbl %%al, %%eax");
}
static void gen_bitfield_load(Node *node, int ofs) {
Member *mem = node->member;
Type *alt_ty = bitwidth_to_ty(mem->bit_width, mem->ty->is_unsigned);
if (alt_ty && (mem->bit_offset == (mem->bit_offset / 8 * 8))) {
load2(alt_ty, ofs + mem->bit_offset / 8, "%rax");
return;
}
load2(mem->ty, ofs, "%rax");
char *ax = regop_ax(mem->ty);
if (mem->ty->is_unsigned) {
if (mem->bit_offset)
println(" shr $%d, %s", mem->bit_offset, ax);
imm_and(ax, "%rdx", (1LL << mem->bit_width) - 1);
return;
}
int shft = ((mem->ty->size == 8) ? 64 : 32) - mem->bit_width;
println(" shl $%d, %s", shft - mem->bit_offset, ax);
println(" sar $%d, %s", shft, ax);
return;
}
static void gen_bitfield_store(Node *node) {
Member *mem = node->member;
Type *alt_ty = bitwidth_to_ty(mem->bit_width, mem->ty->is_unsigned);
if (alt_ty && (mem->bit_offset == (mem->bit_offset / 8 * 8))) {
char *reg = pop_inreg(tmpreg64[0]);
store2(alt_ty, mem->bit_offset / 8, reg);
if (mem->bit_width < 32)
imm_and("%eax", NULL, (1L << mem->bit_width) - 1);
return;
}
char *ax, *dx, *cx;
if (mem->ty->size == 8)
ax = "%rax", cx = "%rcx", dx = "%rdx";
else
ax = "%eax", cx = "%ecx", dx = "%edx";
println(" mov %s, %s", ax, cx);
imm_and(cx, dx, (1LL << mem->bit_width) - 1);
char *ptr = pop_inreg(tmpreg64[0]);
load2(mem->ty, 0, ptr);
imm_and(ax, dx, ~(((1ULL << mem->bit_width) - 1) << mem->bit_offset));
if (mem->bit_offset) {
println(" mov %s, %s", cx, dx);
println(" shl $%d, %s", mem->bit_offset, dx);
println(" or %s, %s", dx, ax);
} else {
println(" or %s, %s", cx, ax);
}
store2(mem->ty, 0, ptr);
println(" mov %s, %s", cx, ax);
if (!mem->ty->is_unsigned) {
int shft = ((mem->ty->size == 8) ? 64 : 32) - mem->bit_width;
println(" shl $%d, %s", shft, ax);
println(" sar $%d, %s", shft, ax);
}
}
// Compute the absolute address of a given node.
// It's an error if a given node does not reside in memory.
static void gen_addr(Node *node) {
if (opt_optimize && gen_addr_opt(node))
return;
switch (node->kind) {
case ND_VAR:
// Variable-length array, which is always local.
if (node->var->ty->kind == TY_VLA) {
println(" mov %d(%s), %%rax", node->var->ofs, node->var->ptr);
return;
}
// Local variable
if (node->var->is_local) {
println(" lea %d(%s), %%rax", node->var->ofs, node->var->ptr);
return;
}
if (opt_fpic) {
// Thread-local variable
if (node->var->is_tls) {
clobber_all_regs();
println(" data16 lea \"%s\"@tlsgd(%%rip), %%rdi", asm_name(node->var));
println(" .value 0x6666");
println(" rex64");
println(" call __tls_get_addr@PLT");
return;
}
// Function or global variable
println(" mov \"%s\"@GOTPCREL(%%rip), %%rax", asm_name(node->var));
return;
}
// Thread-local variable
if (node->var->is_tls) {
println(" mov %%fs:0, %%rax");
println(" add $\"%s\"@tpoff, %%rax", asm_name(node->var));
return;
}
// Here, we generate an absolute address of a function or a global
// variable. Even though they exist at a certain address at runtime,
// their addresses are not known at link-time for the following
// two reasons.
//
// - Address randomization: Executables are loaded to memory as a
// whole but it is not known what address they are loaded to.
// Therefore, at link-time, relative address in the same
// exectuable (i.e. the distance between two functions in the
// same executable) is known, but the absolute address is not
// known.
//
// - Dynamic linking: Dynamic shared objects (DSOs) or .so files
// are loaded to memory alongside an executable at runtime and
// linked by the runtime loader in memory. We know nothing
// about addresses of global stuff that may be defined by DSOs
// until the runtime relocation is complete.
//
// In order to deal with the former case, we use RIP-relative
// addressing, denoted by `(%rip)`. For the latter, we obtain an
// address of a stuff that may be in a shared object file from the
// Global Offset Table using `@GOTPCREL(%rip)` notation.
// Function
if (node->ty->kind == TY_FUNC) {
if (node->var->is_definition)
println(" lea \"%s\"(%%rip), %%rax", asm_name(node->var));
else
println(" mov \"%s\"@GOTPCREL(%%rip), %%rax", asm_name(node->var));
return;
}
// Global variable
println(" lea \"%s\"(%%rip), %%rax", asm_name(node->var));
return;
case ND_DEREF:
gen_expr(node->lhs);
return;
case ND_CHAIN:
case ND_COMMA:
gen_void_expr(node->lhs);
gen_addr(node->rhs);
return;
case ND_MEMBER:
switch (node->lhs->kind) {
case ND_FUNCALL:
case ND_ASSIGN:
case ND_COND:
case ND_STMT_EXPR:
case ND_VA_ARG:
gen_expr(node->lhs);
imm_add("%rax", "%rdx", node->member->offset);
return;
default:
gen_addr(node->lhs);
imm_add("%rax", "%rdx", node->member->offset);
return;
}
}
error_tok(node->tok, "not an lvalue");
}
static void load3(Type *ty, char *sofs, char *sptr) {
switch (ty->kind) {
case TY_FLOAT:
println(" movss %s(%s), %%xmm0", sofs, sptr);
return;
case TY_DOUBLE:
println(" movsd %s(%s), %%xmm0", sofs, sptr);
return;
case TY_LDOUBLE:
println(" fninit; fldt %s(%s)", sofs, sptr);
return;
}
load_extend_int(ty, sofs, sptr, regop_ax(ty));
}
static void load2(Type *ty, int sofs, char *sptr) {
char ofs_buf[STRBUF_SZ];
snprintf(ofs_buf, STRBUF_SZ, "%d", sofs);
load3(ty, ofs_buf, sptr);
}
static void load(Node *node, int ofs) {
if (is_bitfield(node)) {
gen_bitfield_load(node, ofs);
return;
}
if (is_scalar(node->ty)) {
load2(node->ty, ofs, "%rax");
return;
}
switch (node->ty->kind) {
case TY_ARRAY:
case TY_STRUCT:
case TY_UNION:
case TY_FUNC:
case TY_VLA:
// If it is an array, do not attempt to load a value to the
// register because in general we can't load an entire array to a
// register. As a result, the result of an evaluation of an array
// becomes not the array itself but the address of the array.
// This is where "array is automatically converted to a pointer to
// the first element of the array in C" occurs.
return;
}
internal_error();
}
static void store3(Type *ty, char *dofs, char *dptr) {
switch (ty->kind) {
case TY_ARRAY:
case TY_STRUCT:
case TY_UNION:
gen_mem_copy2("0", "%rax", dofs, dptr, ty->size);
return;
case TY_FLOAT:
println(" movss %%xmm0, %s(%s)", dofs, dptr);
return;
case TY_DOUBLE:
println(" movsd %%xmm0, %s(%s)", dofs, dptr);
return;
case TY_LDOUBLE:
println(" fstpt %s(%s)", dofs, dptr);
println(" fninit; fldt %s(%s)", dofs, dptr);
return;
}
println(" mov %s, %s(%s)", reg_ax(ty->size), dofs, dptr);
}
static void store2(Type *ty, int dofs, char *dptr) {
char ofs_buf[STRBUF_SZ];
snprintf(ofs_buf, STRBUF_SZ, "%d", dofs);
store3(ty, ofs_buf, dptr);
}
static void store(Node *node) {
if (is_bitfield(node)) {
gen_bitfield_store(node);
return;
}
char *reg = pop_inreg(tmpreg64[0]);
store2(node->ty, 0, reg);
}
static void load_val2(Type *ty, int64_t val, char *gp32, char *gp64) {
if (val == 0) {
println(" xor %s, %s", gp32, gp32);
return;
}
if (val == (uint32_t)val) {
println(" movl $%"PRIi64", %s", val, gp32);
return;
}
if (val == (int32_t)val) {
if (ty->size == 8)
println(" movq $%"PRIi64", %s", val, gp64);
else
println(" movl $%"PRIi64", %s", val, gp32);
return;
}
println(" movabsq $%"PRIi64", %s", val, gp64);
}
static void load_val(Type *ty, int64_t val) {
load_val2(ty, val, "%eax", "%rax");
}
static void load_fval2(Type *ty, long double fval, int reg) {
if (ty->kind == TY_FLOAT) {
float pos_z = +0.0f;
float fv = fval;
if (!memcmp(&pos_z, &fv, sizeof(float))) {
println(" xorps %%xmm%d, %%xmm%d", reg, reg);
return;
}
union { float f32; uint32_t u32; } u = { fval };
println(" movl $%u, %%eax", u.u32);
println(" movd %%eax, %%xmm%d", reg);
return;
}
double pos_z = +0.0;
double dv = fval;
if (!memcmp(&pos_z, &dv, sizeof(double))) {
println(" xorps %%xmm%d, %%xmm%d", reg, reg);
return;
}
union { double f64; uint64_t u64; } u = { fval };
println(" movq $%"PRIu64", %%rax", u.u64);
println(" movq %%rax, %%xmm%d", reg);
return;
}
static void load_fval(Type *ty, long double fval) {
if (ty->kind == TY_FLOAT || ty->kind == TY_DOUBLE) {
load_fval2(ty, fval, 0);
return;
}
long double pos_z = +0.0L;
if (!memcmp(&pos_z, &fval, 10)) {
println(" fninit; fldz");
return;
}
long double neg_z = -0.0L;
if (!memcmp(&neg_z, &fval, 10)) {
println(" fninit; fldz");
println(" fchs");
return;
}
if (fval == 1) {
println(" fninit; fld1");
return;
}
if (fval == -1) {
println(" fninit; fld1");
println(" fchs");
return;
}
union { long double f80; uint64_t u64[2]; } u;
memset(&u, 0, sizeof(u));
u.f80 = fval;
println(" movq $%"PRIu64", %%rax", u.u64[0]);
println(" movw $%"PRIu16", %%dx", (uint16_t)u.u64[1]);
println(" push %%rdx");
println(" push %%rax");
println(" fninit; fldt (%%rsp)");
println(" add $16, %%rsp");
return;
}
enum { I8, I16, I32, I64, U8, U16, U32, U64, F32, F64, F80 };
static int getTypeId(Type *ty) {
switch (ty->kind) {
case TY_PCHAR:
case TY_CHAR:
return ty->is_unsigned ? U8 : I8;
case TY_SHORT:
return ty->is_unsigned ? U16 : I16;
case TY_INT:
return ty->is_unsigned ? U32 : I32;
case TY_LONG:
case TY_LONGLONG:
return ty->is_unsigned ? U64 : I64;
case TY_FLOAT:
return F32;
case TY_DOUBLE:
return F64;
case TY_LDOUBLE:
return F80;
}
return U64;
}
// The table for type casts
static char i32i8[] = "movsbl %al, %eax";
static char i32u8[] = "movzbl %al, %eax";
static char i32i16[] = "movswl %ax, %eax";