summaryrefslogtreecommitdiffhomepage
path: root/src/3p/chibicc/codegen.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/3p/chibicc/codegen.c')
-rw-r--r--src/3p/chibicc/codegen.c1595
1 files changed, 0 insertions, 1595 deletions
diff --git a/src/3p/chibicc/codegen.c b/src/3p/chibicc/codegen.c
deleted file mode 100644
index da11fd7..0000000
--- a/src/3p/chibicc/codegen.c
+++ /dev/null
@@ -1,1595 +0,0 @@
-#include "chibicc.h"
-
-#define GP_MAX 6
-#define FP_MAX 8
-
-static FILE *output_file;
-static int depth;
-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 Obj *current_fn;
-
-static void gen_expr(Node *node);
-static void gen_stmt(Node *node);
-
-__attribute__((format(printf, 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 int count(void) {
- static int i = 1;
- return i++;
-}
-
-static void push(void) {
- println(" push %%rax");
- depth++;
-}
-
-static void pop(char *arg) {
- println(" pop %s", arg);
- depth--;
-}
-
-static void pushf(void) {
- println(" sub $8, %%rsp");
- println(" movsd %%xmm0, (%%rsp)");
- depth++;
-}
-
-static void popf(int reg) {
- println(" movsd (%%rsp), %%xmm%d", reg);
- println(" add $8, %%rsp");
- depth--;
-}
-
-// 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";
- }
- unreachable();
-}
-
-static char *reg_ax(int sz) {
- switch (sz) {
- case 1: return "%al";
- case 2: return "%ax";
- case 4: return "%eax";
- case 8: return "%rax";
- }
- unreachable();
-}
-
-// 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) {
- switch (node->kind) {
- case ND_VAR:
- // Variable-length array, which is always local.
- if (node->var->ty->kind == TY_VLA) {
- println(" mov %d(%%rbp), %%rax", node->var->offset);
- return;
- }
-
- // Local variable
- if (node->var->is_local) {
- println(" lea %d(%%rbp), %%rax", node->var->offset);
- return;
- }
-
- if (opt_fpic) {
- // Thread-local variable
- if (node->var->is_tls) {
- println(" data16 lea %s@tlsgd(%%rip), %%rdi", node->var->name);
- println(" .value 0x6666");
- println(" rex64");
- println(" call __tls_get_addr@PLT");
- return;
- }
-
- // Function or global variable
- println(" mov %s@GOTPCREL(%%rip), %%rax", node->var->name);
- return;
- }
-
- // Thread-local variable
- if (node->var->is_tls) {
- println(" mov %%fs:0, %%rax");
- println(" add $%s@tpoff, %%rax", node->var->name);
- 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", node->var->name);
- else
- println(" mov %s@GOTPCREL(%%rip), %%rax", node->var->name);
- return;
- }
-
- // Global variable
- println(" lea %s(%%rip), %%rax", node->var->name);
- return;
- case ND_DEREF:
- gen_expr(node->lhs);
- return;
- case ND_COMMA:
- gen_expr(node->lhs);
- gen_addr(node->rhs);
- return;
- case ND_MEMBER:
- gen_addr(node->lhs);
- println(" add $%d, %%rax", node->member->offset);
- return;
- case ND_FUNCALL:
- if (node->ret_buffer) {
- gen_expr(node);
- return;
- }
- break;
- case ND_ASSIGN:
- case ND_COND:
- if (node->ty->kind == TY_STRUCT || node->ty->kind == TY_UNION) {
- gen_expr(node);
- return;
- }
- break;
- case ND_VLA_PTR:
- println(" lea %d(%%rbp), %%rax", node->var->offset);
- return;
- }
-
- error_tok(node->tok, "not an lvalue");
-}
-
-// Load a value from where %rax is pointing to.
-static void load(Type *ty) {
- switch (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;
- case TY_FLOAT:
- println(" movss (%%rax), %%xmm0");
- return;
- case TY_DOUBLE:
- println(" movsd (%%rax), %%xmm0");
- return;
- case TY_LDOUBLE:
- println(" fldt (%%rax)");
- return;
- }
-
- char *insn = ty->is_unsigned ? "movz" : "movs";
-
- // 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. The upper half of a
- // register for char, short and int may contain garbage. When we load
- // a long value to a register, it simply occupies the entire register.
- if (ty->size == 1)
- println(" %sbl (%%rax), %%eax", insn);
- else if (ty->size == 2)
- println(" %swl (%%rax), %%eax", insn);
- else if (ty->size == 4)
- println(" movsxd (%%rax), %%rax");
- else
- println(" mov (%%rax), %%rax");
-}
-
-// Store %rax to an address that the stack top is pointing to.
-static void store(Type *ty) {
- pop("%rdi");
-
- switch (ty->kind) {
- case TY_STRUCT:
- case TY_UNION:
- for (int i = 0; i < ty->size; i++) {
- println(" mov %d(%%rax), %%r8b", i);
- println(" mov %%r8b, %d(%%rdi)", i);
- }
- return;
- case TY_FLOAT:
- println(" movss %%xmm0, (%%rdi)");
- return;
- case TY_DOUBLE:
- println(" movsd %%xmm0, (%%rdi)");
- return;
- case TY_LDOUBLE:
- println(" fstpt (%%rdi)");
- return;
- }
-
- if (ty->size == 1)
- println(" mov %%al, (%%rdi)");
- else if (ty->size == 2)
- println(" mov %%ax, (%%rdi)");
- else if (ty->size == 4)
- println(" mov %%eax, (%%rdi)");
- else
- println(" mov %%rax, (%%rdi)");
-}
-
-static void cmp_zero(Type *ty) {
- switch (ty->kind) {
- case TY_FLOAT:
- println(" xorps %%xmm1, %%xmm1");
- println(" ucomiss %%xmm1, %%xmm0");
- return;
- case TY_DOUBLE:
- println(" xorpd %%xmm1, %%xmm1");
- println(" ucomisd %%xmm1, %%xmm0");
- return;
- case TY_LDOUBLE:
- println(" fldz");
- println(" fucomip");
- println(" fstp %%st(0)");
- return;
- }
-
- if (is_integer(ty) && ty->size <= 4)
- println(" cmp $0, %%eax");
- else
- println(" cmp $0, %%rax");
-}
-
-enum { I8, I16, I32, I64, U8, U16, U32, U64, F32, F64, F80 };
-
-static int getTypeId(Type *ty) {
- switch (ty->kind) {
- 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:
- 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";
-static char i32u16[] = "movzwl %ax, %eax";
-static char i32f32[] = "cvtsi2ssl %eax, %xmm0";
-static char i32i64[] = "movsxd %eax, %rax";
-static char i32f64[] = "cvtsi2sdl %eax, %xmm0";
-static char i32f80[] = "mov %eax, -4(%rsp); fildl -4(%rsp)";
-
-static char u32f32[] = "mov %eax, %eax; cvtsi2ssq %rax, %xmm0";
-static char u32i64[] = "mov %eax, %eax";
-static char u32f64[] = "mov %eax, %eax; cvtsi2sdq %rax, %xmm0";
-static char u32f80[] = "mov %eax, %eax; mov %rax, -8(%rsp); fildll -8(%rsp)";
-
-static char i64f32[] = "cvtsi2ssq %rax, %xmm0";
-static char i64f64[] = "cvtsi2sdq %rax, %xmm0";
-static char i64f80[] = "movq %rax, -8(%rsp); fildll -8(%rsp)";
-
-static char u64f32[] = "cvtsi2ssq %rax, %xmm0";
-static char u64f64[] =
- "test %rax,%rax; js 1f; pxor %xmm0,%xmm0; cvtsi2sd %rax,%xmm0; jmp 2f; "
- "1: mov %rax,%rdi; and $1,%eax; pxor %xmm0,%xmm0; shr %rdi; "
- "or %rax,%rdi; cvtsi2sd %rdi,%xmm0; addsd %xmm0,%xmm0; 2:";
-static char u64f80[] =
- "mov %rax, -8(%rsp); fildq -8(%rsp); test %rax, %rax; jns 1f;"
- "mov $1602224128, %eax; mov %eax, -4(%rsp); fadds -4(%rsp); 1:";
-
-static char f32i8[] = "cvttss2sil %xmm0, %eax; movsbl %al, %eax";
-static char f32u8[] = "cvttss2sil %xmm0, %eax; movzbl %al, %eax";
-static char f32i16[] = "cvttss2sil %xmm0, %eax; movswl %ax, %eax";
-static char f32u16[] = "cvttss2sil %xmm0, %eax; movzwl %ax, %eax";
-static char f32i32[] = "cvttss2sil %xmm0, %eax";
-static char f32u32[] = "cvttss2siq %xmm0, %rax";
-static char f32i64[] = "cvttss2siq %xmm0, %rax";
-static char f32u64[] = "cvttss2siq %xmm0, %rax";
-static char f32f64[] = "cvtss2sd %xmm0, %xmm0";
-static char f32f80[] = "movss %xmm0, -4(%rsp); flds -4(%rsp)";
-
-static char f64i8[] = "cvttsd2sil %xmm0, %eax; movsbl %al, %eax";
-static char f64u8[] = "cvttsd2sil %xmm0, %eax; movzbl %al, %eax";
-static char f64i16[] = "cvttsd2sil %xmm0, %eax; movswl %ax, %eax";
-static char f64u16[] = "cvttsd2sil %xmm0, %eax; movzwl %ax, %eax";
-static char f64i32[] = "cvttsd2sil %xmm0, %eax";
-static char f64u32[] = "cvttsd2siq %xmm0, %rax";
-static char f64i64[] = "cvttsd2siq %xmm0, %rax";
-static char f64u64[] = "cvttsd2siq %xmm0, %rax";
-static char f64f32[] = "cvtsd2ss %xmm0, %xmm0";
-static char f64f80[] = "movsd %xmm0, -8(%rsp); fldl -8(%rsp)";
-
-#define FROM_F80_1 \
- "fnstcw -10(%rsp); movzwl -10(%rsp), %eax; or $12, %ah; " \
- "mov %ax, -12(%rsp); fldcw -12(%rsp); "
-
-#define FROM_F80_2 " -24(%rsp); fldcw -10(%rsp); "
-
-static char f80i8[] = FROM_F80_1 "fistps" FROM_F80_2 "movsbl -24(%rsp), %eax";
-static char f80u8[] = FROM_F80_1 "fistps" FROM_F80_2 "movzbl -24(%rsp), %eax";
-static char f80i16[] = FROM_F80_1 "fistps" FROM_F80_2 "movzbl -24(%rsp), %eax";
-static char f80u16[] = FROM_F80_1 "fistpl" FROM_F80_2 "movswl -24(%rsp), %eax";
-static char f80i32[] = FROM_F80_1 "fistpl" FROM_F80_2 "mov -24(%rsp), %eax";
-static char f80u32[] = FROM_F80_1 "fistpl" FROM_F80_2 "mov -24(%rsp), %eax";
-static char f80i64[] = FROM_F80_1 "fistpq" FROM_F80_2 "mov -24(%rsp), %rax";
-static char f80u64[] = FROM_F80_1 "fistpq" FROM_F80_2 "mov -24(%rsp), %rax";
-static char f80f32[] = "fstps -8(%rsp); movss -8(%rsp), %xmm0";
-static char f80f64[] = "fstpl -8(%rsp); movsd -8(%rsp), %xmm0";
-
-static char *cast_table[][11] = {
- // i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 f80
- {NULL, NULL, NULL, i32i64, i32u8, i32u16, NULL, i32i64, i32f32, i32f64, i32f80}, // i8
- {i32i8, NULL, NULL, i32i64, i32u8, i32u16, NULL, i32i64, i32f32, i32f64, i32f80}, // i16
- {i32i8, i32i16, NULL, i32i64, i32u8, i32u16, NULL, i32i64, i32f32, i32f64, i32f80}, // i32
- {i32i8, i32i16, NULL, NULL, i32u8, i32u16, NULL, NULL, i64f32, i64f64, i64f80}, // i64
-
- {i32i8, NULL, NULL, i32i64, NULL, NULL, NULL, i32i64, i32f32, i32f64, i32f80}, // u8
- {i32i8, i32i16, NULL, i32i64, i32u8, NULL, NULL, i32i64, i32f32, i32f64, i32f80}, // u16
- {i32i8, i32i16, NULL, u32i64, i32u8, i32u16, NULL, u32i64, u32f32, u32f64, u32f80}, // u32
- {i32i8, i32i16, NULL, NULL, i32u8, i32u16, NULL, NULL, u64f32, u64f64, u64f80}, // u64
-
- {f32i8, f32i16, f32i32, f32i64, f32u8, f32u16, f32u32, f32u64, NULL, f32f64, f32f80}, // f32
- {f64i8, f64i16, f64i32, f64i64, f64u8, f64u16, f64u32, f64u64, f64f32, NULL, f64f80}, // f64
- {f80i8, f80i16, f80i32, f80i64, f80u8, f80u16, f80u32, f80u64, f80f32, f80f64, NULL}, // f80
-};
-
-static void cast(Type *from, Type *to) {
- if (to->kind == TY_VOID)
- return;
-
- if (to->kind == TY_BOOL) {
- cmp_zero(from);
- println(" setne %%al");
- println(" movzx %%al, %%eax");
- return;
- }
-
- int t1 = getTypeId(from);
- int t2 = getTypeId(to);
- if (cast_table[t1][t2])
- println(" %s", cast_table[t1][t2]);
-}
-
-// Structs or unions equal or smaller than 16 bytes are passed
-// using up to two registers.
-//
-// If the first 8 bytes contains only floating-point type members,
-// they are passed in an XMM register. Otherwise, they are passed
-// in a general-purpose register.
-//
-// If a struct/union is larger than 8 bytes, the same rule is
-// applied to the the next 8 byte chunk.
-//
-// This function returns true if `ty` has only floating-point
-// members in its byte range [lo, hi).
-static bool has_flonum(Type *ty, int lo, int hi, int offset) {
- if (ty->kind == TY_STRUCT || ty->kind == TY_UNION) {
- for (Member *mem = ty->members; mem; mem = mem->next)
- if (!has_flonum(mem->ty, lo, hi, offset + mem->offset))
- return false;
- return true;
- }
-
- if (ty->kind == TY_ARRAY) {
- for (int i = 0; i < ty->array_len; i++)
- if (!has_flonum(ty->base, lo, hi, offset + ty->base->size * i))
- return false;
- return true;
- }
-
- return offset < lo || hi <= offset || ty->kind == TY_FLOAT || ty->kind == TY_DOUBLE;
-}
-
-static bool has_flonum1(Type *ty) {
- return has_flonum(ty, 0, 8, 0);
-}
-
-static bool has_flonum2(Type *ty) {
- return has_flonum(ty, 8, 16, 0);
-}
-
-static void push_struct(Type *ty) {
- int sz = align_to(ty->size, 8);
- println(" sub $%d, %%rsp", sz);
- depth += sz / 8;
-
- for (int i = 0; i < ty->size; i++) {
- println(" mov %d(%%rax), %%r10b", i);
- println(" mov %%r10b, %d(%%rsp)", i);
- }
-}
-
-static void push_args2(Node *args, bool first_pass) {
- if (!args)
- return;
- push_args2(args->next, first_pass);
-
- if ((first_pass && !args->pass_by_stack) || (!first_pass && args->pass_by_stack))
- return;
-
- gen_expr(args);
-
- switch (args->ty->kind) {
- case TY_STRUCT:
- case TY_UNION:
- push_struct(args->ty);
- break;
- case TY_FLOAT:
- case TY_DOUBLE:
- pushf();
- break;
- case TY_LDOUBLE:
- println(" sub $16, %%rsp");
- println(" fstpt (%%rsp)");
- depth += 2;
- break;
- default:
- push();
- }
-}
-
-// Load function call arguments. Arguments are already evaluated and
-// stored to the stack as local variables. What we need to do in this
-// function is to load them to registers or push them to the stack as
-// specified by the x86-64 psABI. Here is what the spec says:
-//
-// - Up to 6 arguments of integral type are passed using RDI, RSI,
-// RDX, RCX, R8 and R9.
-//
-// - Up to 8 arguments of floating-point type are passed using XMM0 to
-// XMM7.
-//
-// - If all registers of an appropriate type are already used, push an
-// argument to the stack in the right-to-left order.
-//
-// - Each argument passed on the stack takes 8 bytes, and the end of
-// the argument area must be aligned to a 16 byte boundary.
-//
-// - If a function is variadic, set the number of floating-point type
-// arguments to RAX.
-static int push_args(Node *node) {
- int stack = 0, gp = 0, fp = 0;
-
- // If the return type is a large struct/union, the caller passes
- // a pointer to a buffer as if it were the first argument.
- if (node->ret_buffer && node->ty->size > 16)
- gp++;
-
- // Load as many arguments to the registers as possible.
- for (Node *arg = node->args; arg; arg = arg->next) {
- Type *ty = arg->ty;
-
- switch (ty->kind) {
- case TY_STRUCT:
- case TY_UNION:
- if (ty->size > 16) {
- arg->pass_by_stack = true;
- stack += align_to(ty->size, 8) / 8;
- } else {
- bool fp1 = has_flonum1(ty);
- bool fp2 = has_flonum2(ty);
-
- if (fp + fp1 + fp2 < FP_MAX && gp + !fp1 + !fp2 < GP_MAX) {
- fp = fp + fp1 + fp2;
- gp = gp + !fp1 + !fp2;
- } else {
- arg->pass_by_stack = true;
- stack += align_to(ty->size, 8) / 8;
- }
- }
- break;
- case TY_FLOAT:
- case TY_DOUBLE:
- if (fp++ >= FP_MAX) {
- arg->pass_by_stack = true;
- stack++;
- }
- break;
- case TY_LDOUBLE:
- arg->pass_by_stack = true;
- stack += 2;
- break;
- default:
- if (gp++ >= GP_MAX) {
- arg->pass_by_stack = true;
- stack++;
- }
- }
- }
-
- if ((depth + stack) % 2 == 1) {
- println(" sub $8, %%rsp");
- depth++;
- stack++;
- }
-
- push_args2(node->args, true);
- push_args2(node->args, false);
-
- // If the return type is a large struct/union, the caller passes
- // a pointer to a buffer as if it were the first argument.
- if (node->ret_buffer && node->ty->size > 16) {
- println(" lea %d(%%rbp), %%rax", node->ret_buffer->offset);
- push();
- }
-
- return stack;
-}
-
-static void copy_ret_buffer(Obj *var) {
- Type *ty = var->ty;
- int gp = 0, fp = 0;
-
- if (has_flonum1(ty)) {
- assert(ty->size == 4 || 8 <= ty->size);
- if (ty->size == 4)
- println(" movss %%xmm0, %d(%%rbp)", var->offset);
- else
- println(" movsd %%xmm0, %d(%%rbp)", var->offset);
- fp++;
- } else {
- for (int i = 0; i < MIN(8, ty->size); i++) {
- println(" mov %%al, %d(%%rbp)", var->offset + i);
- println(" shr $8, %%rax");
- }
- gp++;
- }
-
- if (ty->size > 8) {
- if (has_flonum2(ty)) {
- assert(ty->size == 12 || ty->size == 16);
- if (ty->size == 12)
- println(" movss %%xmm%d, %d(%%rbp)", fp, var->offset + 8);
- else
- println(" movsd %%xmm%d, %d(%%rbp)", fp, var->offset + 8);
- } else {
- char *reg1 = (gp == 0) ? "%al" : "%dl";
- char *reg2 = (gp == 0) ? "%rax" : "%rdx";
- for (int i = 8; i < MIN(16, ty->size); i++) {
- println(" mov %s, %d(%%rbp)", reg1, var->offset + i);
- println(" shr $8, %s", reg2);
- }
- }
- }
-}
-
-static void copy_struct_reg(void) {
- Type *ty = current_fn->ty->return_ty;
- int gp = 0, fp = 0;
-
- println(" mov %%rax, %%rdi");
-
- if (has_flonum(ty, 0, 8, 0)) {
- assert(ty->size == 4 || 8 <= ty->size);
- if (ty->size == 4)
- println(" movss (%%rdi), %%xmm0");
- else
- println(" movsd (%%rdi), %%xmm0");
- fp++;
- } else {
- println(" mov $0, %%rax");
- for (int i = MIN(8, ty->size) - 1; i >= 0; i--) {
- println(" shl $8, %%rax");
- println(" mov %d(%%rdi), %%al", i);
- }
- gp++;
- }
-
- if (ty->size > 8) {
- if (has_flonum(ty, 8, 16, 0)) {
- assert(ty->size == 12 || ty->size == 16);
- if (ty->size == 4)
- println(" movss 8(%%rdi), %%xmm%d", fp);
- else
- println(" movsd 8(%%rdi), %%xmm%d", fp);
- } else {
- char *reg1 = (gp == 0) ? "%al" : "%dl";
- char *reg2 = (gp == 0) ? "%rax" : "%rdx";
- println(" mov $0, %s", reg2);
- for (int i = MIN(16, ty->size) - 1; i >= 8; i--) {
- println(" shl $8, %s", reg2);
- println(" mov %d(%%rdi), %s", i, reg1);
- }
- }
- }
-}
-
-static void copy_struct_mem(void) {
- Type *ty = current_fn->ty->return_ty;
- Obj *var = current_fn->params;
-
- println(" mov %d(%%rbp), %%rdi", var->offset);
-
- for (int i = 0; i < ty->size; i++) {
- println(" mov %d(%%rax), %%dl", i);
- println(" mov %%dl, %d(%%rdi)", i);
- }
-}
-
-static void builtin_alloca(void) {
- // Align size to 16 bytes.
- println(" add $15, %%rdi");
- println(" and $0xfffffff0, %%edi");
-
- // Shift the temporary area by %rdi.
- println(" mov %d(%%rbp), %%rcx", current_fn->alloca_bottom->offset);
- println(" sub %%rsp, %%rcx");
- println(" mov %%rsp, %%rax");
- println(" sub %%rdi, %%rsp");
- println(" mov %%rsp, %%rdx");
- println("1:");
- println(" cmp $0, %%rcx");
- println(" je 2f");
- println(" mov (%%rax), %%r8b");
- println(" mov %%r8b, (%%rdx)");
- println(" inc %%rdx");
- println(" inc %%rax");
- println(" dec %%rcx");
- println(" jmp 1b");
- println("2:");
-
- // Move alloca_bottom pointer.
- println(" mov %d(%%rbp), %%rax", current_fn->alloca_bottom->offset);
- println(" sub %%rdi, %%rax");
- println(" mov %%rax, %d(%%rbp)", current_fn->alloca_bottom->offset);
-}
-
-// Generate code for a given node.
-static void gen_expr(Node *node) {
- println(" .loc %d %d", node->tok->file->file_no, node->tok->line_no);
-
- switch (node->kind) {
- case ND_NULL_EXPR:
- return;
- case ND_NUM: {
- switch (node->ty->kind) {
- case TY_FLOAT: {
- union { float f32; uint32_t u32; } u = { node->fval };
- println(" mov $%u, %%eax # float %Lf", u.u32, node->fval);
- println(" movq %%rax, %%xmm0");
- return;
- }
- case TY_DOUBLE: {
- union { double f64; uint64_t u64; } u = { node->fval };
- println(" mov $%lu, %%rax # double %Lf", u.u64, node->fval);
- println(" movq %%rax, %%xmm0");
- return;
- }
- case TY_LDOUBLE: {
- union { long double f80; uint64_t u64[2]; } u;
- memset(&u, 0, sizeof(u));
- u.f80 = node->fval;
- println(" mov $%lu, %%rax # long double %Lf", u.u64[0], node->fval);
- println(" mov %%rax, -16(%%rsp)");
- println(" mov $%lu, %%rax", u.u64[1]);
- println(" mov %%rax, -8(%%rsp)");
- println(" fldt -16(%%rsp)");
- return;
- }
- }
-
- println(" mov $%ld, %%rax", node->val);
- return;
- }
- case ND_NEG:
- gen_expr(node->lhs);
-
- switch (node->ty->kind) {
- case TY_FLOAT:
- println(" mov $1, %%rax");
- println(" shl $31, %%rax");
- println(" movq %%rax, %%xmm1");
- println(" xorps %%xmm1, %%xmm0");
- return;
- case TY_DOUBLE:
- println(" mov $1, %%rax");
- println(" shl $63, %%rax");
- println(" movq %%rax, %%xmm1");
- println(" xorpd %%xmm1, %%xmm0");
- return;
- case TY_LDOUBLE:
- println(" fchs");
- return;
- }
-
- println(" neg %%rax");
- return;
- case ND_VAR:
- gen_addr(node);
- load(node->ty);
- return;
- case ND_MEMBER: {
- gen_addr(node);
- load(node->ty);
-
- Member *mem = node->member;
- if (mem->is_bitfield) {
- println(" shl $%d, %%rax", 64 - mem->bit_width - mem->bit_offset);
- if (mem->ty->is_unsigned)
- println(" shr $%d, %%rax", 64 - mem->bit_width);
- else
- println(" sar $%d, %%rax", 64 - mem->bit_width);
- }
- return;
- }
- case ND_DEREF:
- gen_expr(node->lhs);
- load(node->ty);
- return;
- case ND_ADDR:
- gen_addr(node->lhs);
- return;
- case ND_ASSIGN:
- gen_addr(node->lhs);
- push();
- gen_expr(node->rhs);
-
- if (node->lhs->kind == ND_MEMBER && node->lhs->member->is_bitfield) {
- println(" mov %%rax, %%r8");
-
- // If the lhs is a bitfield, we need to read the current value
- // from memory and merge it with a new value.
- Member *mem = node->lhs->member;
- println(" mov %%rax, %%rdi");
- println(" and $%ld, %%rdi", (1L << mem->bit_width) - 1);
- println(" shl $%d, %%rdi", mem->bit_offset);
-
- println(" mov (%%rsp), %%rax");
- load(mem->ty);
-
- long mask = ((1L << mem->bit_width) - 1) << mem->bit_offset;
- println(" mov $%ld, %%r9", ~mask);
- println(" and %%r9, %%rax");
- println(" or %%rdi, %%rax");
- store(node->ty);
- println(" mov %%r8, %%rax");
- return;
- }
-
- store(node->ty);
- return;
- case ND_STMT_EXPR:
- for (Node *n = node->body; n; n = n->next)
- gen_stmt(n);
- return;
- case ND_COMMA:
- gen_expr(node->lhs);
- gen_expr(node->rhs);
- return;
- case ND_CAST:
- gen_expr(node->lhs);
- cast(node->lhs->ty, node->ty);
- return;
- case ND_MEMZERO:
- // `rep stosb` is equivalent to `memset(%rdi, %al, %rcx)`.
- println(" mov $%d, %%rcx", node->var->ty->size);
- println(" lea %d(%%rbp), %%rdi", node->var->offset);
- println(" mov $0, %%al");
- println(" rep stosb");
- return;
- case ND_COND: {
- int c = count();
- gen_expr(node->cond);
- cmp_zero(node->cond->ty);
- println(" je .L.else.%d", c);
- gen_expr(node->then);
- println(" jmp .L.end.%d", c);
- println(".L.else.%d:", c);
- gen_expr(node->els);
- println(".L.end.%d:", c);
- return;
- }
- case ND_NOT:
- gen_expr(node->lhs);
- cmp_zero(node->lhs->ty);
- println(" sete %%al");
- println(" movzx %%al, %%rax");
- return;
- case ND_BITNOT:
- gen_expr(node->lhs);
- println(" not %%rax");
- return;
- case ND_LOGAND: {
- int c = count();
- gen_expr(node->lhs);
- cmp_zero(node->lhs->ty);
- println(" je .L.false.%d", c);
- gen_expr(node->rhs);
- cmp_zero(node->rhs->ty);
- println(" je .L.false.%d", c);
- println(" mov $1, %%rax");
- println(" jmp .L.end.%d", c);
- println(".L.false.%d:", c);
- println(" mov $0, %%rax");
- println(".L.end.%d:", c);
- return;
- }
- case ND_LOGOR: {
- int c = count();
- gen_expr(node->lhs);
- cmp_zero(node->lhs->ty);
- println(" jne .L.true.%d", c);
- gen_expr(node->rhs);
- cmp_zero(node->rhs->ty);
- println(" jne .L.true.%d", c);
- println(" mov $0, %%rax");
- println(" jmp .L.end.%d", c);
- println(".L.true.%d:", c);
- println(" mov $1, %%rax");
- println(".L.end.%d:", c);
- return;
- }
- case ND_FUNCALL: {
- if (node->lhs->kind == ND_VAR && !strcmp(node->lhs->var->name, "alloca")) {
- gen_expr(node->args);
- println(" mov %%rax, %%rdi");
- builtin_alloca();
- return;
- }
-
- int stack_args = push_args(node);
- gen_expr(node->lhs);
-
- int gp = 0, fp = 0;
-
- // If the return type is a large struct/union, the caller passes
- // a pointer to a buffer as if it were the first argument.
- if (node->ret_buffer && node->ty->size > 16)
- pop(argreg64[gp++]);
-
- for (Node *arg = node->args; arg; arg = arg->next) {
- Type *ty = arg->ty;
-
- switch (ty->kind) {
- case TY_STRUCT:
- case TY_UNION:
- if (ty->size > 16)
- continue;
-
- bool fp1 = has_flonum1(ty);
- bool fp2 = has_flonum2(ty);
-
- if (fp + fp1 + fp2 < FP_MAX && gp + !fp1 + !fp2 < GP_MAX) {
- if (fp1)
- popf(fp++);
- else
- pop(argreg64[gp++]);
-
- if (ty->size > 8) {
- if (fp2)
- popf(fp++);
- else
- pop(argreg64[gp++]);
- }
- }
- break;
- case TY_FLOAT:
- case TY_DOUBLE:
- if (fp < FP_MAX)
- popf(fp++);
- break;
- case TY_LDOUBLE:
- break;
- default:
- if (gp < GP_MAX)
- pop(argreg64[gp++]);
- }
- }
-
- println(" mov %%rax, %%r10");
- println(" mov $%d, %%rax", fp);
- println(" call *%%r10");
- println(" add $%d, %%rsp", stack_args * 8);
-
- depth -= stack_args;
-
- // It looks like the most significant 48 or 56 bits in RAX may
- // contain garbage if a function return type is short or bool/char,
- // respectively. We clear the upper bits here.
- switch (node->ty->kind) {
- case TY_BOOL:
- println(" movzx %%al, %%eax");
- return;
- case TY_CHAR:
- if (node->ty->is_unsigned)
- println(" movzbl %%al, %%eax");
- else
- println(" movsbl %%al, %%eax");
- return;
- case TY_SHORT:
- if (node->ty->is_unsigned)
- println(" movzwl %%ax, %%eax");
- else
- println(" movswl %%ax, %%eax");
- return;
- }
-
- // If the return type is a small struct, a value is returned
- // using up to two registers.
- if (node->ret_buffer && node->ty->size <= 16) {
- copy_ret_buffer(node->ret_buffer);
- println(" lea %d(%%rbp), %%rax", node->ret_buffer->offset);
- }
-
- return;
- }
- case ND_LABEL_VAL:
- println(" lea %s(%%rip), %%rax", node->unique_label);
- return;
- case ND_CAS: {
- gen_expr(node->cas_addr);
- push();
- gen_expr(node->cas_new);
- push();
- gen_expr(node->cas_old);
- println(" mov %%rax, %%r8");
- load(node->cas_old->ty->base);
- pop("%rdx"); // new
- pop("%rdi"); // addr
-
- int sz = node->cas_addr->ty->base->size;
- println(" lock cmpxchg %s, (%%rdi)", reg_dx(sz));
- println(" sete %%cl");
- println(" je 1f");
- println(" mov %s, (%%r8)", reg_ax(sz));
- println("1:");
- println(" movzbl %%cl, %%eax");
- return;
- }
- case ND_EXCH: {
- gen_expr(node->lhs);
- push();
- gen_expr(node->rhs);
- pop("%rdi");
-
- int sz = node->lhs->ty->base->size;
- println(" xchg %s, (%%rdi)", reg_ax(sz));
- return;
- }
- }
-
- switch (node->lhs->ty->kind) {
- case TY_FLOAT:
- case TY_DOUBLE: {
- gen_expr(node->rhs);
- pushf();
- gen_expr(node->lhs);
- popf(1);
-
- char *sz = (node->lhs->ty->kind == TY_FLOAT) ? "ss" : "sd";
-
- switch (node->kind) {
- case ND_ADD:
- println(" add%s %%xmm1, %%xmm0", sz);
- return;
- case ND_SUB:
- println(" sub%s %%xmm1, %%xmm0", sz);
- return;
- case ND_MUL:
- println(" mul%s %%xmm1, %%xmm0", sz);
- return;
- case ND_DIV:
- println(" div%s %%xmm1, %%xmm0", sz);
- return;
- case ND_EQ:
- case ND_NE:
- case ND_LT:
- case ND_LE:
- println(" ucomi%s %%xmm0, %%xmm1", sz);
-
- if (node->kind == ND_EQ) {
- println(" sete %%al");
- println(" setnp %%dl");
- println(" and %%dl, %%al");
- } else if (node->kind == ND_NE) {
- println(" setne %%al");
- println(" setp %%dl");
- println(" or %%dl, %%al");
- } else if (node->kind == ND_LT) {
- println(" seta %%al");
- } else {
- println(" setae %%al");
- }
-
- println(" and $1, %%al");
- println(" movzb %%al, %%rax");
- return;
- }
-
- error_tok(node->tok, "invalid expression");
- }
- case TY_LDOUBLE: {
- gen_expr(node->lhs);
- gen_expr(node->rhs);
-
- switch (node->kind) {
- case ND_ADD:
- println(" faddp");
- return;
- case ND_SUB:
- println(" fsubrp");
- return;
- case ND_MUL:
- println(" fmulp");
- return;
- case ND_DIV:
- println(" fdivrp");
- return;
- case ND_EQ:
- case ND_NE:
- case ND_LT:
- case ND_LE:
- println(" fcomip");
- println(" fstp %%st(0)");
-
- if (node->kind == ND_EQ)
- println(" sete %%al");
- else if (node->kind == ND_NE)
- println(" setne %%al");
- else if (node->kind == ND_LT)
- println(" seta %%al");
- else
- println(" setae %%al");
-
- println(" movzb %%al, %%rax");
- return;
- }
-
- error_tok(node->tok, "invalid expression");
- }
- }
-
- gen_expr(node->rhs);
- push();
- gen_expr(node->lhs);
- pop("%rdi");
-
- char *ax, *di, *dx;
-
- if (node->lhs->ty->kind == TY_LONG || node->lhs->ty->base) {
- ax = "%rax";
- di = "%rdi";
- dx = "%rdx";
- } else {
- ax = "%eax";
- di = "%edi";
- dx = "%edx";
- }
-
- switch (node->kind) {
- case ND_ADD:
- println(" add %s, %s", di, ax);
- return;
- case ND_SUB:
- println(" sub %s, %s", di, ax);
- return;
- case ND_MUL:
- println(" imul %s, %s", di, ax);
- return;
- case ND_DIV:
- case ND_MOD:
- if (node->ty->is_unsigned) {
- println(" mov $0, %s", dx);
- println(" div %s", di);
- } else {
- if (node->lhs->ty->size == 8)
- println(" cqo");
- else
- println(" cdq");
- println(" idiv %s", di);
- }
-
- if (node->kind == ND_MOD)
- println(" mov %%rdx, %%rax");
- return;
- case ND_BITAND:
- println(" and %s, %s", di, ax);
- return;
- case ND_BITOR:
- println(" or %s, %s", di, ax);
- return;
- case ND_BITXOR:
- println(" xor %s, %s", di, ax);
- return;
- case ND_EQ:
- case ND_NE:
- case ND_LT:
- case ND_LE:
- println(" cmp %s, %s", di, ax);
-
- if (node->kind == ND_EQ) {
- println(" sete %%al");
- } else if (node->kind == ND_NE) {
- println(" setne %%al");
- } else if (node->kind == ND_LT) {
- if (node->lhs->ty->is_unsigned)
- println(" setb %%al");
- else
- println(" setl %%al");
- } else if (node->kind == ND_LE) {
- if (node->lhs->ty->is_unsigned)
- println(" setbe %%al");
- else
- println(" setle %%al");
- }
-
- println(" movzb %%al, %%rax");
- return;
- case ND_SHL:
- println(" mov %%rdi, %%rcx");
- println(" shl %%cl, %s", ax);
- return;
- case ND_SHR:
- println(" mov %%rdi, %%rcx");
- if (node->lhs->ty->is_unsigned)
- println(" shr %%cl, %s", ax);
- else
- println(" sar %%cl, %s", ax);
- return;
- }
-
- error_tok(node->tok, "invalid expression");
-}
-
-static void gen_stmt(Node *node) {
- println(" .loc %d %d", node->tok->file->file_no, node->tok->line_no);
-
- switch (node->kind) {
- case ND_IF: {
- int c = count();
- gen_expr(node->cond);
- cmp_zero(node->cond->ty);
- println(" je .L.else.%d", c);
- gen_stmt(node->then);
- println(" jmp .L.end.%d", c);
- println(".L.else.%d:", c);
- if (node->els)
- gen_stmt(node->els);
- println(".L.end.%d:", c);
- return;
- }
- case ND_FOR: {
- int c = count();
- if (node->init)
- gen_stmt(node->init);
- println(".L.begin.%d:", c);
- if (node->cond) {
- gen_expr(node->cond);
- cmp_zero(node->cond->ty);
- println(" je %s", node->brk_label);
- }
- gen_stmt(node->then);
- println("%s:", node->cont_label);
- if (node->inc)
- gen_expr(node->inc);
- println(" jmp .L.begin.%d", c);
- println("%s:", node->brk_label);
- return;
- }
- case ND_DO: {
- int c = count();
- println(".L.begin.%d:", c);
- gen_stmt(node->then);
- println("%s:", node->cont_label);
- gen_expr(node->cond);
- cmp_zero(node->cond->ty);
- println(" jne .L.begin.%d", c);
- println("%s:", node->brk_label);
- return;
- }
- case ND_SWITCH:
- gen_expr(node->cond);
-
- for (Node *n = node->case_next; n; n = n->case_next) {
- char *ax = (node->cond->ty->size == 8) ? "%rax" : "%eax";
- char *di = (node->cond->ty->size == 8) ? "%rdi" : "%edi";
-
- if (n->begin == n->end) {
- println(" cmp $%ld, %s", n->begin, ax);
- println(" je %s", n->label);
- continue;
- }
-
- // [GNU] Case ranges
- println(" mov %s, %s", ax, di);
- println(" sub $%ld, %s", n->begin, di);
- println(" cmp $%ld, %s", n->end - n->begin, di);
- println(" jbe %s", n->label);
- }
-
- if (node->default_case)
- println(" jmp %s", node->default_case->label);
-
- println(" jmp %s", node->brk_label);
- gen_stmt(node->then);
- println("%s:", node->brk_label);
- return;
- case ND_CASE:
- println("%s:", node->label);
- gen_stmt(node->lhs);
- return;
- case ND_BLOCK:
- for (Node *n = node->body; n; n = n->next)
- gen_stmt(n);
- return;
- case ND_GOTO:
- println(" jmp %s", node->unique_label);
- return;
- case ND_GOTO_EXPR:
- gen_expr(node->lhs);
- println(" jmp *%%rax");
- return;
- case ND_LABEL:
- println("%s:", node->unique_label);
- gen_stmt(node->lhs);
- return;
- case ND_RETURN:
- if (node->lhs) {
- gen_expr(node->lhs);
- Type *ty = node->lhs->ty;
-
- switch (ty->kind) {
- case TY_STRUCT:
- case TY_UNION:
- if (ty->size <= 16)
- copy_struct_reg();
- else
- copy_struct_mem();
- break;
- }
- }
-
- println(" jmp .L.return.%s", current_fn->name);
- return;
- case ND_EXPR_STMT:
- gen_expr(node->lhs);
- return;
- case ND_ASM:
- println(" %s", node->asm_str);
- return;
- }
-
- error_tok(node->tok, "invalid statement");
-}
-
-// Assign offsets to local variables.
-static void assign_lvar_offsets(Obj *prog) {
- for (Obj *fn = prog; fn; fn = fn->next) {
- if (!fn->is_function)
- continue;
-
- // If a function has many parameters, some parameters are
- // inevitably passed by stack rather than by register.
- // The first passed-by-stack parameter resides at RBP+16.
- int top = 16;
- int bottom = 0;
-
- int gp = 0, fp = 0;
-
- // Assign offsets to pass-by-stack parameters.
- for (Obj *var = fn->params; var; var = var->next) {
- Type *ty = var->ty;
-
- switch (ty->kind) {
- case TY_STRUCT:
- case TY_UNION:
- if (ty->size <= 16) {
- bool fp1 = has_flonum(ty, 0, 8, 0);
- bool fp2 = has_flonum(ty, 8, 16, 8);
- if (fp + fp1 + fp2 < FP_MAX && gp + !fp1 + !fp2 < GP_MAX) {
- fp = fp + fp1 + fp2;
- gp = gp + !fp1 + !fp2;
- continue;
- }
- }
- break;
- case TY_FLOAT:
- case TY_DOUBLE:
- if (fp++ < FP_MAX)
- continue;
- break;
- case TY_LDOUBLE:
- break;
- default:
- if (gp++ < GP_MAX)
- continue;
- }
-
- top = align_to(top, 8);
- var->offset = top;
- top += var->ty->size;
- }
-
- // Assign offsets to pass-by-register parameters and local variables.
- for (Obj *var = fn->locals; var; var = var->next) {
- if (var->offset)
- continue;
-
- // AMD64 System V ABI has a special alignment rule for an array of
- // length at least 16 bytes. We need to align such array to at least
- // 16-byte boundaries. See p.14 of
- // https://github.com/hjl-tools/x86-psABI/wiki/x86-64-psABI-draft.pdf.
- int align = (var->ty->kind == TY_ARRAY && var->ty->size >= 16)
- ? MAX(16, var->align) : var->align;
-
- bottom += var->ty->size;
- bottom = align_to(bottom, align);
- var->offset = -bottom;
- }
-
- fn->stack_size = align_to(bottom, 16);
- }
-}
-
-static void emit_data(Obj *prog) {
- for (Obj *var = prog; var; var = var->next) {
- if (var->is_function || !var->is_definition)
- continue;
-
- if (var->is_static)
- println(" .local %s", var->name);
- else
- println(" .globl %s", var->name);
-
- int align = (var->ty->kind == TY_ARRAY && var->ty->size >= 16)
- ? MAX(16, var->align) : var->align;
-
- // Common symbol
- if (opt_fcommon && var->is_tentative) {
- println(" .comm %s, %d, %d", var->name, var->ty->size, align);
- continue;
- }
-
- // .data or .tdata
- if (var->init_data) {
- if (var->is_tls)
- println(" .section .tdata,\"awT\",@progbits");
- else
- println(" .data");
-
- println(" .type %s, @object", var->name);
- println(" .size %s, %d", var->name, var->ty->size);
- println(" .align %d", align);
- println("%s:", var->name);
-
- Relocation *rel = var->rel;
- int pos = 0;
- while (pos < var->ty->size) {
- if (rel && rel->offset == pos) {
- println(" .quad %s%+ld", *rel->label, rel->addend);
- rel = rel->next;
- pos += 8;
- } else {
- println(" .byte %d", var->init_data[pos++]);
- }
- }
- continue;
- }
-
- // .bss or .tbss
- if (var->is_tls)
- println(" .section .tbss,\"awT\",@nobits");
- else
- println(" .bss");
-
- println(" .align %d", align);
- println("%s:", var->name);
- println(" .zero %d", var->ty->size);
- }
-}
-
-static void store_fp(int r, int offset, int sz) {
- switch (sz) {
- case 4:
- println(" movss %%xmm%d, %d(%%rbp)", r, offset);
- return;
- case 8:
- println(" movsd %%xmm%d, %d(%%rbp)", r, offset);
- return;
- }
- unreachable();
-}
-
-static void store_gp(int r, int offset, int sz) {
- switch (sz) {
- case 1:
- println(" mov %s, %d(%%rbp)", argreg8[r], offset);
- return;
- case 2:
- println(" mov %s, %d(%%rbp)", argreg16[r], offset);
- return;
- case 4:
- println(" mov %s, %d(%%rbp)", argreg32[r], offset);
- return;
- case 8:
- println(" mov %s, %d(%%rbp)", argreg64[r], offset);
- return;
- default:
- for (int i = 0; i < sz; i++) {
- println(" mov %s, %d(%%rbp)", argreg8[r], offset + i);
- println(" shr $8, %s", argreg64[r]);
- }
- return;
- }
-}
-
-static void emit_text(Obj *prog) {
- for (Obj *fn = prog; fn; fn = fn->next) {
- if (!fn->is_function || !fn->is_definition)
- continue;
-
- // No code is emitted for "static inline" functions
- // if no one is referencing them.
- if (!fn->is_live)
- continue;
-
- if (fn->is_static)
- println(" .local %s", fn->name);
- else
- println(" .globl %s", fn->name);
-
- println(" .text");
- println(" .type %s, @function", fn->name);
- println("%s:", fn->name);
- current_fn = fn;
-
- // Prologue
- println(" push %%rbp");
- println(" mov %%rsp, %%rbp");
- println(" sub $%d, %%rsp", fn->stack_size);
- println(" mov %%rsp, %d(%%rbp)", fn->alloca_bottom->offset);
-
- // Save arg registers if function is variadic
- if (fn->va_area) {
- int gp = 0, fp = 0;
- for (Obj *var = fn->params; var; var = var->next) {
- if (is_flonum(var->ty))
- fp++;
- else
- gp++;
- }
-
- int off = fn->va_area->offset;
-
- // va_elem
- println(" movl $%d, %d(%%rbp)", gp * 8, off); // gp_offset
- println(" movl $%d, %d(%%rbp)", fp * 8 + 48, off + 4); // fp_offset
- println(" movq %%rbp, %d(%%rbp)", off + 8); // overflow_arg_area
- println(" addq $16, %d(%%rbp)", off + 8);
- println(" movq %%rbp, %d(%%rbp)", off + 16); // reg_save_area
- println(" addq $%d, %d(%%rbp)", off + 24, off + 16);
-
- // __reg_save_area__
- println(" movq %%rdi, %d(%%rbp)", off + 24);
- println(" movq %%rsi, %d(%%rbp)", off + 32);
- println(" movq %%rdx, %d(%%rbp)", off + 40);
- println(" movq %%rcx, %d(%%rbp)", off + 48);
- println(" movq %%r8, %d(%%rbp)", off + 56);
- println(" movq %%r9, %d(%%rbp)", off + 64);
- println(" movsd %%xmm0, %d(%%rbp)", off + 72);
- println(" movsd %%xmm1, %d(%%rbp)", off + 80);
- println(" movsd %%xmm2, %d(%%rbp)", off + 88);
- println(" movsd %%xmm3, %d(%%rbp)", off + 96);
- println(" movsd %%xmm4, %d(%%rbp)", off + 104);
- println(" movsd %%xmm5, %d(%%rbp)", off + 112);
- println(" movsd %%xmm6, %d(%%rbp)", off + 120);
- println(" movsd %%xmm7, %d(%%rbp)", off + 128);
- }
-
- // Save passed-by-register arguments to the stack
- int gp = 0, fp = 0;
- for (Obj *var = fn->params; var; var = var->next) {
- if (var->offset > 0)
- continue;
-
- Type *ty = var->ty;
-
- switch (ty->kind) {
- case TY_STRUCT:
- case TY_UNION:
- assert(ty->size <= 16);
- if (has_flonum(ty, 0, 8, 0))
- store_fp(fp++, var->offset, MIN(8, ty->size));
- else
- store_gp(gp++, var->offset, MIN(8, ty->size));
-
- if (ty->size > 8) {
- if (has_flonum(ty, 8, 16, 0))
- store_fp(fp++, var->offset + 8, ty->size - 8);
- else
- store_gp(gp++, var->offset + 8, ty->size - 8);
- }
- break;
- case TY_FLOAT:
- case TY_DOUBLE:
- store_fp(fp++, var->offset, ty->size);
- break;
- default:
- store_gp(gp++, var->offset, ty->size);
- }
- }
-
- // Emit code
- gen_stmt(fn->body);
- assert(depth == 0);
-
- // [https://www.sigbus.info/n1570#5.1.2.2.3p1] The C spec defines
- // a special rule for the main function. Reaching the end of the
- // main function is equivalent to returning 0, even though the
- // behavior is undefined for the other functions.
- if (strcmp(fn->name, "main") == 0)
- println(" mov $0, %%rax");
-
- // Epilogue
- println(".L.return.%s:", fn->name);
- println(" mov %%rbp, %%rsp");
- println(" pop %%rbp");
- println(" ret");
- }
-}
-
-void codegen(Obj *prog, FILE *out) {
- output_file = out;
-
- File **files = get_input_files();
- for (int i = 0; files[i]; i++)
- println(" .file %d \"%s\"", files[i]->file_no, files[i]->name);
-
- assign_lvar_offsets(prog);
- emit_data(prog);
- emit_text(prog);
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-10 05:21:15 +0000