scc/libs/mcode/include/x86/scc_x86_encode.h

#ifndef __SCC_X86_ENCODE_H__
#define __SCC_X86_ENCODE_H__

#include "../scc_mcode.h"
#include "scc_x86_iform.h"
#include "scc_x86_reg.h"

typedef struct {
    i64 displacement;
    u32 displacement_bits;
} scc_x86_disp_t;

typedef struct {
    scc_x86_reg_t seg;
    scc_x86_reg_t base;
    scc_x86_reg_t index;
    u32 scale;
    scc_x86_disp_t disp;
} scc_x86_mem_t;

typedef enum {
    SCC_X86_RELOC_TARGET_SYMBOL,
    SCC_X86_RELOC_TARGET_BBLOCK,
} scc_x86_reloc_target_t;

typedef struct scc_x86_reloc_op {
    scc_x86_operand_kind_t kind; // 原始操作数类型
    scc_x86_reloc_target_t target;
    union {
        i64 imm;
        int bblock_id;           // 如果 kind == RELBR
        const char *global_name; // 如果 kind == SYMBOL
    };
    i64 addend; // 额外常量偏移，用于 sym+addend
} scc_x86_reloc_op_t;

typedef struct {
    scc_x86_operand_kind_t kind;
    union {
        scc_x86_reg_t reg;
        i32 brdisp;
        i64 simm0;
        u64 imm0;
        u8 imm1;
        scc_x86_mem_t mem;
        scc_x86_reloc_op_t reloc;
    };
    u8 size_bits;
} scc_x86_operand_value_t;

static inline scc_x86_operand_value_t scc_x86_op_preg(scc_x86_reg_t reg,
                                                      u8 size_bits) {
    Assert(size_bits % 8 == 0);
    scc_x86_operand_value_t o = {
        .kind = SCC_X86_OPR_REG,
        .reg = reg,
        .size_bits = size_bits,
    };
    return o;
}
static inline scc_x86_reg_t scc_x86_op_vreg_reg(int vreg) {
    return (int)SCC_X86_REG_COUNT + vreg;
}
static inline scc_x86_operand_value_t scc_x86_op_vreg(int vreg, u8 size_bits) {
    Assert(size_bits % 8 == 0);
    scc_x86_operand_value_t o = {
        .kind = SCC_X86_OPR_REG,
        .reg = scc_x86_op_vreg_reg(vreg),
        .size_bits = size_bits,
    };
    return o;
}
static inline scc_x86_operand_value_t scc_x86_op_relbr(i32 rel) {
    scc_x86_operand_value_t o = {
        .kind = SCC_X86_OPR_RELBR,
        .brdisp = rel,
        .size_bits = 32,
    };
    return o;
}
static inline scc_x86_operand_value_t scc_x86_op_imm(i64 imm, u8 size_bits) {
    Assert(size_bits % 8 == 0);
    scc_x86_operand_value_t o = {
        .kind = SCC_X86_OPR_IMM,
        .simm0 = imm,
        .size_bits = size_bits,
    };
    return o;
}
static inline scc_x86_operand_value_t scc_x86_op_mem(scc_x86_mem_t mem,
                                                     u8 size_bits) {
    Assert(size_bits % 8 == 0);
    scc_x86_operand_value_t o = {
        .kind = SCC_X86_OPR_MEM,
        .mem = mem,
        .size_bits = size_bits,
    };
    return o;
}

// 1. 全局符号重定位（绝对地址加载：MOV reg, imm32/64）
static inline scc_x86_operand_value_t
scc_x86_op_reloc_global_imm(const char *sym, i64 addend) {
    scc_x86_operand_value_t op = {.kind = SCC_X86_OPR_RELOC};
    op.reloc.kind = SCC_X86_OPR_IMM;
    op.reloc.target = SCC_X86_RELOC_TARGET_SYMBOL;
    op.reloc.global_name = sym;
    op.reloc.addend = addend;
    op.size_bits = 0;
    return op;
}

static inline scc_x86_operand_value_t
scc_x86_op_reloc_global_relrip(const char *sym, i64 addend) {
    scc_x86_operand_value_t op = {.kind = SCC_X86_OPR_RELOC};
    op.reloc.kind = SCC_X86_OPR_MEM;
    op.reloc.target = SCC_X86_RELOC_TARGET_SYMBOL;
    op.reloc.global_name = sym;
    op.reloc.addend = addend;
    op.size_bits = 32;
    return op;
}

// 2. 全局符号重定位（相对跳转/调用：CALL/JMP rel32）
static inline scc_x86_operand_value_t
scc_x86_op_reloc_global_relbr(const char *sym, i64 addend) {
    scc_x86_operand_value_t op = {.kind = SCC_X86_OPR_RELOC};
    op.reloc.kind = SCC_X86_OPR_RELBR;
    op.reloc.target = SCC_X86_RELOC_TARGET_SYMBOL;
    op.reloc.global_name = sym;
    op.reloc.addend = addend;
    op.size_bits = 32;
    return op;
}

// 3. 基本块重定位（相对跳转）
static inline scc_x86_operand_value_t scc_x86_op_reloc_block(int bid,
                                                             i64 addend) {
    scc_x86_operand_value_t op = {.kind = SCC_X86_OPR_RELOC};
    op.reloc.kind = SCC_X86_OPR_RELBR;
    op.reloc.target = SCC_X86_RELOC_TARGET_BBLOCK;
    op.reloc.bblock_id = bid;
    op.reloc.addend = addend;
    op.size_bits = 32;
    return op;
}

// 4. 如果需要支持符号的内存寻址（如 [RIP + sym]），可扩展 kind =
// SCC_X86_OPR_MEM
static inline scc_x86_operand_value_t
scc_x86_op_reloc_global_mem(const char *sym, i64 addend) {
    scc_x86_operand_value_t op = {.kind = SCC_X86_OPR_RELOC};
    op.reloc.kind = SCC_X86_OPR_MEM;
    op.reloc.target = SCC_X86_RELOC_TARGET_SYMBOL;
    op.reloc.global_name = sym;
    op.reloc.addend = addend;
    // 编码时需生成 RIP 相对寻址的 ModRM/SIB
    op.size_bits = 0;
    return op;
}

/* 按 iform 发射一条指令，ops 数组长度需与 iform 定义的操作数数目一致 */
int scc_x86_encode_inst(scc_mcode_t *mcode, scc_x86_iform_t iform,
                        const scc_x86_operand_value_t *ops);
scc_x86_iform_t scc_x86_iclass_to_iform(scc_x86_iclass_t iclass,
                                        const scc_x86_operand_value_t *ops,
                                        int num_ops);

#endif /* __SCC_X86_ENCODE_H__ */