parse_arm_pseudo.c

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// SPDX-FileCopyrightText: 2015-2018 pancake <pancake@nopcode.org>
// SPDX-FileCopyrightText: 2021 deroad <wargio@libero.it>
// SPDX-License-Identifier: LGPL-3.0-only
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <rz_lib.h>
#include <rz_util.h>
#include <rz_flag.h>
#include <rz_analysis.h>
#include <rz_parse.h>
 
#include "parse_common.c"
 
static RzList *arm_tokenize(const char *assembly, size_t length);
 
static const RzPseudoGrammar arm_lexicon[] = {
    RZ_PSEUDO_DEFINE_GRAMMAR("abs", "1 = abs(1)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("adc", "1 = 2 + 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("add", "1 = 2 + 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("add.w", "1 = 2 + 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("adds", "1 = 2 + 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("addw", "1 = 2 + 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("adf", "1 = 2 + 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("adr", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("adrp", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("and", "1 = 2 & 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("ands", "1 &= 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("asl", "1 = 2 << 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("asls", "1 = 2 << 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("asr", "1 = 2 >> 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("asrs", "1 = 2 >> 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("b", "goto 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("b.gt", "if (? > ?) goto 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("b.le", "if (? < ?) goto 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("b.w", "goto 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("beq", "if (? == ?) goto 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("bge", "if (? >= ?) goto 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("bkpt", "breakpoint 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("bl", "1 ()"),
    RZ_PSEUDO_DEFINE_GRAMMAR("blx", "1 ()"),
    RZ_PSEUDO_DEFINE_GRAMMAR("bxeq", "if (? == ?) goto 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("call", "1 ()"),
    RZ_PSEUDO_DEFINE_GRAMMAR("cbnz", "if (1) goto 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("cbz", "if (!1) goto 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("cmf", "if (1 == 2)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("cmn", "if (1 != 2)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("cmp", "if (1 == 2)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("div", "1 = 2 / 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("dvf", "1 = 2 / 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("eor", "1 = 2 ^ 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("fcmp", "if (1 == 2)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("fdiv", "1 = 2 / 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("fdv", "1 = 2 / 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("fml", "1 = 2 * 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("fmov", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("fmul", "1 = 2 * 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("fsub", "1 = 2 - 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("ldp", "(1, 2) = 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("ldr", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("ldr.w", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("ldrb", "1 = (byte) 2 + 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("ldrh", "1 = (word) 2 + 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("ldrsb", "1 = (byte) 2 + 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("ldrsw", "1 = 2 + 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("ldrsw", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("lsl", "1 = 2 << 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("lsls", "1 = 2 << 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("lsr", "1 = 2 >> 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("lsrs", "1 = 2 >> 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("mov", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("movk", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("movn", "1 = ~2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("movz", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("muf", "1 = 2 * 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("mul", "1 = 2 * 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("muls", "1 = 2 * 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("mvn", "1 = ~2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("neg", "1 = !2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("orr", "1 = 2 | 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("rmf", "1 = 2 % 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("sbc", "1 = 2 - 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("sqt", "1 = sqrt(2)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("stp", "3 = (1, 2)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("str", "2 = 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("strb", "2 = (byte) 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("strh", "2 = (half) 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("strh.w", "2 = (half) 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("stur", "2 = 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("sub", "1 = 2 - 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("subs", "1 = 2 - 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("swp", "swap(1, 2)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("sxtb", "1 = (char) 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("sxth", "1 = (short) 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("sxtw", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("tst", "if ((1 & 2) == 0)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("udf", "undefined 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("udiv", "1 = (unsigned) 2 / 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("vmov.i32", "1 = 2"),
    /* arm thumb */
    RZ_PSEUDO_DEFINE_GRAMMAR("lsl.w", "1 = 2 << 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("lsr.w", "1 = 2 >> 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("movs", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("movt", "1 |= 2 << #16"),
    RZ_PSEUDO_DEFINE_GRAMMAR("movw", "1 = 2"),
    RZ_PSEUDO_DEFINE_GRAMMAR("pop", "pop 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("pop.w", "pop 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("push", "push 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("push.w", "push 1"),
    RZ_PSEUDO_DEFINE_GRAMMAR("sub", "1 -= 2"), // THUMB
    RZ_PSEUDO_DEFINE_GRAMMAR("sub.w", "1 = 2 - 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("subs", "1 -= 2"), // THUMB
    RZ_PSEUDO_DEFINE_GRAMMAR("tst.w", "if ((1 & 2) == 0)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("vdiv.f64", "1 = (float) 2 / 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("vmov", "1 = (float) 2 . 3"),
    RZ_PSEUDO_DEFINE_GRAMMAR("vpop", "pop(1)"),
    RZ_PSEUDO_DEFINE_GRAMMAR("vpush", "push(1)"),
};
 
static const RzPseudoDirect arm_direct[] = {
    RZ_PSEUDO_DEFINE_DIRECT("beq lr", "if (? == ?) return"),
    RZ_PSEUDO_DEFINE_DIRECT("bx lr", "return"),
};
 
static const RzPseudoReplace arm_replace[] = {
    RZ_PSEUDO_DEFINE_REPLACE(" + 0]", "]", 0),
    RZ_PSEUDO_DEFINE_REPLACE("+ -", "- ", 1),
    RZ_PSEUDO_DEFINE_REPLACE("0 << 16", "0", 1),
    RZ_PSEUDO_DEFINE_REPLACE("{", "(", 1),
    RZ_PSEUDO_DEFINE_REPLACE("}", ")", 1),
};
 
static const RzPseudoConfig arm_config = RZ_PSEUDO_DEFINE_CONFIG(arm_direct, arm_lexicon, arm_replace, 5, arm_tokenize);
 
RzList *arm_tokenize(const char *assembly, size_t length) {
    size_t i, p;
    char *buf = NULL;
    const char *comma_replace = NULL;
    bool keep = false;
    RzList *tokens = NULL;
 
    buf = rz_str_ndup(assembly, length);
    if (!buf) {
        return NULL;
    }
 
    for (i = 0, p = 0; p < length; ++i, ++p) {
        if (buf[p] == ',') {
            if (!keep) {
                p++;
            } else if (buf[p + 1] == ' ') {
                buf[i] = buf[p];
                p++;
                continue;
            }
        } else if (buf[p] == '(') {
            buf[p] = ' ';
        } else if (buf[p] == ')') {
            buf[p] = ' ';
        } else if (buf[p] == '[') {
            keep = true;
            comma_replace = " + ";
        } else if (buf[p] == ']') {
            keep = false;
        } else if (buf[p] == '{') {
            if (strchr(buf + p + 1, ',') < strchr(buf + p + 1, '}')) {
                keep = true;
                comma_replace = ", ";
            } else {
                p++;
            }
        } else if (buf[p] == '}') {
            if (!comma_replace) {
                p++;
            }
            keep = false;
        } else if ((buf[p] == 'w' || buf[p] == 'x') && buf[p + 1] == 'z' && buf[p + 2] == 'r') {
            p += 2;
            buf[p] = '0';
        }
        if (p > i) {
            buf[i] = buf[p];
        }
    }
    buf[i] = 0;
 
    tokens = rz_str_split_duplist(buf, " ", true);
    free(buf);
    if (!tokens) {
        return NULL;
    }
 
    if (comma_replace) {
        RzListIter *it;
        rz_list_foreach (tokens, it, buf) {
            it->data = rz_str_replace(buf, ",", comma_replace, 1);
        }
    }
 
    return tokens;
}
 
static bool parse(RzParse *p, const char *assembly, RzStrBuf *sb) {
    return rz_pseudo_convert(&arm_config, assembly, sb);
}
 
static char *subs_var_string(RzParse *p, RzAnalysisVarField *var, char *tstr, const char *oldstr, const char *reg, int delta) {
    char *newstr = p->localvar_only
        ? rz_str_newf("%s", var->name)
        : rz_str_newf("%s %c %s", reg, delta > 0 ? '+' : '-', var->name);
    if (IS_UPPER(*tstr)) {
        char *space = strrchr(newstr, ' ');
        if (space) {
            *space = 0;
            rz_str_case(newstr, true);
            *space = ' ';
        }
    }
    char *ret = rz_str_replace(tstr, oldstr, newstr, 1);
    free(newstr);
    return ret;
}
 
static char *mount_oldstr(RzParse *p, const char *reg, st64 delta, bool ucase) {
    const char *tmplt;
    char *oldstr;
    if (delta > -10 && delta < 10) {
        if (p->pseudo) {
            char sign = '+';
            if (delta < 0) {
                sign = '-';
            }
            oldstr = rz_str_newf("%s %c %" PFMT64d, reg, sign, RZ_ABS(delta));
        } else {
            oldstr = rz_str_newf("%s, %" PFMT64d, reg, delta);
        }
    } else if (delta > 0) {
        tmplt = p->pseudo ? "%s + 0x%x" : (ucase ? "%s, 0x%X" : "%s, 0x%x");
        oldstr = rz_str_newf(tmplt, reg, delta);
    } else {
        tmplt = p->pseudo ? "%s - 0x%x" : (ucase ? "%s, -0x%X" : "%s, -0x%x");
        oldstr = rz_str_newf(tmplt, reg, -delta);
    }
    if (ucase) {
        char *comma = strchr(oldstr, ',');
        if (comma) {
            *comma = 0;
            rz_str_case(oldstr, true);
            *comma = ',';
        }
    }
    return oldstr;
}
 
static bool subvar(RzParse *p, RzAnalysisFunction *f, RzAnalysisOp *op, char *data, char *str, int len) {
    const ut64 addr = op->addr;
    const int oplen = op->size;
    RzList *spargs = NULL;
    RzList *bpargs = NULL;
    RzListIter *iter;
    RzAnalysis *analysis = p->analb.analysis;
    char *oldstr;
    char *tstr = strdup(data);
    if (!tstr) {
        return false;
    }
 
    if (!p->varlist) {
        free(tstr);
        return false;
    }
    if (p->subrel) {
        char *rip;
        if (p->pseudo) {
            rip = (char *)rz_str_casestr(tstr, "[pc +");
            if (!rip) {
                rip = (char *)rz_str_casestr(tstr, "[pc -");
            }
        } else {
            rip = (char *)rz_str_casestr(tstr, "[pc, ");
        }
 
        if (rip) {
            rip += 4;
            char *tstr_new, *ripend = strchr(rip, ']');
            const char *neg = strchr(rip, '-');
            ut64 off = (oplen == 2 || strstr(tstr, ".w") || strstr(tstr, ".W")) ? 4 : 8;
            ut64 repl_num = (addr + off) & ~3;
            if (!ripend) {
                ripend = "]";
            }
            const char *maybe_num = neg ? neg + 1 : rip;
            maybe_num = rz_str_trim_head_ro(maybe_num);
            if (rz_is_valid_input_num_value(NULL, maybe_num)) {
                if (neg) {
                    repl_num -= rz_num_get(NULL, maybe_num);
                } else {
                    repl_num += rz_num_get(NULL, maybe_num);
                }
                rip -= 3;
                *rip = 0;
                tstr_new = rz_str_newf("%s0x%08" PFMT64x "%s", tstr, repl_num, ripend);
                free(tstr);
                tstr = tstr_new;
            }
        }
    }
 
    bpargs = p->varlist(f, 'b');
    spargs = p->varlist(f, 's');
    bool ucase = IS_UPPER(*tstr);
    RzAnalysisVarField *var;
    rz_list_foreach (bpargs, iter, var) {
        st64 delta = p->get_ptr_at
            ? p->get_ptr_at(f, var->delta, addr)
            : ST64_MAX;
        if (delta == ST64_MAX && var->field) {
            delta = var->delta + f->bp_off;
        } else if (delta == ST64_MAX) {
            continue;
        }
        const char *reg = NULL;
        if (p->get_reg_at) {
            reg = p->get_reg_at(f, var->delta, addr);
        }
        if (!reg) {
            reg = analysis->reg->name[RZ_REG_NAME_BP];
        }
        oldstr = mount_oldstr(p, reg, delta, ucase);
        if (strstr(tstr, oldstr)) {
            tstr = subs_var_string(p, var, tstr, oldstr, reg, delta);
            free(oldstr);
            break;
        }
        free(oldstr);
    }
    rz_list_foreach (spargs, iter, var) {
        st64 delta = p->get_ptr_at
            ? p->get_ptr_at(f, var->delta, addr)
            : ST64_MAX;
        if (delta == ST64_MAX && var->field) {
            delta = var->delta;
        } else if (delta == ST64_MAX) {
            continue;
        }
        const char *reg = NULL;
        if (p->get_reg_at) {
            reg = p->get_reg_at(f, var->delta, addr);
        }
        if (!reg) {
            reg = analysis->reg->name[RZ_REG_NAME_SP];
        }
        oldstr = mount_oldstr(p, reg, delta, ucase);
        if (strstr(tstr, oldstr)) {
            tstr = subs_var_string(p, var, tstr, oldstr, reg, delta);
            free(oldstr);
            break;
        }
        free(oldstr);
    }
    rz_list_free(bpargs);
    rz_list_free(spargs);
    if (len > strlen(tstr)) {
        strcpy(str, tstr);
    } else {
        // TOO BIG STRING CANNOT REPLACE HERE
        free(tstr);
        return false;
    }
    free(tstr);
    return true;
}
 
RzParsePlugin rz_parse_plugin_arm_pseudo = {
    .name = "arm.pseudo",
    .desc = "ARM/ARM64 pseudo syntax",
    .parse = parse,
    .subvar = &subvar,
};
 
#ifndef RZ_PLUGIN_INCORE
RZ_API RzLibStruct rizin_plugin = {
    .type = RZ_LIB_TYPE_PARSE,
    .data = &rz_parse_plugin_arm_pseudo,
    .version = RZ_VERSION
};
#endif