expr_error - handle precedence when pretty-printing expression.

sanity check the expression can reduce to a single value when parsing.
This commit is contained in:
Kelvin Sherlock 2017-01-17 19:47:19 -05:00
parent adafabd419
commit c08c84c593
1 changed files with 149 additions and 92 deletions

241
link.cpp
View File

@ -223,7 +223,145 @@ std::vector<symbol> symbols;
std::set<std::string> undefined_symbols;
inline std::string parenthesize(const std::string &s) {
std::string tmp;
tmp.push_back('(');
tmp.append(s);
tmp.push_back(')');
return tmp;
}
inline void expr_error(bool fatal, const expression &e, const char *msg) {
warnx("%s:%04x %s", sections[e.section].name.c_str(), e.offset, msg);
// pretty-print the expression...
bool underflow = false;
struct pair { std::string name; int precedence = 0; };
std::vector<pair> stack;
int p;
for (auto &x : e.stack) {
auto tag = x.tag;
switch(tag) {
case OP_VAL: {
p = 0;
char buffer[6];
snprintf(buffer, sizeof(buffer), "$%02x", x.value);
stack.emplace_back(pair{buffer, p});
break;
}
case OP_SYM: {
p = 0;
stack.emplace_back(pair{symbols[x.section].name, p});
break;
}
case OP_LOC: {
p = 0;
std::string tmp = sections[x.section].name;
if (x.value) {
char buffer[6];
snprintf(buffer, sizeof(buffer), "$%02x", x.value);
tmp.push_back('+');
tmp.append(buffer);
p = 3;
}
stack.emplace_back(pair{tmp, p});
break;
}
case OP_NOT:
case OP_NEG:
case OP_FLP: {
static const std::string ops[] = {
".NOT.", "-", "\\"
};
p = 0;
if (stack.empty()) {
underflow = true;
} else {
auto &back = stack.back();
if (p < back.precedence) {
back.name = parenthesize(back.name);
}
back.name = ops[tag - OP_UNA] + back.name;
back.precedence = p;
}
break;
}
case OP_EXP:
case OP_MUL:
case OP_DIV:
case OP_MOD:
case OP_SHR:
case OP_SHL:
case OP_ADD:
case OP_SUB:
case OP_AND:
case OP_OR:
case OP_XOR:
case OP_EQ:
case OP_GT:
case OP_LT:
case OP_UGT:
case OP_ULT: {
static const pair ops[] = {
{ "**", 1 },
{ "*", 2 },
{ "/", 2 },
{ ".MOD.", 2 },
{ ">>", 2 },
{ "<<", 2 },
{ "+", 3 },
{ "-", 3 },
{ "&", 4 },
{ "|", 5 },
{ "^", 5 },
{ "=", 6 },
{ ">", 6},
{ "<", 6},
{ ".UGT.", 6},
{ ".ULT.", 6 }
};
p = ops[tag - OP_BIN].precedence;
if (stack.size() < 2) {
underflow = true;
} else {
pair b = std::move(stack.back());
stack.pop_back();
pair &a = stack.back();
if (p < b.precedence) b.name = parenthesize(b.name);
if (p < a.precedence) a.name = parenthesize(a.name);
a.name += ops[tag - OP_BIN].name + b.name;
a.precedence = p;
}
break;
}
default:
fprintf(stderr, "Unrecognized expression op %02x\n", tag);
break;
}
}
if (stack.size() == 1) {
fprintf(stderr, "Expression: %s\n", stack.front().name.c_str());
} else if (stack.empty() || underflow) {
fprintf(stderr, "Expression underflow error.\n");
fatal = true;
} else {
fprintf(stderr, "Expression overflow error.\n");
fatal = true;
}
if (fatal) flags._errors++;
}
@ -456,6 +594,7 @@ void one_module(const std::vector<uint8_t> &data,
data_ptr->insert(data_ptr->end(), e.size, 0);
int reduced_size = 0;
/**/
for(;;) {
op = read_8(iter);
@ -463,11 +602,13 @@ void one_module(const std::vector<uint8_t> &data,
switch(op) {
case OP_VAL: {
reduced_size++;
uint32_t offset = read_32(iter);
e.stack.emplace_back(op, offset);
break;
}
case OP_SYM: {
reduced_size++;
uint16_t symbol = read_16(iter);
assert(symbol < local_symbols.size());
auto &s = local_symbols[symbol];
@ -492,6 +633,7 @@ void one_module(const std::vector<uint8_t> &data,
break;
}
case OP_LOC: {
reduced_size++;
uint8_t section = read_8(iter);
uint32_t offset = read_32(iter);
int real_section = remap_section[section];
@ -504,6 +646,8 @@ void one_module(const std::vector<uint8_t> &data,
case OP_NOT:
case OP_NEG:
case OP_FLP:
e.stack.emplace_back(op);
break;
// binary
case OP_EXP:
case OP_MUL:
@ -521,12 +665,17 @@ void one_module(const std::vector<uint8_t> &data,
case OP_LT:
case OP_UGT:
case OP_ULT:
reduced_size--;
e.stack.emplace_back(op);
break;
default:
assert(!"unsupported expression opcode.");
}
}
if (reduced_size != 1) {
expr_error(true, e, "Malformed expression");
}
sections[current_section].expressions.emplace_back(std::move(e));
break;
}
@ -677,98 +826,6 @@ inline bool in_range(int value, int low, int high) {
return value >= low && value <= high;
}
inline void expr_error(bool fatal, const expression &e, const char *msg) {
warnx("%s:%04x %s", sections[e.section].name.c_str(), e.offset, msg);
// pretty-print the expression...
bool underflow = false;
std::vector<std::string> stack;
for (auto &x : e.stack) {
auto tag = x.tag;
switch(tag) {
case OP_VAL: {
char buffer[6];
snprintf(buffer, sizeof(buffer), "$%02x", x.value);
stack.emplace_back(buffer);
break;
}
case OP_SYM: {
stack.emplace_back(symbols[x.section].name);
break;
}
case OP_LOC: {
std::string tmp = sections[x.section].name;
if (x.value) {
char buffer[6];
snprintf(buffer, sizeof(buffer), "$%02x", x.value);
tmp.push_back('+');
tmp.append(buffer);
}
stack.emplace_back(std::move(tmp));
break;
}
case OP_NOT:
case OP_NEG:
case OP_FLP: {
static const std::string ops[] = {
".NOT.", "-", "\\"
};
if (stack.empty()) {
underflow = true;
} else {
stack.back() = ops[tag - OP_UNA] + stack.back();
}
break;
}
case OP_EXP:
case OP_MUL:
case OP_DIV:
case OP_MOD:
case OP_SHR:
case OP_SHL:
case OP_ADD:
case OP_SUB:
case OP_AND:
case OP_OR:
case OP_XOR:
case OP_EQ:
case OP_GT:
case OP_LT:
case OP_UGT:
case OP_ULT: {
static const std::string ops[] = {
"**", "*", "/", ".MOD.", ">>", "<<", "+", "-", "&", "|", "^", "=", ">", "<", ">", "<"
};
if (stack.size() < 2) {
underflow = true;
} else {
std::string tmp = std::move(stack.back());
stack.pop_back();
stack.back() += ops[tag - OP_BIN] + tmp;
}
break;
}
default:
fprintf(stderr, "Unrecognized expression op %02x\n", tag);
break;
}
if (stack.size() == 1) {
fprintf(stderr, "Expression: %s\n", stack.front().c_str());
} else if (stack.empty() || underflow) {
fprintf(stderr, "Expression underflow error.\n");
fatal = true;
} else {
fprintf(stderr, "Expression overflow error.\n");
fatal = true;
}
}
if (fatal) flags._errors++;
}
void to_omf(const expression &e, omf::segment &seg) {
if (e.stack.empty() || e.size == 0) {
expr_error(false, e, "Expression empty");