Apple-2-SW/merlin-utils
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add support for -D defines

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fix segfault (switch id to be 0-based)
handle absolute symbols
This commit is contained in:
Kelvin Sherlock 2019-12-10 21:39:51 -05:00
parent 43fd7a1b6e
commit debb2aebe9
1 changed files with 89 additions and 11 deletions
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98
link.cpp
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@ -1,11 +1,13 @@
/* c++17 */
#include <vector>
#include <unordered_map>
#include <algorithm>
#include <charconv>
#include <string>
#include <string_view>
#include <system_error>
#include <algorithm>
#include <unordered_map>
#include <utility>
#include <vector>
#include <cstdint>
#include <cassert>
@ -59,9 +61,9 @@ std::vector<omf::segment> segments;
symbol *find_symbol(const std::string &name) {
auto iter = symbol_map.find(name);
if (iter != symbol_map.end()) return &symbol_table[iter->second - 1];
if (iter != symbol_map.end()) return &symbol_table[iter->second];
unsigned id = symbol_table.size() + 1;
unsigned id = symbol_table.size();
symbol_map.emplace(name, id);
auto &rv = symbol_table.emplace_back();
@ -222,7 +224,7 @@ void process_reloc(byte_view &data, cookie &cookie) {
/* x = local symbol # */
pending_reloc r;
assert(x < cookie.remap.size());
r.id = cookie.remap[x]; /* label reference is 0-based */
r.id = cookie.remap[x];
r.size = size;
r.offset = offset;
r.value = value;
@ -326,9 +328,29 @@ void finalize(void) {
auto &seg = segments.back();
for (auto &r : relocations) {
assert(r.id <= symbol_map.size());
const auto &label = symbol_table[r.id];
r.value = label.value;
assert(r.id < symbol_map.size());
const auto &e = symbol_table[r.id];
/* if this is an absolute value, do the math */
if (!e.defined) {
warnx("%s is not defined", e.name.c_str());
continue;
}
if (e.absolute) {
uint32_t value = e.value + r.value;
value >>= -r.shift;
unsigned offset = r.offset;
unsigned size = r.size;
while (size--) {
seg.data[offset++] = value & 0xff;
value >>= 8;
}
continue;
}
r.value += e.value;
seg.relocs.emplace_back(r);
}
relocations.clear();
@ -360,12 +382,66 @@ void print_symbols(void) {
}
void usage(int ex) {
fputs("merlin-link [-o outfile] infile...\n", stderr);
exit(ex);
}
static void add_define(std::string str) {
/* -D key[=value]
value = 0x, $, % or base 10 */
uint32_t value = 0;
auto ix = str.find('=');
if (ix == 0) usage(EX_USAGE);
if (ix == str.npos) {
value = 1;
} else {
int base = 10;
auto pos = ++ix;
char c = str[pos]; /* returns 0 if == size */
switch(c) {
case '%':
base = 2; ++pos; break;
case '$':
base = 16; ++pos; break;
case '0':
c = str[pos+1];
if (c == 'x' || c == 'X') {
base = 16; pos += 2;
}
break;
}
auto end = str.data() + str.length();
auto r = std::from_chars(str.data() + pos, end, value, base);
if (r.ec != std::errc() || r.ptr != end)
usage(EX_USAGE);
str.resize(ix-1);
}
symbol *e = find_symbol(str);
if (e->defined && e->absolute && e->value == value) return;
if (e->defined) {
warnx("%s previously defined", str.c_str());
return;
}
e->defined = true;
e->absolute = true;
e->file = "-D";
e->value = value;
}
int main(int argc, char **argv) {
int c;
@ -374,13 +450,14 @@ int main(int argc, char **argv) {
bool compress = true;
while ((c = getopt(argc, argv, "o:XC")) != -1) {
while ((c = getopt(argc, argv, "o:D:XC")) != -1) {
switch(c) {
case 'o':
gs_out = optarg;
break;
case 'X': express = false; break;
case 'C': compress = false; break;
case 'D': add_define(optarg); break;
case ':':
case '?':
default:
@ -404,6 +481,7 @@ int main(int argc, char **argv) {
}
}
finalize();
print_symbols();
try {