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[ASan] Don't use large stack buffer for local variable name in stack frame description 

llvm-svn: 218827
This commit is contained in:
Alexey Samsonov 2014-10-01 21:28:54 +00:00
parent c3285a1ded
commit 1b42bde30d
1 changed files with 17 additions and 17 deletions
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34
compiler-rt/lib/asan/asan_report.cc
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@ -341,16 +341,15 @@ const char *ThreadNameWithParenthesis(u32 tid, char buff[],
return ThreadNameWithParenthesis(t, buff, buff_len);
}
void PrintAccessAndVarIntersection(const char *var_name,
uptr var_beg, uptr var_size,
uptr addr, uptr access_size,
uptr prev_var_end, uptr next_var_beg) {
uptr var_end = var_beg + var_size;
static void PrintAccessAndVarIntersection(const StackVarDescr &var, uptr addr,
uptr access_size, uptr prev_var_end,
uptr next_var_beg) {
uptr var_end = var.beg + var.size;
uptr addr_end = addr + access_size;
const char *pos_descr = 0;
// If the variable [var_beg, var_end) is the nearest variable to the
// If the variable [var.beg, var_end) is the nearest variable to the
// current memory access, indicate it in the log.
if (addr >= var_beg) {
if (addr >= var.beg) {
if (addr_end <= var_end)
pos_descr = "is inside"; // May happen if this is a use-after-return.
else if (addr < var_end)
@ -359,14 +358,20 @@ void PrintAccessAndVarIntersection(const char *var_name,
next_var_beg - addr_end >= addr - var_end)
pos_descr = "overflows";
} else {
if (addr_end > var_beg)
if (addr_end > var.beg)
pos_descr = "partially underflows";
else if (addr >= prev_var_end &&
addr - prev_var_end >= var_beg - addr_end)
addr - prev_var_end >= var.beg - addr_end)
pos_descr = "underflows";
}
InternalScopedString str(1024);
str.append(" [%zd, %zd) '%s'", var_beg, var_beg + var_size, var_name);
str.append(" [%zd, %zd)", var.beg, var_end);
// Render variable name.
str.append(" '");
for (uptr i = 0; i < var.name_len; ++i) {
str.append("%c", var.name_pos[i]);
}
str.append("'");
if (pos_descr) {
Decorator d;
// FIXME: we may want to also print the size of the access here,
@ -455,16 +460,11 @@ bool DescribeAddressIfStack(uptr addr, uptr access_size) {
Printf(" This frame has %zu object(s):\n", n_objects);
// Report all objects in this frame.
const uptr kBufSize = 4095;
char buf[kBufSize];
for (uptr i = 0; i < n_objects; i++) {
buf[0] = 0;
internal_strncat(buf, vars[i].name_pos,
static_cast<uptr>(Min(kBufSize, vars[i].name_len)));
uptr prev_var_end = i ? vars[i - 1].beg + vars[i - 1].size : 0;
uptr next_var_beg = i + 1 < n_objects ? vars[i + 1].beg : ~(0UL);
PrintAccessAndVarIntersection(buf, vars[i].beg, vars[i].size, access.offset,
access_size, prev_var_end, next_var_beg);
PrintAccessAndVarIntersection(vars[i], access.offset, access_size,
prev_var_end, next_var_beg);
}
Printf("HINT: this may be a false positive if your program uses "
"some custom stack unwind mechanism or swapcontext\n");