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#include <atomic>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static void message(const char *msg) {
write(2, msg, strlen(msg));
}
static const int kMaxCallerPcs = 20;
static std::atomic<void *> caller_pcs[kMaxCallerPcs];
// Number of elements in caller_pcs. A special value of kMaxCallerPcs + 1 means
// that "too many errors" has already been reported.
static std::atomic<int> caller_pcs_sz;
__attribute__((noinline))
static bool report_this_error(void *caller) {
if (caller == nullptr) return false;
while (true) {
int sz = caller_pcs_sz.load(std::memory_order_relaxed);
if (sz > kMaxCallerPcs) return false; // early exit
// when sz==kMaxCallerPcs print "too many errors", but only when cmpxchg
// succeeds in order to not print it multiple times.
if (sz > 0 && sz < kMaxCallerPcs) {
void *p;
for (int i = 0; i < sz; ++i) {
p = caller_pcs[i].load(std::memory_order_relaxed);
if (p == nullptr) break; // Concurrent update.
if (p == caller) return false;
}
if (p == nullptr) continue; // FIXME: yield?
}
if (!caller_pcs_sz.compare_exchange_strong(sz, sz + 1))
continue; // Concurrent update! Try again from the start.
if (sz == kMaxCallerPcs) {
message("ubsan: too many errors\n");
return false;
}
caller_pcs[sz].store(caller, std::memory_order_relaxed);
return true;
}
}
#if defined(__ANDROID__)
extern "C" __attribute__((weak)) void android_set_abort_message(const char *);
static void abort_with_message(const char *msg) {
if (&android_set_abort_message) android_set_abort_message(msg);
abort();
}
#else
static void abort_with_message(const char *) { abort(); }
#endif
#define INTERFACE extern "C" __attribute__((visibility("default")))
// FIXME: add caller pc to the error message (possibly as "ubsan: error-type
// @1234ABCD").
#define HANDLER(name, msg) \
INTERFACE void __ubsan_handle_##name##_minimal() { \
if (!report_this_error(__builtin_return_address(0))) return; \
message("ubsan: " msg "\n"); \
} \
\
INTERFACE void __ubsan_handle_##name##_minimal_abort() { \
message("ubsan: " msg "\n"); \
abort_with_message("ubsan: " msg); \
}
HANDLER(type_mismatch, "type-mismatch")
HANDLER(add_overflow, "add-overflow")
HANDLER(sub_overflow, "sub-overflow")
HANDLER(mul_overflow, "mul-overflow")
HANDLER(negate_overflow, "negate-overflow")
HANDLER(divrem_overflow, "divrem-overflow")
HANDLER(shift_out_of_bounds, "shift-out-of-bounds")
HANDLER(out_of_bounds, "out-of-bounds")
HANDLER(builtin_unreachable, "builtin-unreachable")
HANDLER(missing_return, "missing-return")
HANDLER(vla_bound_not_positive, "vla-bound-not-positive")
HANDLER(float_cast_overflow, "float-cast-overflow")
HANDLER(load_invalid_value, "load-invalid-value")
HANDLER(invalid_builtin, "invalid-builtin")
HANDLER(function_type_mismatch, "function-type-mismatch")
HANDLER(nonnull_arg, "nonnull-arg")
HANDLER(nullability_arg, "nullability-arg")
HANDLER(pointer_overflow, "pointer-overflow")
HANDLER(cfi_check_fail, "cfi-check-fail")
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