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fix: make the stack handling more robust to sanitizers and -O3 (#6143)

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This PR should make lean better-behaved around sanitizers, per
https://github.com/google/sanitizers/issues/1688.
As far as I can tell,
https://github.com/google/sanitizers/wiki/AddressSanitizerUseAfterReturn#algorithm
replaces local variables with heap allocations, and so taking the
address of a local is not effective at producing a monotonic measure of
stack usage.

The approach used here is the same as the one used by clang.
This commit is contained in:
Eric Wieser 2024-11-22 15:10:20 +00:00 • committed by GitHub
parent 1126407d9b
commit 5adcd520fa
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1 changed files with 20 additions and 6 deletions
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26
src/runtime/stackinfo.cpp
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@ -73,6 +73,23 @@ size_t get_stack_size(bool main) {
}
#endif
#ifndef __has_builtin
#define __has_builtin(x) 0 /* for non-clang compilers */
#endif
// taken from https://github.com/llvm/llvm-project/blob/llvmorg-10.0.0-rc1/clang/lib/Basic/Stack.cpp#L24
static void *get_stack_pointer() {
#if __GNUC__ || __has_builtin(__builtin_frame_address)
return __builtin_frame_address(0);
#elif defined(_MSC_VER)
return _AddressOfReturnAddress();
#else
char x = 0;
char *volatile ptr = &x;
return ptr;
#endif
}
LEAN_THREAD_VALUE(bool, g_stack_info_init, false);
LEAN_THREAD_VALUE(size_t, g_stack_size, 0);
LEAN_THREAD_VALUE(size_t, g_stack_base, 0);
@ -81,8 +98,7 @@ LEAN_THREAD_VALUE(size_t, g_stack_threshold, 0);
void save_stack_info(bool main) {
g_stack_info_init = true;
g_stack_size = get_stack_size(main);
char x;
g_stack_base = reinterpret_cast<size_t>(&x);
g_stack_base = reinterpret_cast<size_t>(get_stack_pointer());
/* g_stack_threshold is a redundant value used to optimize check_stack */
g_stack_threshold = g_stack_base + LEAN_STACK_BUFFER_SPACE - g_stack_size;
if (g_stack_threshold > g_stack_base + LEAN_STACK_BUFFER_SPACE) {
@ -92,8 +108,7 @@ void save_stack_info(bool main) {
}
size_t get_used_stack_size() {
char y;
size_t curr_stack = reinterpret_cast<size_t>(&y);
size_t curr_stack = reinterpret_cast<size_t>(get_stack_pointer());
return g_stack_base - curr_stack;
}
@ -113,8 +128,7 @@ void throw_stack_space_exception(char const * component_name) {
void check_stack(char const * component_name) {
if (!g_stack_info_init)
save_stack_info(false);
char y;
size_t curr_stack = reinterpret_cast<size_t>(&y);
size_t curr_stack = reinterpret_cast<size_t>(get_stack_pointer());
if (curr_stack < g_stack_threshold)
throw_stack_space_exception(component_name);
}