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[sanitizer] Fall back to fast unwinder 

`-fno-exceptions -fno-asynchronous-unwind-tables` compiled programs don't
produce .eh_frame on Linux and other ELF platforms, so the slow unwinder cannot
print stack traces. Just fall back to the fast unwinder: this allows
-fno-asynchronous-unwind-tables without requiring the sanitizer option
`fast_unwind_on_fatal=1`

Reviewed By: #sanitizers, vitalybuka

Differential Revision: https://reviews.llvm.org/D102046
This commit is contained in:
Fangrui Song 2021-05-14 12:27:33 -07:00
parent 4901199f5b
commit fa27255d16
2 changed files with 40 additions and 2 deletions
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7
compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_libcdep.cpp
View File

@ -82,12 +82,15 @@ void BufferedStackTrace::Unwind(u32 max_depth, uptr pc, uptr bp, void *context,
UnwindSlow(pc, context, max_depth);
else
UnwindSlow(pc, max_depth);
// If there are too few frames, the program may be built with
// -fno-asynchronous-unwind-tables. Fall back to fast unwinder below.
if (size > 2)
return;
#else
UNREACHABLE("slow unwind requested but not available");
#endif
} else {
UnwindFast(pc, bp, stack_top, stack_bottom, max_depth);
}
UnwindFast(pc, bp, stack_top, stack_bottom, max_depth);
}
static int GetModuleAndOffsetForPc(uptr pc, char *module_name,

35
compiler-rt/test/sanitizer_common/TestCases/Linux/symbolize_stack_fp.cpp Normal file
View File

@ -0,0 +1,35 @@
/// When the main program doesn't use .eh_frame, the slow unwinder does not work.
/// Test that we can fall back to the fast unwinder.
// RUN: %clangxx -O0 -g1 -fno-exceptions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer %s -o %t
// RUN: llvm-readelf -S %t | FileCheck %s --check-prefix=SEC
// RUN: %run %t 2>&1 | FileCheck %s
/// No .eh_frame && -g => .debug_frame
// SEC: .debug_frame
#include <sanitizer/common_interface_defs.h>
#include <vector>
template <int N>
struct A {
template <class T>
void RecursiveTemplateFunction(const T &t);
};
template <int N>
template <class T>
__attribute__((noinline)) void A<N>::RecursiveTemplateFunction(const T &) {
std::vector<T> t;
return A<N - 1>().RecursiveTemplateFunction(t);
}
template <>
template <class T>
__attribute__((noinline)) void A<0>::RecursiveTemplateFunction(const T &) {
__sanitizer_print_stack_trace();
}
int main() {
// CHECK: {{vector<.*vector<.*vector<.*vector<.*vector<}}
A<10>().RecursiveTemplateFunction(0);
}