Make finding the corresponding BasicBlock more robust. #3
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In a previous PR we modified the .llvm_bb_addr_map section, adding the original basic block index. This commit improves that code in two ways: 1) Catch the case where MachineBasicBlock::getBasicBlock() returns a null pointer. To quote the documentation: > Note that this may be NULL if this instance does not correspond > directly to an LLVM basic block. We use the block index u64::MAX to encode this condition (note that although the field in the section is uleb128, LLVM only allows block indices that fit in a u64). An upcoming change to yk will check for this condition at runtime. 2) Currently if a block isn't found, then the resulting block index is incorrect: The last index used in the loop is erroneously used.This commit causes an error at compile time instead.
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bors r+ |
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Build succeeded: |
ptersilie
reviewed
Jun 14, 2021
| for (auto It = F.begin(); It != F.end(); It++) { | ||
| const BasicBlock *BB = &*It; | ||
| if (BB == FindBB) { | ||
| found = true; |
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Surprised this wasn't caught by clang-format. Will need to look into that as it should flag the indentation.
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I think it's sometimes "best effort", although I agree, this one's a bit surprising!
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Are we running clang-format on the compiler itself? I didn't think so.
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Ah yes, you're right. Though I'm surprised they don't have a formatting test in one of their many checks.
ptersilie
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Aug 8, 2022
We experienced some deadlocks when we used multiple threads for logging using `scan-builds` intercept-build tool when we used multiple threads by e.g. logging `make -j16` ``` (gdb) bt #0 0x00007f2bb3aff110 in __lll_lock_wait () from /lib/x86_64-linux-gnu/libpthread.so.0 #1 0x00007f2bb3af70a3 in pthread_mutex_lock () from /lib/x86_64-linux-gnu/libpthread.so.0 #2 0x00007f2bb3d152e4 in ?? () #3 0x00007ffcc5f0cc80 in ?? () #4 0x00007f2bb3d2bf5b in ?? () from /lib64/ld-linux-x86-64.so.2 #5 0x00007f2bb3b5da27 in ?? () from /lib/x86_64-linux-gnu/libc.so.6 #6 0x00007f2bb3b5dbe0 in exit () from /lib/x86_64-linux-gnu/libc.so.6 #7 0x00007f2bb3d144ee in ?? () #8 0x746e692f706d742f in ?? () #9 0x692d747065637265 in ?? () #10 0x2f653631326b3034 in ?? () #11 0x646d632e35353532 in ?? () #12 0x0000000000000000 in ?? () ``` I think the gcc's exit call caused the injected `libear.so` to be unloaded by the `ld`, which in turn called the `void on_unload() __attribute__((destructor))`. That tried to acquire an already locked mutex which was left locked in the `bear_report_call()` call, that probably encountered some error and returned early when it forgot to unlock the mutex. All of these are speculation since from the backtrace I could not verify if frames 2 and 3 are in fact corresponding to the `libear.so` module. But I think it's a fairly safe bet. So, hereby I'm releasing the held mutex on *all paths*, even if some failure happens. PS: I would use lock_guards, but it's C. Reviewed-by: NoQ Differential Revision: https://reviews.llvm.org/D118439 (cherry picked from commit d919d02)
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Jan 25, 2023
When building/testing ASan inside the GCC tree on Solaris while using GNU `ld` instead of Solaris `ld`, a large number of tests SEGVs on both sparc and x86 like this: Thread 2 received signal SIGSEGV, Segmentation fault. [Switching to Thread 1 (LWP 1)] 0xfe014cfc in __sanitizer::atomic_load<__sanitizer::atomic_uintptr_t> (a=0xfc602a58, mo=__sanitizer::memory_order_acquire) at sanitizer_common/sanitizer_atomic_clang_x86.h:46 46 v = a->val_dont_use; 1: x/i $pc => 0xfe014cfc <_ZN11__sanitizer11atomic_loadINS_16atomic_uintptr_tEEENT_4TypeEPVKS2_NS_12memory_orderE+62>: mov (%eax),%eax (gdb) bt #0 0xfe014cfc in __sanitizer::atomic_load<__sanitizer::atomic_uintptr_t> (a=0xfc602a58, mo=__sanitizer::memory_order_acquire) at sanitizer_common/sanitizer_atomic_clang_x86.h:46 #1 0xfe0bd1d7 in __sanitizer::DTLS_NextBlock (cur=0xfc602a58) at sanitizer_common/sanitizer_tls_get_addr.cpp:53 #2 0xfe0bd319 in __sanitizer::DTLS_Find (id=1) at sanitizer_common/sanitizer_tls_get_addr.cpp:77 #3 0xfe0bd466 in __sanitizer::DTLS_on_tls_get_addr (arg_void=0xfeffd068, res=0xfe602a18, static_tls_begin=0, static_tls_end=0) at sanitizer_common/sanitizer_tls_get_addr.cpp:116 #4 0xfe063f81 in __interceptor___tls_get_addr (arg=0xfeffd068) at sanitizer_common/sanitizer_common_interceptors.inc:5501 #5 0xfe0a3054 in __sanitizer::CollectStaticTlsBlocks (info=0xfeffd108, size=40, data=0xfeffd16c) at sanitizer_common/sanitizer_linux_libcdep.cpp:366 #6 0xfe6ba9fa in dl_iterate_phdr () from /usr/lib/ld.so.1 #7 0xfe0a3132 in __sanitizer::GetStaticTlsBoundary (addr=0xfe608020, size=0xfeffd244, align=0xfeffd1b0) at sanitizer_common/sanitizer_linux_libcdep.cpp:382 #8 0xfe0a33f7 in __sanitizer::GetTls (addr=0xfe608020, size=0xfeffd244) at sanitizer_common/sanitizer_linux_libcdep.cpp:482 #9 0xfe0a34b1 in __sanitizer::GetThreadStackAndTls (main=true, stk_addr=0xfe608010, stk_size=0xfeffd240, tls_addr=0xfe608020, tls_size=0xfeffd244) at sanitizer_common/sanitizer_linux_libcdep.cpp:565 The address being accessed is unmapped. However, even when the tests `PASS` with Solaris `ld`, `ASAN_OPTIONS=verbosity=2` shows ==6582==__tls_get_addr: Can't guess glibc version Given that that the code is stricly `glibc`-specific according to `sanitizer_tls_get_addr.h`, there seems little point in using the interceptor on non-`glibc` targets. That's what this patch does. Tested on `i386-pc-solaris2.11` and `sparc-sun-solaris2.11` inside the GCC tree. Differential Revision: https://reviews.llvm.org/D141385
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In a previous PR we modified the
.llvm_bb_addr_mapsection, adding theorignial basic block index. This commit improves that code in two ways:
null pointer. To quote the documentation:
We use the block index u64::MAX to encode this condition (note that
although the field in the section is uleb128, LLVM only allows block
indices that fit in a u64).
An upcoming change to yk will check for this condition at runtime.
incorrect: The last index used in the loop is erroneously used.This
commit causes an error at compile time instead.