45b8a741fb
This is a follow-up for D70378 (Cover usage of LLD as a library). While debugging an intermittent failure on a bot, I recalled this scenario which causes the issue: 1.When executing lld/test/ELF/invalid/symtab-sh-info.s L45, we reach lld:🧝:Obj-File::ObjFile() which goes straight into its base ELFFileBase(), then ELFFileBase::init(). 2.At that point fatal() is thrown in lld/ELF/InputFiles.cpp L381, leaving a half-initialized ObjFile instance. 3.We then end up in lld::exitLld() and since we are running with LLD_IN_TEST, we hapily restore the control flow to CrashRecoveryContext::RunSafely() then back in lld::safeLldMain(). 4.Before this patch, we called errorHandler().reset() just after, and this attempted to reset the associated SpecificAlloc<ObjFile<ELF64LE>>. That tried to free the half-initialized ObjFile instance, and more precisely its ObjFile::dwarf member. Sometimes that worked, sometimes it failed and was catched by the CrashRecoveryContext. This scenario was the reason we called errorHandler().reset() through a CrashRecoveryContext. But in some rare cases, the above repro somehow corrupted the heap, creating a stack overflow. When the CrashRecoveryContext's filter (that is, __except (ExceptionFilter(GetExceptionInformation()))) tried to handle the exception, it crashed again since the stack was exhausted -- and that took the whole application down. That is the issue seen on the bot. Locally it happens about 1 times out of 15. Now this situation can happen anywhere in LLD. Since catching stack overflows is not a reliable scenario ATM when using CrashRecoveryContext, we're now preventing further re-entrance when such failures occur, by signaling lld::SafeReturn::canRunAgain=false. When running with LLD_IN_TEST=2 (or above), only one iteration will be executed, instead of two. Differential Revision: https://reviews.llvm.org/D88348
14 lines
461 B
ArmAsm
14 lines
461 B
ArmAsm
# REQUIRES: x86
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# RUN: %python %p/Inputs/def-many.py 65535 > %t-65535.def
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# RUN: %python %p/Inputs/def-many.py 65536 > %t-65536.def
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# RUN: llvm-mc -triple x86_64-win32 %s -filetype=obj -o %t.obj
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# RUN: lld-link -dll -noentry %t.obj -out:%t.dll -def:%t-65535.def
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# RUN: env LLD_IN_TEST=1 not lld-link -dll -noentry %t.obj -out:%t.dll -def:%t-65536.def 2>&1 | FileCheck %s
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# CHECK: error: too many exported symbols
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.text
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.globl f
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f:
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ret
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