Strange LLVM behavior after commit r193719

[Michael Kruse]

Quick fix patch


2013/11/13 Michael Kruse <llvm-commits at meinersbur.de>

> Hi Ilia,
>
> you are right, verifying the whole module when only verification of the
> Module is requested is not desirable. My path however prevented crashing
> the verifier in presence of debug infos, even less desirable. Given that
> Verifier is a FunctionPass, letting it do module-level verification seems
> counter-intuitive. I suggest the following solutions:
>
> 1. Quick fix: Remove the call to doFinalization in verifyFunction(), keep
> the doInitialization.Skips most of the module-level verifications.
>
> 2. Better: Introduce a new ModuleVerifier pass and move the module-level
> verifications there.
>
> Michael
>
>
>
>
>
>
>
> 2013/11/13 Dmitry Babokin <babokin at gmail.com>
>
>> Adding llvm-commits alias.
>>
>>
>> On Tue, Nov 12, 2013 at 2:05 PM, Ilia Filippov <ili.filippov at gmail.com>wrote:
>>
>>> Hi Michael,
>>>
>>> Looks like your recent commit (r193719) has undesired / not intended
>>> side effect. Doing *function* verification we end up verifying module's
>>> global values.
>>> Here's a call stack, which leads to such behavior:
>>>
>>> #0  ::Verifier::doFinalization (this=0x490c110, M=...) at
>>> lib/IR/Verifier.cpp:199
>>> #1  llvm::FPPassManager::doFinalization (this=0x490bf60, M=...) at
>>> lib/IR/LegacyPassManager.cpp:1576
>>> #2  llvm::legacy::FunctionPassManagerImpl::doFinalization
>>> (this=0x490bc60, M=...) at lib/IR/LegacyPassManager.cpp:1448
>>> #3  llvm::legacy::FunctionPassManager::doFinalization
>>> (this=0x7fffffffd100) at lib/IR/LegacyPassManager.cpp:1420
>>> #4  llvm::verifyFunction (f=..., action=llvm::ReturnStatusAction) at
>>> lib/IR/Verifier.cpp:2405
>>>
>>> Where #4 is in the function verifyFunction, that you've modified, and #0
>>> contains the loop over all module global values:
>>>
>>>     bool doFinalization(Module &M) {
>>>       // Scan through, checking all of the external function's linkage
>>> now...
>>>       for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
>>>         visitGlobalValue(*I);
>>>         <...>
>>>
>>> So you call a part of whole module verification inside function
>>> verification routine. This seems to be incorrect first of all (and leads to
>>> fails in our project based on LLVM, for example) and also inefficient
>>> (doing the same module walk for each function).
>>>
>>> Any thoughts how to fix it?
>>>
>>> Thanks!
>>>
>>> Ilia.
>>>
>>
>>
>
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