[llvm] r231577 - Make the assertion macros in Verifier and Linter truly variadic.

[Duncan P. N. Exon Smith]

> On 2015 Mar 13, at 20:14, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
> 
> 
>> On 2015 Mar 7, at 13:15, Benjamin Kramer <benny.kra at googlemail.com> wrote:
>> 
>> Author: d0k
>> Date: Sat Mar  7 15:15:40 2015
>> New Revision: 231577
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=231577&view=rev
>> Log:
>> Make the assertion macros in Verifier and Linter truly variadic.
>> 
> 
> Nice cleanup!
> 
>> NFC.
> 
> Actually... (see below)
> 
>> 
>> Modified:
>>   llvm/trunk/lib/Analysis/Lint.cpp
>>   llvm/trunk/lib/IR/Verifier.cpp
>> 
>> Modified: llvm/trunk/lib/Analysis/Lint.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/Lint.cpp?rev=231577&r1=231576&r2=231577&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Analysis/Lint.cpp (original)
>> +++ llvm/trunk/lib/Analysis/Lint.cpp Sat Mar  7 15:15:40 2015
>> @@ -129,27 +129,26 @@ namespace {
>>    }
>>    void print(raw_ostream &O, const Module *M) const override {}
>> 
>> -    void WriteValue(const Value *V) {
>> -      if (!V) return;
>> -      if (isa<Instruction>(V)) {
>> -        MessagesStr << *V << '\n';
>> -      } else {
>> -        V->printAsOperand(MessagesStr, true, Mod);
>> -        MessagesStr << '\n';
>> +    void WriteValues(ArrayRef<const Value *> Vs) {
>> +      for (const Value *V : Vs) {
>> +        if (!V)
>> +          continue;
>> +        if (isa<Instruction>(V)) {
>> +          MessagesStr << *V << '\n';
>> +        } else {
>> +          V->printAsOperand(MessagesStr, true, Mod);
>> +          MessagesStr << '\n';
>> +        }
>>      }
>>    }
>> 
>>    // CheckFailed - A check failed, so print out the condition and the message
>>    // that failed.  This provides a nice place to put a breakpoint if you want
>>    // to see why something is not correct.
> 
> This is no longer true.  I was playing with a similar patch myself
> while I was on holiday -- strange timing -- and I noticed that
> `b CheckFailed` no longer works (at least, not in `lldb`).  The
> problem is that you need to specify `CheckFailed<...>` as the
> breakpoint target.
> 
> My workaround was to add a `CheckFailedMsg()` function:
> 
>    void CheckFailedMsg(const Twine &Message) {
>      MessagesStr << Message.str() << "\n";
>    }
> 
> and have `CheckFailed()` call it.  Then `CheckFailedMsg()` serves
> as a nice target for a breakpoint.
> 
> Any other ideas?

FTR, I noticed this with the Verifier, but I assume the same applies
to the Linter.

> 
>> -    void CheckFailed(const Twine &Message,
>> -                     const Value *V1 = nullptr, const Value *V2 = nullptr,
>> -                     const Value *V3 = nullptr, const Value *V4 = nullptr) {
>> -      MessagesStr << Message.str() << "\n";
>> -      WriteValue(V1);
>> -      WriteValue(V2);
>> -      WriteValue(V3);
>> -      WriteValue(V4);
>> +    template <typename... Ts>
>> +    void CheckFailed(const Twine &Message, const Ts &...Vs) {
>> +      MessagesStr << Message << '\n';
>> +      WriteValues({Vs...});
>>    }
>>  };
>>