[lld] r205332 - s/dyn_cast/cast/ where return value should never be null.

[David Blaikie]

On Tue, Apr 1, 2014 at 11:20 AM, Shankar Easwaran
<shankare at codeaurora.org> wrote:
> We should assert if dyn_cast fails, which would catch issues in the Driver.

That's what cast<T> is for - it asserts on failure.

dyn_cast cannot assert on failure - it's used for doing type tests "if
x = dyn_cast<T1>(a) { do stuff } else if (x = dyn_cast<T2>(b) { ...
}", etc.

>
>
> On 4/1/2014 1:04 PM, Rui Ueyama wrote:
>>
>> Author: ruiu
>> Date: Tue Apr  1 13:04:56 2014
>> New Revision: 205332
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=205332&view=rev
>> Log:
>> s/dyn_cast/cast/ where return value should never be null.
>>
>> cast<X> asserts the type is correct and does not return null on failure.
>> So we should use cast<X> rather than dyn_cast<X> at such places where we
>> don't expect type conversion could fail.
>>
>> Modified:
>>      lld/trunk/lib/Driver/GnuLdDriver.cpp
>>      lld/trunk/lib/Driver/WinLinkDriver.cpp
>>      lld/trunk/unittests/DriverTests/DriverTest.h
>>
>> Modified: lld/trunk/lib/Driver/GnuLdDriver.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/lib/Driver/GnuLdDriver.cpp?rev=205332&r1=205331&r2=205332&view=diff
>>
>> ==============================================================================
>> --- lld/trunk/lib/Driver/GnuLdDriver.cpp (original)
>> +++ lld/trunk/lib/Driver/GnuLdDriver.cpp Tue Apr  1 13:04:56 2014
>> @@ -432,13 +432,13 @@ bool GnuLdDriver::parse(int argc, const
>>       case OPT_start_group: {
>>         std::unique_ptr<InputElement> controlStart(new ELFGroup(*ctx,
>> index++));
>>         controlNodeStack.push(controlStart.get());
>> -
>> dyn_cast<ControlNode>(controlNodeStack.top())->processControlEnter();
>> +      cast<ControlNode>(controlNodeStack.top())->processControlEnter();
>>         inputGraph->addInputElement(std::move(controlStart));
>>         break;
>>       }
>>         case OPT_end_group:
>> -
>> dyn_cast<ControlNode>(controlNodeStack.top())->processControlExit();
>> +      cast<ControlNode>(controlNodeStack.top())->processControlExit();
>>         controlNodeStack.pop();
>>         break;
>>   @@ -485,11 +485,12 @@ bool GnuLdDriver::parse(int argc, const
>>           }
>>         }
>>         std::unique_ptr<InputElement> inputFile(inputNode);
>> -      if (controlNodeStack.empty())
>> +      if (controlNodeStack.empty()) {
>>           inputGraph->addInputElement(std::move(inputFile));
>> -      else
>> -        dyn_cast<ControlNode>(controlNodeStack.top())
>> +      } else {
>> +        cast<ControlNode>(controlNodeStack.top())
>>               ->processInputElement(std::move(inputFile));
>> +      }
>>         break;
>>       }
>>
>> Modified: lld/trunk/lib/Driver/WinLinkDriver.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/lib/Driver/WinLinkDriver.cpp?rev=205332&r1=205331&r2=205332&view=diff
>>
>> ==============================================================================
>> --- lld/trunk/lib/Driver/WinLinkDriver.cpp (original)
>> +++ lld/trunk/lib/Driver/WinLinkDriver.cpp Tue Apr  1 13:04:56 2014
>> @@ -1222,7 +1222,7 @@ bool WinLinkDriver::parse(int argc, cons
>>     // constructed by replacing an extension of the first input file
>>     // with ".exe".
>>     if (ctx.outputPath().empty()) {
>> -    StringRef path = *dyn_cast<FileNode>(&*files[0])->getPath(ctx);
>> +    StringRef path = *cast<FileNode>(&*files[0])->getPath(ctx);
>>       ctx.setOutputPath(replaceExtension(ctx, path, ".exe"));
>>     }
>>
>> Modified: lld/trunk/unittests/DriverTests/DriverTest.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/unittests/DriverTests/DriverTest.h?rev=205332&r1=205331&r2=205332&view=diff
>>
>> ==============================================================================
>> --- lld/trunk/unittests/DriverTests/DriverTest.h (original)
>> +++ lld/trunk/unittests/DriverTests/DriverTest.h Tue Apr  1 13:04:56 2014
>> @@ -35,7 +35,7 @@ protected:
>>     std::string inputFile(int index) {
>>       const InputElement &inputElement =
>> linkingContext()->inputGraph()[index];
>>       if (inputElement.kind() == InputElement::Kind::File)
>> -      return
>> *dyn_cast<FileNode>(&inputElement)->getPath(*linkingContext());
>> +      return *cast<FileNode>(&inputElement)->getPath(*linkingContext());
>>       llvm_unreachable("not handling other types of input files");
>>     }
>>
>>
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>>
>
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