[llvm-commits] [llvm] r123297 - /llvm/trunk/lib/Target/ARM/ARMMCCodeEmitter.cpp

[Nick Lewycky]

On 11 January 2011 17:47, Chris Lattner <clattner at apple.com> wrote:

>
> On Jan 11, 2011, at 5:42 PM, Matt Beaumont-Gay wrote:
>
> > Author: matthewbg
> > Date: Tue Jan 11 19:42:42 2011
> > New Revision: 123297
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=123297&view=rev
> > Log:
> > Prefer llvm_unreachable to assert(0)
>
> Hi Matt,
>
> Please use assert(0) unless we need the "does not fallthrough" behavior of
> llvm_unreachable.
>

The difference is that llvm_unreachable still generates code in a Release
build while assert() doesn't, right?

Matt made this commit because we were seeing:

  llvm/lib/Target/ARM/ARMMCCodeEmitter.cpp:653: error: control reaches end
of non-void function [-Wreturn-type]

so it sounds like llvm_unreachable isn't the right tool, but we'd like to
fix this that doesn't generate warnings in release builds.

Nick


>
> -Chris
>
> >
> > Modified:
> >    llvm/trunk/lib/Target/ARM/ARMMCCodeEmitter.cpp
> >
> > Modified: llvm/trunk/lib/Target/ARM/ARMMCCodeEmitter.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMMCCodeEmitter.cpp?rev=123297&r1=123296&r2=123297&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Target/ARM/ARMMCCodeEmitter.cpp (original)
> > +++ llvm/trunk/lib/Target/ARM/ARMMCCodeEmitter.cpp Tue Jan 11 19:42:42
> 2011
> > @@ -129,7 +129,7 @@
> >                                SmallVectorImpl<MCFixup> &Fixups) const {
> >     ARM_AM::AMSubMode Mode =
> (ARM_AM::AMSubMode)MI.getOperand(OpIdx).getImm();
> >     switch (Mode) {
> > -    default: assert(0 && "Unknown addressing sub-mode!");
> > +    default: llvm_unreachable("Unknown addressing sub-mode!");
> >     case ARM_AM::da: return 0;
> >     case ARM_AM::ia: return 1;
> >     case ARM_AM::db: return 2;
> > @@ -648,7 +648,7 @@
> >   switch (Expr->getKind()) {
> >   case MCExpr::SymbolRef: return false;
> >   case MCExpr::Binary: return true;
> > -  default: assert(0 && "Unexpected expression type");
> > +  default: llvm_unreachable("Unexpected expression type");
> >   }
> > }
> >
> > @@ -669,7 +669,7 @@
> >     const MCExpr *OrigExpr = MO.getExpr();
> >     MCFixupKind Kind;
> >     switch (Expr->getKind()) {
> > -    default: assert(0 && "Unsupported ARMFixup");
> > +    default: llvm_unreachable("Unsupported ARMFixup");
> >     case MCSymbolRefExpr::VK_ARM_HI16:
> >       Kind = MCFixupKind(ARM::fixup_arm_movt_hi16);
> >       if (EvaluateAsPCRel(OrigExpr))
> >
> >
> > _______________________________________________
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>
>
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