AMDGPU/SI: Don't crash on anonymous GlobalValues

Summary:
We need to call AsmPrinter::getNameWithPrefix() in order to handle
anonymous GlobalValues (e.g. @0, @1).

Reviewers: arsenm, b-sumner

Subscribers: arsenm, kzhuravl, wdng, nhaehnle, yaxunl, tony-tye, llvm-commits

Differential Revision: https://reviews.llvm.org/D24865

llvm-svn: 282420
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUMCInstLower.h b/llvm/lib/Target/AMDGPU/AMDGPUMCInstLower.h
index b3008c3..2ea58e4 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUMCInstLower.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUMCInstLower.h
@@ -13,6 +13,7 @@
 namespace llvm {
 
 class AMDGPUSubtarget;
+class AsmPrinter;
 class MachineInstr;
 class MCContext;
 class MCInst;
@@ -20,9 +21,11 @@
 class AMDGPUMCInstLower {
   MCContext &Ctx;
   const AMDGPUSubtarget &ST;
+  const AsmPrinter ≈
 
 public:
-  AMDGPUMCInstLower(MCContext &ctx, const AMDGPUSubtarget &ST);
+  AMDGPUMCInstLower(MCContext &ctx, const AMDGPUSubtarget &ST,
+                    const AsmPrinter &AP);
 
   /// \brief Lower a MachineInstr to an MCInst
   void lower(const MachineInstr *MI, MCInst &OutMI) const;