Rename DEBUG macro to LLVM_DEBUG.
    
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index ead9f0b..52c027b 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -824,8 +824,8 @@
 
     if (CC_RISCV(MF.getDataLayout(), i, ArgVT, ArgVT, CCValAssign::Full,
                  ArgFlags, CCInfo, /*IsRet=*/true, IsRet, ArgTy)) {
-      DEBUG(dbgs() << "InputArg #" << i << " has unhandled type "
-                   << EVT(ArgVT).getEVTString() << '\n');
+      LLVM_DEBUG(dbgs() << "InputArg #" << i << " has unhandled type "
+                        << EVT(ArgVT).getEVTString() << '\n');
       llvm_unreachable(nullptr);
     }
   }
@@ -844,8 +844,8 @@
 
     if (CC_RISCV(MF.getDataLayout(), i, ArgVT, ArgVT, CCValAssign::Full,
                  ArgFlags, CCInfo, Outs[i].IsFixed, IsRet, OrigTy)) {
-      DEBUG(dbgs() << "OutputArg #" << i << " has unhandled type "
-                   << EVT(ArgVT).getEVTString() << "\n");
+      LLVM_DEBUG(dbgs() << "OutputArg #" << i << " has unhandled type "
+                        << EVT(ArgVT).getEVTString() << "\n");
       llvm_unreachable(nullptr);
     }
   }