[llvm] r359559 - [TableGen] Fix null pointer dereferencing in token parser.

[Simon Pilgrim via llvm-commits]

Author: rksimon
Date: Tue Apr 30 06:09:55 2019
New Revision: 359559

URL: http://llvm.org/viewvc/llvm-project?rev=359559&view=rev
Log:
[TableGen] Fix null pointer dereferencing in token parser.

Reported in https://www.viva64.com/en/b/0629/

Modified:
    llvm/trunk/lib/TableGen/TGParser.cpp

Modified: llvm/trunk/lib/TableGen/TGParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/TableGen/TGParser.cpp?rev=359559&r1=359558&r2=359559&view=diff
==============================================================================
--- llvm/trunk/lib/TableGen/TGParser.cpp (original)
+++ llvm/trunk/lib/TableGen/TGParser.cpp Tue Apr 30 06:09:55 2019
@@ -2189,14 +2189,15 @@ Init *TGParser::ParseValue(Record *CurRe
       // Create a !strconcat() operation, first casting each operand to
       // a string if necessary.
       if (LHS->getType() != StringRecTy::get()) {
-        LHS = dyn_cast<TypedInit>(
+        auto CastLHS = dyn_cast<TypedInit>(
             UnOpInit::get(UnOpInit::CAST, LHS, StringRecTy::get())
                 ->Fold(CurRec));
-        if (!LHS) {
-          Error(PasteLoc, Twine("can't cast '") + LHS->getAsString() +
-                              "' to string");
+        if (!CastLHS) {
+          Error(PasteLoc,
+                Twine("can't cast '") + LHS->getAsString() + "' to string");
           return nullptr;
         }
+        LHS = CastLHS;
       }
 
       TypedInit *RHS = nullptr;
@@ -2223,14 +2224,15 @@ Init *TGParser::ParseValue(Record *CurRe
         }
 
         if (RHS->getType() != StringRecTy::get()) {
-          RHS = dyn_cast<TypedInit>(
+          auto CastRHS = dyn_cast<TypedInit>(
               UnOpInit::get(UnOpInit::CAST, RHS, StringRecTy::get())
                   ->Fold(CurRec));
-          if (!RHS) {
-            Error(PasteLoc, Twine("can't cast '") + RHS->getAsString() +
-                                "' to string");
+          if (!CastRHS) {
+            Error(PasteLoc,
+                  Twine("can't cast '") + RHS->getAsString() + "' to string");
             return nullptr;
           }
+          RHS = CastRHS;
         }
 
         break;