From c9456ca64c102516744deb4ba9b0790aea6b5c0a Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Thu, 9 Oct 2003 20:41:16 +0000
Subject: [PATCH] Change getConstantValue to throw an exception on error, not
 return null

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8988 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Bytecode/Reader/ConstantReader.cpp | 12 +++---------
 lib/Bytecode/Reader/Reader.cpp         |  5 ++++-
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/lib/Bytecode/Reader/ConstantReader.cpp b/lib/Bytecode/Reader/ConstantReader.cpp
index 4b6e998fed1..2689362fea6 100644
--- a/lib/Bytecode/Reader/ConstantReader.cpp
+++ b/lib/Bytecode/Reader/ConstantReader.cpp
@@ -165,9 +165,7 @@ Constant *BytecodeParser::parseConstantValue(const unsigned char *&Buf,
                 << ArgValSlot << "\n");
       
       // Get the arg value from its slot if it exists, otherwise a placeholder
-      Constant *C = getConstantValue(ArgTy, ArgValSlot);
-      if (C == 0) throw std::string("No arg value or placeholder found.");
-      ArgVec.push_back(C);
+      ArgVec.push_back(getConstantValue(ArgTy, ArgValSlot));
     }
     
     // Construct a ConstantExpr of the appropriate kind
@@ -241,9 +239,7 @@ Constant *BytecodeParser::parseConstantValue(const unsigned char *&Buf,
     while (NumElements--) {   // Read all of the elements of the constant.
       unsigned Slot;
       if (read_vbr(Buf, EndBuf, Slot)) throw Error_readvbr;
-      Constant *C = getConstantValue(AT->getElementType(), Slot);
-      if (!C) throw std::string("Unable to get const value of array slot.");
-      Elements.push_back(C);
+      Elements.push_back(getConstantValue(AT->getElementType(), Slot));
     }
     return ConstantArray::get(AT, Elements);
   }
@@ -256,9 +252,7 @@ Constant *BytecodeParser::parseConstantValue(const unsigned char *&Buf,
     for (unsigned i = 0; i < ET.size(); ++i) {
       unsigned Slot;
       if (read_vbr(Buf, EndBuf, Slot)) throw Error_readvbr;
-      Constant *C = getConstantValue(ET[i], Slot);
-      if (!C) throw std::string("Could not read const value in struct slot.");
-      Elements.push_back(C);
+      Elements.push_back(getConstantValue(ET[i], Slot));
     }
 
     return ConstantStruct::get(ST, Elements);
diff --git a/lib/Bytecode/Reader/Reader.cpp b/lib/Bytecode/Reader/Reader.cpp
index c515c1575c5..bf2b0118a35 100644
--- a/lib/Bytecode/Reader/Reader.cpp
+++ b/lib/Bytecode/Reader/Reader.cpp
@@ -164,7 +164,10 @@ BasicBlock *BytecodeParser::getBasicBlock(unsigned ID) {
 ///
 Constant *BytecodeParser::getConstantValue(const Type *Ty, unsigned Slot) {
   if (Value *V = getValue(Ty, Slot, false))
-    return dyn_cast<Constant>(V);      // If we already have the value parsed...
+    if (Constant *C = dyn_cast<Constant>(V))
+      return C;   // If we already have the value parsed, just return it
+    else
+      throw std::string("Reference of a value is expected to be a constant!");
 
   std::pair<const Type*, unsigned> Key(Ty, Slot);
   GlobalRefsType::iterator I = GlobalRefs.lower_bound(Key);