Add back the capability to include nul characters in strings with

GetConstantStringInfo.  This will hopefully restore llvm-gcc to 
happy bootstrap land.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52851 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 14 insertions, 8 deletions

diff --git a/include/llvm/Analysis/ValueTracking.h b/include/llvm/Analysis/ValueTracking.h
index 22a605d..1003269 100644
--- a/include/llvm/Analysis/ValueTracking.h
+++ b/include/llvm/Analysis/ValueTracking.h
@@ -76,8 +76,12 @@ namespace llvm {
   
   /// GetConstantStringInfo - This function computes the length of a
   /// null-terminated C string pointed to by V.  If successful, it returns true
-  /// and returns the string in Str.  If unsuccessful, it returns false.
-  bool GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset = 0);
+  /// and returns the string in Str.  If unsuccessful, it returns false.  If
+  /// StopAtNul is set to true (the default), the returned string is truncated
+  /// by a nul character in the global.  If StopAtNul is false, the nul
+  /// character is included in the result string.
+  bool GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset = 0,
+                             bool StopAtNul = true);
 } // end namespace llvm
 
 #endif
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index c804891..e7e291f 100644
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -935,13 +935,14 @@ Value *llvm::FindInsertedValue(Value *V, const unsigned *idx_begin,
 /// GetConstantStringInfo - This function computes the length of a
 /// null-terminated C string pointed to by V.  If successful, it returns true
 /// and returns the string in Str.  If unsuccessful, it returns false.
-bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset) {
+bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset,
+                                 bool StopAtNul) {
   // If V is NULL then return false;
   if (V == NULL) return false;
 
   // Look through bitcast instructions.
   if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
-    return GetConstantStringInfo(BCI->getOperand(0), Str, Offset);
+    return GetConstantStringInfo(BCI->getOperand(0), Str, Offset, StopAtNul);
   
   // If the value is not a GEP instruction nor a constant expression with a
   // GEP instruction, then return false because ConstantArray can't occur
@@ -951,7 +952,7 @@ bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset) {
     GEP = GEPI;
   } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
     if (CE->getOpcode() == Instruction::BitCast)
-      return GetConstantStringInfo(CE->getOperand(0), Str, Offset);
+      return GetConstantStringInfo(CE->getOperand(0), Str, Offset, StopAtNul);
     if (CE->getOpcode() != Instruction::GetElementPtr)
       return false;
     GEP = CE;
@@ -982,7 +983,8 @@ bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset) {
       StartIdx = CI->getZExtValue();
     else
       return false;
-    return GetConstantStringInfo(GEP->getOperand(0), Str, StartIdx+Offset);
+    return GetConstantStringInfo(GEP->getOperand(0), Str, StartIdx+Offset,
+                                 StopAtNul);
   }
   
   // The GEP instruction, constant or instruction, must reference a global
@@ -1020,7 +1022,7 @@ bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset) {
     ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
     if (!CI) // This array isn't suitable, non-int initializer.
       return false;
-    if (CI->isZero())
+    if (StopAtNul && CI->isZero())
       return true; // we found end of string, success!
     Str += (char)CI->getZExtValue();
   }
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 65d2d6b..717ad34 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2594,7 +2594,7 @@ static bool isMemSrcFromString(SDOperand Src, std::string &Str,
     return false;
 
   GlobalVariable *GV = dyn_cast<GlobalVariable>(G->getGlobal());
-  if (GV && GetConstantStringInfo(GV, Str)) {
+  if (GV && GetConstantStringInfo(GV, Str, SrcDelta, false)) {
     SrcOff += SrcDelta;
     return true;
   }