[llvm] r253323 - [AliasAnalysis] CatchPad and CatchRet can modify escaped memory

[David Majnemer via llvm-commits]

Author: majnemer
Date: Tue Nov 17 02:15:14 2015
New Revision: 253323

URL: http://llvm.org/viewvc/llvm-project?rev=253323&view=rev
Log:
[AliasAnalysis] CatchPad and CatchRet can modify escaped memory

CatchPad and CatchRet behave a lot like function calls: they can
potentially modify any memory which has been escaped.

Modified:
    llvm/trunk/include/llvm/Analysis/AliasAnalysis.h
    llvm/trunk/lib/Analysis/AliasAnalysis.cpp

Modified: llvm/trunk/include/llvm/Analysis/AliasAnalysis.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/AliasAnalysis.h?rev=253323&r1=253322&r2=253323&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/AliasAnalysis.h (original)
+++ llvm/trunk/include/llvm/Analysis/AliasAnalysis.h Tue Nov 17 02:15:14 2015
@@ -421,6 +421,26 @@ public:
     return getModRefInfo(I, MemoryLocation(P, Size));
   }
 
+  /// getModRefInfo (for catchpads) - Return information about whether
+  /// a particular catchpad modifies or reads the specified memory location.
+  ModRefInfo getModRefInfo(const CatchPadInst *I, const MemoryLocation &Loc);
+
+  /// getModRefInfo (for catchpads) - A convenience wrapper.
+  ModRefInfo getModRefInfo(const CatchPadInst *I, const Value *P,
+                           uint64_t Size) {
+    return getModRefInfo(I, MemoryLocation(P, Size));
+  }
+
+  /// getModRefInfo (for catchrets) - Return information about whether
+  /// a particular catchret modifies or reads the specified memory location.
+  ModRefInfo getModRefInfo(const CatchReturnInst *I, const MemoryLocation &Loc);
+
+  /// getModRefInfo (for catchrets) - A convenience wrapper.
+  ModRefInfo getModRefInfo(const CatchReturnInst *I, const Value *P,
+                           uint64_t Size) {
+    return getModRefInfo(I, MemoryLocation(P, Size));
+  }
+
   /// Check whether or not an instruction may read or write memory (without
   /// regard to a specific location).
   ///
@@ -461,6 +481,10 @@ public:
       return getModRefInfo((const AtomicRMWInst*)I, Loc);
     case Instruction::Call:   return getModRefInfo((const CallInst*)I,  Loc);
     case Instruction::Invoke: return getModRefInfo((const InvokeInst*)I,Loc);
+    case Instruction::CatchPad:
+      return getModRefInfo((const CatchPadInst *)I, Loc);
+    case Instruction::CatchRet:
+      return getModRefInfo((const CatchReturnInst *)I, Loc);
     default:
       return MRI_NoModRef;
     }

Modified: llvm/trunk/lib/Analysis/AliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/AliasAnalysis.cpp?rev=253323&r1=253322&r2=253323&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/AliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/AliasAnalysis.cpp Tue Nov 17 02:15:14 2015
@@ -247,6 +247,32 @@ ModRefInfo AAResults::getModRefInfo(cons
   return MRI_ModRef;
 }
 
+ModRefInfo AAResults::getModRefInfo(const CatchPadInst *CatchPad,
+                                    const MemoryLocation &Loc) {
+  if (Loc.Ptr) {
+    // If the pointer is a pointer to constant memory,
+    // then it could not have been modified by this catchpad.
+    if (pointsToConstantMemory(Loc))
+      return MRI_NoModRef;
+  }
+
+  // Otherwise, a catchpad reads and writes.
+  return MRI_ModRef;
+}
+
+ModRefInfo AAResults::getModRefInfo(const CatchReturnInst *CatchRet,
+                                    const MemoryLocation &Loc) {
+  if (Loc.Ptr) {
+    // If the pointer is a pointer to constant memory,
+    // then it could not have been modified by this catchpad.
+    if (pointsToConstantMemory(Loc))
+      return MRI_NoModRef;
+  }
+
+  // Otherwise, a catchret reads and writes.
+  return MRI_ModRef;
+}
+
 ModRefInfo AAResults::getModRefInfo(const AtomicCmpXchgInst *CX,
                                     const MemoryLocation &Loc) {
   // Acquire/Release cmpxchg has properties that matter for arbitrary addresses.