Fix lint's memcpy and memmove checks, and its basic block traversal.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104970 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/Lint.cpp b/lib/Analysis/Lint.cpp
index 751c41ce39ccf1c82c345dc29f95709bad604e4e..91929be3462df02c252387a42ff042d0d7b05470 100644 (file)
--- a/lib/Analysis/Lint.cpp
+++ b/lib/Analysis/Lint.cpp
@@ -248,9 +248,9 @@ void Lint::visitCallSite(CallSite CS) {
 
     case Intrinsic::memcpy: {
       MemCpyInst *MCI = cast<MemCpyInst>(&I);
-      visitMemoryReference(I, MCI->getSource(), MCI->getAlignment(), 0,
-                           MemRef::Write);
       visitMemoryReference(I, MCI->getDest(), MCI->getAlignment(), 0,
+                           MemRef::Write);
+      visitMemoryReference(I, MCI->getSource(), MCI->getAlignment(), 0,
                            MemRef::Read);
 
       // Check that the memcpy arguments don't overlap. The AliasAnalysis API
@@ -269,9 +269,9 @@ void Lint::visitCallSite(CallSite CS) {
     }
     case Intrinsic::memmove: {
       MemMoveInst *MMI = cast<MemMoveInst>(&I);
-      visitMemoryReference(I, MMI->getSource(), MMI->getAlignment(), 0,
-                           MemRef::Write);
       visitMemoryReference(I, MMI->getDest(), MMI->getAlignment(), 0,
+                           MemRef::Write);
+      visitMemoryReference(I, MMI->getSource(), MMI->getAlignment(), 0,
                            MemRef::Read);
       break;
     }
@@ -519,11 +519,14 @@ Value *Lint::findValueImpl(Value *V, bool OffsetOk,
   if (LoadInst *L = dyn_cast<LoadInst>(V)) {
     BasicBlock::iterator BBI = L;
     BasicBlock *BB = L->getParent();
+    SmallPtrSet<BasicBlock *, 4> VisitedBlocks;
     for (;;) {
+      if (!VisitedBlocks.insert(BB)) break;
       if (Value *U = FindAvailableLoadedValue(L->getPointerOperand(),
                                               BB, BBI, 6, AA))
         return findValueImpl(U, OffsetOk, Visited);
-      BB = L->getParent()->getUniquePredecessor();
+      if (BBI != BB->begin()) break;
+      BB = BB->getUniquePredecessor();
       if (!BB) break;
       BBI = BB->end();
     }

diff --git a/test/Other/lint.ll b/test/Other/lint.ll
index ea02d431ffda7bb54a491d3bae92ac301a3d1b0d..bed3dba3a59edd8a9fbd130e4e8e81a13bcf641c 100644 (file)
--- a/test/Other/lint.ll
+++ b/test/Other/lint.ll
@@ -3,6 +3,7 @@ target datalayout = "e-p:64:64:64"
 
 declare fastcc void @bar()
 declare void @llvm.stackrestore(i8*)
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
 
 @CG = constant i32 7
 
@@ -54,6 +55,9 @@ define i32 @foo() noreturn {
 ; CHECK: Undefined behavior: Null pointer dereference
   call void @llvm.stackrestore(i8* null)
 
+; CHECK: Write to read-only memory
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* bitcast (i32* @CG to i8*), i8* bitcast (i32* @CG to i8*), i64 1, i32 1, i1 0)
+
   br label %next
 
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