[poolalloc] r177660 - Improved DSA's ability to infer types when structure indexing is lowered to

[John Criswell]

Author: criswell
Date: Thu Mar 21 15:24:41 2013
New Revision: 177660

URL: http://llvm.org/viewvc/llvm-project?rev=177660&view=rev
Log:
Improved DSA's ability to infer types when structure indexing is lowered to
byte-level indexing using constants.
This fixes test/dsa/local/struct_malloc.ll and, I believe, PR#15110:
http://llvm.org/bugs/show_bug.cgi?id=15110

Modified:
    poolalloc/branches/release_32/lib/DSA/Local.cpp
    poolalloc/branches/release_32/test/dsa/local/struct_malloc.ll

Modified: poolalloc/branches/release_32/lib/DSA/Local.cpp
URL: http://llvm.org/viewvc/llvm-project/poolalloc/branches/release_32/lib/DSA/Local.cpp?rev=177660&r1=177659&r2=177660&view=diff
==============================================================================
--- poolalloc/branches/release_32/lib/DSA/Local.cpp (original)
+++ poolalloc/branches/release_32/lib/DSA/Local.cpp Thu Mar 21 15:24:41 2013
@@ -803,9 +803,43 @@ void GraphBuilder::visitGetElementPtrIns
         break;
       }
     } else if (const PointerType *PtrTy = dyn_cast<PointerType>(*I)) {
+      // Get the type pointed to by the pointer
       Type *CurTy = PtrTy->getElementType();
 
       //
+      // Some LLVM transforms lower structure indexing into byte-level
+      // indexing.  Try to recognize forms of that here.
+      //
+      Type * Int8Type  = Type::getInt8Ty(CurTy->getContext());
+      ConstantInt * IS = dyn_cast<ConstantInt>(I.getOperand());
+      if (IS &&
+          (NodeH.getOffset() == 0) &&
+          (!(NodeH.getNode()->isArrayNode())) &&
+          (CurTy == Int8Type)) {
+        // Calculate the offset of the field
+        Offset += IS->getSExtValue() * TD.getTypeAllocSize (Int8Type);
+
+        //
+        // Grow the DSNode size as needed.
+        //
+        unsigned requiredSize = Offset + TD.getTypeAllocSize (Int8Type);
+        if (NodeH.getNode()->getSize() <= requiredSize){
+          NodeH.getNode()->growSize (requiredSize);
+        }
+
+        // Add in the offset calculated...
+        NodeH.setOffset(NodeH.getOffset()+Offset);
+
+        // Check the offset
+        DSNode *N = NodeH.getNode();
+        if (N) N->checkOffsetFoldIfNeeded(NodeH.getOffset());
+
+        // NodeH is now the pointer we want to GEP to be...
+        setDestTo(GEP, NodeH);
+        return;
+      }
+
+      //
       // Unless we're advancing the pointer by zero bytes via array indexing,
       // fold the node (i.e., mark it type-unknown) and indicate that we're
       // indexing zero bytes into the object (because all fields are aliased).

Modified: poolalloc/branches/release_32/test/dsa/local/struct_malloc.ll
URL: http://llvm.org/viewvc/llvm-project/poolalloc/branches/release_32/test/dsa/local/struct_malloc.ll?rev=177660&r1=177659&r2=177660&view=diff
==============================================================================
--- poolalloc/branches/release_32/test/dsa/local/struct_malloc.ll (original)
+++ poolalloc/branches/release_32/test/dsa/local/struct_malloc.ll Thu Mar 21 15:24:41 2013
@@ -1,5 +1,4 @@
-;RUN: dsaopt %s -dsa-local -analyze -check-type=func:struct,0:i32Array
-;XFAIL: *
+;RUN: dsaopt %s -dsa-local -analyze -check-type=func:struct,0:i32::4:i32
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-unknown-linux-gnu"