[llvm] r267708 - NFC. Introduce Value::getPointerDerferecnceableBytes

[Artur Pilipenko via llvm-commits]

This is a non-functional refactoring of existing code, namely extracting a function out of existing code. This function is triggered by any dereferenceability test. Am I missing something?

Artur

On 27 Apr 2016, at 21:10, David Blaikie <dblaikie at gmail.com<mailto:dblaikie at gmail.com>> wrote:

It's generally good to not checkin entirely dead & untested code - could you include a unit test to demonstrate correctness, at least?

On Wed, Apr 27, 2016 at 5:51 AM, Artur Pilipenko via llvm-commits <llvm-commits at lists.llvm.org<mailto:llvm-commits at lists.llvm.org>> wrote:
Author: apilipenko
Date: Wed Apr 27 07:51:01 2016
New Revision: 267708

URL: http://llvm.org/viewvc/llvm-project?rev=267708&view=rev
Log:
NFC. Introduce Value::getPointerDerferecnceableBytes

Extract a part of isDereferenceableAndAlignedPointer functionality to Value::getPointerDerferecnceableBytes. Currently it's a NFC, but in future I'm going to accumulate all the logic about value dereferenceability in this function similarly to Value::getPointerAlignment function (D16144).

Reviewed By: reames

Differential Revision: http://reviews.llvm.org/D17572

Modified:
    llvm/trunk/include/llvm/IR/Value.h
    llvm/trunk/lib/Analysis/Loads.cpp
    llvm/trunk/lib/IR/Value.cpp

Modified: llvm/trunk/include/llvm/IR/Value.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/Value.h?rev=267708&r1=267707&r2=267708&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/Value.h (original)
+++ llvm/trunk/include/llvm/IR/Value.h Wed Apr 27 07:51:01 2016
@@ -504,6 +504,13 @@ public:
     return const_cast<Value*>(this)->stripInBoundsOffsets();
   }

+  /// \brief Returns the number of bytes known to be dereferenceable for the
+  /// pointer value.
+  ///
+  /// If CanBeNull is set by this function the pointer can either be null or be
+  /// dereferenceable up to the returned number of bytes.
+  unsigned getPointerDereferenceableBytes(bool &CanBeNull) const;
+
   /// \brief Returns an alignment of the pointer value.
   ///
   /// Returns an alignment which is either specified explicitly, e.g. via

Modified: llvm/trunk/lib/Analysis/Loads.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/Loads.cpp?rev=267708&r1=267707&r2=267708&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/Loads.cpp (original)
+++ llvm/trunk/lib/Analysis/Loads.cpp Wed Apr 27 07:51:01 2016
@@ -33,34 +33,9 @@ static bool isDereferenceableFromAttribu
   assert(Offset.isNonNegative() && "offset can't be negative");
   assert(Ty->isSized() && "must be sized");

-  APInt DerefBytes(Offset.getBitWidth(), 0);
   bool CheckForNonNull = false;
-  if (const Argument *A = dyn_cast<Argument>(BV)) {
-    DerefBytes = A->getDereferenceableBytes();
-    if (!DerefBytes.getBoolValue()) {
-      DerefBytes = A->getDereferenceableOrNullBytes();
-      CheckForNonNull = true;
-    }
-  } else if (auto CS = ImmutableCallSite(BV)) {
-    DerefBytes = CS.getDereferenceableBytes(0);
-    if (!DerefBytes.getBoolValue()) {
-      DerefBytes = CS.getDereferenceableOrNullBytes(0);
-      CheckForNonNull = true;
-    }
-  } else if (const LoadInst *LI = dyn_cast<LoadInst>(BV)) {
-    if (MDNode *MD = LI->getMetadata(LLVMContext::MD_dereferenceable)) {
-      ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(0));
-      DerefBytes = CI->getLimitedValue();
-    }
-    if (!DerefBytes.getBoolValue()) {
-      if (MDNode *MD =
-              LI->getMetadata(LLVMContext::MD_dereferenceable_or_null)) {
-        ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(0));
-        DerefBytes = CI->getLimitedValue();
-      }
-      CheckForNonNull = true;
-    }
-  }
+  APInt DerefBytes(Offset.getBitWidth(),
+                   BV->getPointerDereferenceableBytes(CheckForNonNull));

   if (DerefBytes.getBoolValue())
     if (DerefBytes.uge(Offset + DL.getTypeStoreSize(Ty)))

Modified: llvm/trunk/lib/IR/Value.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Value.cpp?rev=267708&r1=267707&r2=267708&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Value.cpp (original)
+++ llvm/trunk/lib/IR/Value.cpp Wed Apr 27 07:51:01 2016
@@ -525,6 +525,40 @@ Value *Value::stripInBoundsOffsets() {
   return stripPointerCastsAndOffsets<PSK_InBounds>(this);
 }

+unsigned Value::getPointerDereferenceableBytes(bool &CanBeNull) const {
+  assert(getType()->isPointerTy() && "must be pointer");
+
+  unsigned DerefBytes = 0;
+  CanBeNull = false;
+  if (const Argument *A = dyn_cast<Argument>(this)) {
+    DerefBytes = A->getDereferenceableBytes();
+    if (DerefBytes == 0) {
+      DerefBytes = A->getDereferenceableOrNullBytes();
+      CanBeNull = true;
+    }
+  } else if (auto CS = ImmutableCallSite(this)) {
+    DerefBytes = CS.getDereferenceableBytes(0);
+    if (DerefBytes == 0) {
+      DerefBytes = CS.getDereferenceableOrNullBytes(0);
+      CanBeNull = true;
+    }
+  } else if (const LoadInst *LI = dyn_cast<LoadInst>(this)) {
+    if (MDNode *MD = LI->getMetadata(LLVMContext::MD_dereferenceable)) {
+      ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(0));
+      DerefBytes = CI->getLimitedValue();
+    }
+    if (DerefBytes == 0) {
+      if (MDNode *MD =
+              LI->getMetadata(LLVMContext::MD_dereferenceable_or_null)) {
+        ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(0));
+        DerefBytes = CI->getLimitedValue();
+      }
+      CanBeNull = true;
+    }
+  }
+  return DerefBytes;
+}
+
 unsigned Value::getPointerAlignment(const DataLayout &DL) const {
   assert(getType()->isPointerTy() && "must be pointer");



_______________________________________________
llvm-commits mailing list
llvm-commits at lists.llvm.org<mailto:llvm-commits at lists.llvm.org>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20160427/9b8ab304/attachment.html>