nonnull.patch

commit f377c520ee27e5e284a16597226a44095842c490
Author: Nikita Popov <nikita.ppv@gmail.com>
Date:   Fri Jul 2 21:03:31 2021 +0200

    Add AttributeSet::impliesNonNull()

diff --git a/llvm/include/llvm/IR/Attributes.h b/llvm/include/llvm/IR/Attributes.h
index 50047e25f69d..f4ae08eb9053 100644
--- a/llvm/include/llvm/IR/Attributes.h
+++ b/llvm/include/llvm/IR/Attributes.h
@@ -338,6 +338,13 @@ public:
   std::pair<unsigned, unsigned> getVScaleRangeArgs() const;
   std::string getAsString(bool InAttrGrp = false) const;
 
+  /// Whether this attribute set implies that an argument is non-null.
+  /// NullPointerIsDefined determines whether the null pointer is
+  /// dereferenceable. If AllowPoison is true, then a null argument merely
+  /// results in poison. If it is false, a null argument results in undefined
+  /// behavior.
+  bool impliesNonNull(bool NullPointerIsDefined, bool AllowPoison) const;
+
   /// Return true if this attribute set belongs to the LLVMContext.
   bool hasParentContext(LLVMContext &C) const;
 
diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index 27b5835c8558..0a7aa115274a 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -863,6 +863,14 @@ std::string AttributeSet::getAsString(bool InAttrGrp) const {
   return SetNode ? SetNode->getAsString(InAttrGrp) : "";
 }
 
+bool AttributeSet::impliesNonNull(bool NullPointerIsDefined,
+                                  bool AllowPoison) const {
+  if (hasAttribute(Attribute::NonNull) &&
+      (AllowPoison || hasAttribute(Attribute::NoUndef)))
+    return true;
+  return getDereferenceableBytes() > 0 && !NullPointerIsDefined;
+}
+
 bool AttributeSet::hasParentContext(LLVMContext &C) const {
   assert(hasAttributes() && "empty AttributeSet doesn't refer to any context");
   FoldingSetNodeID ID;
diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index b502e5c48dbc..fd0b5edea372 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -96,15 +96,10 @@ void Argument::setParent(Function *parent) {
 
 bool Argument::hasNonNullAttr(bool AllowUndefOrPoison) const {
   if (!getType()->isPointerTy()) return false;
-  if (getParent()->hasParamAttribute(getArgNo(), Attribute::NonNull) &&
-      (AllowUndefOrPoison ||
-       getParent()->hasParamAttribute(getArgNo(), Attribute::NoUndef)))
-    return true;
-  else if (getDereferenceableBytes() > 0 &&
-           !NullPointerIsDefined(getParent(),
-                                 getType()->getPointerAddressSpace()))
-    return true;
-  return false;
+  bool NullDefined = NullPointerIsDefined(getParent(),
+                                          getType()->getPointerAddressSpace());
+  return getParent()->getAttributes().getParamAttributes(getArgNo())
+         .impliesNonNull(NullDefined, AllowUndefOrPoison);
 }
 
 bool Argument::hasByValAttr() const {
diff --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index bf88a6baccf0..be9d007db7fd 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -325,12 +325,14 @@ bool CallBase::isReturnNonNull() const {
 bool CallBase::paramIsNonNull(unsigned ArgNo, bool AllowUndefOrPoison) const {
   Type *ArgType = getArgOperand(ArgNo)->getType();
   if (!ArgType->isPointerTy()) return false;
-  if (paramHasAttr(ArgNo, Attribute::NonNull) &&
-      (AllowUndefOrPoison || paramHasAttr(ArgNo, Attribute::NoUndef)))
-    return true;
-  if (getDereferenceableBytes(ArgNo) > 0 &&
-      !NullPointerIsDefined(getFunction(), ArgType->getPointerAddressSpace()))
+  bool NullDefined = NullPointerIsDefined(getFunction(),
+                                          ArgType->getPointerAddressSpace());
+  if (Attrs.getParamAttributes(ArgNo)
+      .impliesNonNull(NullDefined, AllowUndefOrPoison))
     return true;
+  if (const Function *F = getCalledFunction())
+    return F->getAttributes().getParamAttributes(ArgNo)
+           .impliesNonNull(NullDefined, AllowUndefOrPoison);
   return false;
 }