[MemoryBuiltins] Remove isOperatorNewLike by consolidating non-null inference handling

This patch removes the isOperatorNewLike predicate since it was only being used to establish a non-null return value and we have attributes specifically for that purpose with generic handling. To keep approximate the same behaviour for existing frontends, I added the various operator new like (i.e. instances of operator new) to InferFunctionAttrs. It's not really clear to me why this isn't handled in Clang, but I didn't want to break existing code and any subtle assumptions it might have.

Once this patch is in, I'm going to start separating the isAllocLike family of predicates. These appear to be being used for a mixture of things which should be more clearly separated and documented. Today, they're being used to indicate (at least) aliasing facts, CSE-ability, and default values from an allocation site.

Differential Revision: http://reviews.llvm.org/D15820

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256787 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Analysis/MemoryBuiltins.h b/include/llvm/Analysis/MemoryBuiltins.h
index 87fb3efaf50e3e33a6255882328f2ff99a076757..493a99a4b11e6c5dac1f8e5b7341fea8b625e2b5 100644 (file)
--- a/include/llvm/Analysis/MemoryBuiltins.h
+++ b/include/llvm/Analysis/MemoryBuiltins.h
@@ -59,11 +59,6 @@ bool isCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
 bool isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
                    bool LookThroughBitCast = false);
 
-/// \brief Tests if a value is a call or invoke to a library function that
-/// allocates memory and never returns null (such as operator new).
-bool isOperatorNewLikeFn(const Value *V, const TargetLibraryInfo *TLI,
-                         bool LookThroughBitCast = false);
-
 //===----------------------------------------------------------------------===//
 //  malloc Call Utility Functions.
 //

diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
index b19ecadd31619ed627e5f7f7d11a998c9a9f11f4..9e896aed0dce574d138f06071501655dab69fe2e 100644 (file)
--- a/lib/Analysis/MemoryBuiltins.cpp
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -187,13 +187,6 @@ bool llvm::isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
   return getAllocationData(V, AllocLike, TLI, LookThroughBitCast);
 }
 
-/// \brief Tests if a value is a call or invoke to a library function that
-/// allocates memory and never returns null (such as operator new).
-bool llvm::isOperatorNewLikeFn(const Value *V, const TargetLibraryInfo *TLI,
-                               bool LookThroughBitCast) {
-  return getAllocationData(V, OpNewLike, TLI, LookThroughBitCast);
-}
-
 /// extractMallocCall - Returns the corresponding CallInst if the instruction
 /// is a malloc call.  Since CallInst::CreateMalloc() only creates calls, we
 /// ignore InvokeInst here.

diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index 7e56f1ebe60dbc25ec29b1d82464176d7effb997..ef045dc16bbc601294dcf584ac389ab6c0d0ad2f 100644 (file)
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -3480,10 +3480,6 @@ bool llvm::isKnownNonNull(const Value *V, const TargetLibraryInfo *TLI) {
     if (CS.isReturnNonNull())
       return true;
 
-  // operator new never returns null.
-  if (isOperatorNewLikeFn(V, TLI, /*LookThroughBitCast=*/true))
-    return true;
-
   return false;
 }
 

diff --git a/lib/Transforms/IPO/InferFunctionAttrs.cpp b/lib/Transforms/IPO/InferFunctionAttrs.cpp
index d02c861a294817e97308e5a0e226fd047a98df5f..0f0182ef92be9e6270776554cd1c3325366bd837 100644 (file)
--- a/lib/Transforms/IPO/InferFunctionAttrs.cpp
+++ b/lib/Transforms/IPO/InferFunctionAttrs.cpp
@@ -10,6 +10,7 @@
 #include "llvm/Transforms/IPO/InferFunctionAttrs.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Analysis/MemoryBuiltins.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
@@ -25,6 +26,7 @@ STATISTIC(NumNoUnwind, "Number of functions inferred as nounwind");
 STATISTIC(NumNoCapture, "Number of arguments inferred as nocapture");
 STATISTIC(NumReadOnlyArg, "Number of arguments inferred as readonly");
 STATISTIC(NumNoAlias, "Number of function returns inferred as noalias");
+STATISTIC(NumNonNull, "Number of function returns inferred as nonnull returns");
 
 static bool setDoesNotAccessMemory(Function &F) {
   if (F.doesNotAccessMemory())
@@ -74,6 +76,17 @@ static bool setDoesNotAlias(Function &F, unsigned n) {
   return true;
 }
 
+static bool setNonNull(Function &F, unsigned n) {
+  assert((n != AttributeSet::ReturnIndex ||
+          F.getReturnType()->isPointerTy()) &&
+         "nonnull applies only to pointers");
+  if (F.getAttributes().hasAttribute(n, Attribute::NonNull))
+    return false;
+  F.addAttribute(n, Attribute::NonNull);
+  ++NumNonNull;
+  return true;
+}
+
 /// Analyze the name and prototype of the given function and set any applicable
 /// attributes.
 ///
@@ -89,7 +102,6 @@ static bool inferPrototypeAttributes(Function &F,
     return false;
 
   bool Changed = false;
-
   switch (TheLibFunc) {
   case LibFunc::strlen:
     if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
@@ -873,6 +885,21 @@ static bool inferPrototypeAttributes(Function &F,
     Changed |= setDoesNotCapture(F, 2);
     return Changed;
 
+  case LibFunc::Znwj: // new(unsigned int)
+  case LibFunc::Znwm: // new(unsigned long)
+  case LibFunc::Znaj: // new[](unsigned int)
+  case LibFunc::Znam: // new[](unsigned long)
+  case LibFunc::msvc_new_int: // new(unsigned int)
+  case LibFunc::msvc_new_longlong: // new(unsigned long long)
+  case LibFunc::msvc_new_array_int: // new[](unsigned int)
+  case LibFunc::msvc_new_array_longlong: // new[](unsigned long long)
+    if (FTy->getNumParams() != 1)
+      return false;
+    // Operator new always returns a nonnull noalias pointer
+    Changed |= setNonNull(F, AttributeSet::ReturnIndex);
+    Changed |= setDoesNotAlias(F, AttributeSet::ReturnIndex);
+    return Changed;
+
   default:
     // FIXME: It'd be really nice to cover all the library functions we're
     // aware of here.

diff --git a/test/Transforms/InferFunctionAttrs/annotate.ll b/test/Transforms/InferFunctionAttrs/annotate.ll
index 963f484eb55e48c4f1dd50e280140e07f8704817..709feb486c2013c6c548542a155a5e6b94bcbf10 100644 (file)
--- a/test/Transforms/InferFunctionAttrs/annotate.ll
+++ b/test/Transforms/InferFunctionAttrs/annotate.ll
@@ -16,6 +16,12 @@ declare i32* @realloc(i32*, i32)
 declare i32 @strcpy(...)
 ; CHECK: declare i32 @strcpy(...)
 
+; operator new routines
+declare i8* @_Znwj(i64)
+; CHECK: declare noalias nonnull i8* @_Znwj(i64)
+declare i8* @_Znwm(i64)
+; CHECK: declare noalias nonnull i8* @_Znwm(i64)
+
 declare i32 @gettimeofday(i8*, i8*)
 ; CHECK-POSIX: declare i32 @gettimeofday(i8* nocapture, i8* nocapture) [[G0:#[0-9]+]]
 

diff --git a/test/Transforms/InstSimplify/call.ll b/test/Transforms/InstSimplify/call.ll
index 465529aef66aae3a9af66d6aaa9a86908cb08f61..b360ecb843423d1111375364dc878c2471246c28 100644 (file)
--- a/test/Transforms/InstSimplify/call.ll
+++ b/test/Transforms/InstSimplify/call.ll
@@ -144,7 +144,7 @@ cast.end:                                         ; preds = %cast.notnull, %entr
 ; CHECK: br i1 false, label %cast.end, label %cast.notnull
 }
 
-declare noalias i8* @_Znwm(i64)
+declare nonnull noalias i8* @_Znwm(i64)
 
 %"struct.std::nothrow_t" = type { i8 }
 @_ZSt7nothrow = external global %"struct.std::nothrow_t"