[PATCH] D32188: [MemoryBuiltins] Add isMallocOrCallocLikeFn so BasicAA can check for both at the same time

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
Herald added a subscriber: david2050.

BasicAA wants to know if a function is either a malloc or calloc like function. Currently we have to check both separately. This means both calls check if its an intrinsic, query TLI, check the nobuiltin attribute, scan the AllocationFnData, etc.

This patch adds a isMallocOrCallocLikeFn so we can go through all of the checks once per call.

This also changes the one other location I saw that called both together.


https://reviews.llvm.org/D32188

Files:
  include/llvm/Analysis/MemoryBuiltins.h
  lib/Analysis/BasicAliasAnalysis.cpp
  lib/Analysis/CFLGraph.h
  lib/Analysis/MemoryBuiltins.cpp


Index: lib/Analysis/MemoryBuiltins.cpp
===================================================================
--- lib/Analysis/MemoryBuiltins.cpp
+++ lib/Analysis/MemoryBuiltins.cpp
@@ -37,6 +37,7 @@
   CallocLike         = 1<<2, // allocates + bzero
   ReallocLike        = 1<<3, // reallocates
   StrDupLike         = 1<<4,
+  MallocOrCallocLike = MallocLike | CallocLike,
   AllocLike          = MallocLike | CallocLike | StrDupLike,
   AnyAlloc           = AllocLike | ReallocLike
 };
@@ -220,6 +221,14 @@
 }
 
 /// \brief Tests if a value is a call or invoke to a library function that
+/// allocates memory similiar to malloc or calloc.
+bool llvm::isMallocOrCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
+                                  bool LookThroughBitCast) {
+  return getAllocationData(V, MallocOrCallocLike, TLI,
+                           LookThroughBitCast).hasValue();
+}
+
+/// \brief Tests if a value is a call or invoke to a library function that
 /// allocates memory (either malloc, calloc, or strdup like).
 bool llvm::isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
                          bool LookThroughBitCast) {
Index: lib/Analysis/CFLGraph.h
===================================================================
--- lib/Analysis/CFLGraph.h
+++ lib/Analysis/CFLGraph.h
@@ -400,8 +400,7 @@
       // TODO: address other common library functions such as realloc(),
       // strdup(),
       // etc.
-      if (isMallocLikeFn(Inst, &TLI) || isCallocLikeFn(Inst, &TLI) ||
-          isFreeCall(Inst, &TLI))
+      if (isMallocOrCallocLikeFn(Inst, &TLI) || isFreeCall(Inst, &TLI))
         return;
 
       // TODO: Add support for noalias args/all the other fun function
Index: lib/Analysis/BasicAliasAnalysis.cpp
===================================================================
--- lib/Analysis/BasicAliasAnalysis.cpp
+++ lib/Analysis/BasicAliasAnalysis.cpp
@@ -808,7 +808,7 @@
   // well.  Or alternatively, replace all of this with inaccessiblememonly once
   // that's implemented fully. 
   auto *Inst = CS.getInstruction();
-  if (isMallocLikeFn(Inst, &TLI) || isCallocLikeFn(Inst, &TLI)) {
+  if (isMallocOrCallocLikeFn(Inst, &TLI)) {
     // Be conservative if the accessed pointer may alias the allocation -
     // fallback to the generic handling below.
     if (getBestAAResults().alias(MemoryLocation(Inst), Loc) == NoAlias)
Index: include/llvm/Analysis/MemoryBuiltins.h
===================================================================
--- include/llvm/Analysis/MemoryBuiltins.h
+++ include/llvm/Analysis/MemoryBuiltins.h
@@ -54,6 +54,11 @@
                     bool LookThroughBitCast = false);
 
 /// \brief Tests if a value is a call or invoke to a library function that
+/// allocates memory similar to malloc or calloc.
+bool isMallocOrCallocLikeFn(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 (either malloc, calloc, or strdup like).
 bool isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
                    bool LookThroughBitCast = false);


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