Add a new interface for describing the behavior of library calls. This

Currently is sufficient to describe mod/ref behavior but will hopefully
eventually be extended for other purposes.

This isn't used by anything yet.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50820 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/LibCallSemantics.cpp

@@ -0,0 +1,65 @@
+//===- LibCallSemantics.cpp - Describe library semantics ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements interfaces that can be used to describe language
+// specific runtime library interfaces (e.g. libc, libm, etc) to LLVM
+// optimizers.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/LibCallSemantics.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/Function.h"
+using namespace llvm;
+
+/// getMap - This impl pointer in ~LibCallInfo is actually a StringMap.  This
+/// helper does the cast.
+static StringMap<const LibCallFunctionInfo*> *getMap(void *Ptr) {
+  return static_cast<StringMap<const LibCallFunctionInfo*> *>(Ptr);
+}
+
+LibCallInfo::~LibCallInfo() {
+  delete getMap(Impl);
+}
+
+const LibCallLocationInfo &LibCallInfo::getLocationInfo(unsigned LocID) const {
+  // Get location info on the first call.
+  if (NumLocations == 0)
+    NumLocations = getLocationInfo(Locations);
+  
+  assert(LocID < NumLocations && "Invalid location ID!");
+  return Locations[LocID];
+}
+
+
+/// getFunctionInfo - Return the LibCallFunctionInfo object corresponding to
+/// the specified function if we have it.  If not, return null.
+const LibCallFunctionInfo *LibCallInfo::getFunctionInfo(Function *F) const {
+  StringMap<const LibCallFunctionInfo*> *Map = getMap(Impl);
+  
+  /// If this is the first time we are querying for this info, lazily construct
+  /// the StringMap to index it.
+  if (Map == 0) {
+    Impl = Map = new StringMap<const LibCallFunctionInfo*>();
+    
+    const LibCallFunctionInfo *Array = getFunctionInfoArray();
+    if (Array == 0) return 0;
+    
+    // We now have the array of entries.  Populate the StringMap.
+    for (unsigned i = 0; Array[i].Name; ++i)
+      (*Map)[Array[i].Name] = Array+i;
+  }
+  
+  // Look up this function in the string map.
+  const char *ValueName = F->getNameStart();
+  StringMap<const LibCallFunctionInfo*>::iterator I =
+  Map->find(ValueName, ValueName+F->getNameLen());
+  return I != Map->end() ? I->second : 0;
+}
+