introduce a new TargetLibraryInfo pass, which transformations can use to

query about available library functions.  For now this just has 
memset_pattern16, which exists on darwin, but it can be extended for a 
bunch of other things in the future.

llvm-svn: 125965

1 files changed, 49 insertions, 0 deletions

diff --git a/llvm/lib/Target/TargetLibraryInfo.cpp b/llvm/lib/Target/TargetLibraryInfo.cpp
new file mode 100644
index 00000000000..f4a85b0cd62
--- /dev/null
+++ b/llvm/lib/Target/TargetLibraryInfo.cpp
@@ -0,0 +1,49 @@
+//===-- TargetLibraryInfo.cpp - Runtime library information ----------------==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the TargetLibraryInfo class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/ADT/Triple.h"
+using namespace llvm;
+
+// Register the default implementation.
+INITIALIZE_PASS(TargetLibraryInfo, "targetlibinfo",
+                "Target Library Information", false, true)
+char TargetLibraryInfo::ID = 0;
+
+/// initialize - Initialize the set of available library functions based on the
+/// specified target triple.  This should be carefully written so that a missing
+/// target triple gets a sane set of defaults.
+static void initialize(TargetLibraryInfo &TLI, const Triple &T) {
+  initializeTargetLibraryInfoPass(*PassRegistry::getPassRegistry());
+
+  
+  // memset_pattern16 is only available on iOS 3.0 and Mac OS/X 10.5 and later.
+  if (T.getOS() != Triple::Darwin || T.getDarwinMajorNumber() < 9)
+    TLI.setUnavailable(LibFunc::memset_pattern16);
+  
+}
+
+
+TargetLibraryInfo::TargetLibraryInfo() : ImmutablePass(ID) {
+  // Default to everything being available.
+  memset(AvailableArray, -1, sizeof(AvailableArray));
+
+  initialize(*this, Triple());
+}
+
+TargetLibraryInfo::TargetLibraryInfo(const Triple &T) : ImmutablePass(ID) {
+  // Default to everything being available.
+  memset(AvailableArray, -1, sizeof(AvailableArray));
+  
+  initialize(*this, T);
+}