Add new internal-global-symbol mapping info pass... may its life be short

and sweet.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13983 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 80 insertions, 0 deletions

diff --git a/lib/Target/SparcV9/InternalGlobalMapper.cpp b/lib/Target/SparcV9/InternalGlobalMapper.cpp
new file mode 100644
index 0000000000..8df87fd000
--- /dev/null
+++ b/lib/Target/SparcV9/InternalGlobalMapper.cpp
@@ -0,0 +1,80 @@
+//===-- InternalGlobalMapper.cpp - Mapping Info for Internal Globals ------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// InternalGlobalMapper is a pass that helps the runtime trace optimizer map
+// the names of internal GlobalValues (which may have mangled,
+// unreconstructible names in the executable) to pointers. If the name mangler
+// is changed at some point in the future to allow its results to be
+// reconstructible (for instance, by making the type mangling symbolic instead
+// of using a UniqueID) this pass should probably be phased out.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Constants.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Type.h"
+#include "llvm/DerivedTypes.h"
+using namespace llvm;
+
+namespace llvm {
+
+typedef std::vector<Constant *> GVVectorTy;
+
+class InternalGlobalMapper : public Pass {
+public:
+  bool run (Module &M);
+};
+
+Pass *llvm::createInternalGlobalMapperPass () {
+  return new InternalGlobalMapper ();
+}
+
+static void maybeAddInternalValueToVector (GVVectorTy &Vector, GlobalValue &GV){
+  // If it's a GlobalValue with internal linkage and a name (i.e. it's going to
+  // be mangled), then put the GV, casted to sbyte*, in the vector. Otherwise
+  // add a null.
+  if (GV.hasInternalLinkage () && GV.hasName ())
+    Vector.push_back (ConstantExpr::getCast
+      (ConstantPointerRef::get (&GV), PointerType::get (Type::SByteTy)));
+  else
+    Vector.push_back (ConstantPointerNull::get (PointerType::get
+                                                (Type::SByteTy)));
+}
+
+bool InternalGlobalMapper::run (Module &M) {
+  GVVectorTy gvvector;
+
+  // Populate the vector with internal global values and their names.
+  for (Module::giterator i = M.gbegin (), e = M.gend (); i != e; ++i)
+    maybeAddInternalValueToVector (gvvector, *i);
+  for (Module::iterator i = M.begin (), e = M.end (); i != e; ++i)
+    maybeAddInternalValueToVector (gvvector, *i);
+
+  // Convert the vector to a constant struct of type {Size, [Size x sbyte*]}.
+  ArrayType *ATy = ArrayType::get (PointerType::get (Type::SByteTy),
+                                  gvvector.size ());
+  std::vector<const Type *> FieldTypes;
+  FieldTypes.push_back (Type::UIntTy);
+  FieldTypes.push_back (ATy);
+  StructType *STy = StructType::get (FieldTypes);
+  std::vector<Constant *> FieldValues;
+  FieldValues.push_back (ConstantUInt::get (Type::UIntTy, gvvector.size ()));
+  FieldValues.push_back (ConstantArray::get (ATy, gvvector));
+  
+  // Add the constant struct to M as an external global symbol named
+  // "_llvm_internalGlobals".
+  new GlobalVariable (STy, true, GlobalValue::ExternalLinkage,
+                      ConstantStruct::get (STy, FieldValues),
+                      "_llvm_internalGlobals", &M);
+
+  return true; // Module was modified.
+}
+
+} // end namespace llvm