Update aosp/master LLVM for rebase to r222494.

Change-Id: Ic787f5e0124df789bd26f3f24680f45e678eef2d

1 files changed, 155 insertions, 0 deletions

diff --git a/include/llvm/Transforms/Utils/SymbolRewriter.h b/include/llvm/Transforms/Utils/SymbolRewriter.h
new file mode 100644
index 0000000..af79372
--- /dev/null
+++ b/include/llvm/Transforms/Utils/SymbolRewriter.h
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+//===-- SymbolRewriter.h - Symbol Rewriting Pass ----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides the prototypes and definitions related to the Symbol
+// Rewriter pass.
+//
+// The Symbol Rewriter pass takes a set of rewrite descriptors which define
+// transformations for symbol names.  These can be either single name to name
+// trnsformation or more broad regular expression based transformations.
+//
+// All the functions are re-written at the IR level.  The Symbol Rewriter itself
+// is exposed as a module level pass.  All symbols at the module level are
+// iterated.  For any matching symbol, the requested transformation is applied,
+// updating references to it as well (a la RAUW).  The resulting binary will
+// only contain the rewritten symbols.
+//
+// By performing this operation in the compiler, we are able to catch symbols
+// that would otherwise not be possible to catch (e.g. inlined symbols).
+//
+// This makes it possible to cleanly transform symbols without resorting to
+// overly-complex macro tricks and the pre-processor.  An example of where this
+// is useful is the sanitizers where we would like to intercept a well-defined
+// set of functions across the module.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_UTILS_SYMBOL_REWRITER_H
+#define LLVM_TRANSFORMS_UTILS_SYMBOL_REWRITER_H
+
+#include "llvm/ADT/ilist.h"
+#include "llvm/ADT/ilist_node.h"
+#include "llvm/IR/Module.h"
+
+namespace llvm {
+class MemoryBuffer;
+
+namespace yaml {
+class KeyValueNode;
+class MappingNode;
+class ScalarNode;
+class Stream;
+}
+
+namespace SymbolRewriter {
+/// The basic entity representing a rewrite operation.  It serves as the base
+/// class for any rewrite descriptor.  It has a certain set of specializations
+/// which describe a particular rewrite.
+///
+/// The RewriteMapParser can be used to parse a mapping file that provides the
+/// mapping for rewriting the symbols.  The descriptors individually describe
+/// whether to rewrite a function, global variable, or global alias.  Each of
+/// these can be selected either by explicitly providing a name for the ones to
+/// be rewritten or providing a (posix compatible) regular expression that will
+/// select the symbols to rewrite.  This descriptor list is passed to the
+/// SymbolRewriter pass.
+class RewriteDescriptor : public ilist_node<RewriteDescriptor> {
+  RewriteDescriptor(const RewriteDescriptor &) LLVM_DELETED_FUNCTION;
+
+  const RewriteDescriptor &
+  operator=(const RewriteDescriptor &) LLVM_DELETED_FUNCTION;
+
+public:
+  enum class Type {
+    Invalid,        /// invalid
+    Function,       /// function - descriptor rewrites a function
+    GlobalVariable, /// global variable - descriptor rewrites a global variable
+    NamedAlias,     /// named alias - descriptor rewrites a global alias
+  };
+
+  virtual ~RewriteDescriptor() {}
+
+  Type getType() const { return Kind; }
+
+  virtual bool performOnModule(Module &M) = 0;
+
+protected:
+  explicit RewriteDescriptor(Type T) : Kind(T) {}
+
+private:
+  const Type Kind;
+};
+
+typedef iplist<RewriteDescriptor> RewriteDescriptorList;
+
+class RewriteMapParser {
+public:
+  RewriteMapParser() {}
+  ~RewriteMapParser() {}
+
+  bool parse(const std::string &MapFile, RewriteDescriptorList *Descriptors);
+
+private:
+  bool parse(std::unique_ptr<MemoryBuffer> &MapFile, RewriteDescriptorList *DL);
+  bool parseEntry(yaml::Stream &Stream, yaml::KeyValueNode &Entry,
+                  RewriteDescriptorList *DL);
+  bool parseRewriteFunctionDescriptor(yaml::Stream &Stream,
+                                      yaml::ScalarNode *Key,
+                                      yaml::MappingNode *Value,
+                                      RewriteDescriptorList *DL);
+  bool parseRewriteGlobalVariableDescriptor(yaml::Stream &Stream,
+                                            yaml::ScalarNode *Key,
+                                            yaml::MappingNode *Value,
+                                            RewriteDescriptorList *DL);
+  bool parseRewriteGlobalAliasDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
+                                         yaml::MappingNode *V,
+                                         RewriteDescriptorList *DL);
+};
+}
+
+template <>
+struct ilist_traits<SymbolRewriter::RewriteDescriptor>
+    : public ilist_default_traits<SymbolRewriter::RewriteDescriptor> {
+  mutable ilist_half_node<SymbolRewriter::RewriteDescriptor> Sentinel;
+
+public:
+  // createSentinel is used to get a reference to a node marking the end of
+  // the list.  Because the sentinel is relative to this instance, use a
+  // non-static method.
+  SymbolRewriter::RewriteDescriptor *createSentinel() const {
+    // since i[p] lists always publicly derive from the corresponding
+    // traits, placing a data member in this class will augment the
+    // i[p]list.  Since the NodeTy is expected to publicly derive from
+    // ilist_node<NodeTy>, there is a legal viable downcast from it to
+    // NodeTy.  We use this trick to superpose i[p]list with a "ghostly"
+    // NodeTy, which becomes the sentinel.  Dereferencing the sentinel is
+    // forbidden (save the ilist_node<NodeTy>) so no one will ever notice
+    // the superposition.
+    return static_cast<SymbolRewriter::RewriteDescriptor *>(&Sentinel);
+  }
+  void destroySentinel(SymbolRewriter::RewriteDescriptor *) {}
+
+  SymbolRewriter::RewriteDescriptor *provideInitialHead() const {
+    return createSentinel();
+  }
+
+  SymbolRewriter::RewriteDescriptor *
+  ensureHead(SymbolRewriter::RewriteDescriptor *&) const {
+    return createSentinel();
+  }
+
+  static void noteHead(SymbolRewriter::RewriteDescriptor *,
+                       SymbolRewriter::RewriteDescriptor *) {}
+};
+
+ModulePass *createRewriteSymbolsPass();
+ModulePass *createRewriteSymbolsPass(SymbolRewriter::RewriteDescriptorList &);
+}
+
+#endif