llvm-6502/include/llvm/IR/Mangler.h
Rafael Espindola 6880f0e19f Fix PR18743.
The IR
@foo = private constant i32 42

is valid, but before this patch we would produce an invalid MachO from it. It
was invalid because it would use an L label in a section where the liker needs
the labels in order to atomize it.

One way of fixing it would be to just reject this IR in the backend, but that
would not be very front end friendly.

What this patch does is use an 'l' prefix in sections that we know the linker
requires symbols for atomizing them. This allows frontends to just use
private and not worry about which sections they go to or how the linker handles
them.

One small issue with this strategy is that now a symbol name depends on the
section, which is not available before codegen. This is not a problem in
practice. The reason is that it only happens with private linkage, which will
be ignored by the non codegen users (llvm-nm and llvm-ar).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201608 91177308-0d34-0410-b5e6-96231b3b80d8
2014-02-18 22:24:57 +00:00

70 lines
2.3 KiB
C++

//===-- llvm/IR/Mangler.h - Self-contained name mangler ---------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Unified name mangler for various backends.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_MANGLER_H
#define LLVM_TARGET_MANGLER_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/Support/raw_ostream.h"
namespace llvm {
class DataLayout;
class GlobalValue;
template <typename T> class SmallVectorImpl;
class Twine;
class Mangler {
public:
enum ManglerPrefixTy {
Default, ///< Emit default string before each symbol.
Private, ///< Emit "private" prefix before each symbol.
LinkerPrivate ///< Emit "linker private" prefix before each symbol.
};
private:
const DataLayout *DL;
/// AnonGlobalIDs - We need to give global values the same name every time
/// they are mangled. This keeps track of the number we give to anonymous
/// ones.
///
mutable DenseMap<const GlobalValue*, unsigned> AnonGlobalIDs;
/// NextAnonGlobalID - This simple counter is used to unique value names.
///
mutable unsigned NextAnonGlobalID;
public:
Mangler(const DataLayout *DL) : DL(DL), NextAnonGlobalID(1) {}
/// Print the appropriate prefix and the specified global variable's name.
/// If the global variable doesn't have a name, this fills in a unique name
/// for the global.
void getNameWithPrefix(raw_ostream &OS, const GlobalValue *GV,
bool CannotUsePrivateLabel) const;
void getNameWithPrefix(SmallVectorImpl<char> &OutName, const GlobalValue *GV,
bool CannotUsePrivateLabel) const;
/// Print the appropriate prefix and the specified name as the global variable
/// name. GVName must not be empty.
void getNameWithPrefix(raw_ostream &OS, const Twine &GVName,
ManglerPrefixTy PrefixTy = Mangler::Default) const;
void getNameWithPrefix(SmallVectorImpl<char> &OutName, const Twine &GVName,
ManglerPrefixTy PrefixTy = Mangler::Default) const;
};
} // End llvm namespace
#endif // LLVM_TARGET_MANGLER_H