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llvm-mirror/include/llvm/Transforms/IPO.h
Teresa Johnson edf145601a Resubmit "Add new EliminateAvailableExternally module pass" (r239480)
This change includes a fix for https://code.google.com/p/chromium/issues/detail?id=499508#c3,
which required updating the visibility for symbols with eliminated definitions.

--Original Commit Message--

Add new EliminateAvailableExternally module pass, which is performed in
O2 compiles just before GlobalDCE, unless we are preparing for LTO.

This pass eliminates available externally globals (turning them into
declarations), regardless of whether they are dead/unreferenced, since
we are guaranteed to have a copy available elsewhere at link time.
This enables additional opportunities for GlobalDCE.

If we are preparing for LTO (e.g. a -flto -c compile), the pass is not
included as we want to preserve available externally functions for possible
link time inlining. The FE indicates whether we are doing an -flto compile
via the new PrepareForLTO flag on the PassManagerBuilder.

llvm-svn: 241466
2015-07-06 16:22:42 +00:00

215 lines
8.5 KiB
C++

//===- llvm/Transforms/IPO.h - Interprocedural Transformations --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This header file defines prototypes for accessor functions that expose passes
// in the IPO transformations library.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_IPO_H
#define LLVM_TRANSFORMS_IPO_H
#include "llvm/ADT/ArrayRef.h"
namespace llvm {
class ModulePass;
class Pass;
class Function;
class BasicBlock;
class GlobalValue;
//===----------------------------------------------------------------------===//
//
// These functions removes symbols from functions and modules. If OnlyDebugInfo
// is true, only debugging information is removed from the module.
//
ModulePass *createStripSymbolsPass(bool OnlyDebugInfo = false);
//===----------------------------------------------------------------------===//
//
// These functions strips symbols from functions and modules.
// Only debugging information is not stripped.
//
ModulePass *createStripNonDebugSymbolsPass();
//===----------------------------------------------------------------------===//
//
// These pass removes llvm.dbg.declare intrinsics.
ModulePass *createStripDebugDeclarePass();
//===----------------------------------------------------------------------===//
//
// These pass removes unused symbols' debug info.
ModulePass *createStripDeadDebugInfoPass();
//===----------------------------------------------------------------------===//
/// createConstantMergePass - This function returns a new pass that merges
/// duplicate global constants together into a single constant that is shared.
/// This is useful because some passes (ie TraceValues) insert a lot of string
/// constants into the program, regardless of whether or not they duplicate an
/// existing string.
///
ModulePass *createConstantMergePass();
//===----------------------------------------------------------------------===//
/// createGlobalOptimizerPass - This function returns a new pass that optimizes
/// non-address taken internal globals.
///
ModulePass *createGlobalOptimizerPass();
//===----------------------------------------------------------------------===//
/// createGlobalDCEPass - This transform is designed to eliminate unreachable
/// internal globals (functions or global variables)
///
ModulePass *createGlobalDCEPass();
//===----------------------------------------------------------------------===//
/// This transform is designed to eliminate available external globals
/// (functions or global variables)
///
ModulePass *createEliminateAvailableExternallyPass();
//===----------------------------------------------------------------------===//
/// createGVExtractionPass - If deleteFn is true, this pass deletes
/// the specified global values. Otherwise, it deletes as much of the module as
/// possible, except for the global values specified.
///
ModulePass *createGVExtractionPass(std::vector<GlobalValue*>& GVs, bool
deleteFn = false);
//===----------------------------------------------------------------------===//
/// createFunctionInliningPass - Return a new pass object that uses a heuristic
/// to inline direct function calls to small functions.
///
/// The Threshold can be passed directly, or asked to be computed from the
/// given optimization and size optimization arguments.
///
/// The -inline-threshold command line option takes precedence over the
/// threshold given here.
Pass *createFunctionInliningPass();
Pass *createFunctionInliningPass(int Threshold);
Pass *createFunctionInliningPass(unsigned OptLevel, unsigned SizeOptLevel);
//===----------------------------------------------------------------------===//
/// createAlwaysInlinerPass - Return a new pass object that inlines only
/// functions that are marked as "always_inline".
Pass *createAlwaysInlinerPass();
Pass *createAlwaysInlinerPass(bool InsertLifetime);
//===----------------------------------------------------------------------===//
/// createPruneEHPass - Return a new pass object which transforms invoke
/// instructions into calls, if the callee can _not_ unwind the stack.
///
Pass *createPruneEHPass();
//===----------------------------------------------------------------------===//
/// createInternalizePass - This pass loops over all of the functions in the
/// input module, internalizing all globals (functions and variables) it can.
////
/// The symbols in \p ExportList are never internalized.
///
/// The symbol in DSOList are internalized if it is safe to drop them from
/// the symbol table.
///
/// Note that commandline options that are used with the above function are not
/// used now!
ModulePass *createInternalizePass(ArrayRef<const char *> ExportList);
/// createInternalizePass - Same as above, but with an empty exportList.
ModulePass *createInternalizePass();
//===----------------------------------------------------------------------===//
/// createDeadArgEliminationPass - This pass removes arguments from functions
/// which are not used by the body of the function.
///
ModulePass *createDeadArgEliminationPass();
/// DeadArgHacking pass - Same as DAE, but delete arguments of external
/// functions as well. This is definitely not safe, and should only be used by
/// bugpoint.
ModulePass *createDeadArgHackingPass();
//===----------------------------------------------------------------------===//
/// createArgumentPromotionPass - This pass promotes "by reference" arguments to
/// be passed by value if the number of elements passed is smaller or
/// equal to maxElements (maxElements == 0 means always promote).
///
Pass *createArgumentPromotionPass(unsigned maxElements = 3);
//===----------------------------------------------------------------------===//
/// createIPConstantPropagationPass - This pass propagates constants from call
/// sites into the bodies of functions.
///
ModulePass *createIPConstantPropagationPass();
//===----------------------------------------------------------------------===//
/// createIPSCCPPass - This pass propagates constants from call sites into the
/// bodies of functions, and keeps track of whether basic blocks are executable
/// in the process.
///
ModulePass *createIPSCCPPass();
//===----------------------------------------------------------------------===//
//
/// createLoopExtractorPass - This pass extracts all natural loops from the
/// program into a function if it can.
///
Pass *createLoopExtractorPass();
/// createSingleLoopExtractorPass - This pass extracts one natural loop from the
/// program into a function if it can. This is used by bugpoint.
///
Pass *createSingleLoopExtractorPass();
/// createBlockExtractorPass - This pass extracts all blocks (except those
/// specified in the argument list) from the functions in the module.
///
ModulePass *createBlockExtractorPass();
/// createStripDeadPrototypesPass - This pass removes any function declarations
/// (prototypes) that are not used.
ModulePass *createStripDeadPrototypesPass();
//===----------------------------------------------------------------------===//
/// createFunctionAttrsPass - This pass discovers functions that do not access
/// memory, or only read memory, and gives them the readnone/readonly attribute.
/// It also discovers function arguments that are not captured by the function
/// and marks them with the nocapture attribute.
///
Pass *createFunctionAttrsPass();
//===----------------------------------------------------------------------===//
/// createMergeFunctionsPass - This pass discovers identical functions and
/// collapses them.
///
ModulePass *createMergeFunctionsPass();
//===----------------------------------------------------------------------===//
/// createPartialInliningPass - This pass inlines parts of functions.
///
ModulePass *createPartialInliningPass();
//===----------------------------------------------------------------------===//
// createMetaRenamerPass - Rename everything with metasyntatic names.
//
ModulePass *createMetaRenamerPass();
//===----------------------------------------------------------------------===//
/// createBarrierNoopPass - This pass is purely a module pass barrier in a pass
/// manager.
ModulePass *createBarrierNoopPass();
/// \brief This pass lowers bitset metadata and the llvm.bitset.test intrinsic
/// to bitsets.
ModulePass *createLowerBitSetsPass();
} // End llvm namespace
#endif