1//===- llvm/CodeGen/GlobalMerge.h -------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_CODEGEN_GLOBALMERGE_H
10#define LLVM_CODEGEN_GLOBALMERGE_H
11
12#include "llvm/IR/PassManager.h"
13
14namespace llvm {
15
16class TargetMachine;
17
18struct GlobalMergeOptions {
19 // FIXME: Infer the maximum possible offset depending on the actual users
20 // (these max offsets are different for the users inside Thumb or ARM
21 // functions), see the code that passes in the offset in the ARM backend
22 // for more information.
23 unsigned MaxOffset = 0;
24 // The minimum size in bytes of each global that should considered in merging.
25 unsigned MinSize = 0;
26 bool GroupByUse = true;
27 bool IgnoreSingleUse = true;
28 bool MergeConst = false;
29 /// Whether we should merge global variables that have external linkage.
30 bool MergeExternal = true;
31 /// Whether we should try to optimize for size only.
32 /// Currently, this applies a dead simple heuristic: only consider globals
33 /// used in minsize functions for merging.
34 /// FIXME: This could learn about optsize, and be used in the cost model.
35 bool SizeOnly = false;
36};
37
38// FIXME: This pass must run before AsmPrinterPass::doInitialization!
39class GlobalMergePass : public PassInfoMixin<GlobalMergePass> {
40 const TargetMachine *TM;
41 GlobalMergeOptions Options;
42
43public:
44 GlobalMergePass(const TargetMachine *TM, GlobalMergeOptions Options)
45 : TM(TM), Options(Options) {}
46
47 PreservedAnalyses run(Module &M, ModuleAnalysisManager &MAM);
48};
49
50} // namespace llvm
51
52#endif // LLVM_CODEGEN_GLOBALMERGE_H
53