1//===- FunctionAttrs.h - Compute function attributes ------------*- 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/// \file
10/// Provides passes for computing function attributes based on interprocedural
11/// analyses.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_TRANSFORMS_IPO_FUNCTIONATTRS_H
16#define LLVM_TRANSFORMS_IPO_FUNCTIONATTRS_H
17
18#include "llvm/Analysis/AliasAnalysis.h"
19#include "llvm/Analysis/CGSCCPassManager.h"
20#include "llvm/Analysis/LazyCallGraph.h"
21#include "llvm/IR/PassManager.h"
22
23namespace llvm {
24
25class GlobalValueSummary;
26class ModuleSummaryIndex;
27class Function;
28class Module;
29
30/// Returns the memory access properties of this copy of the function.
31MemoryEffects computeFunctionBodyMemoryAccess(Function &F, AAResults &AAR);
32
33/// Propagate function attributes for function summaries along the index's
34/// callgraph during thinlink
35bool thinLTOPropagateFunctionAttrs(
36 ModuleSummaryIndex &Index,
37 function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
38 isPrevailing);
39
40/// Computes function attributes in post-order over the call graph.
41///
42/// By operating in post-order, this pass computes precise attributes for
43/// called functions prior to processsing their callers. This "bottom-up"
44/// approach allows powerful interprocedural inference of function attributes
45/// like memory access patterns, etc. It can discover functions that do not
46/// access memory, or only read memory, and give them the readnone/readonly
47/// attribute. It also discovers function arguments that are not captured by
48/// the function and marks them with the nocapture attribute.
49struct PostOrderFunctionAttrsPass : PassInfoMixin<PostOrderFunctionAttrsPass> {
50 PostOrderFunctionAttrsPass(bool SkipNonRecursive = false)
51 : SkipNonRecursive(SkipNonRecursive) {}
52 PreservedAnalyses run(LazyCallGraph::SCC &C, CGSCCAnalysisManager &AM,
53 LazyCallGraph &CG, CGSCCUpdateResult &UR);
54
55 void printPipeline(raw_ostream &OS,
56 function_ref<StringRef(StringRef)> MapClassName2PassName);
57
58private:
59 bool SkipNonRecursive;
60};
61
62/// A pass to do RPO deduction and propagation of function attributes.
63///
64/// This pass provides a general RPO or "top down" propagation of
65/// function attributes. For a few (rare) cases, we can deduce significantly
66/// more about function attributes by working in RPO, so this pass
67/// provides the complement to the post-order pass above where the majority of
68/// deduction is performed.
69// FIXME: Currently there is no RPO CGSCC pass structure to slide into and so
70// this is a boring module pass, but eventually it should be an RPO CGSCC pass
71// when such infrastructure is available.
72class ReversePostOrderFunctionAttrsPass
73 : public PassInfoMixin<ReversePostOrderFunctionAttrsPass> {
74public:
75 PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
76};
77
78} // end namespace llvm
79
80#endif // LLVM_TRANSFORMS_IPO_FUNCTIONATTRS_H
81

source code of llvm/include/llvm/Transforms/IPO/FunctionAttrs.h