1//===- CallGraphExtractor.cpp - Call Graph Summary Extractor --------------===//
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#include "clang/AST/ASTContext.h"
10#include "clang/AST/Decl.h"
11#include "clang/AST/DeclCXX.h"
12#include "clang/AST/DeclObjC.h"
13#include "clang/Analysis/AnalysisDeclContext.h"
14#include "clang/Analysis/CallGraph.h"
15#include "clang/Basic/SourceManager.h"
16#include "clang/ScalableStaticAnalysis/Analyses/CallGraph/CallGraphSummary.h"
17#include "clang/ScalableStaticAnalysis/Core/TUSummary/ExtractorRegistry.h"
18#include "clang/ScalableStaticAnalysis/Core/TUSummary/TUSummaryBuilder.h"
19#include "llvm/ADT/STLExtras.h"
20#include <memory>
21
22using namespace clang;
23using namespace ssaf;
24
25namespace {
26class CallGraphExtractor final : public TUSummaryExtractor {
27public:
28 using TUSummaryExtractor::TUSummaryExtractor;
29
30private:
31 void HandleTranslationUnit(ASTContext &Ctx) override;
32
33 void handleCallGraphNode(const ASTContext &Ctx, const CallGraphNode *N);
34};
35} // namespace
36
37void CallGraphExtractor::HandleTranslationUnit(ASTContext &Ctx) {
38 // FIXME: Depending on the IncludeLocalEntities option, the extractor should
39 // include or exclude calls to function-local defined:
40 // - lambda functions
41 // - methods of local classes
42 // Currently, the extractor always includes these callees, even if
43 // IncludeLocalEntities is false.
44 CallGraph CG;
45 CG.addToCallGraph(
46 D: const_cast<TranslationUnitDecl *>(Ctx.getTranslationUnitDecl()));
47
48 for (const auto &N : llvm::make_second_range(c&: CG)) {
49 if (N && N->getDecl() && N->getDefinition())
50 handleCallGraphNode(Ctx, N: N.get());
51 }
52}
53
54void CallGraphExtractor::handleCallGraphNode(const ASTContext &Ctx,
55 const CallGraphNode *N) {
56 const FunctionDecl *Definition = N->getDefinition();
57
58 // FIXME: `clang::CallGraph` does not create entries for primary templates.
59 assert(!Definition->isTemplated());
60
61 auto CallerId = addEntity(D: Definition);
62 if (!CallerId)
63 return;
64
65 auto FnSummary = std::make_unique<CallGraphSummary>();
66
67 PresumedLoc Loc =
68 Ctx.getSourceManager().getPresumedLoc(Loc: Definition->getLocation());
69 FnSummary->Definition.File = Loc.getFilename();
70 FnSummary->Definition.Line = Loc.getLine();
71 FnSummary->Definition.Column = Loc.getColumn();
72 FnSummary->PrettyName = AnalysisDeclContext::getFunctionName(D: Definition);
73
74 for (const auto &Record : N->callees()) {
75 const Decl *CalleeDecl = Record.Callee->getDecl();
76
77 // FIXME: `clang::CallGraph` does not consider indirect calls, thus this is
78 // never null.
79 assert(CalleeDecl);
80
81 // `clang::CallGraph` resolves ObjCMessageExprs (including property
82 // dot-syntax) to their ObjCMethodDecls and adds them as callees — see
83 // `CGBuilder::VisitObjCMessageExpr` in clang/lib/Analysis/CallGraph.cpp.
84 // ObjC dispatch is dynamic, so recording these as direct callees would be
85 // misleading; skip them until we model ObjC properly.
86 if (isa<ObjCMethodDecl>(Val: CalleeDecl))
87 continue;
88
89 // FIXME: `clang::CallGraph` does not create entries for primary templates.
90 assert(!CalleeDecl->isTemplated());
91
92 auto CalleeId = addEntity(D: cast<NamedDecl>(Val: CalleeDecl));
93 if (!CalleeId)
94 continue;
95
96 if (const auto *MD = dyn_cast_or_null<CXXMethodDecl>(Val: CalleeDecl);
97 MD && MD->isVirtual()) {
98 FnSummary->VirtualCallees.insert(x: *CalleeId);
99 continue;
100 }
101 FnSummary->DirectCallees.insert(x: *CalleeId);
102 }
103
104 SummaryBuilder.addSummary(Entity: *CallerId, Data: std::move(FnSummary));
105}
106
107static TUSummaryExtractorRegistry::Add<CallGraphExtractor>
108 RegisterExtractor(CallGraphSummary::Name,
109 "Extracts static call-graph information");
110
111namespace clang::ssaf {
112// NOLINTNEXTLINE(misc-use-internal-linkage)
113volatile int CallGraphExtractorAnchorSource = 0;
114} // namespace clang::ssaf
115