clang/unittests/Analysis/FlowSensitive/CFGMatchSwitchTest.cpp

   1 //===- unittests/Analysis/FlowSensitive/CFGMatchSwitchTest.cpp ------------===//
   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/Analysis/FlowSensitive/CFGMatchSwitch.h"
  10 #include "clang/AST/ASTContext.h"
  11 #include "clang/AST/Decl.h"
  12 #include "clang/AST/Stmt.h"
  13 #include "clang/Analysis/CFG.h"
  14 #include "clang/Tooling/Tooling.h"
  15 #include "llvm/ADT/StringRef.h"
  16 #include "gtest/gtest.h"
  17
  18 using namespace clang;
  19 using namespace dataflow;
  20 using namespace ast_matchers;
  21
  22 namespace {
  23 // State for tracking the number of matches on each kind of CFGElement by the
  24 // CFGMatchSwitch. Currently only tracks CFGStmt and CFGInitializer.
  25 struct CFGElementMatches {
  26   unsigned StmtMatches = 0;
  27   unsigned InitializerMatches = 0;
  28 };
  29
  30 // Returns a match switch that counts the number of local variables
  31 // (singly-declared) and fields initialized to the integer literal 42.
  32 auto buildCFGMatchSwitch() {
  33   return CFGMatchSwitchBuilder<CFGElementMatches>()
  34       .CaseOfCFGStmt<DeclStmt>(
  35           declStmt(hasSingleDecl(
  36               varDecl(hasInitializer(integerLiteral(equals(42)))))),
  37           [](const DeclStmt *, const MatchFinder::MatchResult &,
  38              CFGElementMatches &Counter) { Counter.StmtMatches++; })
  39       .CaseOfCFGInit<CXXCtorInitializer>(
  40           cxxCtorInitializer(withInitializer(integerLiteral(equals(42)))),
  41           [](const CXXCtorInitializer *, const MatchFinder::MatchResult &,
  42              CFGElementMatches &Counter) { Counter.InitializerMatches++; })
  43       .Build();
  44 }
  45
  46 // Runs the match switch `MS` on the control flow graph generated from `Code`,
  47 // tracking information in state `S`. For simplicity, this test utility is
  48 // restricted to CFGs with a single control flow block (excluding entry and
  49 // exit blocks) - generated by `Code` with sequential flow (i.e. no branching).
  50 //
  51 // Requirements:
  52 //
  53 //  `Code` must contain a function named `f`, the body of this function will be
  54 //  used to generate the CFG.
  55 template <typename State>
  56 void applySwitchToCode(CFGMatchSwitch<State> &MS, State &S,
  57                        llvm::StringRef Code) {
  58   auto Unit = tooling::buildASTFromCodeWithArgs(Code, {"-Wno-unused-value"});
  59   auto &Ctx = Unit->getASTContext();
  60   const auto *F = selectFirst<FunctionDecl>(
  61       "f", match(functionDecl(isDefinition(), hasName("f")).bind("f"), Ctx));
  62
  63   CFG::BuildOptions BO;
  64   BO.AddInitializers = true;
  65
  66   auto CFG = CFG::buildCFG(F, F->getBody(), &Ctx, BO);
  67   auto CFGBlock = *CFG->getEntry().succ_begin();
  68   for (auto &Elt : CFGBlock->Elements) {
  69     MS(Elt, Ctx, S);
  70   }
  71 }
  72
  73 TEST(CFGMatchSwitchTest, NoInitializationTo42) {
  74   CFGMatchSwitch<CFGElementMatches> Switch = buildCFGMatchSwitch();
  75   CFGElementMatches Counter;
  76   applySwitchToCode(Switch, Counter, R"(
  77     void f() {
  78       42;
  79     }
  80   )");
  81   EXPECT_EQ(Counter.StmtMatches, 0u);
  82   EXPECT_EQ(Counter.InitializerMatches, 0u);
  83 }
  84
  85 TEST(CFGMatchSwitchTest, SingleLocalVarInitializationTo42) {
  86   CFGMatchSwitch<CFGElementMatches> Switch = buildCFGMatchSwitch();
  87   CFGElementMatches Counter;
  88   applySwitchToCode(Switch, Counter, R"(
  89     void f() {
  90       int i = 42;
  91     }
  92   )");
  93   EXPECT_EQ(Counter.StmtMatches, 1u);
  94   EXPECT_EQ(Counter.InitializerMatches, 0u);
  95 }
  96
  97 TEST(CFGMatchSwitchTest, SingleFieldInitializationTo42) {
  98   CFGMatchSwitch<CFGElementMatches> Switch = buildCFGMatchSwitch();
  99   CFGElementMatches Counter;
 100   applySwitchToCode(Switch, Counter, R"(
 101     struct f {
 102       int i;
 103       f(): i(42) {}
 104     };
 105   )");
 106   EXPECT_EQ(Counter.StmtMatches, 0u);
 107   EXPECT_EQ(Counter.InitializerMatches, 1u);
 108 }
 109
 110 TEST(CFGMatchSwitchTest, LocalVarAndFieldInitializationTo42) {
 111   CFGMatchSwitch<CFGElementMatches> Switch = buildCFGMatchSwitch();
 112   CFGElementMatches Counter;
 113   applySwitchToCode(Switch, Counter, R"(
 114     struct f {
 115       int i;
 116       f(): i(42) {
 117         int j = 42;
 118       }
 119     };
 120   )");
 121   EXPECT_EQ(Counter.StmtMatches, 1u);
 122   EXPECT_EQ(Counter.InitializerMatches, 1u);
 123 }
 124 } // namespace