llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: None (martinboehme) <details> <summary>Changes</summary> We definitely know that these operations change the value of their operand, so clear out any value associated with it. We don't create a new value, instead leaving it to the analysis to do this if desired. --- Full diff: https://github.com/llvm/llvm-project/pull/96601.diff 2 Files Affected: - (modified) clang/lib/Analysis/FlowSensitive/Transfer.cpp (+11-6) - (modified) clang/unittests/Analysis/FlowSensitive/TransferTest.cpp (+23-8) ``````````diff diff --git a/clang/lib/Analysis/FlowSensitive/Transfer.cpp b/clang/lib/Analysis/FlowSensitive/Transfer.cpp index 8109ac6a781e7..3c896d373a211 100644 --- a/clang/lib/Analysis/FlowSensitive/Transfer.cpp +++ b/clang/lib/Analysis/FlowSensitive/Transfer.cpp @@ -391,17 +391,22 @@ class TransferVisitor : public ConstStmtVisitor<TransferVisitor> { } case UO_PreInc: case UO_PreDec: - // Propagate the storage location, but don't create a new value; to - // avoid generating unnecessary values, we leave it to the specific - // analysis to do this if desired. + // Propagate the storage location and clear out any value associated with + // it (to represent the fact that the value has definitely changed). + // To avoid generating unnecessary values, we leave it to the specific + // analysis to create a new value if desired. propagateStorageLocation(*S->getSubExpr(), *S, Env); + if (StorageLocation *Loc = Env.getStorageLocation(*S->getSubExpr())) + Env.clearValue(*Loc); break; case UO_PostInc: case UO_PostDec: - // Propagate the old value, but don't create a new value; to avoid - // generating unnecessary values, we leave it to the specific analysis - // to do this if desired. + // Propagate the old value, then clear out any value associated with the + // storage location (to represent the fact that the value has definitely + // changed). See above for rationale. propagateValue(*S->getSubExpr(), *S, Env); + if (StorageLocation *Loc = Env.getStorageLocation(*S->getSubExpr())) + Env.clearValue(*Loc); break; default: break; diff --git a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp index cfbc64c77b0cc..e743eefa5d458 100644 --- a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp +++ b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp @@ -3789,36 +3789,51 @@ TEST(TransferTest, AddrOfReference) { TEST(TransferTest, Preincrement) { std::string Code = R"( void target(int I) { + (void)0; // [[before]] int &IRef = ++I; - // [[p]] + // [[after]] } )"; runDataflow( Code, [](const llvm::StringMap<DataflowAnalysisState<NoopLattice>> &Results, ASTContext &ASTCtx) { - const Environment &Env = getEnvironmentAtAnnotation(Results, "p"); + const Environment &EnvBefore = + getEnvironmentAtAnnotation(Results, "before"); + const Environment &EnvAfter = + getEnvironmentAtAnnotation(Results, "after"); - EXPECT_EQ(&getLocForDecl(ASTCtx, Env, "IRef"), - &getLocForDecl(ASTCtx, Env, "I")); + EXPECT_EQ(&getLocForDecl(ASTCtx, EnvAfter, "IRef"), + &getLocForDecl(ASTCtx, EnvBefore, "I")); + + const ValueDecl *IDecl = findValueDecl(ASTCtx, "I"); + EXPECT_NE(EnvBefore.getValue(*IDecl), nullptr); + EXPECT_EQ(EnvAfter.getValue(*IDecl), nullptr); }); } TEST(TransferTest, Postincrement) { std::string Code = R"( void target(int I) { + (void)0; // [[before]] int OldVal = I++; - // [[p]] + // [[after]] } )"; runDataflow( Code, [](const llvm::StringMap<DataflowAnalysisState<NoopLattice>> &Results, ASTContext &ASTCtx) { - const Environment &Env = getEnvironmentAtAnnotation(Results, "p"); + const Environment &EnvBefore = + getEnvironmentAtAnnotation(Results, "before"); + const Environment &EnvAfter = + getEnvironmentAtAnnotation(Results, "after"); + + EXPECT_EQ(&getValueForDecl(ASTCtx, EnvBefore, "I"), + &getValueForDecl(ASTCtx, EnvAfter, "OldVal")); - EXPECT_EQ(&getValueForDecl(ASTCtx, Env, "OldVal"), - &getValueForDecl(ASTCtx, Env, "I")); + const ValueDecl *IDecl = findValueDecl(ASTCtx, "I"); + EXPECT_EQ(EnvAfter.getValue(*IDecl), nullptr); }); } `````````` </details> https://github.com/llvm/llvm-project/pull/96601 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
