The SwitchStmt::FirstCase member is not initialized when the AST is
built by the ASTStmtReader. See the below code of
ASTStmtReader::VisitSwitchStmt in the case where the for loop does not
have any iterations:
```
// ... more code ...
SwitchCase *PrevSC = nullptr;
for (auto E = Record.size(); Record.getIdx() != E; ) {
SwitchCase *SC = Record.getSwitchCaseWithID(Record.readInt());
if (PrevSC)
PrevSC->setNextSwitchCase(SC);
else
S->setSwitchCaseList(SC); // Sets FirstCase !!!
PrevSC = SC;
}
} // return
```
Later, in ASTNodeImporter::VisitSwitchStmt,
we have a condition that depends on this uninited value:
```
for (SwitchCase *SC = S->getSwitchCaseList(); SC != nullptr;
SC = SC->getNextSwitchCase()) {
// ... more code ...
}
```
This is clearly an UB. This causes non-deterministic crashes when
ClangSA analyzes some code with CTU. See the below report by valgrind
(the whole valgrind output is attached):
```
==31019== Conditional jump or move depends on uninitialised value(s)
==31019== at 0x12ED1983: clang::ASTNodeImporter::VisitSwitchStmt(clang::SwitchStmt*) (ASTImporter.cpp:6195)
==31019== by 0x12F1D509: clang::StmtVisitorBase<std::add_pointer, clang::ASTNodeImporter, llvm::Expected<clang::Stmt*>>::Visit(clang::Stmt*) (StmtNodes.inc:591)
==31019== by 0x12EE4FDF: clang::ASTImporter::Import(clang::Stmt*) (ASTImporter.cpp:8484)
==31019== by 0x12F09498: llvm::Expected<clang::Stmt*> clang::ASTNodeImporter::import<clang::Stmt>(clang::Stmt*) (ASTImporter.cpp:164)
==31019== by 0x12F3A1F5: llvm::Error clang::ASTNodeImporter::ImportArrayChecked<clang::Stmt**, clang::Stmt**>(clang::Stmt**, clang::Stmt**, clang::Stmt**) (ASTImporter.cpp:653)
==31019== by 0x12F13152: llvm::Error clang::ASTNodeImporter::ImportContainerChecked<llvm::iterator_range<clang::Stmt**>, llvm::SmallVector<clang::Stmt*, 8u> >(llvm::iterator_range<clang::Stmt**> const&, llvm::SmallVector<clang::Stmt*, 8u>&) (ASTImporter.cpp:669)
==31019== by 0x12ED099F: clang::ASTNodeImporter::VisitCompoundStmt(clang::CompoundStmt*) (ASTImporter.cpp:6077)
==31019== by 0x12F1CC2D: clang::StmtVisitorBase<std::add_pointer, clang::ASTNodeImporter, llvm::Expected<clang::Stmt*>>::Visit(clang::Stmt*) (StmtNodes.inc:73)
==31019== by 0x12EE4FDF: clang::ASTImporter::Import(clang::Stmt*) (ASTImporter.cpp:8484)
==31019== by 0x12F09498: llvm::Expected<clang::Stmt*> clang::ASTNodeImporter::import<clang::Stmt>(clang::Stmt*) (ASTImporter.cpp:164)
==31019== by 0x12F13275: clang::Stmt* clang::ASTNodeImporter::importChecked<clang::Stmt*>(llvm::Error&, clang::Stmt* const&) (ASTImporter.cpp:197)
==31019== by 0x12ED0CE6: clang::ASTNodeImporter::VisitCaseStmt(clang::CaseStmt*) (ASTImporter.cpp:6098)
```
Differential Revision: https://reviews.llvm.org/D97849
Summary:
Add an option to enable on-demand parsing of needed ASTs during CTU analysis.
Two options are introduced. CTUOnDemandParsing enables the feature, and
CTUOnDemandParsingDatabase specifies the path to a compilation database, which
has all the necessary information to generate the ASTs.
Reviewers: martong, balazske, Szelethus, xazax.hun
Subscribers: ormris, mgorny, whisperity, xazax.hun, baloghadamsoftware, szepet, rnkovacs, a.sidorin, mikhail.ramalho, Szelethus, donat.nagy, dkrupp, Charusso, steakhal, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D75665
Summary: This is just changing naming and documentation to be general about external definitions that can be imported for cross translation unit analysis. There is at least a plan to add VarDecls: D46421
Reviewers: NoQ, xazax.hun, martong, a.sidorin, george.karpenkov, serge-sans-paille
Reviewed By: xazax.hun, martong
Subscribers: mgorny, whisperity, baloghadamsoftware, szepet, rnkovacs, mikhail.ramalho, Szelethus, donat.nagy, dkrupp, cfe-commits
Differential Revision: https://reviews.llvm.org/D56441
llvm-svn: 350852
Summary:
Adding some more CTU list tests. E.g. to check if a construct is unsupported.
We also slightly modify the handling of the return value of the `Import`
function from ASTImporter.
Reviewers: xazax.hun, balazske, a_sidorin
Subscribers: rnkovacs, dkrupp, Szelethus, gamesh411, cfe-commits
Differential Revision: https://reviews.llvm.org/D55131
llvm-svn: 348605
Gabor Marton