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Fix an iterator invalidation issue: deserializing a key function can write to

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the key functions table. Don't hold references to anything within that table
across such an access.

llvm-svn: 212437
This commit is contained in:
Richard Smith 2014-07-07 06:38:20 +00:00
parent f456e44211
commit a9a1c68a1b
3 changed files with 118 additions and 7 deletions
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25
clang/lib/AST/RecordLayoutBuilder.cpp
View File

@ -2860,11 +2860,20 @@ const CXXMethodDecl *ASTContext::getCurrentKeyFunction(const CXXRecordDecl *RD)
assert(RD->getDefinition() && "Cannot get key function for forward decl!");
RD = cast<CXXRecordDecl>(RD->getDefinition());
LazyDeclPtr &Entry = KeyFunctions[RD];
if (!Entry)
Entry = const_cast<CXXMethodDecl*>(computeKeyFunction(*this, RD));
// Beware:
// 1) computing the key function might trigger deserialization, which might
// invalidate iterators into KeyFunctions
// 2) 'get' on the LazyDeclPtr might also trigger deserialization and
// invalidate the LazyDeclPtr within the map itself
LazyDeclPtr Entry = KeyFunctions[RD];
const Decl *Result =
Entry ? Entry.get(getExternalSource()) : computeKeyFunction(*this, RD);
return cast_or_null<CXXMethodDecl>(Entry.get(getExternalSource()));
// Store it back if it changed.
if (Entry.isOffset() || Entry.isValid() != bool(Result))
KeyFunctions[RD] = const_cast<Decl*>(Result);
return cast_or_null<CXXMethodDecl>(Result);
}
void ASTContext::setNonKeyFunction(const CXXMethodDecl *Method) {
@ -2881,10 +2890,12 @@ void ASTContext::setNonKeyFunction(const CXXMethodDecl *Method) {
if (I == KeyFunctions.end()) return;
// If it is cached, check whether it's the target method, and if so,
// remove it from the cache.
if (I->second.get(getExternalSource()) == Method) {
// remove it from the cache. Note, the call to 'get' might invalidate
// the iterator and the LazyDeclPtr object within the map.
LazyDeclPtr Ptr = I->second;
if (Ptr.get(getExternalSource()) == Method) {
// FIXME: remember that we did this for module / chained PCH state?
KeyFunctions.erase(I);
KeyFunctions.erase(Method->getParent());
}
}

3
clang/lib/Serialization/ASTReaderDecl.cpp
View File

@ -1479,6 +1479,9 @@ ASTDeclReader::VisitCXXRecordDeclImpl(CXXRecordDecl *D) {
if (WasDefinition) {
DeclID KeyFn = ReadDeclID(Record, Idx);
if (KeyFn && D->IsCompleteDefinition)
// FIXME: This is wrong for the ARM ABI, where some other module may have
// made this function no longer be a key function. We need an update
// record or similar for that case.
C.KeyFunctions[D] = KeyFn;
}

97
clang/test/PCH/cxx-key-functions.cpp Normal file
View File

@ -0,0 +1,97 @@
// RUN: %clang_cc1 -x c++ -include %s -emit-llvm-only %s
// RUN: %clang_cc1 -x c++ -emit-pch %s -o %t
// RUN: %clang_cc1 -include-pch %t -emit-llvm-only %s
#ifndef HEADER
#define HEADER
struct S00 { virtual void f(); };
struct S01 { virtual void f(); };
struct S02 { virtual void f(); };
struct S03 { virtual void f(); };
struct S04 { virtual void f(); };
struct S05 { virtual void f(); };
struct S06 { virtual void f(); };
struct S07 { virtual void f(); };
struct S08 { virtual void f(); };
struct S09 { virtual void f(); };
struct S10 { virtual void f(); };
struct S11 { virtual void f(); };
struct S12 { virtual void f(); };
struct S13 { virtual void f(); };
struct S14 { virtual void f(); };
struct S15 { virtual void f(); };
struct S16 { virtual void f(); };
struct S17 { virtual void f(); };
struct S18 { virtual void f(); };
struct S19 { virtual void f(); };
struct S20 { virtual void f(); };
struct S21 { virtual void f(); };
struct S22 { virtual void f(); };
struct S23 { virtual void f(); };
struct S24 { virtual void f(); };
struct S25 { virtual void f(); };
struct S26 { virtual void f(); };
struct S27 { virtual void f(); };
struct S28 { virtual void f(); };
struct S29 { virtual void f(); };
struct S30 { virtual void f(); };
struct S31 { virtual void f(); };
struct S32 { virtual void f(); };
struct S33 { virtual void f(); };
struct S34 { virtual void f(); };
struct S35 { virtual void f(); };
struct S36 { virtual void f(); };
struct S37 { virtual void f(); };
struct S38 { virtual void f(); };
struct S39 { virtual void f(); };
struct S40 { virtual void f(); };
struct S41 { virtual void f(); };
struct S42 { virtual void f(); };
struct S43 { virtual void f(); };
struct S44 { virtual void f(); };
struct S45 { virtual void f(); };
struct S46 { virtual void f(); };
struct S47 { virtual void f(); };
struct S48 { virtual void f(); };
struct S49 { virtual void f(); };
struct S50 { virtual void f(); };
struct S51 { virtual void f(); };
struct S52 { virtual void f(); };
struct S53 { virtual void f(); };
struct S54 { virtual void f(); };
struct S55 { virtual void f(); };
struct S56 { virtual void f(); };
struct S57 { virtual void f(); };
struct S58 { virtual void f(); };
struct S59 { virtual void f(); };
struct S60 { virtual void f(); };
struct S61 { virtual void f(); };
struct S62 { virtual void f(); };
struct S63 { virtual void f(); };
struct S64 { virtual void f(); };
struct S65 { virtual void f(); };
struct S66 { virtual void f(); };
struct S67 { virtual void f(); };
struct S68 { virtual void f(); };
struct S69 { virtual void f(); };
struct Test {
// Deserializing this key function should cause the key functions
// table to get resized.
virtual void f(S00, S01, S02, S03, S04, S05, S06, S07, S08, S09,
S10, S11, S12, S13, S14, S15, S16, S17, S18, S19,
S20, S21, S22, S23, S24, S25, S26, S27, S28, S29,
S30, S31, S32, S33, S34, S35, S36, S37, S38, S39,
S40, S41, S42, S43, S44, S45, S46, S47, S48, S49,
S50, S51, S52, S53, S54, S55, S56, S57, S58, S59,
S60, S61, S62, S63, S64, S65, S66, S67, S68, S69);
virtual void g();
};
#else
void Test::g() {}
void h(Test &t) { t.g(); }
#endif