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author | George Karpenkov <ekarpenkov@apple.com> | 2018-03-29 00:56:24 +0000 |
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committer | George Karpenkov <ekarpenkov@apple.com> | 2018-03-29 00:56:24 +0000 |
commit | 4ef199881c98858de8b5e1c3cf9ccd790a24a63a (patch) | |
tree | c1494579db065d6d0828844e8ba3a7b1cb5c8175 /lib/Sema/SemaTemplateInstantiateDecl.cpp | |
parent | 8e76adccd4a0615ae685ba81fc796bfb2c3fbfa1 (diff) | |
download | clang-4ef199881c98858de8b5e1c3cf9ccd790a24a63a.tar.gz |
[ast] Do not auto-initialize Objective-C for-loop variables in Objective-C++ in templatized code under ARC
The AST for the fragment
```
@interface I
@end
template <typename>
void decode(I *p) {
for (I *k in p) {}
}
void decode(I *p) {
decode<int>(p);
}
```
differs heavily when templatized and non-templatized:
```
|-FunctionTemplateDecl 0x7fbfe0863940 <line:4:1, line:7:1> line:5:6 decode
| |-TemplateTypeParmDecl 0x7fbfe0863690 <line:4:11> col:11 typename depth 0 index 0
| |-FunctionDecl 0x7fbfe08638a0 <line:5:1, line:7:1> line:5:6 decode 'void (I *__strong)'
| | |-ParmVarDecl 0x7fbfe08637a0 <col:13, col:16> col:16 referenced p 'I *__strong'
| | `-CompoundStmt 0x7fbfe0863b88 <col:19, line:7:1>
| | `-ObjCForCollectionStmt 0x7fbfe0863b50 <line:6:3, col:20>
| | |-DeclStmt 0x7fbfe0863a50 <col:8, col:13>
| | | `-VarDecl 0x7fbfe08639f0 <col:8, col:11> col:11 k 'I *const __strong'
| | |-ImplicitCastExpr 0x7fbfe0863a90 <col:16> 'I *' <LValueToRValue>
| | | `-DeclRefExpr 0x7fbfe0863a68 <col:16> 'I *__strong' lvalue ParmVar 0x7fbfe08637a0 'p' 'I *__strong'
| | `-CompoundStmt 0x7fbfe0863b78 <col:19, col:20>
| `-FunctionDecl 0x7fbfe0863f80 <line:5:1, line:7:1> line:5:6 used decode 'void (I *__strong)'
| |-TemplateArgument type 'int'
| |-ParmVarDecl 0x7fbfe0863ef8 <col:13, col:16> col:16 used p 'I *__strong'
| `-CompoundStmt 0x7fbfe0890cf0 <col:19, line:7:1>
| `-ObjCForCollectionStmt 0x7fbfe0890cc8 <line:6:3, col:20>
| |-DeclStmt 0x7fbfe0890c70 <col:8, col:13>
| | `-VarDecl 0x7fbfe0890c00 <col:8, col:11> col:11 k 'I *__strong' callinit
| | `-ImplicitValueInitExpr 0x7fbfe0890c60 <<invalid sloc>> 'I *__strong'
| |-ImplicitCastExpr 0x7fbfe0890cb0 <col:16> 'I *' <LValueToRValue>
| | `-DeclRefExpr 0x7fbfe0890c88 <col:16> 'I *__strong' lvalue ParmVar 0x7fbfe0863ef8 'p' 'I *__strong'
| `-CompoundStmt 0x7fbfe0863b78 <col:19, col:20>
```
Note how in the instantiated version ImplicitValueInitExpr unexpectedly appears.
While objects are auto-initialized under ARC, it does not make sense to
have an initializer for a for-loop variable, and it makes even less
sense to have such a different AST for instantiated and non-instantiated
version.
Digging deeper, I have found that there are two separate Sema* files for
dealing with templates and for dealing with non-templatized code.
In a non-templatized version, an initialization was performed only for
variables which are not loop variables for an Objective-C loop and not
variables for a C++ for-in loop:
```
if (FRI && (Tok.is(tok::colon) || isTokIdentifier_in())) {
bool IsForRangeLoop = false;
if (TryConsumeToken(tok::colon, FRI->ColonLoc)) {
IsForRangeLoop = true;
if (Tok.is(tok::l_brace))
FRI->RangeExpr = ParseBraceInitializer();
else
FRI->RangeExpr = ParseExpression();
}
Decl *ThisDecl = Actions.ActOnDeclarator(getCurScope(), D);
if (IsForRangeLoop)
Actions.ActOnCXXForRangeDecl(ThisDecl);
Actions.FinalizeDeclaration(ThisDecl);
D.complete(ThisDecl);
return Actions.FinalizeDeclaratorGroup(getCurScope(), DS, ThisDecl);
}
SmallVector<Decl *, 8> DeclsInGroup;
Decl *FirstDecl = ParseDeclarationAfterDeclaratorAndAttributes(
D, ParsedTemplateInfo(), FRI);
```
However the code in SemaTemplateInstantiateDecl was inconsistent,
guarding only against C++ for-in loops.
rdar://38391075
Differential Revision: https://reviews.llvm.org/D44989
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@328749 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Sema/SemaTemplateInstantiateDecl.cpp')
-rw-r--r-- | lib/Sema/SemaTemplateInstantiateDecl.cpp | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp index 9e09a6aa35..a7883c67b8 100644 --- a/lib/Sema/SemaTemplateInstantiateDecl.cpp +++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp @@ -4083,6 +4083,7 @@ void Sema::BuildVariableInstantiation( NewVar->setTSCSpec(OldVar->getTSCSpec()); NewVar->setInitStyle(OldVar->getInitStyle()); NewVar->setCXXForRangeDecl(OldVar->isCXXForRangeDecl()); + NewVar->setObjCForDecl(OldVar->isObjCForDecl()); NewVar->setConstexpr(OldVar->isConstexpr()); NewVar->setInitCapture(OldVar->isInitCapture()); NewVar->setPreviousDeclInSameBlockScope( @@ -4215,7 +4216,7 @@ void Sema::InstantiateVariableInitializer( } // We'll add an initializer to a for-range declaration later. - if (Var->isCXXForRangeDecl()) + if (Var->isCXXForRangeDecl() || Var->isObjCForDecl()) return; ActOnUninitializedDecl(Var); |