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[Sema] Don't crash on scanf on forward-declared enums. 

This is valid in GNU C, which allows pointers to incomplete enums. GCC
just pretends that the underlying type is 'int' in those cases, follow
that behavior.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279374 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer 2016-08-20 16:51:33 +00:00
parent dde85a8d60
commit 9c27c6bd26
3 changed files with 35 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
lib/Analysis/FormatString.cpp
View File

@ -310,8 +310,13 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
return Match;
case AnyCharTy: {
if (const EnumType *ETy = argTy->getAs<EnumType>())
if (const EnumType *ETy = argTy->getAs<EnumType>()) {
// If the enum is incomplete we know nothing about the underlying type.
// Assume that it's 'int'.
if (!ETy->getDecl()->isComplete())
return NoMatch;
argTy = ETy->getDecl()->getIntegerType();
}
if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
switch (BT->getKind()) {
@ -327,8 +332,14 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
}
case SpecificTy: {
if (const EnumType *ETy = argTy->getAs<EnumType>())
argTy = ETy->getDecl()->getIntegerType();
if (const EnumType *ETy = argTy->getAs<EnumType>()) {
// If the enum is incomplete we know nothing about the underlying type.
// Assume that it's 'int'.
if (!ETy->getDecl()->isComplete())
argTy = C.IntTy;
else
argTy = ETy->getDecl()->getIntegerType();
}
argTy = C.getCanonicalType(argTy).getUnqualifiedType();
if (T == argTy)

6
lib/Analysis/ScanfFormatString.cpp
View File

@ -418,8 +418,12 @@ bool ScanfSpecifier::fixType(QualType QT, QualType RawQT,
QualType PT = QT->getPointeeType();
// If it's an enum, get its underlying type.
if (const EnumType *ETy = PT->getAs<EnumType>())
if (const EnumType *ETy = PT->getAs<EnumType>()) {
// Don't try to fix incomplete enums.
if (!ETy->getDecl()->isComplete())
return false;
PT = ETy->getDecl()->getIntegerType();
}
const BuiltinType *BT = PT->getAs<BuiltinType>();
if (!BT)

16
test/Sema/format-strings-enum.c
View File

@ -11,6 +11,7 @@
#endif
EXTERN_C int printf(const char *,...);
EXTERN_C int scanf(const char *, ...);
typedef enum { Constant = 0 } TestEnum;
// Note that in C, the type of 'Constant' is 'int'. In C++ it is 'TestEnum'.
@ -34,3 +35,18 @@ void testLong(LongEnum input) {
printf("%lu", input);
printf("%lu", LongConstant);
}
#ifndef __cplusplus
// GNU C allows forward declaring enums.
extern enum forward_declared *fwd;
void forward_enum() {
printf("%u", fwd); // expected-warning{{format specifies type 'unsigned int' but the argument has type 'enum forward_declared *}}
printf("%p", fwd);
scanf("%c", fwd); // expected-warning{{format specifies type 'char *' but the argument has type 'enum forward_declared *}}
scanf("%u", fwd);
scanf("%lu", fwd); // expected-warning{{format specifies type 'unsigned long *' but the argument has type 'enum forward_declared *}}
scanf("%p", fwd); // expected-warning{{format specifies type 'void **' but the argument has type 'enum forward_declared *}}
}
#endif