Clang checks whether the type given to va_arg will automatically cause
undefined behavior, but this check was issuing false positives for
enumerations in C++. The issue turned out to be because
typesAreCompatible() in C++ checks whether the types are *the same*, so
this uses custom logic if the type compatibility check fails.
This issue was found by a user on code like:
typedef enum {
CURLINFO_NONE,
CURLINFO_EFFECTIVE_URL,
CURLINFO_LASTONE = 60
} CURLINFO;
...
__builtin_va_arg(list, CURLINFO); // false positive warning
Given that C++ defers to C for the rules around va_arg, the behavior
should be the same in both C and C++ and not diagnose because int and
CURLINFO are "compatible enough" types for va_arg.
Reland https://reviews.llvm.org/D76696
All known crashes have been fixed, another attemption.
We have rolled out this to all internal users for a while, didn't see
big issues, we consider it is stable enough.
Reviewed By: sammccall
Subscribers: rsmith, hubert.reinterpretcast, ebevhan, jkorous, arphaman, kadircet, usaxena95, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D78350
This reverts commit 0788acbccb.
This reverts commit c2d7a1f79cedfc9fcb518596aa839da4de0adb69: Revert "[clangd] Add test for FindTarget+RecoveryExpr (which already works). NFC"
It causes a crash on invalid code:
class X {
decltype(unresolved()) foo;
};
constexpr int s = sizeof(X);
Summary:
First, getCurFunction looks through blocks and lambdas, which is wrong.
Inside a lambda, va_start should refer to the lambda call operator
prototype. This fixes PR32737.
Second, we shouldn't use any of the getCur* methods, because they look
through contexts that we don't want to look through (EnumDecl,
CapturedStmtDecl). We can use CurContext directly as the calling
context.
Finally, this code assumed that CallExprs would never appear outside of
code contexts (block, function, obj-c method), which is wrong. Struct
member initializers are an easy way to create and parse exprs in a
non-code context.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D32761
llvm-svn: 302188
Aaron Ballman