11 Commits

Author SHA1 Message Date
Vladimir Vuksanovic
9d1dd9a264
[Sema] Fix false positive warnings for misaligned member access (#150025)
These warnings are reported on a per expression basis, however some
potential misaligned accesses are discarded before that happens. The
problem is when a new expression starts while processing another
expression. The new expression will end first and emit all potential
misaligned accesses collected up to that point. That includes candidates
that were found in the parent expression, even though they might have
gotten discarded later.

Fixed by checking if the candidate is located withing the currently
processed expression.

Fixes #144729
2025-08-14 06:14:43 -07:00
Aaron Ballman
19e984ef8f Properly print unnamed TagDecl objects in diagnostics
The diagnostics engine is very smart about being passed a NamedDecl to
print as part of a diagnostic; it gets the "right" form of the name,
quotes it properly, etc. However, the result of using an unnamed tag
declaration was to print '' instead of anything useful.

This patch causes us to print the same information we'd have gotten if
we had printed the type of the declaration rather than the name of it,
as that's the most relevant information we can display.

Differential Revision: https://reviews.llvm.org/D134813
2022-10-14 08:18:28 -04:00
Aaron Ballman
e765e0bc8e Use functions with prototypes when appropriate; NFC
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,

  void func();

becomes

  void func(void);

This is the first batch of tests being updated (there are a significant
number of other tests left to be updated).
2022-02-03 16:42:27 -05:00
Olivier Goffart
67049f034d Fix crash parsing invalid code
The code in the test caused a crash with this backtrace:

 RecordLayoutBuilder.cpp:2934: const clang::ASTRecordLayout &clang::ASTContext::getASTRecordLayout(const clang::RecordDecl *) const: Assertion `!D->isInvalidDecl() && "Cannot get layout of invalid decl!"' failed.
 [...]
 #7 0x00007f63963d845a __assert_fail_base (/usr/lib/libc.so.6+0x2c45a)
 #8 0x00007f63963d84d2 (/usr/lib/libc.so.6+0x2c4d2)
 #9 0x00007f63937a0631 clang::ASTContext::getASTRecordLayout(clang::RecordDecl const*) const /home/olivier/prog/llvm/tools/clang/lib/AST/RecordLayoutBuilder.cpp:2935:3
 #10 0x00007f63937a1ad5 getFieldOffset(clang::ASTContext const&, clang::FieldDecl const*) /home/olivier/prog/llvm/tools/clang/lib/AST/RecordLayoutBuilder.cpp:3057:37
 #11 0x00007f6391869f14 clang::Sema::RefersToMemberWithReducedAlignment(clang::Expr*, llvm::function_ref<void (clang::Expr*, clang::RecordDecl*, clang::FieldDecl*, clang::CharUnits)>) /home/olivier/prog/llvm/tools/clang/lib/Sema/SemaChecking.cpp:12139:23
 #12 0x00007f639186a2f8 clang::Sema::CheckAddressOfPackedMember(clang::Expr*) /home/olivier/prog/llvm/tools/clang/lib/Sema/SemaChecking.cpp:12190:1
 #13 0x00007f6391a7a81c clang::Sema::CheckAddressOfOperand(clang::ActionResult<clang::Expr*, true>&, clang::SourceLocation) /home/olivier/prog/llvm/tools/clang/lib/Sema/SemaExpr.cpp:11111:10
 #14 0x00007f6391a7f5d2 clang::Sema::CreateBuiltinUnaryOp(clang::SourceLocation, clang::UnaryOperatorKind, clang::Expr*) /home/olivier/prog/llvm/tools/clang/lib/Sema/SemaExpr.cpp:11932:18

Fixing by bailing out for invalid classes.

Differential Revision: https://reviews.llvm.org/D35108

llvm-svn: 307371
2017-07-07 09:38:59 +00:00
Roger Ferrer Ibanez
e3d8026cc7 Remove some false positives when taking the address of packed members
Differential Revision: https://reviews.llvm.org/D23657

llvm-svn: 286798
2016-11-14 08:53:27 +00:00
Alex Lorenz
014181e7f4 [Sema] Packed member warning: Use the typedef name for anonymous structures
This commit improves the packed member warning by showing the name of the
anonymous structure/union when it was defined within a typedef declaration.

rdar://28498901

Differential Revision: https://reviews.llvm.org/D25106

llvm-svn: 283304
2016-10-05 09:27:48 +00:00
Roger Ferrer Ibanez
f7b9f3149b Add missing tests
Change r278483 was missing the tests

Differential Revision: https://reviews.llvm.org/D20561

llvm-svn: 278908
2016-08-17 06:52:15 +00:00
Roger Ferrer Ibanez
58b8e483f0 Reverting 275417
This change has triggered unexpected failures.

llvm-svn: 275462
2016-07-14 20:05:30 +00:00
Roger Ferrer Ibanez
585ea9ddce Diagnose taking address and reference binding of packed members
This patch implements PR#22821.

Taking the address of a packed member is dangerous since the reduced
alignment of the pointee is lost. This can lead to memory alignment
faults in some architectures if the pointer value is dereferenced.

This change adds a new warning to clang emitted when taking the address
of a packed member. A packed member is either a field/data member
declared as attribute((packed)) or belonging to a struct/class
declared as such. The associated flag is -Waddress-of-packed-member.
Conversions (either implicit or via a valid casting) to pointer types
with lower or equal alignment requirements (e.g. void* or char*)
silence the warning.

This change also adds a new error diagnostic when the user attempts to
bind a reference to a packed member, regardless of the alignment.

Differential Revision: https://reviews.llvm.org/D20561

llvm-svn: 275417
2016-07-14 14:10:43 +00:00
Roger Ferrer Ibanez
985c0c274b Reverting "Warn when taking address of a packed member"
This new diagnostic is causing some false positives that have to be addressed.

This reverts commit 272552

llvm-svn: 272653
2016-06-14 11:20:07 +00:00
Roger Ferrer Ibanez
ac6617b288 Warn when taking address of a packed member
This patch implements PR#22821.

Taking the address of a packed member is dangerous since the reduced
alignment of the pointee is lost. This can lead to memory alignment
faults in some architectures if the pointer value is dereferenced.

This change adds a new warning to clang emitted when taking the address
of a packed member. A packed member is either a field/data member
declared as attribute((packed)) or belonging to a struct/class
declared as such. The associated flag is -Waddress-of-packed-member

Differential Revision: http://reviews.llvm.org/D20561

llvm-svn: 272552
2016-06-13 15:41:40 +00:00