Summary:
Patch by Klaus Kretzschmar
We would like to introduce a new type of llvm error handler for handling
bad alloc fault situations. LLVM already provides a fatal error handler
for serious non-recoverable error situations which by default writes
some error information to stderr and calls exit(1) at the end (functions
are marked as 'noreturn').
For long running processes (e.g. a server application), exiting the
process is not an acceptable option, especially not when the system is
in a temporary resource bottleneck with a good chance to recover from
this fault situation. In such a situation you would rather throw an
exception to stop the current compilation and try to overcome the
resource bottleneck. The user should be aware of the problem of throwing
an exception in bad alloc situations, e.g. you must not do any
allocations in the unwind chain. This is especially true when adding
exceptions in existing unfamiliar code (as already stated in the comment
of the current fatal error handler)
So the new handler can also be used to distinguish from general fatal
error situations where recovering is no option. It should be used in
cases where a clean unwind after the allocation is guaranteed.
This patch contains:
- A report_bad_alloc function which calls a user defined bad alloc
error handler. If no user handler is registered the
report_fatal_error function is called. This function is not marked as
'noreturn'.
- A install/restore_bad_alloc_error_handler to install/restore the bad
alloc handler.
- An example (in Mutex.cpp) where the report_bad_alloc function is
called in case of a malloc returns a nullptr.
If this patch gets accepted we would create similar patches to fix
corresponding malloc/calloc usages in the llvm code.
Reviewers: chandlerc, greened, baldrick, rnk
Reviewed By: rnk
Subscribers: llvm-commits, MatzeB
Differential Revision: https://reviews.llvm.org/D34753
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I tried to compile LLD using GCC 7.1.0 and got warnings like
"warning: this statement may fall through [-Wimplicit-fallthrough=]"
(some more details are here: D32907)
GCC's __cplusplus value is 201402L by default, so macro expands to nothing,
though GCC 7 has support for [[fallthrough]].
Patch uses gnu::fallthrough when it is available and fixes warning I am observing.
Initial idea of way to fix belongs to Davide Italiano.
Differential revision: https://reviews.llvm.org/D33036
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We had various variants of defining dump() functions in LLVM. Normalize
them (this should just consistently implement the things discussed in
http://lists.llvm.org/pipermail/cfe-dev/2014-January/034323.html
For reference:
- Public headers should just declare the dump() method but not use
LLVM_DUMP_METHOD or #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
- The definition of a dump method should look like this:
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void MyClass::dump() {
// print stuff to dbgs()...
}
#endif
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Also clean up the legacy hacks for AlignedCharArray. I'm keeping
LLVM_ALIGNAS alive for a bit longer because GCC 4.8.0 (which we still
support apparently) shipped a buggy alignas(). All other supported
compilers have a working alignas.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284736 91177308-0d34-0410-b5e6-96231b3b80d8
Now that we have dropped MSVC 2013, all supported compilers support
noexcept and we can drop this portability macro.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284672 91177308-0d34-0410-b5e6-96231b3b80d8
Uses of this have all been updated to use LLVM_NODISCARD, which
matches the C++17 [[nodiscard]] semantics rather than those of GCC's
__attribute__((warn_unused_result)).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284367 91177308-0d34-0410-b5e6-96231b3b80d8
This is essentially a more powerful version of our current
LLVM_ATTRIBUTE_UNUSED_RESULT, in that it can also be applied to types
and generate warnings whenever an object of that type is returned by
value and the value is discarded.
I'll replace uses of LLVM_ATTRIBUTE_UNUSED_RESULT and remove that
macro in follow up commits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284286 91177308-0d34-0410-b5e6-96231b3b80d8
Older versions of clang defined __has_cpp_attribute in C mode, but
would choke on scoped attributes, as per llvm.org/PR23435. Since we
support building with clang all the way back to 3.1, we have to work
around this issue.
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can given the current __cplusplus definitions).
Without this, Clang triggers TONS of warnings about using a C++17
extension. I tried using LLVM_EXTENSION to turn these off and it doesn't
work.
Suggestions on a better approach are welcome, but at least this makes
the build usable for me again.
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This allows you to annotate switch case fallthrough in a better way
than a "// FALLTHROUGH" comment. Eventually it would be nice to turn
on -Wimplicit-fallthrough, if we can get the code base clean.
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In case there are compilers that support neither __FUNCSIG__ or
__PRETTY_FUNCTION__, we fall back to __func__ as a last resort,
which should be guaranteed by C++11 and C99.
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MSVC doesn't have this, it only has __FUNCSIG__. So this adds
a new macro called LLVM_PRETTY_FUNCTION which evaluates to the
right thing on any platform.
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Summary:
This provides a macro that expands to __builtin_debugtrap() for clang,
and __debugbreak() for MSVC.
It intentionally expands to nothing for compilers that do not support a
similar mechanism that halts the debugger without otherwise crashing the
process.
Differential Revision: http://reviews.llvm.org/D18002
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We have known UB in some ilists where we static cast half nodes to
(larger) derived types and use the address. See llvm.org/PR26753.
This needs to be fixed, but in the meantime it'd be nice if running
ubsan didn't complain. This adds annotations in the two places where
ubsan complains while running check-all of a sanitized clang build.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262683 91177308-0d34-0410-b5e6-96231b3b80d8
Patch by Alexander Riccio
This patch enables `constexpr` on Visual Studio 2015 by adding `||
LLVM_MSC_PREREQ(1900)` to the preprocessor `#if` statement. Since VS2013
doesn't support `constexpr`, that's purposely excluded. The
`LLVM_CONSTEXPR` macro is used in ~25 places.
I also added the MSVC/SAL equivalent of:
- `__attribute__((__warn_unused_result__))` as an
`LLVM_ATTRIBUTE_UNUSED_RESULT` definition
- `__attribute__((returns_nonnull))` as an
`LLVM_ATTRIBUTE_RETURNS_NONNULL` definition
...in case anybody ever decides to run `/analyze` on LLVM (probably
myself, if anybody)
Reviewers: rnk, aaron.ballman
Differential Revision: http://reviews.llvm.org/D16751
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1. A macro with argument: LLVM_PACKED(StructDefinition)
2. A pair of macros defining scope of region with packing:
LLVM_PACKED_START
struct A { ... };
struct B { ... };
LLVM_PACKED_END
Differential Revision: http://reviews.llvm.org/D14337
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'inline' specifier. That specifier may or may not be valid for a given
function, or it may be required for correct linkage even when the
compiler doesn't support the always_inline attribute.
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This would have suppressed bug 24578, about use-after-
destroy on User and MDNode. Rolled back suppression for
the sake of code cleanliness, in preferance for bug
tracking to keep track of this issue.
This reverts commit 6ff2baabc4625d5b0a8dccf76aa0f72d930ea6c0.
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Remove support for Valgrind-based TSan, which hasn't been maintained for a
few years. We now use the TSan annotations only if LLVM is compiled with
-fsanitize=thread. We no longer need the weak function definitions as we
are guaranteed that our program is linked directly with the TSan runtime.
Differential Revision: http://reviews.llvm.org/D12121
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This is a C++11 feature that both GCC and MSVC have supported as ane extension
long before C++11 was approved.
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The value of this macro seems to be very low unless we actually start
using it everywhere, and I don't have immediate plans to make that
happen.
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The GCC attribute is curiously named 'malloc', but I think it's better
to use LLVM terminology for the wrapper macro.
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MSVC 2013 requires the argument to __declspec(align()) to be an integer
constant expression that doesn't involve any identifiers like sizeof.
For GCC and Clang, LLVM_PTR_SIZE is equivalent to __SIZEOF_POINTER__,
which dates back to GCC 4.6 and Clang 2010. If that's not available, we
get sizeof(void*), which works with alignas() and
__attribute__((aligned())).
For MSVC, LLVM_PTR_SIZE is 4 or 8 depending on _WIN64.
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We wrap __attribute((aligned)) for GCC 4.7 and __declspec(align) for
MSVC. The latter behaves weird in some contexts so this should be used
carefully.
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If any of the bots complain (perhaps due to an antiquated version of an STL implementation), I will revert.
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On Windows, we now use RaiseException to generate the kind of trap we require (one which calls our vectored exception handler), and fall back to using a volatile write to simulate a trap elsewhere.
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