The bitstream reader handles errors poorly. This has two effects:
* Bugs in file handling (especially modules) manifest as an "unexpected end of
file" crash
* Users of clang as a library end up aborting because the code unconditionally
calls `report_fatal_error`
The bitstream reader should be more resilient and return Expected / Error as
soon as an error is encountered, not way late like it does now. This patch
starts doing so and adopting the error handling where I think it makes sense.
There's plenty more to do: this patch propagates errors to be minimally useful,
and follow-ups will propagate them further and improve diagnostics.
https://bugs.llvm.org/show_bug.cgi?id=42311
<rdar://problem/33159405>
Differential Revision: https://reviews.llvm.org/D63518
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to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
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In a lot of places an empty string was passed as the ErrorBanner to
logAllUnhandledErrors. This patch makes that argument optional to
simplify the call sites.
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FileError is meant to encapsulate both an Error and a file name/path. It should be used in cases where an Error occurs deep down the call chain, and we want to return it to the caller along with the file name.
StringError was updated to display the error messages in different ways. These can be:
1. display the error_code message, and convert to the same error_code (ECError behavior)
2. display an arbitrary string, and convert to a provided error_code (current StringError behavior)
3. display both an error_code message and a string, in this order; and convert to the same error_code
These behaviors can be triggered depending on the constructor. The goal is to use StringError as a base class, when a library needs to provide a explicit Error type.
Differential Revision: https://reviews.llvm.org/D50807
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Summary:
The C-API supports consuming errors, converting an error to a string error
message, and querying an error's type. Other LLVM C APIs that wish to use
llvm::Error can supply error-type-id checkers and custom
error-to-structured-type converters for any custom errors they provide.
Reviewers: bogner, zturner, labath, dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50716
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The function in question is copy-pasted lots of times in DWARF-related classes.
Thus it will make sense to place its implementation into the Support library.
Reviewed by: lhames
Differential Revision: https://reviews.llvm.org/D49824
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Summary:
Error's new operator<< is the first way to print an error without consuming it.
formatv() can now print objects with an operator<< that works with raw_ostream.
Reviewers: bkramer
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D48966
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We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
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Whenever LLVM_ENABLE_ABI_BREAKING_CHECKS is enabled, which
is usually the case for example when asserts are enabled,
Error's destructor does some additional checking to make sure
that that it does not represent an error condition and that it
was checked.
However, this is -- by definition -- not the likely codepath.
Some profiling shows that at least with some compilers, simply
calling assertIsChecked -- in a release build with full
optimizations -- can account for up to 15% of the entire
runtime of the program, even though this function should almost
literally be a no-op.
The problem is that the assertIsChecked function can be considered
too big to inline depending on the compiler's inliner. Since it's
unlikely to ever need to failure path though, we can move it out
of line and force it to not be inlined, so that the fast path
can be inlined.
In my test (using lld to link clang with CMAKE_BUILD_TYPE=Release
and LLVM_ENABLE_ASSERTIONS=ON), this reduces link time from 27
seconds to 23.5 seconds, which is a solid 15% gain.
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This reverts commit 4e4ee1c507e2707bb3c208e1e1b6551c3015cbf5.
This is failing due to some code that isn't built on MSVC
so I didn't catch. Not immediately obvious how to fix this
at first glance, so I'm reverting for now.
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There's a lot of misuse of Twine scattered around LLVM. This
ranges in severity from benign (returning a Twine from a function
by value that is just a string literal) to pretty sketchy (storing
a Twine by value in a class). While there are some uses for
copying Twines, most of the very compelling ones are confined
to the Twine class implementation itself, and other uses are
either dubious or easily worked around.
This patch makes Twine's copy constructor private, and fixes up
all callsites.
Differential Revision: https://reviews.llvm.org/D38767
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cantFail is the moral equivalent of an assertion that the wrapped call must
return a success value. This patch allows clients to include an associated
error message (the same way they would for an assertion for llvm_unreachable).
If the error message is not specified it will default to: "Failure value
returned from cantFail wrapped call".
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handleExpected is similar to handleErrors, but takes an Expected<T> as its first
input value and a fallback functor as its second, followed by an arbitary list
of error handlers (equivalent to the handler list of handleErrors). If the first
input value is a success value then it is returned from handleErrors
unmodified. Otherwise the contained error(s) are passed to handleErrors, along
with the handlers. If handleErrors returns success (indicating that all errors
have been handled) then handleExpected runs the fallback functor and returns its
result. If handleErrors returns a failure value then the failure value is
returned and the fallback functor is never run.
This simplifies the process of re-trying operations that return Expected values.
Without this utility such retry logic is cumbersome as the internal Error must
be explicitly extracted from the Expected value, inspected to see if its
handleable and then consumed:
enum FooStrategy { Aggressive, Conservative };
Expected<Foo> tryFoo(FooStrategy S);
Expected<Foo> Result;
(void)!!Result; // "Check" Result so that it can be safely overwritten.
if (auto ValOrErr = tryFoo(Aggressive))
Result = std::move(ValOrErr);
else {
auto Err = ValOrErr.takeError();
if (Err.isA<HandleableError>()) {
consumeError(std::move(Err));
Result = tryFoo(Conservative);
} else
return std::move(Err);
}
with handleExpected, this can be re-written as:
auto Result =
handleExpected(
tryFoo(Aggressive),
[]() { return tryFoo(Conservative); },
[](HandleableError&) { /* discard to handle */ });
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This just switches handleAllErrors from using custom assertions that all errors
have been handled to using cantFail. This change involves moving some of the
class and function definitions around though.
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I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.
I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.
This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.
Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).
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This patch allows Error and Expected types to be passed to and returned from
RPC functions.
Serializers and deserializers for custom error types (types deriving from the
ErrorInfo class template) can be registered with the SerializationTraits for
a given channel type (see registerStringError in RPCSerialization.h for an
example), allowing a given custom type to be sent/received. Unregistered types
will be serialized/deserialized as StringErrors using the custom type's log
message as the error string.
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fallible functions.
Some fallible functions (those returning Error or Expected<T>) may only fail
for a subset of their inputs. For example, a "safe" square root function will
succeed for all finite positive inputs:
Expected<double> safeSqrt(double d) {
if (d < 0 && !isnan(d) && !isinf(d))
return make_error<...>("Cannot sqrt -ve values, nans or infs");
return sqrt(d);
}
At a safe callsite for such a function, checking the error return value is
redundant:
if (auto ValOrErr = safeSqrt(42.0)) {
// use *ValOrErr.
} else
llvm_unreachable("safeSqrt should always succeed for +ve values");
The cantFail function wraps this check and extracts the contained value,
simplifying control flow:
double Result = cantFail(safeSqrt(42.0));
This function should be used with care: it is a programmatic error to wrap a
call with cantFail if it can in fact fail. For debug builds this will
result in llvm_unreachable being called. For release builds the behavior is
undefined.
Use of this function is likely to be rare in library code, but more common
for tool and unit-test code where inputs and mock functions may be known to be
safe.
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This macro is supposed to be the one controlling the compatibility
of ABI breaks induced when enabling or disabling assertions in LLVM.
The macro is enabled by default in assertions build, so this commit
won't disable the tests.
Differential Revision: https://reviews.llvm.org/D26700
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The macro LLVM_ENABLE_ABI_BREAKING_CHECKS is moved to a new header
abi-breaking.h, from llvm-config.h. Only headers that are using the
macro are including this new header.
LLVM will define a symbol, either EnableABIBreakingChecks or
DisableABIBreakingChecks depending on the configuration setting for
LLVM_ABI_BREAKING_CHECKS.
The abi-breaking.h header will add weak references to these symbols in
every clients that includes this header. This should ensure that
a mismatch triggers a link failure (or a load time failure for DSO).
On MSVC, the pragma "detect_mismatch" is used instead.
Differential Revision: https://reviews.llvm.org/D26876
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This fixes a mismatch between the declared error_type and the type used with
the placement new that initializes the field.
Patch by Yichao Yu.
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(1) Switches to raw pointer and bitmasking operations for Error payload.
(2) Always includes the 'unchecked' bitfield in Expected<T>, even in -Asserts.
(3) Always propagates checked bit status in move-ops for both classes, even in
-Asserts.
This should allow debug programs to link against release libraries without
encountering spurious 'unchecked error' terminations.
Error checks still aren't verified in release mode so this doesn't introduce
any new control flow, but it does require new bit-masking ops in release mode
to preserve the flag values during move ops. I expect the overhead to be
minimal, but if we discover any corner cases where it matters we could fix
this by making flag propagation conditional on a new build option.
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This reverts commit r280016, and the followups of r280017, r280027,
r280051, r280058, and r280059.
MSVC's implementation of std::promise does not get along with
llvm::Error. It uses its promised value too much like a normal value
type.
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This allows ErrorAsOutParameter to work better with "optional" errors. For
example, consider a function where for certain input values it is known that
the function can't fail. This can now be written as:
Result foo(Arg X, Error *Err) {
ErrorAsOutParameter EAO(Err);
if (<Error Condition>) {
if (Err)
*Err = <report error>;
else
llvm_unreachable("Unexpected failure!");
}
}
Rather than having to construct an ErrorAsOutParameter under every conditional
where Err is known to be non-null.
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See http://reviews.llvm.org/D22079
Changes the Archive::child_begin and Archive::children to require a reference
to an Error. If iterator increment fails (because the archive header is
damaged) the iterator will be set to 'end()', and the error stored in the
given Error&. The Error value should be checked by the user immediately after
the loop. E.g.:
Error Err;
for (auto &C : A->children(Err)) {
// Do something with archive child C.
}
// Check the error immediately after the loop.
if (Err)
return Err;
Failure to check the Error will result in an abort() when the Error goes out of
scope (as guaranteed by the Error class).
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When concatenating two error lists the ErrorList::join method (which is called
by joinErrors) was failing to set the checked bit on the second error, leading
to a 'failure to check error' assertion.
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This comment was included in Peter Collingbourne's original version of
StringError (see http://reviews.llvm.org/D20550), where it made sense. It was
accidentally copied over with the rest of the class, but no longer applies.
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