Summary:
The current implementation eats the current errors and just outputs
the message parameter passed to llvm::cantFail. This change appends
the original error message(s), so the user can see exactly why
cantFail failed. New logic is conditional on NDEBUG.
Reviewed By: lhames
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69057
llvm-svn: 375176
This reverts commit r368849, because it breaks some bots (e.g.
llvm-clang-x86_64-win-fast).
It turns out this is not as NFC as we had hoped, because operator== will
consider two std::error_codes to be distinct even though they both hold
"success" values if they have different categories.
llvm-svn: 368854
Summary:
The main motivation for this is unit tests, which contain a large macro
for pretty-printing std::error_code, and this macro is duplicated in
every file that needs to do this. However, the functionality may be
useful elsewhere too.
In this patch I have reimplemented the existing ASSERT_NO_ERROR macros
to reuse the new functionality, but I have kept the macro (as a
one-liner) as it is slightly more readable than ASSERT_EQ(...,
std::error_code()).
Reviewers: sammccall, ilya-biryukov
Subscribers: zturner, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65643
llvm-svn: 368849
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.
llvm-svn: 351636
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.
llvm-svn: 346604
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
llvm-svn: 341064
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
llvm-svn: 339802
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
llvm-svn: 337995
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
llvm-svn: 336412
Failed<ErrorInfoBase>() did not compile, because it was attempting to
create a copy of the Error object when passing it to the nested matcher,
which was not possible because ErrorInfoBase is abstract.
This commit fixes the problem by making sure we pass the ErrorInfo
object by reference, which also improves the handling of non-abstract
objects, as we avoid potentially slicing an object during the copy.
llvm-svn: 329703
Summary:
The existing Failed() matcher only allowed asserting that the operation
failed, but it was not possible to verify any details of the returned
error.
This patch adds two new matchers, which make this possible:
- Failed<InfoT>() verifies that the operation failed with a single error
of a given type.
- Failed<InfoT>(M) additionally check that the contained error info
object is matched by the nested matcher M.
To make these work, I've changed the implementation of the ErrorHolder
class. Now, instead of just storing the string representation of the
Error, it fetches the ErrorInfo objects and stores then as a list of
shared pointers. This way, ErrorHolder remains copyable, while still
retaining the full information contained in the Error object.
In case the Error object contains two or more errors, the new matchers
will fail to match, instead of trying to match all (or any) of the
individual ErrorInfo objects. This seemed to be the most sensible
behavior for when one wants to match exact error details, but I could be
convinced otherwise...
Reviewers: zturner, lhames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D44925
llvm-svn: 329288
Summary:
This makes it possible to run an arbitrary matcher on the value
contained within the Expected<T> object.
To do this, I've needed to fully spell out the matcher, instead of using
the shorthand MATCHER_P macro.
The slight gotcha here is that standard template deduction will fail if
one tries to match HasValue(47) against an Expected<int &> -- the
workaround is to use HasValue(testing::Eq(47)).
The explanations produced by this matcher have changed a bit, since now
we delegate to the nested matcher to print the value. Since these don't
put quotes around the value, I've changed our PrintTo methods to match.
Reviewers: zturner
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41065
llvm-svn: 320561
Summary:
This did not work because the ExpectedHolder was trying to hold the
value in an Optional<T*>. Instead of trying to mimic the behavior of
Expected and try to make ExpectedHolder work with references and
non-references, I simply store the reference to the Expected object in
the holder.
I also add a bunch of tests for these matchers, which have helped me
flesh out some problems in my initial implementation of this patch, and
uncovered the fact that we are not consistent in quoting our values in
the matcher output (which I also fix).
Reviewers: zturner, chandlerc
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D40904
llvm-svn: 320025
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".
llvm-svn: 312066
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 */ });
llvm-svn: 311870
Summary:
If assertions are disabled, but LLVM_ABI_BREAKING_CHANGES is enabled,
this will cause an issue with an unchecked Success. Switching to
consumeError() is the correct way to bypass the check. This patch also
includes disabling 2 tests that can't work without assertions enabled,
since llvm_unreachable() with NDEBUG won't crash.
Reviewers: llvm-commits, lhames
Reviewed By: lhames
Subscribers: lhames, pirama
Differential Revision: https://reviews.llvm.org/D36729
llvm-svn: 311739
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.
llvm-svn: 311631
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.
llvm-svn: 296384
This is consistent with the header (after r288087) and fixes the
test for the configuration:
-DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_ABI_BREAKING_CHECKS=FORCE_OFF
llvm-svn: 288196
This is forcing to use Error::success(), which is in a wide majority
of cases a lot more readable.
Differential Revision: https://reviews.llvm.org/D26481
llvm-svn: 286561
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.
llvm-svn: 276430
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.
llvm-svn: 274249
StringError can be used to represent Errors that aren't recoverable based on
the error type, but that have a useful error message that can be reported to
the user or logged.
llvm-svn: 270948
toString() consumes an Error and returns a string representation of its
contents. This commit also adds a message() method to ErrorInfoBase for
convenience.
Differential Revision: http://reviews.llvm.org/D19883
llvm-svn: 268465
destruction.
This makes the Expected<T> class behave like Error, even when in success mode.
Expected<T> values must be checked to see whether they contain an error prior
to being dereferenced, assigned to, or destructed.
llvm-svn: 265446
This helper method creates a pre-checked Error suitable for use as an out
parameter in a constructor. This avoids the need to have the constructor
check a known-good error before assigning to it.
llvm-svn: 264467
This is a temporary crutch to enable code that currently uses std::error_code
to be incrementally moved over to Error. Requiring all Error instances be
convertible enables clients to call errorToErrorCode on any error (not just
ECErrors created by conversion *from* an error_code).
This patch also moves code for Error from ErrorHandling.cpp into a new
Error.cpp file.
llvm-svn: 264221
idiom.
Most LLVM tool code exits immediately when an error is encountered and prints an
error message to stderr. The ExitOnError class supports this by providing two
call operators - one for Errors, and one for Expected<T>s. Calls to code that
can return Errors (or Expected<T>s) can use these calls to bail out on error,
and otherwise continue as if the operation had succeeded. E.g.
Error foo();
Expected<int> bar();
int main(int argc, char *argv[]) {
ExitOnError ExitOnErr;
ExitOnErr.setBanner(std::string("Error in ") + argv[0] + ":");
// Exit if foo returns an error. No need to manually check error return.
ExitOnErr(foo());
// Exit if bar returns an error, otherwise unwrap the contained int and
// continue.
int X = ExitOnErr(bar());
// ...
return 0;
}
llvm-svn: 263749
This patch introduces the Error classs for lightweight, structured,
recoverable error handling. It includes utilities for creating, manipulating
and handling errors. The scheme is similar to exceptions, in that errors are
described with user-defined types. Unlike exceptions however, errors are
represented as ordinary return types in the API (similar to the way
std::error_code is used).
For usage notes see the LLVM programmer's manual, and the Error.h header.
Usage examples can be found in unittests/Support/ErrorTest.cpp.
Many thanks to David Blaikie, Mehdi Amini, Kevin Enderby and others on the
llvm-dev and llvm-commits lists for lots of discussion and review.
llvm-svn: 263609
