Use text suggested by Justin Bogner in post-commit review of r311146
<http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20170814/479898.html>,
which makes it clear that report_fatal_error shouldn't be used when there is a
practicable alternative. Also make this clearer in CodingStandards.
llvm-svn: 311147
The current ProgrammersManual.rst document has a lot of well-written
documentation on error handling thanks to @lhames. It suggests errors can be
split cleanly into "programmatic" and "recoverable" errors. However, the
reality in current LLVM seems to be there are a number of cases where a
non-programmatic error is not easily recoverable. Therefore, add a note to
indicate the existence of report_fatal_error for these cases. I've also added
a reminder to CodingStandards.rst in the section on assertions, to indicate
that llvm_unreachable and assertions should not be relied upon to report
errors triggered by user input.
The ProgrammersManual is also silent on the use of LLVMContext::diagnose,
which is used in BPF+WebAssembly+AMDGPU to report some errors during
instruction selection. I don't address that in this patch, as it's not quite
clear how to fit in to the current error handling story
Differential Revision: https://reviews.llvm.org/D36826
llvm-svn: 311146
This make it consistent with STATISTIC which it will often appears near.
While there move one DEBUG_COUNTER instance out of an anonymous namespace. It's already declaring a static variable so the namespace is unnecessary.
llvm-svn: 310637
Commits were:
"Use WeakVH instead of WeakTrackingVH in AliasSetTracker's UnkownInsts"
"Add a new WeakVH value handle; NFC"
"Rename WeakVH to WeakTrackingVH; NFC"
The changes assumed pointers are 8 byte aligned on all architectures.
llvm-svn: 301429
Summary:
I plan to use WeakVH to mean "nulls itself out on deletion, but does
not track RAUW" in a subsequent commit.
Reviewers: dblaikie, davide
Reviewed By: davide
Subscribers: arsenm, mehdi_amini, mcrosier, mzolotukhin, jfb, llvm-commits, nhaehnle
Differential Revision: https://reviews.llvm.org/D32266
llvm-svn: 301424
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
Summary:
Fixed bunch of for loops to range based for loop
and bunch of rendundat types with auto.
Reviewers: echristo, silvas, chandlerc
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D30338
llvm-svn: 296251
Summary:
This replaces the format member search, which was quite complicated, with a more
direct approach to detecting whether a class should be formatted using the
format-member method. Instead we use a special type llvm::format_adapter, which
every adapter must inherit from. Then the search can be simply implemented with
the is_base_of type trait.
Aside from the simplification, I like this way more because it makes it more
explicit that you are supposed to use this type only for adapter-like
formattings, and the other approach (format_provider overloads) should be used
as a default (a mistake I made when first trying to use this library).
The only slight change in behaviour here is that now choose the format-adapter
branch even if the format member invocation will fail to compile (e.g. because it is a
non-const member function and we are passing a const adapter), whereas
previously we would have gone on to search for format_providers for the type.
However, I think that is actually a good thing, as it probably means the
programmer did something wrong.
Reviewers: zturner, inglorion
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D27679
llvm-svn: 289795
Now that PointerType is no longer a SequentialType, all SequentialTypes
have an associated number of elements, so we can move that information to
the base class, allowing for a number of simplifications.
Differential Revision: https://reviews.llvm.org/D27122
llvm-svn: 288464
As proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/106640.html
This is for a couple of reasons:
- Values of type PointerType are unlike the other SequentialTypes (arrays
and vectors) in that they do not hold values of the element type. By moving
PointerType we can unify certain aspects of how the other SequentialTypes
are handled.
- PointerType will have no place in the SequentialType hierarchy once
pointee types are removed, so this is a necessary step towards removing
pointee types.
Differential Revision: https://reviews.llvm.org/D26595
llvm-svn: 288462
This introduces a new type-safe general purpose formatting
library. It provides compile-time type safety, does not require
a format specifier (since the type is deduced), and provides
mechanisms for extending the format capability to user defined
types, and overriding the formatting behavior for existing types.
This patch additionally adds documentation for the API to the
LLVM programmer's manual.
Mailing List Thread:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/105836.html
Differential Revision: https://reviews.llvm.org/D25587
llvm-svn: 286682
programmer's manual.
ExitOnError is often a better alternative to handleErrors for tool code. This
patch makes it easier to find the ExitOnError discussion when reading the
handleErrors section.
Thanks to Peter Collingbourne for the suggestion.
llvm-svn: 286167
This patch updates some of the existing Error examples, expands on the
documentation for handleErrors, and includes new sections that cover
a number of helpful utilities and common error usage idioms.
llvm-svn: 285122
At the same time, fixes InstructionsTest::CastInst unittest: yes
you can leave the IR in an invalid state and exit when you don't
destroy the context (like the global one), no longer now.
This is the first part of http://reviews.llvm.org/D19094
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266379
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
This means that the DEBUG_TYPE cannot take a comma anymore. All existing passes
conform to this rule.
Differential Revision: http://reviews.llvm.org/D15645
llvm-svn: 257466
