Previously, __weak was silently accepted and ignored in MRC mode.
That makes this a potentially source-breaking change that we have to
roll out cautiously. Accordingly, for the time being, actual support
for __weak references in MRC is experimental, and the compiler will
reject attempts to actually form such references. The intent is to
eventually enable the feature by default in all non-GC modes.
(It is, of course, incompatible with ObjC GC's interpretation of
__weak.)
If you like, you can enable this feature with
-Xclang -fobjc-weak
but like any -Xclang option, this option may be removed at any point,
e.g. if/when it is eventually enabled by default.
This patch also enables the use of the ARC __unsafe_unretained qualifier
in MRC. Unlike __weak, this is being enabled immediately. Since
variables are essentially __unsafe_unretained by default in MRC,
the only practical uses are (1) communication and (2) changing the
default behavior of by-value block capture.
As an implementation matter, this means that the ObjC ownership
qualifiers may appear in any ObjC language mode, and so this patch
removes a number of checks for getLangOpts().ObjCAutoRefCount
that were guarding the processing of these qualifiers. I don't
expect this to be a significant drain on performance; it may even
be faster to just check for these qualifiers directly on a type
(since it's probably in a register anyway) than to do N dependent
loads to grab the LangOptions.
rdar://9674298
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@251041 91177308-0d34-0410-b5e6-96231b3b80d8
Now that -Winfinite-recursion no longer uses recursive calls to before path
analysis, several bits of the code can be improved. The main changes:
1) Early return when finding a path to the exit block without a recursive call
2) Moving the states vector into checkForRecursiveFunctionCall instead of
passing it in by reference
3) Change checkForRecursiveFunctionCall to return a bool when the warning
should be emitted.
4) Use the State vector instead of storing it in the Stack vector.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@245666 91177308-0d34-0410-b5e6-96231b3b80d8
In llvm commit r243581, a reverse range adapter was added which allows
us to change code such as
for (auto I = Fields.rbegin(), E = Fields.rend(); I != E; ++I) {
in to
for (const FieldDecl *I : llvm::reverse(Fields))
This commit changes a few of the places in clang which are eligible to use
this new adapter.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@243663 91177308-0d34-0410-b5e6-96231b3b80d8
Large CFGs cause `checkForFunctionCall()` to overflow its stack. Break
the recursion by manually managing the call stack instead.
Patch by Vedant Kumar!
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@243039 91177308-0d34-0410-b5e6-96231b3b80d8
Split out `hasRecursiveCallInPath()` from `checkForFunctionCall()` to
flatten nesting and clarify the code. This also simplifies a follow-up
patch that refactors the other logic in `checkForFunctionCall()`.
Patch by Vedant Kumar!
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@243038 91177308-0d34-0410-b5e6-96231b3b80d8
The pattern was born out of the lack of range-based for loops in C++98
and is somewhat obscure. No functionality change intended.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@241300 91177308-0d34-0410-b5e6-96231b3b80d8
The patch is generated using this command:
$ tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
work/llvm/tools/clang
To reduce churn, not touching namespaces spanning less than 10 lines.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@240270 91177308-0d34-0410-b5e6-96231b3b80d8
If the type isn't trivially moveable emplace can skip a potentially
expensive move. It also saves a couple of characters.
Call sites were found with the ASTMatcher + some semi-automated cleanup.
memberCallExpr(
argumentCountIs(1), callee(methodDecl(hasName("push_back"))),
on(hasType(recordDecl(has(namedDecl(hasName("emplace_back")))))),
hasArgument(0, bindTemporaryExpr(
hasType(recordDecl(hasNonTrivialDestructor())),
has(constructExpr()))),
unless(isInTemplateInstantiation()))
No functional change intended.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@238601 91177308-0d34-0410-b5e6-96231b3b80d8
These checks detect potential deadlocks caused by inconsistent lock
ordering. The checks are implemented under the -Wthread-safety-beta flag.
This patch also replaces calls to getAttrs() with calls to attrs() throughout
ThreadSafety.cpp, which fixes the earlier issue that cause assert failures.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@228051 91177308-0d34-0410-b5e6-96231b3b80d8
These checks detect potential deadlocks caused by inconsistent lock
ordering. The checks are implemented under the -Wthread-safety-beta flag.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@227997 91177308-0d34-0410-b5e6-96231b3b80d8
warns when a guarded variable is passed by reference as a function argument.
This is released as a separate warning flag, because it could potentially
break existing code that uses thread safety analysis.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@218087 91177308-0d34-0410-b5e6-96231b3b80d8
a mutex is acquired, but corresponding mutex is not provably not-held. This
is based on the earlier negative requirements patch.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214789 91177308-0d34-0410-b5e6-96231b3b80d8
til::SExpr. This is a large patch, with many small changes to pretty printing
and expression lowering to make the new SExpr representation equivalent in
functionality to the old.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214089 91177308-0d34-0410-b5e6-96231b3b80d8
The compilation pipeline doesn't actually need to know about the high-level
concept of diagnostic mappings, and hiding the final computed level presents
several simplifications and other potential benefits.
The only exceptions are opportunistic checks to see whether expensive code
paths can be avoided for diagnostics that are guaranteed to be ignored at a
certain SourceLocation.
This commit formalizes that invariant by introducing and using
DiagnosticsEngine::isIgnored() in place of individual level checks throughout
lex, parse and sema.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211005 91177308-0d34-0410-b5e6-96231b3b80d8
which warns on compound conditionals that always evaluate to the same value.
For instance, (x > 5 && x < 3) will always be false since no value for x can
satisfy both conditions.
This patch also changes the CFG to use these tautological values for better
branch analysis. The test for -Wunreachable-code shows how this change catches
additional dead code.
Patch by Anders Rönnholm.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205665 91177308-0d34-0410-b5e6-96231b3b80d8
Taking a hint from -Wparentheses, use an extra '()' as a sigil that
a dead condition is intentionally dead. For example:
if ((0)) { dead }
When this sigil is found, do not emit a dead code warning. When the
analysis sees:
if (0)
it suggests inserting '()' as a Fix-It.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205069 91177308-0d34-0410-b5e6-96231b3b80d8
The exception is return statements that include control-flow,
which are clearly doing something "interesting".
99% of the cases I examined for -Wunreachable-code that fired
on return statements were not interesting enough to warrant
being in -Wunreachable-code by default. Thus the move to
include them in -Wunreachable-code-return.
This simplifies a bunch of logic, including removing the ad hoc
logic to look for std::string literals.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@204307 91177308-0d34-0410-b5e6-96231b3b80d8
Also relax unreachable 'break' and 'return' to not check for being
preceded by a call to 'noreturn'. That turns out to not be so
interesting in practice.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@204000 91177308-0d34-0410-b5e6-96231b3b80d8
Recent work on -Wunreachable-code has focused on suppressing uninteresting
unreachable code that center around "configuration values", but
there are still some set of cases that are sometimes interesting
or uninteresting depending on the codebase. For example, a dead
"break" statement may not be interesting for a particular codebase,
potentially because it is auto-generated or simply because code
is written defensively.
To address these workflow differences, -Wunreachable-code is now
broken into several diagnostic groups:
-Wunreachable-code: intended to be a reasonable "default" for
most users.
and then other groups that turn on more aggressive checking:
-Wunreachable-code-break: warn about dead break statements
-Wunreachable-code-trivial-return: warn about dead return statements
that return "trivial" values (e.g., return 0). Other return
statements that return non-trivial values are still reported
under -Wunreachable-code (this is an area subject to more refinement).
-Wunreachable-code-aggressive: supergroup that enables all these
groups.
The goal is to eventually make -Wunreachable-code good enough to
either be in -Wall or on-by-default, thus finessing these warnings
into different groups helps achieve maximum signal for more users.
TODO: the tests need to be updated to reflect this extra control
via diagnostic flags.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@203994 91177308-0d34-0410-b5e6-96231b3b80d8
This warning has a whole bunch of known false positives, much of them due
to code that is "sometimes unreachable". This can caused by code that
is conditionally generated by the preprocessor, branches that are defined
in terms of architecture-specific details (e.g., the size of a type), and
so on. While these are all good things to address one by one, the reality
is that this warning has received little love lately. By restricting
its purvue, we can focus on the top issues effecting main files, which
should be smaller, and then gradually widen the scope.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201607 91177308-0d34-0410-b5e6-96231b3b80d8
A return type is the declared or deduced part of the function type specified in
the declaration.
A result type is the (potentially adjusted) type of the value of an expression
that calls the function.
Rule of thumb:
* Declarations have return types and parameters.
* Expressions have result types and arguments.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@200082 91177308-0d34-0410-b5e6-96231b3b80d8
John McCall