Found by valgrind.

llvm-svn: 134733

rather than a computed std::distance(). At some point I had convinced
myself that these two were different; but as far as I can tell on
re-exampination they aren't, and the number of block IDs is actually
just a count of the blocks in the CFG.

While this removes the primary motivation for guarding all of this with
CollectStats, I have a patch coming up that will almost certainly make
it important again.

llvm-svn: 134552

Special detail is added for uninitialized variable analysis as this has
serious performance problems than need to be tracked.

Computing some of this data is expensive, for example walking the CFG to
determine its size. To avoid doing that unless the stats data is going
to be used, we thread a bit into the Sema object to track whether
detailed stats should be collected or not. This bit is used to avoid
computations whereever the computations are likely to be more expensive
than checking the state of the flag. Thus, counters are in some cases
unconditionally updated, but the more expensive (and less frequent)
aggregation steps are skipped.

With this patch, we're able to see that for 'gcc.c':
*** Analysis Based Warnings Stats:
232 functions analyzed (0 w/o CFGs).
  7151 CFG blocks built.
  30 average CFG blocks per function.
  1167 max CFG blocks per function.
163 functions analyzed for uninitialiazed variables
  640 variables analyzed.
  3 average variables per function.
  94 max variables per function.
  96409 block visits.
  591 average block visits per function.
  61546 max block visits per function.

And for the reduced testcase in PR10183:
*** Analysis Based Warnings Stats:
98 functions analyzed (0 w/o CFGs).
  8526 CFG blocks built.
  87 average CFG blocks per function.
  7277 max CFG blocks per function.
68 functions analyzed for uninitialiazed variables
  1359 variables analyzed.
  19 average variables per function.
  1196 max variables per function.
  2540494 block visits.
  37360 average block visits per function.
  2536495 max block visits per function.

That last number is the somewhat scary one that indicates the problem in
PR10183.

llvm-svn: 134494

over "= 0". Fixes <rdar://problem/9714386>.

llvm-svn: 134302

then teach -Wreturn-type to handle the same.  Net effect:  we now correctly
handle noreturn attributes on member calls in the CFG.

llvm-svn: 131178

function more clear and obvious in behavior.

Add some comments documenting the behavior of the primary diagnostic helper.

llvm-svn: 128901

diagnostic emission. The fixit hint, when suggested, typically has
nothing to do with the nature or form of the reference.

llvm-svn: 128899

extracts a function to handle the emission of the diagnostic separately
from the walking over the set of uninitialized uses.

Also updates the naming used within this extracted function to be a bit
more consistent with the rest of Clang's naming patterns.

The next step will be breaking this apart so that we can go through
different functions rather than tracking so many boolean variables.

llvm-svn: 128898

  int x = x;

GCC disables its warnings on this construct as a way of indicating that
the programmer intentionally wants the variable to be uninitialized.
Only the warning on the initializer is turned off in this iteration.

This makes the code a lot more ugly, but starts commenting the
surprising behavior here. This is a WIP, I want to refactor it
substantially for clarity, and to determine whether subsequent warnings
should be suppressed or not.

llvm-svn: 128894

I think this moves the code in the desired direction of the new style
recommendations (and style conventional in Clang), but if anyone prefers
the previous style, or has other suggestions just chime in and I'll
follow up.

llvm-svn: 128878

Fix PR 9626 (duplicated self-init warnings under -Wuninitialized) with numerous CFG and UninitializedValues analysis changes:

1) Change the CFG to include the DeclStmt for conditional variables, instead of using the condition itself as a faux DeclStmt.
2) Update ExprEngine (the static analyzer) to understand (1), so not to regress.
3) Update UninitializedValues.cpp to initialize all tracked variables to Uninitialized at the start of the function/method.
4) Only use the SelfReferenceChecker (SemaDecl.cpp) on global variables, leaving the dataflow analysis to handle other cases.

The combination of (1) and (3) allows the dataflow-based -Wuninitialized to find self-init problems when the initializer
contained control-flow.

llvm-svn: 128858

-Wuninitialized: use "self-init" warning when issue uninitialized values warnings from the dataflow analysis that include within the initializer of a variable.

llvm-svn: 128843

-Wuninitialized: don't issue fixit for initializer if a variable declaration already has an initializer.

llvm-svn: 128838

This rename serves two purposes:

- It reflects the actual functionality of this analysis.
- We will have more than one reachability analysis.

llvm-svn: 127930

Don't construct two CFGs just to run -Wuninitialized.  While this causes new warnings to be flagged under -Wconditional-uninitialized, this is something we
can improve over time.

llvm-svn: 127802

Split warnings from -Wuninitialized-experimental into "must-be-initialized" and "may-be-initialized" warnings, each controlled by different flags.

llvm-svn: 127669

Split warnings from -Wuninitialized-experimental into "must-be-initialized" and "may-be-initialized" warnings, each controlled by different flags.

llvm-svn: 127666

llvm-svn: 127657

When doing reachability analysis for warnings issued under DiagRuntimeBehavior, don't construct a ParentMap or CFGStmtMap.
Instead, create a small set of Stmt* -> CFGBlock* mappings during CFG construction for only the statements we care about
relating to the diagnostics we want to check for reachability.

llvm-svn: 127396

llvm-svn: 126910

Introduce CFGImplicitDtor::isNoReturn() to query whether a destructor actually returns.  Use this for -Wreturn-type to prune false positives reported in PR 6884.

llvm-svn: 126875

Enhance Sema::DiagRuntimeBehavior() to delay some diagnostics to see if the related code is reachable.  This suppresses some
diagnostics that occur in unreachable code (e.g., -Warray-bound).

We only pay the cost of doing the reachability analysis when we issue one of these diagnostics.

llvm-svn: 126290

llvm-svn: 126288

Issue AnalysisBasedWarnings as part of calling Sema::PopBlockOrFunctionScope().  No real functionality change.

llvm-svn: 126287

llvm-svn: 124924

Based on user feedback, swap -Wuninitialized diagnostics to have the warning refer to the bad use, and the note to the variable declaration.

llvm-svn: 124758

Add temporary hack to -Wuninitialize to create a separate CFG (for C++ code) that doesn't include implicit dtors.

Implicit dtors confuse the ad hoc path-sensitivity of UninitializedValuesV2.cpp.  This isn't
the ideal solution, as it will directly impact compile time, but should significantly reduce
the noise of -Wuninitialized on some code bases.

This immediately "fixes" the false positive reported in PR 9063, although this
isn't the right fix in the long run.

llvm-svn: 124667

Tweak -Wuninitialized fixit for '_Bool' types to be initialized to 0, and C++ 'bool' types to false.

llvm-svn: 124356

llvm-svn: 124352

after a 'return' in a CFGBlock.  This accidentally
was working before, but the false assumption that
'return' always appeared at the end of the block
was uncovered by a recent change.

llvm-svn: 124280

handling all CFGElement kinds.  While writing
the test case, it turned out that return-noreturn.cpp
wasn't actually testing anything since it has the wrong -W
flag.  That uncovered another regression with
the handling of destructors marked noreturn.  WIP.

llvm-svn: 124238

about uninitialized variables captured by blocks.

llvm-svn: 124213

for floats, and also check if 'nil' is declared
when suggesting it for initializing ObjC pointers.

llvm-svn: 124004

to suggest initializations for pointer and
ObjC pointer types.

llvm-svn: 123995

to issue the warning at an uninitialized variable's
declaration, but to issue notes at possible
uninitialized uses (which could be multiple).

llvm-svn: 123994

references by monitoring whether an access to
a variable is solely to compute it's lvalue or
to do an lvalue-to-rvalue conversion (i.e., a load).

llvm-svn: 123777

llvm-svn: 123667

Fix a bug where the -Wmissing-noreturn would always treat constructors with base or member initializers as noreturn.

llvm-svn: 123603

-Wuninitialized based on CFG dataflow analysis.  WIP.

llvm-svn: 123512

temporaries with no-return destructors. The CFG now properly supports
temporaries and implicit destructors which both makes this kludge no
longer work, and conveniently removes the need for it.

Turn on CFG handling of implicit destructors and initializers. Several
ad-hoc benchmarks don't indicate any measurable performance impact from
growing the CFG, and it fixes real correctness problems with warnings.

As a result of turning on these CFG elements, we started to tickle an
inf-loop in the unreachable code logic used for warnings. The fix is
trivial.

llvm-svn: 123056