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
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
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
This rename serves two purposes:
- It reflects the actual functionality of this analysis.
- We will have more than one reachability analysis.
llvm-svn: 127930
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
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
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
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
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
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
Diagnostic pragmas are broken because we don't keep track of the diagnostic state changes and we only check the current/latest state.
Problems manifest if a diagnostic is emitted for a source line that has different diagnostic state than the current state; this can affect
a lot of places, like C++ inline methods, template instantiations, the lexer, etc.
Fix the issue by having the Diagnostic object keep track of the source location of the pragmas so that it is able to know what is the diagnostic state at any given source location.
Fixes rdar://8365684.
llvm-svn: 121873
if *none* of the successors of the call expression is the exit block.
This matters when a call of bool type is the condition of (say) a while
loop in a function with no statements after the loop. This *can* happen
in C, but it's much more common in C++ because of overloaded operators.
Suppresses some substantial number of spurious -Wmissing-noreturn warnings.
llvm-svn: 102696
unless they are used. I discussed this with Daniel Dunbar, and we agreed that this
provides an inconsistent warnings experience for the user and that there were
genuine cases where we wouldn't want to do this optimization.
llvm-svn: 100800
This introduces FunctionType::ExtInfo to hold the calling convention and the
noreturn attribute. The next patch will extend it to include the regparm
attribute and fix the bug.
llvm-svn: 99920
This object controls when the warnings are executed, allowing the client code
in Sema to selectively disable warnings as needed.
Centralizing the logic for analysis-based warnings allows us to optimize
when and how they are run.
Along the way, remove the redundant logic for the 'check fall-through' warning
for blocks; now the same logic is used for both blocks and functions.
llvm-svn: 99085
Benjamin Kramer