incorrectly in the CFG, and also the static analyzer. This patch regresses the analyzer a bit, but
that needs to be followed up with a better solution.
Fixes <rdar://problem/10008112>.
llvm-svn: 138372
Having a notion of an actual ProgramPointTag will aid in introspection of the analyzer's behavior.
For example, the GraphViz output of the analyzer will pretty-print the tags in a useful manner.
llvm-svn: 137529
The motivation of this large change is to drastically simplify the logic in ExprEngine going forward.
Some fallout is that the output of some BugReporterVisitors is not as accurate as before; those will
need to be fixed over time. There is also some possible performance regression as RemoveDeadBindings
will be called frequently; this can also be improved over time.
llvm-svn: 136419
AnalysisBasedWarnings Sema layer and out of the Analysis library itself.
This returns the uninitialized values analysis to a more pure form,
allowing its original logic to correctly detect some categories of
definitely uninitialized values. Fixes PR10358 (again).
Thanks to Ted for reviewing and updating this patch after his rewrite of
several portions of this analysis.
llvm-svn: 135748
This is accomplished by forcing the needed expressions for -Wuninitialized to always be CFGElements in the CFG.
This allows us to remove a fair amount of the code for -Wuninitialized.
Some fallout:
- AnalysisBasedWarnings.cpp now specifically toggles the CFGBuilder to create a CFG that is suitable for -Wuninitialized. This
is a layering violation, since the logic for -Wuninitialized is in libAnalysis. This can be fixed with the proper refactoring.
- Some of the source locations for -Wunreachable-code warnings have shifted. While not ideal, this is okay because that analysis
already needs some serious reworking.
llvm-svn: 135480
patch, we actually move the state-machine for the value set backwards
one step. This can pretty easily lead to infinite loops where we
continually try to propagate a bit, succeed for one iteration, but then
back up because we find an uninitialized use.
A reduced test case from PR10379 is included.
llvm-svn: 135359
Previously, despite the names 'enqueue' and 'dequeue', it behaved as
a stack and visited blocks in a LIFO fashion. This interacts badly with
extremely broad CFGs *inside* of a loop (such as a large switch inside
a state machine) where every block updates a different variable.
When encountering such a CFG, the checker visited blocks in essentially
a "depth first" order due to the stack-like behavior of the work list.
Combined with each block updating a different variable, the saturation
logic of the checker caused it to re-traverse blocks [1,N-1] of the
broad CFG inside the loop after traversing block N. These re-traversals
were to propagate the variable values derived from block N. Assuming
approximately the same number of variables as inner blocks exist, the
end result is O(N^2) updates. By making this a queue, we also make the
traversal essentially "breadth-first" across each of the N inner blocks
of the loop. Then all of this state is propagated around to all N inner
blocks of the loop. The result is O(N) updates.
The truth is in the numbers:
Before, gcc.c: 96409 block visits (max: 61546, avg: 591)
After, gcc.c: 69958 block visits (max: 33090, avg: 429)
Before, PR10183: 2540494 block vists (max: 2536495, avg: 37360)
After, PR10183: 137803 block visits (max: 134406, avg: 2026)
The nearly 20x reduction in work for PR10183 corresponds to a roughly
100x speedup in compile time.
I've tested it on all the code I can get my hands on, and I've seen no
slowdowns due to this change. Where I've collected stats, the ammount of
work done is on average less. I'll also commit shortly some synthetic
test cases useful in analyzing the performance of CFG-based warnings.
Submitting this based on Doug's feedback that post-commit review should
be good. Ted, please review! Hopefully this helps compile times until
then.
llvm-svn: 134697
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
specifiers. Fixes <rdar://problem/9607158>." because it causes false positives
on some code that uses CF toll free bridging.
- I'll let Doug or Ted figure out the right fix here, possibly just to accept
any pointer type.
llvm-svn: 134041
MaterializeTemporaryExpr captures a reference binding to a temporary
value, making explicit that the temporary value (a prvalue) needs to
be materialized into memory so that its address can be used. The
intended AST invariant here is that a reference will always bind to a
glvalue, and MaterializeTemporaryExpr will be used to convert prvalues
into glvalues for that binding to happen. For example, given
const int& r = 1.0;
The initializer of "r" will be a MaterializeTemporaryExpr whose
subexpression is an implicit conversion from the double literal "1.0"
to an integer value.
IR generation benefits most from this new node, since it was
previously guessing (badly) when to materialize temporaries for the
purposes of reference binding. There are likely more refactoring and
cleanups we could perform there, but the introduction of
MaterializeTemporaryExpr fixes PR9565, a case where IR generation
would effectively bind a const reference directly to a bitfield in a
struct. Addresses <rdar://problem/9552231>.
llvm-svn: 133521
Language-design credit goes to a lot of people, but I particularly want
to single out Blaine Garst and Patrick Beard for their contributions.
Compiler implementation credit goes to Argyrios, Doug, Fariborz, and myself,
in no particular order.
llvm-svn: 133103
Related result types apply Cocoa conventions to the type of message
sends and property accesses to Objective-C methods that are known to
always return objects whose type is the same as the type of the
receiving class (or a subclass thereof), such as +alloc and
-init. This tightens up static type safety for Objective-C, so that we
now diagnose mistakes like this:
t.m:4:10: warning: incompatible pointer types initializing 'NSSet *'
with an
expression of type 'NSArray *' [-Wincompatible-pointer-types]
NSSet *array = [[NSArray alloc] init];
^ ~~~~~~~~~~~~~~~~~~~~~~
/System/Library/Frameworks/Foundation.framework/Headers/NSObject.h:72:1:
note:
instance method 'init' is assumed to return an instance of its
receiver
type ('NSArray *')
- (id)init;
^
It also means that we get decent type inference when writing code in
Objective-C++0x:
auto array = [[NSMutableArray alloc] initWithObjects:@"one", @"two",nil];
// ^ now infers NSMutableArray* rather than id
llvm-svn: 132868
Also, have Environment stop looking through NoOp casts; it didn't match the behavior of LiveVariables. And once that's gone, the whole cast block of that switch is unnecessary.
llvm-svn: 132840
This introduces a generic base class for the expression evaluator
classes, which handles a few common expression types which were
previously handled separately in each class. Also, the expression
evaluator now uses ConstStmtVisitor.
llvm-svn: 131281
instantiation), be sure to add the transformed declaration into the
current DeclContext. Also, remove the -Wuninitialized hack that works
around this bug. Fixes <rdar://problem/9200676>.
llvm-svn: 129544
evaluated and unevaluated contexts. Add some testing of sizeof and
typeid.
Both of the typeid tests added here were triggering warnings previously.
Now the one false positive is suppressed without suppressing the warning
on actually buggy code.
llvm-svn: 129431
marked explicitly as uninitialized through direct self initialization:
int x = x;
With r128894 we prevented warnings about this code, and this patch
teaches the analysis engine to continue analyzing subsequent uses of
'x'. This should wrap up PR9624.
There is still an open question of whether we should suppress the
maybe-uninitialized warnings resulting from variables initialized in
this fashion. The definitely-uninitialized uses should always be warned.
llvm-svn: 128932
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
Note this can potentially be enhanced to detect if the __block variable
is actually written by the block, or only when the block "escapes" or
is actually used, but that requires more analysis than it is probably worth
for this simple check.
llvm-svn: 128681
my expertise on the template instantiation logic isn't good enough to fix this problem for real. This patch worksaround the
problem in -Wuninitialized, but we should fix it for real later.
llvm-svn: 128443
This rename serves two purposes:
- It reflects the actual functionality of this analysis.
- We will have more than one reachability analysis.
llvm-svn: 127930
Change the interface to expose the new information and deal with the enormous fallout.
Introduce the new ExceptionSpecificationType value EST_DynamicNone to more easily deal with empty throw specifications.
Update the tests for noexcept and fix the various bugs uncovered, such as lack of tentative parsing support.
llvm-svn: 127537
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
Moreover, change AnalysisContext to use an OwningPtr for created analysis objects instead
of directly managing them.
Finally, add a 'forcedBlkExprs' entry to CFG::BuildOptions that will be used by the
CFGBuilder to force specific expressions to be block-level expressions.
llvm-svn: 127385
conventional categories into Basic and AST. Update the self-init checker
to use this logic; CFRefCountChecker is complicated enough that I didn't
want to touch it.
llvm-svn: 126817
This fixes a crash reported in PR9287, and also fixes a false positive involving the value of such ternary
expressions not properly getting propagated.
llvm-svn: 126362
class and to bind the shared value using OpaqueValueExpr. This fixes an
unnoticed problem with deserialization of these expressions where the
deserialized form would lose the vital pointer-equality trait; or rather,
it fixes it because this patch also does the right thing for deserializing
OVEs.
Change OVEs to not be a "temporary object" in the sense that copy elision is
permitted.
This new representation is not totally unawkward to work with, but I think
that's really part and parcel with the semantics we're modelling here. In
particular, it's much easier to fix things like the copy elision bug and to
make the CFG look right.
I've tried to update the analyzer to deal with this in at least some
obvious cases, and I think we get a much better CFG out, but the printing
of OpaqueValueExprs probably needs some work.
llvm-svn: 125744
LabelDecl and LabelStmt. There is a 1-1 correspondence between the
two, but this simplifies a bunch of code by itself. This is because
labels are the only place where we previously had references to random
other statements, causing grief for AST serialization and other stuff.
This does cause one regression (attr(unused) doesn't silence unused
label warnings) which I'll address next.
This does fix some minor bugs:
1. "The only valid attribute " diagnostic was capitalized.
2. Various diagnostics printed as ''labelname'' instead of 'labelname'
3. This reduces duplication of label checking between functions and blocks.
Review appreciated, particularly for the cindex and template bits.
llvm-svn: 125733
handling pseudo-path sensitivity, and instead
use those assertion conditions as dynamic checks.
These assertions would be violated when analyzing
a CFG where some branches where optimized away
during CFG construction because their branch
conditions could be trivially determined.
llvm-svn: 123943
analysis for short-circuited operations. For branch written like "if (x && y)",
we maintain two sets of dataflow values for the outgoing
branches. This suppresses some common false positives
for -Wuninitialized-experimental.
This change introduces some assertion failures
when running on the LLVM codebase. WIP.
llvm-svn: 123923
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
the prefix should be ignored.
E.g. if ignorePrefix is true, "_init" and "init" selectors will both be result in InitRule, but if
ignorePrefix is false, only "init" will return InitRule.
llvm-svn: 123262
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
16-bits in size. Implement this by splitting WChar into two enums, like we have
for char. This fixes a miscompmilation of XULRunner, PR8856.
llvm-svn: 122558
to libAnalysis. Similar to Format (format string checking),
CocoaConventions has the
potential to serve clients other than the
static analyzer.
llvm-svn: 122040
implicit lvalue-to-rvalue casts that John McCall
recently introduced. This causes a whole bunch
of logic in the analyzer for handling lvalues
to vanish. It does, however, raise a few issues
in the analyzer w.r.t to modeling various constructs
(e.g., field accesses to compound literals).
The .c/.m analysis test cases that fail are
due to a missing lvalue-to-rvalue cast that
will get introduced into the AST. The .cpp
failures were more than I could investigate in
one go, and the patch was already getting huge.
I have XFAILED some of these tests, and they
should obviously be further investigated.
Some highlights of this patch include:
- CFG no longer requires an lvalue bit for
CFGElements
- StackFrameContext doesn't need an 'asLValue'
flag
- The "VisitLValue" path from GRExprEngine has
been eliminated.
Besides the test case failures (XFAILed), there
are surely other bugs that are fallout from
this change.
llvm-svn: 121960
struct X {
X() : au_i1(123) {}
union {
int au_i1;
float au_f1;
};
};
clang will now deal with au_i1 explicitly as an IndirectFieldDecl.
llvm-svn: 120900
not actually frequently used, because ImpCastExprToType only creates a node
if the types differ. So explicitly create an ICE in the lvalue-to-rvalue
conversion code in DefaultFunctionArrayLvalueConversion() as well as several
other new places, and consistently deal with the consequences throughout the
compiler.
In addition, introduce a new cast kind for loading an ObjCProperty l-value,
and make sure we emit those nodes whenever an ObjCProperty l-value appears
that's not on the LHS of an assignment operator.
This breaks a couple of rewriter tests, which I've x-failed until future
development occurs on the rewriter.
Ted Kremenek kindly contributed the analyzer workarounds in this patch.
llvm-svn: 120890
1. "no 'else' after 'return'" -- this is for conformance with the
coding standards.
2. move 'else' to the line of the previous '}' -- this is for consistency.
Reviewed by kremenek.
llvm-svn: 119983
it is possible for the confluence block to only have a single predecessor due to calls to 'noreturn'
functions. Fixes assertion failure reported in PR 8619.
llvm-svn: 119284
Elidable CXXConstructExpr should inhibit calling destructor for temporary
that is copied, not the one created. This is because eliding copy constructor
means that the object that was to be copied will be constructed directly in
memory the copy would be constructed in.
llvm-svn: 119044
1. For statement: const C& c = C(0) ?: C(1) destructors generated for condition will not differ from those generated for case without prolonged lifetime of temporary,
2. There will be no destructor for constant reference member bound to temporary at the exit from constructor.
llvm-svn: 118158
containing a DoStmt, and the LHS doesn't create a new block, then we should
return RBlock. Otherwise we'll incorrectly return NULL.
Also relax an assertion in VisitWhileStmt(). Reset 'Block' when it is finished.
llvm-svn: 117436
- Adding LocalScope for CompoundStmt,
- Adding CFGAutomaticObjDtors for end of scope, return, goto, break, continue,
- Regression tests for above cases.
llvm-svn: 115252
- post-increament, distance and bool conversion methods to LocalScope::const_iterator,
- adding VarDecl to LocalScope.
Fixed some misspells in comments.
llvm-svn: 115227
-cfg-add-implicit-dtors - sets CFG::BuildOptions::AddImplicitDtors for AnalysisCosumer to true,
-cfg-add-initializers - sets CFG::BuildOptions::AddInitializers for AnalysisCosumer to true.
llvm-svn: 115142
- LocalScope class with iterator used to pointing into it,
- fat doxygen comment for LocalScope indended usage,
- BlockScopePosPair class used for storing jump targets/sources (for: goto, break, continue), that replaces raw CFGBlock pointer used earlier for this purpose.
llvm-svn: 114790
- definitions of interfaces for CFGInitializer and CFGAutomaticObjDtor,
- support for above classes to print_elem function (renamed print_stmt),
- support for VarDecls in StmtPrinterHelper.
llvm-svn: 114403
Ted Kremenek