This change was a lot bigger than I originally anticipated; among
other things it requires us storing more information in the CFG to
record what block-level expressions need to be evaluated as lvalues.

The big change is that CFGBlocks no longer contain Stmt*'s by
CFGElements.  Currently CFGElements just wrap Stmt*, but they also
store a bit indicating whether the block-level expression should be
evalauted as an lvalue.  DeclStmts involving the initialization of a
reference require us treating the initialization expression as an
lvalue, even though that information isn't recorded in the AST.
Conceptually this change isn't that complicated, but it required
bubbling up the data through the CFGBuilder, to GRCoreEngine, and
eventually to GRExprEngine.

The addition of CFGElement is also useful for when we want to handle
more control-flow constructs or other data we want to keep in the CFG
that isn't represented well with just a block of statements.

In GRExprEngine, this patch introduces logic for evaluating the
lvalues of references, which currently retrieves the internal "pointer
value" that the reference represents.  EvalLoad does a two stage load
to catch null dereferences involving an invalid reference (although
this could possibly be caught earlier during the initialization of a
reference).

Symbols are currently symbolicated using the reference type, instead
of a pointer type, and special handling is required creating
ElementRegions that layer on SymbolicRegions (see the changes to
RegionStoreManager).

Along the way, the DeadStoresChecker also silences warnings involving
dead stores to references.  This was the original change I introduced
(which I wrote test cases for) that I realized caused GRExprEngine to
crash.

llvm-svn: 91501

Until we can make the dead stores checker smarter, dont' emit dead store warnings for C++ objects (whose constructors/destructors have possible side-effects).

llvm-svn: 91412

Add a heuristic to the dead stores checker to prune dead stores for variables annotated with '__block'.  This is overly conservative, but now the analyzer doesn't report dead stores for variables that can be updated by a block call.

llvm-svn: 90364

llvm-svn: 90086

llvm-svn: 90028

Change CheckDeadStores to use Expr::isNullPointerConstant, which will correctly determine whether an expression is a null pointer constant.

Patch by Kovarththanan Rajaratnam!

llvm-svn: 89621

local node information.

llvm-svn: 81433

llvm-svn: 81346

The implementations of these methods can Use Decl::getASTContext() to get the ASTContext.

This commit touches a lot of files since call sites for these methods are everywhere.
I used pre-tokenized "carbon.h" and "cocoa.h" headers to do some timings, and there was no real time difference between before the commit and after it.

llvm-svn: 74501

llvm-svn: 73702

are considered 'live'. This hack isn't needed anymore because we have a
separation in the path-sensitive analyzer between variable names and bindings;
the analyzer can continue to reason about the storage of a variable after its
name is no longer directly referenced.  Now the live variables analysis literally means "is this name live".

Along this line, update the dead stores checker to explicitly look for variables
whose values have escaped.

llvm-svn: 68504

llvm-svn: 68345

should only be an error if that value is consumed. This fix was largely
accomplished by moving 'isConsumedExpr' back to ParentMap.

llvm-svn: 68195

Fix PR 2514: Do not flag dead initializations for variables initialized to a constant global variable.

llvm-svn: 64149

accurately states what the function is trying to do and how it is 
different from Expr::isEvaluatable.  Also get rid of a parameter that is both 
unused and inaccurate.

llvm-svn: 62951

Dead stores checker: Fix <rdar://problem/6506065> by being more selective when say that a store is dead even though the computed value is used in the enclosing expression.

llvm-svn: 62552

Dead stores checker: Don't flag dead stores for self-assignments (common escape hatch for 'unused variable' warnings).

llvm-svn: 62010

uses of getName() with uses of getDeclName().  This upgrades a bunch of
diags to take DeclNames instead of std::strings.

This also tweaks a couple of diagnostics to be cleaner and changes
CheckInitializerTypes/PerformInitializationByConstructor to pass
around DeclarationNames instead of std::strings.

llvm-svn: 59947

Enhance dead store checker to not flag preincrements to dead variables where the preincrement is a subexpression, e.g. foo(++x);  This can cause false negatives, but will remove a whole class of false positives.

llvm-svn: 57554

Changed casing of many bug names.  The convention will be to have bug names (mostly) lower cased, and categories use some capitalization.

llvm-svn: 56385

llvm-svn: 54568

llvm-svn: 54563

llvm-svn: 54492

Added decl_iterator to DeclStmt to provide an abstract interface to iterate over the ScopedDecls of a DeclStmt.
Updated a few clients of DeclStmt::getNextDeclarator() to use decl_iterator instead.  Will update other clients after additional testing.

llvm-svn: 54368

llvm-svn: 54268

This fixes PR 2573: http://llvm.org/bugs/show_bug.cgi?id=2573

llvm-svn: 54009

llvm-svn: 53983

Don't flag dead stores when the result of a preincrement/predecrement is used in an enclosing expression.

llvm-svn: 53964

llvm-svn: 53960

llvm-svn: 53906

llvm-svn: 53628

llvm-svn: 53573

Have BugReporter::getCFG and BugReporter::getLiveVariables returns pointers instead of references, because they can both fail
on functions we cannot construct full CFGs for yet.

llvm-svn: 53081

Added static analysis check to see if a subclass of NSObject implements -dealloc, and whether or not that implementation calls [super dealloc].

llvm-svn: 53075

llvm-svn: 53054

Refactored some of the BugReporter interface so that data such as the ASTContext&, PathDiagnosticClient*, can be provided by an external source.
Split BugReporter into BugReporter and GRBugReporter so checkers not based on GRExprEngine can still use the BugReporter mechanism.

llvm-svn: 53048

Modified the DeadStores logic in AnalysisConsumer.cpp to use the LiveVariables object created by the AnalysisManager.

llvm-svn: 53043

When using the dead-stores checker with the BugReporter class, properly capture the diagnostic associated with a specific warning and emit it.

llvm-svn: 52565

1) Check if a dead store appears as a subexpression.  For such cases, we emit
   a verbose diagnostic so that users aren't confused.  This addresses:
   
   <rdar://problem/5968508> checker gives misleading report for dead store in loop
   
2) Don't emit a dead store warning when assigning a null value to a pointer.
   This is a common form of defensive programming.  We may wish to make
   this an option to the the checker one day.
   
   This addresses the feature request in the following email:
   
   http://lists.cs.uiuc.edu/pipermail/cfe-dev/2008-June/001978.html

llvm-svn: 52555

Don't use ostringstream (pulling in <sstream>) when creating the dead store diagnostic (simply not needed).

llvm-svn: 51432