- Generate atomicrmw operations in most of the cases when it's sensible to do
so.
- Don't crash in several common cases (and hopefully don't crash in more of
them).
- Add some better tests.
We now generate significantly better code for things like:
_Atomic(int) x;
...
x++;
On MIPS, this now generates a 4-instruction ll/sc loop, where previously it
generated about 30 instructions in two nested loops. On x86-64, we generate a
single lock incl, instead of a lock cmpxchgl loop (one instruction instead of
ten).
llvm-svn: 176420
Inlining brought a few "null pointer use" false positives, which occur because
the callee defensively checks if a pointer is NULL, whereas the caller knows
that the pointer cannot be NULL in the context of the given call.
This is a first attempt to silence these warnings by tracking the symbolic value
along the execution path in the BugReporter. The new visitor finds the node
in which the symbol was first constrained to NULL. If the node belongs to
a function on the active stack, the warning is reported, otherwise, it is
suppressed.
There are several areas for follow up work, for example:
- How do we differentiate the cases where the first check is followed by
another one, which does happen on the active stack?
Also, this only silences a fraction of null pointer use warnings. For example, it
does not do anything for the cases where NULL was assigned inside a callee.
llvm-svn: 176402
In LLVM, -pedantic is not set unless LLVM_ENABLE_PEDANTIC is set.
However, Clang's CMakeLists.txt unilaterally adds -pedantic to the run
line, so we need to disable -Wnested-anon-types explicitly.
llvm-svn: 176393
Previously we were assuming that we'd never ask for the sub-region bindings
of a bitfield, since a bitfield cannot have subregions. However,
unification of code paths has made that assumption invalid. While we could
take advantage of this by just checking for the single possible binding,
it's probably better to do the right thing, so that if/when we someday
support unions we'll do the right thing there, too.
This fixes a handful of false positives in analyzing LLVM.
<rdar://problem/13325522>
llvm-svn: 176388
Most map types have an operator[] that inserts a new element if the key
isn't found, then returns a reference to the value slot so that you can
assign into it. However, if the value type is a pointer, it will be
initialized to null. This is usually no problem.
However, if the user /knows/ the map contains a value for a particular key,
they may just use it immediately:
// From ClangSACheckersEmitter.cpp
recordGroupMap[group]->Checkers
In this case the analyzer reports a null dereference on the path where the
key is not in the map, even though the user knows that path is impossible
here. They could silence the warning by adding an assertion, but that means
splitting up the expression and introducing a local variable. (Note that
the analyzer has no way of knowing that recordGroupMap[group] will return
the same reference if called twice in a row!)
We already have logic that says a null dereference has a high chance of
being a false positive if the null came from an inlined function. This
patch simply extends that to references whose rvalues are null as well,
silencing several false positives in LLVM.
<rdar://problem/13239854>
llvm-svn: 176371
In builder type call, we indent to the laster function calls.
However, for the last element of such a call, we don't need to do
so, as that normally just wastes space and does not increase
readability.
Before:
aaaaaa->aaaaaa->aaaaaa( // break
aaaaaa);
aaaaaaaaaaaaaaaaaaaaa->aaaaaaaaaaaaaaaaaaaaaa
->aaaaaaaaaaaaaaaaaaaaaaaaaa(
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa);
After:
aaaaaa->aaaaaa->aaaaaa( // break
aaaaaa);
aaaaaaaaaaaaaaaaaaaaa->aaaaaaaaaaaaaaaaaaaaaa->aaaaaaaaaaaaaaaaaaaaaaaaaa(
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa);
llvm-svn: 176352
We now break at a slash if we do not find a space to break on.
Also fixes a bug where we would go over the limit when breaking the
second line.
llvm-svn: 176350
If we don't find a natural split point (currently space) in a string
literal protruding over the line, we just split at the last possible
point.
llvm-svn: 176349
whether we already have a method. Fixes a bug where we were
failing to properly contextually convert a message receiver
during template instantiation.
As a side-effect, we now actually perform correct method lookup
after adjusting a message-send to integral or non-ObjC pointer
types (legal outside of ARC).
rdar://13305374
llvm-svn: 176339
of block declarators. Document the rule we use.
Also document the rule that Doug implemented a few weeks ago
which drops ownership qualifiers on function result types.
rdar://10127067
llvm-svn: 176336
Previously we would return null for an out-of-date file. This inhibited ASTReader::ReadSLocEntry
from creating a FileID to recover gracefully in such a case.
llvm-svn: 176332
calls and declarations.
LLVM has a default CC determined by the target triple. This is
not always the actual default CC for the ABI we've been asked to
target, and so we sometimes find ourselves annotating all user
functions with an explicit calling convention. Since these
calling conventions usually agree for the simple set of argument
types passed to most runtime functions, using the LLVM-default CC
in principle has no effect. However, the LLVM optimizer goes
into histrionics if it sees this kind of formal CC mismatch,
since it has no concept of CC compatibility. Therefore, if this
module happens to define the "runtime" function, or got LTO'ed
with such a definition, we can miscompile; so it's quite
important to get this right.
Defining runtime functions locally is quite common in embedded
applications.
llvm-svn: 176286
This does not yet implement the LimitNode approach discussed.
The impact of this is an O(n) in the number of nodes in the AST
reduction of complexity for certain kinds of matchers (as otherwise the
parent map gets recreated for every new MatchFinder).
See FIXMEs in the comments for the direction of future work.
llvm-svn: 176251
Two improvements:
1) Always leave at least one space before "\". Otherwise is can look bad
and there is a risk of unwillingly joining to characters to a different
token.
2) Use the full column limit for single-line #defines.
Fixes llvm.org/PR15148
llvm-svn: 176245
By returning the (key, value) binding pairs, we save lookups afterwards.
This also enables further work later on.
No functionality change.
llvm-svn: 176230
Consider this case:
int *p = 0;
p = getPointerThatMayBeNull();
*p = 1;
If we inline 'getPointerThatMayBeNull', we might know that the value of 'p'
is NULL, and thus emit a null pointer dereference report. However, we
usually want to suppress such warnings as error paths, and we do so by using
FindLastStoreBRVisitor to see where the NULL came from. In this case, though,
because 'p' was NULL both before and after the assignment, the visitor
would decide that the "last store" was the initialization, not the
re-assignment.
This commit changes FindLastStoreBRVisitor to consider all PostStore nodes
that assign to this region. This still won't catches changes made directly
by checkers if they re-assign the same value, but it does handle the common
case in user-written code and will trigger ReturnVisitor's suppression
machinery as expected.
<rdar://problem/13299738>
llvm-svn: 176201
This enables constructor inlining for types with non-trivial destructors.
The plan is to enable destructor inlining within the next month, but that
needs further verification.
<rdar://problem/12295329>
llvm-svn: 176200
single translation unit should prevent later phases from executing. Otherwise,
this generates lots of noise in build systems. This a fallout from r173825.
Patch by Matthew Curtis <mcurtis@codeaurora.org>.
rdar://13298009
llvm-svn: 176198
After some discussions, it seems that this is the better path in
the long run. Does not change Chromium style, as there, bin packing
is forbidden by the style guide.
Also fix two minor bugs wrt. formatting:
1. If a call parameter is a function call itself and is split before
the "." or "->", split before the next parameter.
2. If a call parameter is string literal that has to be split onto
two lines, split before the next parameter.
llvm-svn: 176177
Since r175326 an implicitly hidden template argument can cause a template
installation to become hidden, even if the template itself has an explicit
default visibility. This requires that we keep track of "late" additions
of the visibility attribute.
This is hopefully the last followup change. It just removes the caching of
visibilities from types so that we can see new attributes even after a type has
been used.
llvm-svn: 176164
bitfield. CGBitField::StorageAlignment holds the alignment in chars, but
emitMemcpy had been treating it as if it were held in bits, leading to
underaligned memcpys.
Related to PR15348.
Thanks very much to Chandler for the diagnosis.
llvm-svn: 176163
This potentially reduces a performance optimization of throwing away
PreStmtPurgeDeadSymbols nodes. I'll investigate the performance impact
soon and see if we need something better.
llvm-svn: 176149
This is essentially the same problem as r174031: a lazy binding for the first
field of a struct may stomp on an existing default binding for the
entire struct. Because of the way RegionStore is set up, we can't help
but lose the top-level binding, but then we need to make sure that accessing
one of the other fields doesn't come back as Undefined.
In this case, RegionStore is now correctly detecting that the lazy binding
we have isn't the right type, but then failing to follow through on the
implications of that: we don't know anything about the other fields in the
aggregate. This fix adds a test when searching for other kinds of default
values to see if there's a lazy binding we rejected, and if so returns
a symbolic value instead of Undefined.
The long-term fix for this is probably a new Store model; see
<rdar://problem/12701038>.
Fixes <rdar://problem/13292559>.
llvm-svn: 176144
isBeforeInTranslationUnit() uses a cache to reduce the expensive work
to compute a common ancestor for two FileIDs. This work is very
expensive, so even caching the latest used FileIDs was a big win.
A closer analysis of the cache before, however, shows that the cache
access pattern would oscillate between a working set of FileIDs, and
thus caching more pairs would be profitable.
This patch adds a side table for extending caching. This side table
is bounded in size (experimentally determined in this case from
a simple Objective-C project), and when the table gets too large
we fall back to the single entry caching before as before.
On Sketch (a small example Objective-C project), this optimization
reduces -fsyntax-only time on SKTGraphicView.m by 5%. This is
for a project that is already using PCH.
Fixes <rdar://problem/13299847>
llvm-svn: 176142
This would error in C++ mode unless the variable also had a cv
qualifier.
e.g.
__attribute__((address_space(2))) float foo = 1.0f; would error but
__attribute__((address_space(2))) const float foo = 1.0f; would not.
llvm-svn: 176121
Fixes PR15358 and <rdar://problem/13295437>.
Along the way, shorten path diagnostics that say "Variable 'x'" to just
be "'x'". By the context, it is obvious that we have a variable,
and so this just consumes text space.
llvm-svn: 176115
Now that implicitly hidden template arguments can make an instantiation hidden,
it is important to look at more than just the canonical decl of the argument
in order to see if an attribute is available in a more recent decl.
This has the disadvantage of exposing when getExplicitVisibility is called,
but lets us handle cases like
template <typename T>
struct __attribute__((visibility("default"))) barT {
static void zed() {}
};
class foo;
class __attribute__((visibility("default"))) foo;
template struct barT<foo>;
llvm-svn: 176112
GCC applies a pragma weak to a decl if it matches the mangled name. We used
to apply if it matched the plain name.
This patch is a compromise: we apply the pragma only if it matches the name
and the decl has C language linkage.
llvm-svn: 176110
Empty lines followed by line comments are often used to highlight the
comment. Empty lines somewhere else are usually left over from manual or
automatic formatting and should probably be removed.
Before (clang-format would keep):
S s = {
a,
b
};
After:
S s = { a, b };
llvm-svn: 176086
We might want to move towards doing this if the formatting can be
significantly improved, but we need to carefully evaluate the different
situations first.
Before (the string literal was split by clang-format here):
aaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaa, aaaaaa("aaa aaaaa aaa aaa aaaaa aaa "
"aaaaa aaa aaa aaaaaa"));
After:
aaaaaaaaaaaaaaaaaaaa(
aaaaaaaaaaaaaaaaaaaa,
aaaaaa("aaa aaaaa aaa aaa aaaaa aaa aaaaa aaa aaa aaaaaa"));
llvm-svn: 176084
David Chisnall