Summary:
Dear All,

We have been looking at the following problem, where any code after the constant bound loop is not analyzed because of the limit on how many times the same block is visited, as described in bugzillas #7638 and #23438. This problem is of interest to us because we have identified significant bugs that the checkers are not locating. We have been discussing a solution involving ranges as a longer term project, but I would like to propose a patch to improve the current implementation.

Example issue:
```
for (int i = 0; i < 1000; ++i) {...something...}
int *p = 0;
*p = 0xDEADBEEF;
```

The proposal is to go through the first and last iterations of the loop. The patch creates an exploded node for the approximate last iteration of constant bound loops, before the max loop limit / block visit limit is reached. It does this by identifying the variable in the loop condition and finding the value which is “one away” from the loop being false. For example, if the condition is (x < 10), then an exploded node is created where the value of x is 9. Evaluating the loop body with x = 9 will then result in the analysis continuing after the loop, providing x is incremented.

The patch passes all the tests, with some modifications to coverage.c, in order to make the ‘function_which_gives_up’ continue to give up, since the changes allowed the analysis to progress past the loop.

This patch does introduce possible false positives, as a result of not knowing the state of variables which might be modified in the loop. I believe that, as a user, I would rather have false positives after loops than do no analysis at all. I understand this may not be the common opinion and am interested in hearing your views. There are also issues regarding break statements, which are not considered. A more advanced implementation of this approach might be able to consider other conditions in the loop, which would allow paths leading to breaks to be analyzed.

Lastly, I have performed a study on large code bases and I think there is little benefit in having “max-loop” default to 4 with the patch. For variable bound loops this tends to result in duplicated analysis after the loop, and it makes little difference to any constant bound loop which will do more than a few iterations. It might be beneficial to lower the default to 2, especially for the shallow analysis setting.

Please let me know your opinions on this approach to processing constant bound loops and the patch itself.

Regards,

Sean Eveson
SN Systems - Sony Computer Entertainment Group

Reviewers: jordan_rose, krememek, xazax.hun, zaks.anna, dcoughlin

Subscribers: krememek, xazax.hun, cfe-commits

Differential Revision: http://reviews.llvm.org/D12358

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Remove a check that won't be valid when LLVM stops
emitting runtime hook user function.


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Accidentally made the test too strict.

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Add the required libraries to the linker invocation when building with
sanitizers.

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Use an initializer list to remove a couple of small static arrays.  NFC.

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Indicate support for ASAN on the CrossWindows toolchain.  Although this is
insufficient, this at least permits the handling of the driver flag.

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GCC has a warning called -Wdouble-promotion, which warns you when
an implicit conversion increases the width of a floating point type.

This is useful when writing code for architectures that can perform
hardware FP ops on floats, but must fall back to software emulation for
larger types (i.e. double, long double).

This fixes PR15109 <https://llvm.org/bugs/show_bug.cgi?id=15109>.

Thanks to Carl Norum for the patch!



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This works around PR25162. The MSVC tables make it very difficult to
correctly inline a C++ destructor that contains try / catch.  We've
attempted to address PR25162 in LLVM's backend, but it feels pretty
infeasible.  MSVC and ICC both appear to avoid inlining such complex
destructors.

Long term, we want to fix this by making the inliner smart enough to
know when it is inlining into a cleanup, so it can inline simple
destructors (~unique_ptr and ~vector) while avoiding destructors
containing try / catch.

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GCC uses the x87DoubleExtended model for long doubles, and passes them
indirectly by address through function calls.

Also replace the existing mingw-long-double assembly emitting test with
an IR-level test.

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Use the *current* state of "is-moduleness" rather than the state at
serialization time so that if we read a builtin identifier from a module
that wasn't "interesting" to that module, we will still write it out to
a PCH that imports that module.

Otherwise, we would get mysterious "unknown builtin" errors when using
PCH+modules.

rdar://problem/23287656

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In addition to r251524: preserve the order the checkers were enabled/disabled to be deterministic.
Additionally return the number of arguments read by 'ProcessArgs' - for debug purpose.

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A checker may be enabled/disabled multiple times via -enable-checker and -disable-checker scan-build arguments. Currently the conflicting and repetitive arguments are passed to the analyzer as is.
With this patch only the last enable/disable of a particular checker is accepted and passed to the analyzer.
This change is mostly done for the upcoming 'config for scan-build' patch when multiple inclusions/exclusions of a checker are expected to be more common.

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Most of the cases belong into an anonymous namespace. No functionality
change intended.

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that has a thumb only CPU by default (cortex-m3), and when using the assembler,
the default thumb state of the CPU does not get passed via the triple to LLVM:

$ clang -target thumbv7m-none-eabi -c -v test.s
clang -cc1as ... -triple armv7m-none--eabi ... test.s

Differential Revision: http://reviews.llvm.org/D14121

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for all the reasons that ARC makes things implicitly unavailable.

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Update the linker selection to support the `-fuse-ld=` option for selecting a
linker.

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functions.

This commit fixes a bug in CGOpenMPRuntime.cpp and CGObjC.cpp where
some of the function attributes are not attached to newly created
functions.

rdar://problem/20828324

Differential Revision: http://reviews.llvm.org/D13928


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Summary: This is especially important so that if a change is solely inserting a block around a few statements, clang-format-diff.py will still clean up and add indentation to the inner parts.

Reviewers: klimek

Subscribers: cfe-commits, klimek

Differential Revision: http://reviews.llvm.org/D14105

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Fake arguments are automatically handled for serialization, cloning,
and other representational tasks, but aren't included in pretty-printing
or parsing (should we eventually ever automate that).

This is chiefly useful for attributes that can be written by the
user, but which are also frequently synthesized by the compiler,
and which we'd like to remember details of the synthesis for.
As a simple example, use this to narrow the cases in which we were
generating a specialized note for implicitly unavailable declarations.

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With more complex structures in C++ Lambdas and JavaScript function
literals, the old value was simply to small. However, this is a
temporary solution, I need to look at this more closely a) to find a
fundamentally better approach and b) to look at whether the more recent
usage of NoLineBreak makes us visit stuff in an unfortunate order
where clang-format waste many states in dead ends.

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If the user configured clang with a custom GCC toolchain that will take precedence on what the ToolChainTest.cpp expects to evaluate. 
This is fixed here by passing --gcc-toolchain= to the driver, in order to override any user defined GCC toolchain.



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The analyzer assumes that system functions will not free memory or modify the
arguments in other ways, so we assume that arguments do not escape when
those are called. However, this may lead to false positive leak errors. For
example, in code like this where the pointers added to the rb_tree are freed
later on:

		struct alarm_event *e = calloc(1, sizeof(*e));
<snip>

		rb_tree_insert_node(&alarm_tree, e);

Add a heuristic to assume that calls to system functions taking void*
arguments allow for pointer escape.

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1. Make the warning more strict in C mode. r172696 added code to suppress
   warnings from macro expansions in system headers, which checks
   `SourceMgr.isMacroBodyExpansion(E->IgnoreParens()->getExprLoc())`. Consider
   this snippet:

   #define FOO(x) (x)
   void f(int a) {
     FOO(a);
   }

   In C, the line `FOO(a)` is an `ImplicitCastExpr(ParenExpr(DeclRefExpr))`,
   while it's just a `ParenExpr(DeclRefExpr)` in C++. So in C++,
   `E->IgnoreParens()` returns the `DeclRefExpr` and the check tests the
   SourceLoc of `a`. In C, the `ImplicitCastExpr` has the effect of checking the
   SourceLoc of `FOO`, which is a macro body expansion, which causes the
   diagnostic to be skipped. It looks unintentional that clang does different
   things for C and C++ here, so use `IgnoreParenImpCasts` instead of
   `IgnoreParens` here. This has the effect of the warning firing more often
   than previously in C code – it now fires as often as it fires in C++ code.

2. Suppress the warning if it would warn on `UNREFERENCED_PARAMETER`.
   `UNREFERENCED_PARAMETER` is a commonly used macro on Windows and it happens
   to uselessly trigger -Wunused-value. As discussed in the thread
   "rfc: winnt.h's UNREFERENCED_PARAMETER() vs clang's -Wunused-value" on
   cfe-dev, fix this by special-casing this specific macro. (This costs a string
   comparison and some fast-path lexing per warning, but the warning is emitted
   rarely. It fires once in Windows.h itself, so this code runs at least once
   per TU including Windows.h, but it doesn't run hundreds of times.)

http://reviews.llvm.org/D13969


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Summary: This is a follow on to post review comments on revision r248276.

Patch by Scott Egerton.

Reviewers: vkalintiris, dsanders

Subscribers: joerg, rengolin, cfe-commits

Differential Revision: http://reviews.llvm.org/D13100


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Linking options for particular file depend on the option that specifies the file.
Currently there are two:

* -mlink-bitcode-file links in complete content of the specified file.
* -mlink-cuda-bitcode links in only the symbols needed by current TU.
   Linked symbols are internalized. This bitcode linking mode is used to
   link device-specific bitcode provided by CUDA.

Files are linked in order they are specified on command line.

-mlink-cuda-bitcode replaces -fcuda-uses-libdevice flag.

Differential Revision: http://reviews.llvm.org/D13913

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Microsoft connect bug: https://connect.microsoft.com/VisualStudio/feedback/details/1741530


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Expose isMutable via libClang and python bindings.

Patch by Jonathan B Coe!

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Specifically, don't wrap between the {} of an empty constructor if the
"}" falls on column 81 and ConstructorInitializerAllOnOneLineOrOnePerLine
is set.

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Summary:
If this option is set, clang-format will always insert a line wrap, e.g.
before the first parameter of a function call unless all parameters fit
on the same line. This obviates the need to make a decision on the
alignment itself.

Use this style for Google's JavaScript style and add some minor tweaks
to correctly handle nested blocks etc. with it. Don't use this option
for for/while loops.

Reviewers: klimek

Subscribers: klimek, cfe-commits

Differential Revision: http://reviews.llvm.org/D14104

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hopefully make bots happy again.


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