[clang] Omit most AttributedStatements from the CFG

`[[clang::fallthrough]]` has meaning for the CFG, but all other
StmtAttrs we currently have don't. So omit them, as AttributedStatements
with chil

[clang] Omit most AttributedStatements from the CFG

`[[clang::fallthrough]]` has meaning for the CFG, but all other
StmtAttrs we currently have don't. So omit them, as AttributedStatements
with children cause several issues and there's no benefit in including
them.

Fixes PR52103 and PR49454. See PR52103 for details.

Differential Revision: https://reviews.llvm.org/D111568

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[clang] Expose unreachable fallthrough annotation warning

The Linux kernel has a macro called IS_ENABLED(), which evaluates to a
constant 1 or 0 based on Kconfig selections, allowing C code to be
un

[clang] Expose unreachable fallthrough annotation warning

The Linux kernel has a macro called IS_ENABLED(), which evaluates to a
constant 1 or 0 based on Kconfig selections, allowing C code to be
unconditionally enabled or disabled at build time. For example:

int foo(struct *a, int b) {
switch (b) {
case 1:
if (a->flag || !IS_ENABLED(CONFIG_64BIT))
return 1;
__attribute__((fallthrough));
case 2:
return 2;
default:
return 3;
}
}

There is an unreachable warning about the fallthrough annotation in the
first case because !IS_ENABLED(CONFIG_64BIT) can be evaluated to 1,
which looks like

return 1;
__attribute__((fallthrough));

to clang.

This type of warning is pointless for the Linux kernel because it does
this trick all over the place due to the sheer number of configuration
options that it has.

Add -Wunreachable-code-fallthrough, enabled under -Wunreachable-code, so
that projects that want to warn on unreachable code get this warning but
projects that do not care about unreachable code can still use
-Wimplicit-fallthrough without having to make changes to their code
base.

Fixes PR51094.

Reviewed By: aaron.ballman, nickdesaulniers

Differential Revision: https://reviews.llvm.org/D107933

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[clang][parser] Set source ranges for GNU-style attributes

Set the source ranges for parsed GNU-style attributes in
ParseGNUAttributes(), the same way that ParseCXX11Attributes() does it.

Different

[clang][parser] Set source ranges for GNU-style attributes

Set the source ranges for parsed GNU-style attributes in
ParseGNUAttributes(), the same way that ParseCXX11Attributes() does it.

Differential Revision: https://reviews.llvm.org/D75844

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Revert "[clang][parser] Set source ranges for GNU-style attributes"

This reverts commit 1ea9fa8c507ec360cf43faf46d13b149e37c950d.

[clang][parser] Set source ranges for GNU-style attributes

Set the source ranges for parsed GNU-style attributes in
ParseGNUAttributes(), the same way that ParseCXX11Attributes() does it.

Different

[clang][parser] Set source ranges for GNU-style attributes

Set the source ranges for parsed GNU-style attributes in
ParseGNUAttributes(), the same way that ParseCXX11Attributes() does it.

Differential Revision: https://reviews.llvm.org/D75844

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Automate common diagnostic checking for statement attributes

Clang currently automates a fair amount of diagnostic checking for
declaration attributes based on the declarations in Attr.td. It checks

Automate common diagnostic checking for statement attributes

Clang currently automates a fair amount of diagnostic checking for
declaration attributes based on the declarations in Attr.td. It checks
for things like subject appertainment, number of arguments, language
options, etc. This patch uses the same machinery to perform diagnostic
checking on statement attributes.

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[Attr] Support _attribute__ ((fallthrough))

Summary: Fixed extraneous matches of non-NullStmt

Reviewers: aaron.ballman, rsmith, efriedma, xbolva00

Reviewed By: aaron.ballman, rsmith, xbolva00

Sub

[Attr] Support _attribute__ ((fallthrough))

Summary: Fixed extraneous matches of non-NullStmt

Reviewers: aaron.ballman, rsmith, efriedma, xbolva00

Reviewed By: aaron.ballman, rsmith, xbolva00

Subscribers: riccibruno, arphaman, ziangwan, ojeda, xbolva00, nickdesaulniers, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64838

llvm-svn: 369414

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Allow a double-underscore spelling of Clang attributes using double square bracket syntax.

This matches a similar behavior with GCC accepting [[gnu::__attr__]] as a alias for [[gnu::attr]] in that c

Allow a double-underscore spelling of Clang attributes using double square bracket syntax.

This matches a similar behavior with GCC accepting [[gnu::__attr__]] as a alias for [[gnu::attr]] in that clang attributes can now be spelled with two leading and trailing underscores.

I had always intended for this to work, but missed the critical bit. We already had an existing test in test/Preprocessor/has_attribute.cpp for [[clang::__fallthrough__]] but using that spelling would still give an "unknown attribute" diagnostic.

llvm-svn: 346547

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P0188R1: add support for standard [[fallthrough]] attribute. This is almost
exactly the same as clang's existing [[clang::fallthrough]] attribute, which
has been updated to have the same semantics. T

P0188R1: add support for standard [[fallthrough]] attribute. This is almost
exactly the same as clang's existing [[clang::fallthrough]] attribute, which
has been updated to have the same semantics. The one significant difference
is that [[fallthrough]] is ill-formed if it's not used immediately before a
switch label (even when -Wimplicit-fallthrough is disabled). To support that,
we now build a CFG of any function that uses a '[[fallthrough]];' statement
to check.

In passing, fix some bugs with our support for statement attributes -- in
particular, diagnose their use on declarations, rather than asserting.

llvm-svn: 262881

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Revert r234786, it contained a bunch of stuff I did not mean to commit.

llvm-svn: 234787

Revert r234613 (and follow-ups 234614, 234616, 234618), it caused PR23216.

llvm-svn: 234786

Fix "warning: fallthrough annotation does not directly precede switch label" in lambdas.

Summary: This patch fixes http://llvm.org/PR17864 - "warning: fallthrough annotation does not directly preced

Fix "warning: fallthrough annotation does not directly precede switch label" in lambdas.

Summary: This patch fixes http://llvm.org/PR17864 - "warning: fallthrough annotation does not directly precede switch label" in lambdas.

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: rnk, cfe-commits

Differential Revision: http://reviews.llvm.org/D4258

llvm-svn: 211599

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As of r202325, CFGBlock predecessors may be NULL. Ignore such preds. Fixes a crasher, PR18983.

llvm-svn: 202340

Moved fallthrough regression test to switch-implicit-fallthrough.cpp.

llvm-svn: 178554

-Wimplicit-fallthrough: fixed two cases where "fallthrough annotation in unreachable code" was issued incorrectly.

Summary:
-Wimplicit-fallthrough: fixed two cases where "fallthrough annotation in u

-Wimplicit-fallthrough: fixed two cases where "fallthrough annotation in unreachable code" was issued incorrectly.

Summary:
-Wimplicit-fallthrough: fixed two cases where "fallthrough annotation in unreachable code" was issued incorrectly:

1. In actual unreachable code, but not immediately on a fall-through execution
path "fallthrough annotation does not directly precede switch label" is better;
2. After default: in a switch with covered enum cases. Actually, these shouldn't
be treated as unreachable code for our purpose.

Reviewers: rsmith

Reviewed By: rsmith

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D374

llvm-svn: 174575

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Fixed segmentation fault when a CFGBlock has NULL successor.

llvm-svn: 174182

Don't warn on fall-through from unreachable code.

Summary:
A motivating example:
class ClassWithDtor {
public:
~ClassWithDtor() {}
};
void fallthrough3(int n) {
switch (n) {
case 2:
do

Don't warn on fall-through from unreachable code.

Summary:
A motivating example:
class ClassWithDtor {
public:
~ClassWithDtor() {}
};
void fallthrough3(int n) {
switch (n) {
case 2:
do {
ClassWithDtor temp;
return;
} while (0); // This generates a chain of unreachable CFG blocks.
case 3:
break;
}
}

Reviewers: rsmith, doug.gregor, alexfh

Reviewed By: alexfh

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D330

llvm-svn: 173889

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Silence unintended fallthrough diagnostic on a case label preceded with a normal label.

Summary:
It's unlikely that a fallthrough is unintended in the following code:
switch (n) {
...
label:
cas

Silence unintended fallthrough diagnostic on a case label preceded with a normal label.

Summary:
It's unlikely that a fallthrough is unintended in the following code:
switch (n) {
...
label:
case 1:
...
goto label;
...
}

Reviewers: rsmith, doug.gregor

Reviewed By: doug.gregor

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D329

llvm-svn: 173486

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Don't suggest to insert [[clang::fallthrough]] before empty cases. Fix for multiple case labels.

llvm-svn: 173458

Added test with sizeof conditions (relies on to-be-implemented functionality of CFG, discussion: http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20120507/057370.html)

llvm-svn: 158854

Don't offer '[[clang::fallthrough]];' fix-it when a fall-through occurs to a
switch label immediately followed by a 'break;'.

llvm-svn: 157508

Add -Wimplicit-fallthrough warning flag, which warns on fallthrough between
cases in switch statements. Also add a [[clang::fallthrough]] attribute, which
can be used to suppress the warning in the c

Add -Wimplicit-fallthrough warning flag, which warns on fallthrough between
cases in switch statements. Also add a [[clang::fallthrough]] attribute, which
can be used to suppress the warning in the case of intentional fallthrough.

Patch by Alexander Kornienko!

The handling of C++11 attribute namespaces in this patch is temporary, and will
be replaced with a cleaner mechanism in a subsequent patch.

llvm-svn: 156086

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