Author: aaronballman
Date: Wed Oct 18 07:33:27 2017
New Revision: 316083
URL: http://llvm.org/viewvc/llvm-project?rev=316083&view=rev
Log:
Enable support for the [[fallthrough]] attribute from WG14 N2052 when enabling
double square bracket attributes in C code.
Added:
cfe/trunk/test/Sema/c2x-fallthrough.c
Modified:
cfe/trunk/include/clang/Basic/Attr.td
cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
Modified: cfe/trunk/include/clang/Basic/Attr.td
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Attr.td?rev=316083&r1=316082&r2=316083&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/Attr.td (original)
+++ cfe/trunk/include/clang/Basic/Attr.td Wed Oct 18 07:33:27 2017
@@ -1009,7 +1009,7 @@ def ExtVectorType : Attr {
}
def FallThrough : StmtAttr {
- let Spellings = [CXX11<"", "fallthrough", 201603>,
+ let Spellings = [CXX11<"", "fallthrough", 201603>, C2x<"", "fallthrough">,
CXX11<"clang", "fallthrough">];
// let Subjects = [NullStmt];
let Documentation = [FallthroughDocs];
Modified: cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp?rev=316083&r1=316082&r2=316083&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp (original)
+++ cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp Wed Oct 18 07:33:27 2017
@@ -1291,16 +1291,15 @@ static StringRef getFallthroughAttrSpell
static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC,
bool PerFunction) {
- // Only perform this analysis when using C++11. There is no good workflow
- // for this warning when not using C++11. There is no good way to silence
- // the warning (no attribute is available) unless we are using C++11's
support
- // for generalized attributes. Once could use pragmas to silence the
warning,
- // but as a general solution that is gross and not in the spirit of this
- // warning.
+ // Only perform this analysis when using [[]] attributes. There is no good
+ // workflow for this warning when not using C++11. There is no good way to
+ // silence the warning (no attribute is available) unless we are using
+ // [[]] attributes. One could use pragmas to silence the warning, but as a
+ // general solution that is gross and not in the spirit of this warning.
//
- // NOTE: This an intermediate solution. There are on-going discussions on
+ // NOTE: This an intermediate solution. There are on-going discussions on
// how to properly support this warning outside of C++11 with an annotation.
- if (!AC.getASTContext().getLangOpts().CPlusPlus11)
+ if (!AC.getASTContext().getLangOpts().DoubleSquareBracketAttributes)
return;
FallthroughMapper FM(S);
Added: cfe/trunk/test/Sema/c2x-fallthrough.c
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/c2x-fallthrough.c?rev=316083&view=auto
==============================================================================
--- cfe/trunk/test/Sema/c2x-fallthrough.c (added)
+++ cfe/trunk/test/Sema/c2x-fallthrough.c Wed Oct 18 07:33:27 2017
@@ -0,0 +1,75 @@
+// RUN: %clang_cc1 -fsyntax-only -fdouble-square-bracket-attributes -verify %s
+
+void f(int n) {
+ switch (n) {
+ case 0:
+ n += 1;
+ [[fallthrough]]; // ok
+ case 1:
+ if (n) {
+ [[fallthrough]]; // ok
+ } else {
+ return;
+ }
+ case 2:
+ for (int n = 0; n != 10; ++n)
+ [[fallthrough]]; // expected-error {{does not directly precede switch
label}}
+ case 3:
+ while (1)
+ [[fallthrough]]; // expected-error {{does not directly precede switch
label}}
+ case 4:
+ while (0)
+ [[fallthrough]]; // expected-error {{does not directly precede switch
label}}
+ case 5:
+ do [[fallthrough]]; while (1); // expected-error {{does not directly
precede switch label}}
+ case 6:
+ do [[fallthrough]]; while (0); // expected-error {{does not directly
precede switch label}}
+ case 7:
+ switch (n) {
+ case 0:
+ // FIXME: This should be an error, even though the next thing we do is to
+ // fall through in an outer switch statement.
+ [[fallthrough]];
+ }
+ case 8:
+ [[fallthrough]]; // expected-error {{does not directly precede switch
label}}
+ goto label;
+ label:
+ case 9:
+ n += 1;
+ case 10: // no warning, -Wimplicit-fallthrough is not enabled in this test,
and does not need to
+ // be enabled for these diagnostics to be produced.
+ break;
+ }
+}
+
+[[fallthrough]] typedef int n; // expected-error {{'fallthrough' attribute
cannot be applied to a declaration}}
+typedef int [[fallthrough]] n; // expected-error {{'fallthrough' attribute
cannot be applied to types}}
+typedef int n [[fallthrough]]; // expected-error {{'fallthrough' attribute
cannot be applied to a declaration}}
+
+enum [[fallthrough]] E { // expected-error {{'fallthrough' attribute cannot be
applied to a declaration}}
+ One
+};
+struct [[fallthrough]] S { // expected-error {{'fallthrough' attribute cannot
be applied to a declaration}}
+ int i;
+};
+
+[[fallthrough]] // expected-error {{'fallthrough' attribute cannot be applied
to a declaration}}
+void g(void) {
+ [[fallthrough]] int n; // expected-error {{'fallthrough' attribute cannot be
applied to a declaration}}
+ [[fallthrough]] ++n; // expected-error-re {{{{^}}fallthrough attribute is
only allowed on empty statements}}
+
+ switch (n) {
+ // FIXME: This should be an error.
+ [[fallthrough]];
+ return;
+
+ case 0:
+ [[fallthrough, fallthrough]]; // expected-error {{multiple times}}
+ case 1:
+ [[fallthrough(0)]]; // expected-error {{argument list}}
+ case 2:
+ break;
+ }
+}
+
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