Nathan-Huckleberry created this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
Fixed extraneous matches of non-NullStmt
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D64838
Files:
clang/include/clang/Basic/Attr.td
clang/include/clang/Parse/Parser.h
clang/lib/Parse/ParseStmt.cpp
clang/lib/Parse/ParseTentative.cpp
clang/lib/Sema/AnalysisBasedWarnings.cpp
clang/test/Sema/fallthrough-attr.c
clang/test/SemaCXX/switch-implicit-fallthrough.cpp
Index: clang/test/SemaCXX/switch-implicit-fallthrough.cpp
===================================================================
--- clang/test/SemaCXX/switch-implicit-fallthrough.cpp
+++ clang/test/SemaCXX/switch-implicit-fallthrough.cpp
@@ -329,3 +329,15 @@
}
return n;
}
+
+int fallthrough_attribute_spelling(int n) {
+ switch (n) {
+ case 0:
+ n++;
+ __attribute__ ((fallthrough));
+ case 1:
+ n++;
+ break;
+ }
+ return n;
+}
Index: clang/test/Sema/fallthrough-attr.c
===================================================================
--- /dev/null
+++ clang/test/Sema/fallthrough-attr.c
@@ -0,0 +1,48 @@
+// RUN: %clang_cc1 -fsyntax-only -std=gnu89 -verify -Wimplicit-fallthrough %s
+
+int foo(int x)
+{
+ int a = 0;
+
+ switch (x) {
+ case 0:
+ a++;
+ case 1:
+ // expected-warning@-1{{unannotated fall-through between switch labels}}
+ //expected-note@-2{{insert 'break;' to avoid fall-through}}
+ a--;
+ case 2:
+ // expected-warning@-1{{unannotated fall-through between switch labels}}
+ // expected-note@-2{{insert 'break;' to avoid fall-through}}
+ break;
+ default:
+ a = 1;
+ }
+
+ return 0;
+}
+
+int bar(int x)
+{
+ int a = 0;
+
+ switch (x) {
+ case 0:
+ a++;
+ __attribute__ ((fallthrough));
+ case 1:
+ a--;
+ __attribute__ ((fallthrough));
+ case 2:
+ break;
+ default:
+ a = 1;
+ }
+
+ return 0;
+}
+
+__attribute__ ((fallthrough)); // expected-warning {{declaration does not declare anything}}
+void baz(int x) {
+ __attribute__ ((fallthrough)); // expected-error {{fallthrough annotation is outside switch statement}}
+}
Index: clang/lib/Sema/AnalysisBasedWarnings.cpp
===================================================================
--- clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -1215,7 +1215,7 @@
tok::r_square, tok::r_square
};
- bool PreferClangAttr = !PP.getLangOpts().CPlusPlus17;
+ bool PreferClangAttr = !PP.getLangOpts().CPlusPlus17 && !PP.getLangOpts().C2x;
StringRef MacroName;
if (PreferClangAttr)
@@ -1224,24 +1224,19 @@
MacroName = PP.getLastMacroWithSpelling(Loc, FallthroughTokens);
if (MacroName.empty() && !PreferClangAttr)
MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
- if (MacroName.empty())
- MacroName = PreferClangAttr ? "[[clang::fallthrough]]" : "[[fallthrough]]";
+ if (MacroName.empty()) {
+ if (!PreferClangAttr)
+ MacroName = "[[fallthrough]]";
+ else if (PP.getLangOpts().CPlusPlus)
+ MacroName = "[[clang::fallthrough]]";
+ else
+ MacroName = "__attribute__((fallthrough))";
+ }
return MacroName;
}
static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC,
bool PerFunction) {
- // 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
- // how to properly support this warning outside of C++11 with an annotation.
- if (!AC.getASTContext().getLangOpts().DoubleSquareBracketAttributes)
- return;
-
FallthroughMapper FM(S);
FM.TraverseStmt(AC.getBody());
@@ -1281,7 +1276,7 @@
SourceLocation L = Label->getBeginLoc();
if (L.isMacroID())
continue;
- if (S.getLangOpts().CPlusPlus11) {
+ if (S.getLangOpts().CPlusPlus11 || S.getLangOpts().C99) {
const Stmt *Term = B->getTerminatorStmt();
// Skip empty cases.
while (B->empty() && !Term && B->succ_size() == 1) {
Index: clang/lib/Parse/ParseTentative.cpp
===================================================================
--- clang/lib/Parse/ParseTentative.cpp
+++ clang/lib/Parse/ParseTentative.cpp
@@ -2121,3 +2121,28 @@
return TPResult::Ambiguous;
return TPResult::False;
}
+
+Parser::TPResult Parser::TryParseNullStmtWithAttributes() {
+ if(Tok.isNot(tok::kw___attribute)) {
+ return TPResult::False;
+ }
+ ParsedAttributesWithRange attrs(AttrFactory);
+ ParseGNUAttributes(attrs, nullptr, nullptr);
+ if(attrs.size() <= 0) {
+ return TPResult::False;
+ }
+ for(auto &attr : attrs) {
+ if(!attr.isStmtAttr()) {
+ return TPResult::False;
+ }
+ }
+ if(Tok.isNot(tok::semi)) {
+ return TPResult::False;
+ }
+ return TPResult::True;
+}
+
+bool Parser::isNullStmtWithAttributes() {
+ RevertingTentativeParsingAction PA(*this);
+ return TryParseNullStmtWithAttributes() == TPResult::True;
+}
Index: clang/lib/Parse/ParseStmt.cpp
===================================================================
--- clang/lib/Parse/ParseStmt.cpp
+++ clang/lib/Parse/ParseStmt.cpp
@@ -100,6 +100,11 @@
ParsedAttributesWithRange Attrs(AttrFactory);
MaybeParseCXX11Attributes(Attrs, nullptr, /*MightBeObjCMessageSend*/ true);
+
+ if(isNullStmtWithAttributes()) {
+ MaybeParseGNUAttributes(Attrs);
+ }
+
if (!MaybeParseOpenCLUnrollHintAttribute(Attrs))
return StmtError();
Index: clang/include/clang/Parse/Parser.h
===================================================================
--- clang/include/clang/Parse/Parser.h
+++ clang/include/clang/Parse/Parser.h
@@ -2326,6 +2326,8 @@
/// a type-specifier other than a cv-qualifier.
bool isCXXDeclarationSpecifierAType();
+ bool isNullStmtWithAttributes();
+
/// Determine whether the current token sequence might be
/// '<' template-argument-list '>'
/// rather than a less-than expression.
@@ -2357,6 +2359,7 @@
TPResult TryParseFunctionDeclarator();
TPResult TryParseBracketDeclarator();
TPResult TryConsumeDeclarationSpecifier();
+ TPResult TryParseNullStmtWithAttributes();
public:
TypeResult ParseTypeName(SourceRange *Range = nullptr,
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -1170,7 +1170,7 @@
def FallThrough : StmtAttr {
let Spellings = [CXX11<"", "fallthrough", 201603>, C2x<"", "fallthrough">,
- CXX11<"clang", "fallthrough">];
+ CXX11<"clang", "fallthrough">, GCC<"fallthrough">];
// let Subjects = [NullStmt];
let Documentation = [FallthroughDocs];
}
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