hazohelet updated this revision to Diff 504933.
hazohelet added a comment.
Address comments from @aaron.ballman
- NFC stylistic changes
Thanks for the review! Since I don't have commit access, would you please land
this patch for me?
Please use "Takuya Shimizu <shimizu2...@gmail.com>" for the patch attribution.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D145842/new/
https://reviews.llvm.org/D145842
Files:
clang/docs/ReleaseNotes.rst
clang/include/clang/Analysis/Analyses/ReachableCode.h
clang/lib/Analysis/ReachableCode.cpp
clang/lib/Sema/AnalysisBasedWarnings.cpp
clang/test/Sema/warn-unreachable-fallthrough.c
Index: clang/test/Sema/warn-unreachable-fallthrough.c
===================================================================
--- /dev/null
+++ clang/test/Sema/warn-unreachable-fallthrough.c
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c2x -Wunreachable-code-fallthrough %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c2x -Wunreachable-code %s
+// RUN: %clang_cc1 -fsyntax-only -verify=code -std=c2x -Wunreachable-code -Wno-unreachable-code-fallthrough %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c2x -Wno-unreachable-code -Wunreachable-code-fallthrough %s
+
+int n;
+void f(void){
+ switch (n){
+ [[fallthrough]]; // expected-warning{{fallthrough annotation in unreachable code}}
+ // code-warning@-1{{never be executed}}
+ case 1:;
+ }
+}
Index: clang/lib/Sema/AnalysisBasedWarnings.cpp
===================================================================
--- clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -66,11 +66,17 @@
public:
UnreachableCodeHandler(Sema &s) : S(s) {}
- void HandleUnreachable(reachable_code::UnreachableKind UK,
- SourceLocation L,
- SourceRange SilenceableCondVal,
- SourceRange R1,
- SourceRange R2) override {
+ void HandleUnreachable(reachable_code::UnreachableKind UK, SourceLocation L,
+ SourceRange SilenceableCondVal, SourceRange R1,
+ SourceRange R2, bool HasFallThroughAttr) override {
+ // If the diagnosed code is `[[fallthrough]];` and
+ // `-Wunreachable-code-fallthrough` is enabled, suppress `code will never
+ // be executed` warning to avoid generating diagnostic twice
+ if (HasFallThroughAttr &&
+ !S.getDiagnostics().isIgnored(diag::warn_unreachable_fallthrough_attr,
+ SourceLocation()))
+ return;
+
// Avoid reporting multiple unreachable code diagnostics that are
// triggered by the same conditional value.
if (PreviousSilenceableCondVal.isValid() &&
Index: clang/lib/Analysis/ReachableCode.cpp
===================================================================
--- clang/lib/Analysis/ReachableCode.cpp
+++ clang/lib/Analysis/ReachableCode.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "clang/Analysis/Analyses/ReachableCode.h"
+#include "clang/AST/Attr.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
@@ -629,6 +630,10 @@
UK = reachable_code::UK_Return;
}
+ const auto *AS = dyn_cast<AttributedStmt>(S);
+ bool HasFallThroughAttr =
+ AS && hasSpecificAttr<FallThroughAttr>(AS->getAttrs());
+
SourceRange SilenceableCondVal;
if (UK == reachable_code::UK_Other) {
@@ -645,8 +650,9 @@
R2 = Inc->getSourceRange();
}
- CB.HandleUnreachable(reachable_code::UK_Loop_Increment,
- Loc, SourceRange(), SourceRange(Loc, Loc), R2);
+ CB.HandleUnreachable(reachable_code::UK_Loop_Increment, Loc,
+ SourceRange(), SourceRange(Loc, Loc), R2,
+ HasFallThroughAttr);
return;
}
@@ -665,7 +671,7 @@
SourceRange R1, R2;
SourceLocation Loc = GetUnreachableLoc(S, R1, R2);
- CB.HandleUnreachable(UK, Loc, SilenceableCondVal, R1, R2);
+ CB.HandleUnreachable(UK, Loc, SilenceableCondVal, R1, R2, HasFallThroughAttr);
}
//===----------------------------------------------------------------------===//
Index: clang/include/clang/Analysis/Analyses/ReachableCode.h
===================================================================
--- clang/include/clang/Analysis/Analyses/ReachableCode.h
+++ clang/include/clang/Analysis/Analyses/ReachableCode.h
@@ -48,11 +48,9 @@
virtual void anchor();
public:
virtual ~Callback() {}
- virtual void HandleUnreachable(UnreachableKind UK,
- SourceLocation L,
- SourceRange ConditionVal,
- SourceRange R1,
- SourceRange R2) = 0;
+ virtual void HandleUnreachable(UnreachableKind UK, SourceLocation L,
+ SourceRange ConditionVal, SourceRange R1,
+ SourceRange R2, bool HasFallThroughAttr) = 0;
};
/// ScanReachableFromBlock - Mark all blocks reachable from Start.
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -167,6 +167,9 @@
``<built-in>``.
- Clang constexpr evaluator now provides a more concise diagnostic when calling
function pointer that is known to be null.
+- Clang now avoids duplicate warnings on unreachable ``[[fallthrough]];`` statements
+ previously issued from ``-Wunreachable-code`` and ``-Wunreachable-code-fallthrough``
+ by prioritizing ``-Wunreachable-code-fallthrough``.
Bug Fixes in This Version
-------------------------
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