[clang] Fix suppressing diagnostics for uninitialized variables #148336
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When one kind of diagnostics is disabled, this should not preclude other
diagnostics from displaying, even if they have lower priority.
For example, this should print a warning about passing an uninitialized
variable as a const reference:
```
> cat test.cpp
void foo(const int &);
int f(bool a) {
int v;
if (a) {
foo(v);
v = 5;
}
return v;
}
> clang test.cpp -fsyntax-only -Wuninitialized -Wno-sometimes-uninitialized
```
igorkudrin
added
clang
llvmbot
added
the
clang:frontend
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@llvm/pr-subscribers-clang-analysis Author: Igor Kudrin (igorkudrin) ChangesWhen one kind of diagnostics is disabled, this should not preclude other diagnostics from displaying, even if they have lower priority. For example, this should print a warning about passing an uninitialized variable as a const reference: Full diff: https://github.com/llvm/llvm-project/pull/148336.diff 2 Files Affected:
diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index ec8acbdff3b49..a4e5519f13d18 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -987,10 +987,11 @@ static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use,
}
/// Diagnose uninitialized const reference usages.
-static void DiagnoseUninitializedConstRefUse(Sema &S, const VarDecl *VD,
+static bool DiagnoseUninitializedConstRefUse(Sema &S, const VarDecl *VD,
const UninitUse &Use) {
S.Diag(Use.getUser()->getBeginLoc(), diag::warn_uninit_const_reference)
<< VD->getDeclName() << Use.getUser()->getSourceRange();
+ return !S.getDiagnostics().isLastDiagnosticIgnored();
}
/// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
@@ -1022,7 +1023,7 @@ static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
if (CR.doesContainReference()) {
S.Diag(DRE->getBeginLoc(), diag::warn_uninit_self_reference_in_init)
<< VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
- return true;
+ return !S.getDiagnostics().isLastDiagnosticIgnored();
}
}
@@ -1045,7 +1046,7 @@ static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
S.Diag(VD->getBeginLoc(), diag::note_var_declared_here)
<< VD->getDeclName();
- return true;
+ return !S.getDiagnostics().isLastDiagnosticIgnored();
}
namespace {
@@ -1559,43 +1560,7 @@ class UninitValsDiagReporter : public UninitVariablesHandler {
UsesVec *vec = V.getPointer();
bool hasSelfInit = V.getInt();
- // Specially handle the case where we have uses of an uninitialized
- // variable, but the root cause is an idiomatic self-init. We want
- // to report the diagnostic at the self-init since that is the root cause.
- if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
- DiagnoseUninitializedUse(S, vd,
- UninitUse(vd->getInit()->IgnoreParenCasts(),
- /* isAlwaysUninit */ true),
- /* alwaysReportSelfInit */ true);
- else {
- // Sort the uses by their SourceLocations. While not strictly
- // guaranteed to produce them in line/column order, this will provide
- // a stable ordering.
- llvm::sort(*vec, [](const UninitUse &a, const UninitUse &b) {
- // Move ConstRef uses to the back.
- if (a.isConstRefUse() != b.isConstRefUse())
- return b.isConstRefUse();
- // Prefer a more confident report over a less confident one.
- if (a.getKind() != b.getKind())
- return a.getKind() > b.getKind();
- return a.getUser()->getBeginLoc() < b.getUser()->getBeginLoc();
- });
-
- for (const auto &U : *vec) {
- if (U.isConstRefUse()) {
- DiagnoseUninitializedConstRefUse(S, vd, U);
- break;
- }
-
- // If we have self-init, downgrade all uses to 'may be uninitialized'.
- UninitUse Use = hasSelfInit ? UninitUse(U.getUser(), false) : U;
-
- if (DiagnoseUninitializedUse(S, vd, Use))
- // Skip further diagnostics for this variable. We try to warn only
- // on the first point at which a variable is used uninitialized.
- break;
- }
- }
+ diagnoseUnitializedVar(vd, hasSelfInit, vec);
// Release the uses vector.
delete vec;
@@ -1612,6 +1577,49 @@ class UninitValsDiagReporter : public UninitVariablesHandler {
U.getKind() == UninitUse::AfterDecl;
});
}
+
+ // Print the diagnostic for the variable. We try to warn only on the first
+ // point at which a variable is used uninitialized. After the first
+ // diagnostic is printed, further diagnostics for this variable are skipped.
+ void diagnoseUnitializedVar(const VarDecl *vd, bool hasSelfInit,
+ UsesVec *vec) {
+ // Specially handle the case where we have uses of an uninitialized
+ // variable, but the root cause is an idiomatic self-init. We want
+ // to report the diagnostic at the self-init since that is the root cause.
+ if (hasSelfInit && hasAlwaysUninitializedUse(vec)) {
+ if (DiagnoseUninitializedUse(S, vd,
+ UninitUse(vd->getInit()->IgnoreParenCasts(),
+ /*isAlwaysUninit=*/true),
+ /*alwaysReportSelfInit=*/true))
+ return;
+ }
+
+ // Sort the uses by their SourceLocations. While not strictly
+ // guaranteed to produce them in line/column order, this will provide
+ // a stable ordering.
+ llvm::sort(*vec, [](const UninitUse &a, const UninitUse &b) {
+ // Prefer the direct use of an uninitialized variable over its use via
+ // constant reference.
+ if (a.isConstRefUse() != b.isConstRefUse())
+ return b.isConstRefUse();
+ // Prefer a more confident report over a less confident one.
+ if (a.getKind() != b.getKind())
+ return a.getKind() > b.getKind();
+ return a.getUser()->getBeginLoc() < b.getUser()->getBeginLoc();
+ });
+
+ for (const auto &U : *vec) {
+ if (U.isConstRefUse()) {
+ if (DiagnoseUninitializedConstRefUse(S, vd, U))
+ return;
+ } else {
+ // If we have self-init, downgrade all uses to 'may be uninitialized'.
+ UninitUse Use = hasSelfInit ? UninitUse(U.getUser(), false) : U;
+ if (DiagnoseUninitializedUse(S, vd, Use))
+ return;
+ }
+ }
+ }
};
/// Inter-procedural data for the called-once checker.
diff --git a/clang/test/SemaCXX/warn-no-sometimes-uninitialized.cpp b/clang/test/SemaCXX/warn-no-sometimes-uninitialized.cpp
new file mode 100644
index 0000000000000..71e5faeec63fb
--- /dev/null
+++ b/clang/test/SemaCXX/warn-no-sometimes-uninitialized.cpp
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -fsyntax-only -Wuninitialized -Wno-sometimes-uninitialized -verify %s
+
+void foo(const int &);
+
+int f(bool a) {
+ int v;
+ if (a) {
+ foo(v); // expected-warning {{variable 'v' is uninitialized when passed as a const reference argument here}}
+ v = 5;
+ }
+ return v;
+}
|
|
@llvm/pr-subscribers-clang Author: Igor Kudrin (igorkudrin) ChangesWhen one kind of diagnostics is disabled, this should not preclude other diagnostics from displaying, even if they have lower priority. For example, this should print a warning about passing an uninitialized variable as a const reference: Full diff: https://github.com/llvm/llvm-project/pull/148336.diff 2 Files Affected:
diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index ec8acbdff3b49..a4e5519f13d18 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -987,10 +987,11 @@ static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use,
}
/// Diagnose uninitialized const reference usages.
-static void DiagnoseUninitializedConstRefUse(Sema &S, const VarDecl *VD,
+static bool DiagnoseUninitializedConstRefUse(Sema &S, const VarDecl *VD,
const UninitUse &Use) {
S.Diag(Use.getUser()->getBeginLoc(), diag::warn_uninit_const_reference)
<< VD->getDeclName() << Use.getUser()->getSourceRange();
+ return !S.getDiagnostics().isLastDiagnosticIgnored();
}
/// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
@@ -1022,7 +1023,7 @@ static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
if (CR.doesContainReference()) {
S.Diag(DRE->getBeginLoc(), diag::warn_uninit_self_reference_in_init)
<< VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
- return true;
+ return !S.getDiagnostics().isLastDiagnosticIgnored();
}
}
@@ -1045,7 +1046,7 @@ static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
S.Diag(VD->getBeginLoc(), diag::note_var_declared_here)
<< VD->getDeclName();
- return true;
+ return !S.getDiagnostics().isLastDiagnosticIgnored();
}
namespace {
@@ -1559,43 +1560,7 @@ class UninitValsDiagReporter : public UninitVariablesHandler {
UsesVec *vec = V.getPointer();
bool hasSelfInit = V.getInt();
- // Specially handle the case where we have uses of an uninitialized
- // variable, but the root cause is an idiomatic self-init. We want
- // to report the diagnostic at the self-init since that is the root cause.
- if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
- DiagnoseUninitializedUse(S, vd,
- UninitUse(vd->getInit()->IgnoreParenCasts(),
- /* isAlwaysUninit */ true),
- /* alwaysReportSelfInit */ true);
- else {
- // Sort the uses by their SourceLocations. While not strictly
- // guaranteed to produce them in line/column order, this will provide
- // a stable ordering.
- llvm::sort(*vec, [](const UninitUse &a, const UninitUse &b) {
- // Move ConstRef uses to the back.
- if (a.isConstRefUse() != b.isConstRefUse())
- return b.isConstRefUse();
- // Prefer a more confident report over a less confident one.
- if (a.getKind() != b.getKind())
- return a.getKind() > b.getKind();
- return a.getUser()->getBeginLoc() < b.getUser()->getBeginLoc();
- });
-
- for (const auto &U : *vec) {
- if (U.isConstRefUse()) {
- DiagnoseUninitializedConstRefUse(S, vd, U);
- break;
- }
-
- // If we have self-init, downgrade all uses to 'may be uninitialized'.
- UninitUse Use = hasSelfInit ? UninitUse(U.getUser(), false) : U;
-
- if (DiagnoseUninitializedUse(S, vd, Use))
- // Skip further diagnostics for this variable. We try to warn only
- // on the first point at which a variable is used uninitialized.
- break;
- }
- }
+ diagnoseUnitializedVar(vd, hasSelfInit, vec);
// Release the uses vector.
delete vec;
@@ -1612,6 +1577,49 @@ class UninitValsDiagReporter : public UninitVariablesHandler {
U.getKind() == UninitUse::AfterDecl;
});
}
+
+ // Print the diagnostic for the variable. We try to warn only on the first
+ // point at which a variable is used uninitialized. After the first
+ // diagnostic is printed, further diagnostics for this variable are skipped.
+ void diagnoseUnitializedVar(const VarDecl *vd, bool hasSelfInit,
+ UsesVec *vec) {
+ // Specially handle the case where we have uses of an uninitialized
+ // variable, but the root cause is an idiomatic self-init. We want
+ // to report the diagnostic at the self-init since that is the root cause.
+ if (hasSelfInit && hasAlwaysUninitializedUse(vec)) {
+ if (DiagnoseUninitializedUse(S, vd,
+ UninitUse(vd->getInit()->IgnoreParenCasts(),
+ /*isAlwaysUninit=*/true),
+ /*alwaysReportSelfInit=*/true))
+ return;
+ }
+
+ // Sort the uses by their SourceLocations. While not strictly
+ // guaranteed to produce them in line/column order, this will provide
+ // a stable ordering.
+ llvm::sort(*vec, [](const UninitUse &a, const UninitUse &b) {
+ // Prefer the direct use of an uninitialized variable over its use via
+ // constant reference.
+ if (a.isConstRefUse() != b.isConstRefUse())
+ return b.isConstRefUse();
+ // Prefer a more confident report over a less confident one.
+ if (a.getKind() != b.getKind())
+ return a.getKind() > b.getKind();
+ return a.getUser()->getBeginLoc() < b.getUser()->getBeginLoc();
+ });
+
+ for (const auto &U : *vec) {
+ if (U.isConstRefUse()) {
+ if (DiagnoseUninitializedConstRefUse(S, vd, U))
+ return;
+ } else {
+ // If we have self-init, downgrade all uses to 'may be uninitialized'.
+ UninitUse Use = hasSelfInit ? UninitUse(U.getUser(), false) : U;
+ if (DiagnoseUninitializedUse(S, vd, Use))
+ return;
+ }
+ }
+ }
};
/// Inter-procedural data for the called-once checker.
diff --git a/clang/test/SemaCXX/warn-no-sometimes-uninitialized.cpp b/clang/test/SemaCXX/warn-no-sometimes-uninitialized.cpp
new file mode 100644
index 0000000000000..71e5faeec63fb
--- /dev/null
+++ b/clang/test/SemaCXX/warn-no-sometimes-uninitialized.cpp
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -fsyntax-only -Wuninitialized -Wno-sometimes-uninitialized -verify %s
+
+void foo(const int &);
+
+int f(bool a) {
+ int v;
+ if (a) {
+ foo(v); // expected-warning {{variable 'v' is uninitialized when passed as a const reference argument here}}
+ v = 5;
+ }
+ return v;
+}
|
zygoloid
approved these changes
Jul 12, 2025
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When one kind of diagnostics is disabled, this should not preclude other diagnostics from displaying, even if they have lower priority. For example, this should print a warning about passing an uninitialized variable as a const reference: