zequanwu created this revision.
zequanwu added reviewers: hans, nick.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
Some libraries use empty function to ignore unused variable warnings, which
gets a new warning from `-Wuninitialized-const-reference`, discussed here
https://reviews.llvm.org/D79895#2107604.
This patch should fix that.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D82425
Files:
clang/lib/Analysis/UninitializedValues.cpp
clang/test/SemaCXX/warn-uninitialized-const-reference.cpp
Index: clang/test/SemaCXX/warn-uninitialized-const-reference.cpp
===================================================================
--- clang/test/SemaCXX/warn-uninitialized-const-reference.cpp
+++ clang/test/SemaCXX/warn-uninitialized-const-reference.cpp
@@ -9,6 +9,9 @@
bool operator!=(const A &);
};
+template <class T>
+inline void ignore_template(T const &) {}
+void ignore(const int &i) {}
A const_ref_use_A(const A &a);
int const_ref_use(const int &i);
A const_use_A(const A a);
@@ -33,4 +36,8 @@
if (a < 42)
m = 1;
const_ref_use(m);
+
+ int l;
+ ignore_template(l);
+ ignore(l);
}
Index: clang/lib/Analysis/UninitializedValues.cpp
===================================================================
--- clang/lib/Analysis/UninitializedValues.cpp
+++ clang/lib/Analysis/UninitializedValues.cpp
@@ -405,6 +405,15 @@
return QT->isAnyPointerType() && QT->getPointeeType().isConstQualified();
}
+static bool hasTrivialBody(CallExpr *CE) {
+ if (FunctionDecl *fd = CE->getDirectCallee()) {
+ if (FunctionTemplateDecl *ftd = fd->getPrimaryTemplate())
+ return ftd->getTemplatedDecl()->hasTrivialBody();
+ return fd->hasTrivialBody();
+ }
+ return false;
+}
+
void ClassifyRefs::VisitCallExpr(CallExpr *CE) {
// Classify arguments to std::move as used.
if (CE->isCallToStdMove()) {
@@ -423,7 +432,8 @@
I != E; ++I) {
if ((*I)->isGLValue()) {
if ((*I)->getType().isConstQualified())
- classify((*I), ConstRefUse);
+ if (!hasTrivialBody(CE))
+ classify((*I), ConstRefUse);
} else if (isPointerToConst((*I)->getType())) {
const Expr *Ex = stripCasts(DC->getParentASTContext(), *I);
const auto *UO = dyn_cast<UnaryOperator>(Ex);
Index: clang/test/SemaCXX/warn-uninitialized-const-reference.cpp
===================================================================
--- clang/test/SemaCXX/warn-uninitialized-const-reference.cpp
+++ clang/test/SemaCXX/warn-uninitialized-const-reference.cpp
@@ -9,6 +9,9 @@
bool operator!=(const A &);
};
+template <class T>
+inline void ignore_template(T const &) {}
+void ignore(const int &i) {}
A const_ref_use_A(const A &a);
int const_ref_use(const int &i);
A const_use_A(const A a);
@@ -33,4 +36,8 @@
if (a < 42)
m = 1;
const_ref_use(m);
+
+ int l;
+ ignore_template(l);
+ ignore(l);
}
Index: clang/lib/Analysis/UninitializedValues.cpp
===================================================================
--- clang/lib/Analysis/UninitializedValues.cpp
+++ clang/lib/Analysis/UninitializedValues.cpp
@@ -405,6 +405,15 @@
return QT->isAnyPointerType() && QT->getPointeeType().isConstQualified();
}
+static bool hasTrivialBody(CallExpr *CE) {
+ if (FunctionDecl *fd = CE->getDirectCallee()) {
+ if (FunctionTemplateDecl *ftd = fd->getPrimaryTemplate())
+ return ftd->getTemplatedDecl()->hasTrivialBody();
+ return fd->hasTrivialBody();
+ }
+ return false;
+}
+
void ClassifyRefs::VisitCallExpr(CallExpr *CE) {
// Classify arguments to std::move as used.
if (CE->isCallToStdMove()) {
@@ -423,7 +432,8 @@
I != E; ++I) {
if ((*I)->isGLValue()) {
if ((*I)->getType().isConstQualified())
- classify((*I), ConstRefUse);
+ if (!hasTrivialBody(CE))
+ classify((*I), ConstRefUse);
} else if (isPointerToConst((*I)->getType())) {
const Expr *Ex = stripCasts(DC->getParentASTContext(), *I);
const auto *UO = dyn_cast<UnaryOperator>(Ex);
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