zequanwu created this revision.
zequanwu added reviewers: rsmith, rnk.
zequanwu added a project: clang.
Herald added a subscriber: cfe-commits.
bug filed here: https://bugs.llvm.org/show_bug.cgi?id=45624
Uninitialized variable as function const reference parameter should be use.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D79895
Files:
clang/lib/Analysis/UninitializedValues.cpp
clang/test/SemaCXX/uninit-variables.cpp
clang/test/SemaCXX/uninitialized.cpp
Index: clang/test/SemaCXX/uninitialized.cpp
===================================================================
--- clang/test/SemaCXX/uninitialized.cpp
+++ clang/test/SemaCXX/uninitialized.cpp
@@ -59,13 +59,13 @@
int d = ({ d + d ;}); // expected-warning {{variable 'd' is uninitialized
when used within its own initialization}}
int e = static_cast<long>(e) + 1; // expected-warning {{variable 'e' is
uninitialized when used within its own initialization}}
int f = foo(f); // expected-warning {{variable 'f' is uninitialized when
used within its own initialization}}
+ int j = far(j); // expected-warning {{variable 'j' is uninitialized when
used within its own initialization}}
// These don't warn as they don't require the value.
int g = sizeof(g);
void* ptr = &ptr;
int h = bar(&h);
int i = boo(i);
- int j = far(j);
int k = __alignof__(k);
int l = k ? l : l; // expected-warning {{variable 'l' is uninitialized when
used within its own initialization}}
@@ -93,13 +93,13 @@
int d = ({ d + d ;}); // expected-warning {{variable 'd' is uninitialized
when used within its own initialization}}
int e = static_cast<long>(e) + 1; // expected-warning {{variable 'e' is
uninitialized when used within its own initialization}}
int f = foo(f); // expected-warning {{variable 'f' is uninitialized when
used within its own initialization}}
+ int j = far(j); // expected-warning {{variable 'j' is uninitialized when
used within its own initialization}}
// These don't warn as they don't require the value.
int g = sizeof(g);
void* ptr = &ptr;
int h = bar(&h);
int i = boo(i);
- int j = far(j);
int k = __alignof__(k);
int l = k ? l : l; // expected-warning {{variable 'l' is uninitialized
when used within its own initialization}}
@@ -284,8 +284,8 @@
A a34(std::move(a34)); // expected-warning {{variable 'a34' is
uninitialized when used within its own initialization}}
A a35 = std::move(x ? a34 : (37, a35)); // expected-warning {{variable
'a35' is uninitialized when used within its own initialization}}
- A a36 = const_refA(a36);
- A a37(const_refA(a37));
+ A a36 = const_refA(a36); // expected-warning {{variable 'a36' is
uninitialized when used within its own initialization}}
+ A a37(const_refA(a37)); // expected-warning {{variable 'a37' is
uninitialized when used within its own initialization}}
A a38({a38}); // expected-warning {{variable 'a38' is uninitialized when
used within its own initialization}}
A a39 = {a39}; // expected-warning {{variable 'a39' is uninitialized when
used within its own initialization}}
@@ -294,9 +294,9 @@
A a41 = !a41; // expected-warning {{variable 'a41' is uninitialized when
used within its own initialization}}
A a42 = !(a42); // expected-warning {{variable 'a42' is uninitialized when
used within its own initialization}}
A a43 = a43 != a42; // expected-warning {{variable 'a43' is uninitialized
when used within its own initialization}}
- A a44 = a43 != a44; // expected-warning {{variable 'a44' is uninitialized
when used within its own initialization}}
+ A a44 = a43 != a44; // expected-warning 2{{variable 'a44' is uninitialized
when used within its own initialization}}
A a45 = a45 != a45; // expected-warning 2{{variable 'a45' is uninitialized
when used within its own initialization}}
- A a46 = 0 != a46; // expected-warning {{variable 'a46' is uninitialized
when used within its own initialization}}
+ A a46 = 0 != a46; // expected-warning 2{{variable 'a46' is uninitialized
when used within its own initialization}}
A a47(a47.set(a47.num)); // expected-warning 2{{variable 'a47' is
uninitialized when used within its own initialization}}
A a48(a47.set(a48.num)); // expected-warning {{variable 'a48' is
uninitialized when used within its own initialization}}
Index: clang/test/SemaCXX/uninit-variables.cpp
===================================================================
--- clang/test/SemaCXX/uninit-variables.cpp
+++ clang/test/SemaCXX/uninit-variables.cpp
@@ -144,8 +144,8 @@
void consume_const_ref(const int &n);
int test_const_ref() {
int n; // expected-note {{variable}}
- consume_const_ref(n);
- return n; // expected-warning {{uninitialized when used here}}
+ consume_const_ref(n); // expected-warning {{variable 'n' is uninitialized
when used here}}
+ return n;
}
// Don't crash here.
Index: clang/lib/Analysis/UninitializedValues.cpp
===================================================================
--- clang/lib/Analysis/UninitializedValues.cpp
+++ clang/lib/Analysis/UninitializedValues.cpp
@@ -413,14 +413,16 @@
return;
}
- // If a value is passed by const pointer or by const reference to a function,
+ // If a value is passed by const pointer to a function,
// we should not assume that it is initialized by the call, and we
// conservatively do not assume that it is used.
+ // If a value is passed by const reference to a function,
+ // it should already be initialized.
for (CallExpr::arg_iterator I = CE->arg_begin(), E = CE->arg_end();
I != E; ++I) {
if ((*I)->isGLValue()) {
if ((*I)->getType().isConstQualified())
- classify((*I), Ignore);
+ classify((*I), Use);
} else if (isPointerToConst((*I)->getType())) {
const Expr *Ex = stripCasts(DC->getParentASTContext(), *I);
const auto *UO = dyn_cast<UnaryOperator>(Ex);
Index: clang/test/SemaCXX/uninitialized.cpp
===================================================================
--- clang/test/SemaCXX/uninitialized.cpp
+++ clang/test/SemaCXX/uninitialized.cpp
@@ -59,13 +59,13 @@
int d = ({ d + d ;}); // expected-warning {{variable 'd' is uninitialized when used within its own initialization}}
int e = static_cast<long>(e) + 1; // expected-warning {{variable 'e' is uninitialized when used within its own initialization}}
int f = foo(f); // expected-warning {{variable 'f' is uninitialized when used within its own initialization}}
+ int j = far(j); // expected-warning {{variable 'j' is uninitialized when used within its own initialization}}
// These don't warn as they don't require the value.
int g = sizeof(g);
void* ptr = &ptr;
int h = bar(&h);
int i = boo(i);
- int j = far(j);
int k = __alignof__(k);
int l = k ? l : l; // expected-warning {{variable 'l' is uninitialized when used within its own initialization}}
@@ -93,13 +93,13 @@
int d = ({ d + d ;}); // expected-warning {{variable 'd' is uninitialized when used within its own initialization}}
int e = static_cast<long>(e) + 1; // expected-warning {{variable 'e' is uninitialized when used within its own initialization}}
int f = foo(f); // expected-warning {{variable 'f' is uninitialized when used within its own initialization}}
+ int j = far(j); // expected-warning {{variable 'j' is uninitialized when used within its own initialization}}
// These don't warn as they don't require the value.
int g = sizeof(g);
void* ptr = &ptr;
int h = bar(&h);
int i = boo(i);
- int j = far(j);
int k = __alignof__(k);
int l = k ? l : l; // expected-warning {{variable 'l' is uninitialized when used within its own initialization}}
@@ -284,8 +284,8 @@
A a34(std::move(a34)); // expected-warning {{variable 'a34' is uninitialized when used within its own initialization}}
A a35 = std::move(x ? a34 : (37, a35)); // expected-warning {{variable 'a35' is uninitialized when used within its own initialization}}
- A a36 = const_refA(a36);
- A a37(const_refA(a37));
+ A a36 = const_refA(a36); // expected-warning {{variable 'a36' is uninitialized when used within its own initialization}}
+ A a37(const_refA(a37)); // expected-warning {{variable 'a37' is uninitialized when used within its own initialization}}
A a38({a38}); // expected-warning {{variable 'a38' is uninitialized when used within its own initialization}}
A a39 = {a39}; // expected-warning {{variable 'a39' is uninitialized when used within its own initialization}}
@@ -294,9 +294,9 @@
A a41 = !a41; // expected-warning {{variable 'a41' is uninitialized when used within its own initialization}}
A a42 = !(a42); // expected-warning {{variable 'a42' is uninitialized when used within its own initialization}}
A a43 = a43 != a42; // expected-warning {{variable 'a43' is uninitialized when used within its own initialization}}
- A a44 = a43 != a44; // expected-warning {{variable 'a44' is uninitialized when used within its own initialization}}
+ A a44 = a43 != a44; // expected-warning 2{{variable 'a44' is uninitialized when used within its own initialization}}
A a45 = a45 != a45; // expected-warning 2{{variable 'a45' is uninitialized when used within its own initialization}}
- A a46 = 0 != a46; // expected-warning {{variable 'a46' is uninitialized when used within its own initialization}}
+ A a46 = 0 != a46; // expected-warning 2{{variable 'a46' is uninitialized when used within its own initialization}}
A a47(a47.set(a47.num)); // expected-warning 2{{variable 'a47' is uninitialized when used within its own initialization}}
A a48(a47.set(a48.num)); // expected-warning {{variable 'a48' is uninitialized when used within its own initialization}}
Index: clang/test/SemaCXX/uninit-variables.cpp
===================================================================
--- clang/test/SemaCXX/uninit-variables.cpp
+++ clang/test/SemaCXX/uninit-variables.cpp
@@ -144,8 +144,8 @@
void consume_const_ref(const int &n);
int test_const_ref() {
int n; // expected-note {{variable}}
- consume_const_ref(n);
- return n; // expected-warning {{uninitialized when used here}}
+ consume_const_ref(n); // expected-warning {{variable 'n' is uninitialized when used here}}
+ return n;
}
// Don't crash here.
Index: clang/lib/Analysis/UninitializedValues.cpp
===================================================================
--- clang/lib/Analysis/UninitializedValues.cpp
+++ clang/lib/Analysis/UninitializedValues.cpp
@@ -413,14 +413,16 @@
return;
}
- // If a value is passed by const pointer or by const reference to a function,
+ // If a value is passed by const pointer to a function,
// we should not assume that it is initialized by the call, and we
// conservatively do not assume that it is used.
+ // If a value is passed by const reference to a function,
+ // it should already be initialized.
for (CallExpr::arg_iterator I = CE->arg_begin(), E = CE->arg_end();
I != E; ++I) {
if ((*I)->isGLValue()) {
if ((*I)->getType().isConstQualified())
- classify((*I), Ignore);
+ classify((*I), Use);
} else if (isPointerToConst((*I)->getType())) {
const Expr *Ex = stripCasts(DC->getParentASTContext(), *I);
const auto *UO = dyn_cast<UnaryOperator>(Ex);
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