tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, erichkeane, tahonermann, shafik.
Herald added a project: All.
tbaeder requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
We need to run the functions we compiled immediately after to check if
they can ever be a constant expression.
I removed this before, thinking it was unneeded. Turns out it is needed to get
the "constexpr function never produces a constant expression" diagnostics.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D140724
Files:
clang/lib/AST/Interp/Context.cpp
clang/lib/AST/Interp/Interp.cpp
clang/lib/AST/Interp/Interp.h
clang/test/AST/Interp/arrays.cpp
clang/test/AST/Interp/literals.cpp
clang/test/AST/Interp/records.cpp
clang/test/AST/Interp/shifts.cpp
Index: clang/test/AST/Interp/shifts.cpp
===================================================================
--- clang/test/AST/Interp/shifts.cpp
+++ clang/test/AST/Interp/shifts.cpp
@@ -8,7 +8,9 @@
namespace shifts {
constexpr void test() { // ref-error {{constexpr function never produces a constant expression}} \
- // ref-cxx17-error {{constexpr function never produces a constant expression}}
+ // ref-cxx17-error {{constexpr function never produces a constant expression}} \
+ // expected-error {{constexpr function never produces a constant expression}} \
+ // cxx17-error {{constexpr function never produces a constant expression}} \
char c; // cxx17-warning {{uninitialized variable}} \
// ref-cxx17-warning {{uninitialized variable}}
@@ -19,6 +21,8 @@
c = 1 << -0;
c = 1 >> -0;
c = 1 << -1; // expected-warning {{shift count is negative}} \
+ // expected-note {{negative shift count -1}} \
+ // cxx17-note {{negative shift count -1}} \
// cxx17-warning {{shift count is negative}} \
// ref-warning {{shift count is negative}} \
// ref-note {{negative shift count -1}} \
Index: clang/test/AST/Interp/records.cpp
===================================================================
--- clang/test/AST/Interp/records.cpp
+++ clang/test/AST/Interp/records.cpp
@@ -166,10 +166,11 @@
constexpr int get12() { return 12; }
};
- constexpr int foo() { // ref-error {{never produces a constant expression}}
+ constexpr int foo() { // ref-error {{never produces a constant expression}} \
+ // expected-error {{never produces a constant expression}}
S *s = nullptr;
return s->get12(); // ref-note 2{{member call on dereferenced null pointer}} \
- // expected-note {{member call on dereferenced null pointer}}
+ // expected-note 2{{member call on dereferenced null pointer}}
}
static_assert(foo() == 12, ""); // ref-error {{not an integral constant expression}} \
Index: clang/test/AST/Interp/literals.cpp
===================================================================
--- clang/test/AST/Interp/literals.cpp
+++ clang/test/AST/Interp/literals.cpp
@@ -452,10 +452,11 @@
static_assert(uninit(), ""); // ref-error {{not an integral constant expression}} \
// ref-note {{in call to 'uninit()'}}
- constexpr int OverFlow() { // ref-error {{never produces a constant expression}}
+ constexpr int OverFlow() { // ref-error {{never produces a constant expression}} \
+ // expected-error {{never produces a constant expression}}
int a = INT_MAX;
++a; // ref-note 2{{is outside the range}} \
- // expected-note {{is outside the range}}
+ // expected-note 2{{is outside the range}}
return -1;
}
static_assert(OverFlow() == -1, ""); // expected-error {{not an integral constant expression}} \
@@ -464,10 +465,11 @@
// ref-note {{in call to 'OverFlow()'}}
- constexpr int UnderFlow() { // ref-error {{never produces a constant expression}}
+ constexpr int UnderFlow() { // ref-error {{never produces a constant expression}} \
+ // expected-error {{never produces a constant expression}}
int a = INT_MIN;
--a; // ref-note 2{{is outside the range}} \
- // expected-note {{is outside the range}}
+ // expected-note 2{{is outside the range}}
return -1;
}
static_assert(UnderFlow() == -1, ""); // expected-error {{not an integral constant expression}} \
Index: clang/test/AST/Interp/arrays.cpp
===================================================================
--- clang/test/AST/Interp/arrays.cpp
+++ clang/test/AST/Interp/arrays.cpp
@@ -209,7 +209,8 @@
public:
int a;
constexpr AU() : a(5 / 0) {} // expected-warning {{division by zero is undefined}} \
- // expected-note {{division by zero}} \
+ // expected-note 2{{division by zero}} \
+ // expected-error {{never produces a constant expression}} \
// ref-error {{never produces a constant expression}} \
// ref-note 2{{division by zero}} \
// ref-warning {{division by zero is undefined}}
@@ -296,10 +297,11 @@
}
static_assert(getSecondToLast2() == 3, "");
- constexpr int bad1() { // ref-error {{never produces a constant expression}}
+ constexpr int bad1() { // ref-error {{never produces a constant expression}} \
+ // expected-error {{never produces a constant expression}}
const int *e = E + 3;
e++; // This is fine because it's a one-past-the-end pointer
- return *e; // expected-note {{read of dereferenced one-past-the-end pointer}} \
+ return *e; // expected-note 2{{read of dereferenced one-past-the-end pointer}} \
// ref-note 2{{read of dereferenced one-past-the-end pointer}}
}
static_assert(bad1() == 0, ""); // expected-error {{not an integral constant expression}} \
@@ -307,9 +309,10 @@
// ref-error {{not an integral constant expression}} \
// ref-note {{in call to}}
- constexpr int bad2() { // ref-error {{never produces a constant expression}}
+ constexpr int bad2() { // ref-error {{never produces a constant expression}} \
+ // expected-error {{never produces a constant expression}}
const int *e = E + 4;
- e++; // expected-note {{cannot refer to element 5 of array of 4 elements}} \
+ e++; // expected-note 2{{cannot refer to element 5 of array of 4 elements}} \
// ref-note 2{{cannot refer to element 5 of array of 4 elements}}
return *e; // This is UB as well
}
@@ -319,9 +322,10 @@
// ref-note {{in call to}}
- constexpr int bad3() { // ref-error {{never produces a constant expression}}
+ constexpr int bad3() { // ref-error {{never produces a constant expression}} \
+ // expected-error {{never produces a constant expression}}
const int *e = E;
- e--; // expected-note {{cannot refer to element -1 of array of 4 elements}} \
+ e--; // expected-note 2{{cannot refer to element -1 of array of 4 elements}} \
// ref-note 2{{cannot refer to element -1 of array of 4 elements}}
return *e; // This is UB as well
}
Index: clang/lib/AST/Interp/Interp.h
===================================================================
--- clang/lib/AST/Interp/Interp.h
+++ clang/lib/AST/Interp/Interp.h
@@ -1298,6 +1298,8 @@
inline bool RVOPtr(InterpState &S, CodePtr OpPC) {
assert(S.Current->getFunction()->hasRVO());
+ if (S.checkingPotentialConstantExpression())
+ return false;
S.Stk.push<Pointer>(S.Current->getRVOPtr());
return true;
}
@@ -1375,9 +1377,11 @@
Pointer ThisPtr;
if (Func->hasThisPointer()) {
ThisPtr = NewFrame->getThis();
- if (!CheckInvoke(S, PC, ThisPtr)) {
+ if (!CheckInvoke(S, PC, ThisPtr))
+ return false;
+
+ if (S.checkingPotentialConstantExpression())
return false;
- }
}
if (!CheckCallable(S, PC, Func))
Index: clang/lib/AST/Interp/Interp.cpp
===================================================================
--- clang/lib/AST/Interp/Interp.cpp
+++ clang/lib/AST/Interp/Interp.cpp
@@ -350,6 +350,11 @@
}
if (!F->isConstexpr()) {
+ // Don't emit anything if we're checking for a potential constant
+ // expression. That will happen later when actually executing.
+ if (S.checkingPotentialConstantExpression())
+ return false;
+
const SourceLocation &Loc = S.Current->getLocation(OpPC);
if (S.getLangOpts().CPlusPlus11) {
const FunctionDecl *DiagDecl = F->getDecl();
Index: clang/lib/AST/Interp/Context.cpp
===================================================================
--- clang/lib/AST/Interp/Context.cpp
+++ clang/lib/AST/Interp/Context.cpp
@@ -42,6 +42,11 @@
}
}
+ APValue DummyResult;
+ if (!Run(Parent, Func, DummyResult)) {
+ return false;
+ }
+
return Func->isConstexpr();
}
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