* [PATCH v5 0/3] c++: Track lifetimes in constant evaluation [PR70331, ...]
@ 2023-07-22 15:12 Nathaniel Shead
2023-07-22 15:13 ` [PATCH v5 1/3] c++: Improve location information in constant evaluation Nathaniel Shead
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: Nathaniel Shead @ 2023-07-22 15:12 UTC (permalink / raw)
To: gcc-patches; +Cc: Jason Merrill, Patrick Palka, Nathaniel Shead
This is an update of the patch series at
https://gcc.gnu.org/pipermail/gcc-patches/2023-July/625050.html
Changes since v4:
- Reordered patches to be more independent from each other (they don't need
to keep updating the new tests)
- Removed workaround for better locations in cxx_eval_store_expression
- Don't bother checking lifetime for CONST_DECLs
- Rewrite patch for dangling pointers to keep the transformation to
`return (&x, nullptr)`, but only perform it when genericising. It turns out
that implementing this wasn't as hard as I thought it might be, at least for
this specific case.
Thanks very much for all the reviews and comments so far!
Bootstrapped and regtested on x86_64-pc-linux-gnu.
Nathaniel Shead (3):
c++: Improve location information in constant evaluation
c++: Prevent dangling pointers from becoming nullptr in constexpr
[PR110619]
c++: Track lifetimes in constant evaluation [PR70331,PR96630,PR98675]
gcc/cp/constexpr.cc | 159 +++++++++++++-----
gcc/cp/cp-gimplify.cc | 23 ++-
gcc/cp/cp-tree.h | 8 +-
gcc/cp/semantics.cc | 4 +-
gcc/cp/typeck.cc | 9 +-
gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C | 10 +-
gcc/testsuite/g++.dg/cpp0x/constexpr-70323.C | 8 +-
gcc/testsuite/g++.dg/cpp0x/constexpr-70323a.C | 8 +-
.../g++.dg/cpp0x/constexpr-delete2.C | 5 +-
gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C | 2 +-
gcc/testsuite/g++.dg/cpp0x/constexpr-ice20.C | 1 +
.../g++.dg/cpp0x/constexpr-recursion.C | 6 +-
gcc/testsuite/g++.dg/cpp0x/overflow1.C | 2 +-
gcc/testsuite/g++.dg/cpp1y/constexpr-110619.C | 10 ++
gcc/testsuite/g++.dg/cpp1y/constexpr-89285.C | 5 +-
gcc/testsuite/g++.dg/cpp1y/constexpr-89481.C | 3 +-
.../g++.dg/cpp1y/constexpr-lifetime1.C | 13 ++
.../g++.dg/cpp1y/constexpr-lifetime2.C | 20 +++
.../g++.dg/cpp1y/constexpr-lifetime3.C | 13 ++
.../g++.dg/cpp1y/constexpr-lifetime4.C | 11 ++
.../g++.dg/cpp1y/constexpr-lifetime5.C | 11 ++
.../g++.dg/cpp1y/constexpr-lifetime6.C | 15 ++
.../g++.dg/cpp1y/constexpr-tracking-const14.C | 3 +-
.../g++.dg/cpp1y/constexpr-tracking-const16.C | 3 +-
.../g++.dg/cpp1y/constexpr-tracking-const18.C | 4 +-
.../g++.dg/cpp1y/constexpr-tracking-const19.C | 4 +-
.../g++.dg/cpp1y/constexpr-tracking-const21.C | 4 +-
.../g++.dg/cpp1y/constexpr-tracking-const22.C | 4 +-
.../g++.dg/cpp1y/constexpr-tracking-const3.C | 3 +-
.../g++.dg/cpp1y/constexpr-tracking-const4.C | 3 +-
.../g++.dg/cpp1y/constexpr-tracking-const7.C | 3 +-
gcc/testsuite/g++.dg/cpp1y/constexpr-union5.C | 4 +-
gcc/testsuite/g++.dg/cpp1y/pr68180.C | 4 +-
.../g++.dg/cpp1z/constexpr-lambda6.C | 4 +-
.../g++.dg/cpp1z/constexpr-lambda8.C | 5 +-
gcc/testsuite/g++.dg/cpp2a/bit-cast11.C | 10 +-
gcc/testsuite/g++.dg/cpp2a/bit-cast12.C | 10 +-
gcc/testsuite/g++.dg/cpp2a/bit-cast14.C | 14 +-
gcc/testsuite/g++.dg/cpp2a/constexpr-98122.C | 4 +-
.../g++.dg/cpp2a/constexpr-dynamic17.C | 5 +-
gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C | 5 +-
gcc/testsuite/g++.dg/cpp2a/constexpr-new12.C | 6 +-
gcc/testsuite/g++.dg/cpp2a/constexpr-new3.C | 10 +-
gcc/testsuite/g++.dg/cpp2a/constinit10.C | 5 +-
.../g++.dg/cpp2a/is-corresponding-member4.C | 4 +-
gcc/testsuite/g++.dg/ext/constexpr-vla2.C | 4 +-
gcc/testsuite/g++.dg/ext/constexpr-vla3.C | 4 +-
gcc/testsuite/g++.dg/ubsan/pr63956.C | 23 +--
.../25_algorithms/equal/constexpr_neg.cc | 7 +-
.../testsuite/26_numerics/gcd/105844.cc | 10 +-
.../testsuite/26_numerics/lcm/105844.cc | 14 +-
51 files changed, 361 insertions(+), 168 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-110619.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime1.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime2.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime3.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime4.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime5.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime6.C
--
2.41.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v5 1/3] c++: Improve location information in constant evaluation
2023-07-22 15:12 [PATCH v5 0/3] c++: Track lifetimes in constant evaluation [PR70331, ...] Nathaniel Shead
@ 2023-07-22 15:13 ` Nathaniel Shead
2023-07-22 15:14 ` [PATCH v5 2/3] c++: Prevent dangling pointers from becoming nullptr in constexpr [PR110619] Nathaniel Shead
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Nathaniel Shead @ 2023-07-22 15:13 UTC (permalink / raw)
To: gcc-patches; +Cc: Jason Merrill, Patrick Palka
This patch updates 'input_location' during constant evaluation to ensure
that errors in subexpressions that lack location information still
provide accurate diagnostics.
By itself this change causes some small regressions in diagnostic
quality for circumstances where errors used 'input_location' but the
location of the parent subexpression doesn't make sense, so this patch
also includes a small diagnostic improvement to fix the most egregious
case.
gcc/cp/ChangeLog:
* constexpr.cc (modifying_const_object_error): Find the source
location of the const object's declaration.
(cxx_eval_constant_expression): Update input_location to the location
of the currently evaluated expression, if possible.
libstdc++-v3/ChangeLog:
* testsuite/25_algorithms/equal/constexpr_neg.cc: Update diagnostic
locations.
* testsuite/26_numerics/gcd/105844.cc: Likewise.
* testsuite/26_numerics/lcm/105844.cc: Likewise.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/constexpr-48089.C: Update diagnostic locations.
* g++.dg/cpp0x/constexpr-70323.C: Likewise.
* g++.dg/cpp0x/constexpr-70323a.C: Likewise.
* g++.dg/cpp0x/constexpr-delete2.C: Likewise.
* g++.dg/cpp0x/constexpr-diag3.C: Likewise.
* g++.dg/cpp0x/constexpr-ice20.C: Likewise.
* g++.dg/cpp0x/constexpr-recursion.C: Likewise.
* g++.dg/cpp0x/overflow1.C: Likewise.
* g++.dg/cpp1y/constexpr-89285.C: Likewise.
* g++.dg/cpp1y/constexpr-89481.C: Likewise.
* g++.dg/cpp1y/constexpr-tracking-const14.C: Likewise.
* g++.dg/cpp1y/constexpr-tracking-const16.C: Likewise.
* g++.dg/cpp1y/constexpr-tracking-const18.C: Likewise.
* g++.dg/cpp1y/constexpr-tracking-const19.C: Likewise.
* g++.dg/cpp1y/constexpr-tracking-const21.C: Likewise.
* g++.dg/cpp1y/constexpr-tracking-const22.C: Likewise.
* g++.dg/cpp1y/constexpr-tracking-const3.C: Likewise.
* g++.dg/cpp1y/constexpr-tracking-const4.C: Likewise.
* g++.dg/cpp1y/constexpr-tracking-const7.C: Likewise.
* g++.dg/cpp1y/constexpr-union5.C: Likewise.
* g++.dg/cpp1y/pr68180.C: Likewise.
* g++.dg/cpp1z/constexpr-lambda6.C: Likewise.
* g++.dg/cpp1z/constexpr-lambda8.C: Likewise.
* g++.dg/cpp2a/bit-cast11.C: Likewise.
* g++.dg/cpp2a/bit-cast12.C: Likewise.
* g++.dg/cpp2a/bit-cast14.C: Likewise.
* g++.dg/cpp2a/constexpr-98122.C: Likewise.
* g++.dg/cpp2a/constexpr-dynamic17.C: Likewise.
* g++.dg/cpp2a/constexpr-init1.C: Likewise.
* g++.dg/cpp2a/constexpr-new12.C: Likewise.
* g++.dg/cpp2a/constexpr-new3.C: Likewise.
* g++.dg/cpp2a/constinit10.C: Likewise.
* g++.dg/cpp2a/is-corresponding-member4.C: Likewise.
* g++.dg/ext/constexpr-vla2.C: Likewise.
* g++.dg/ext/constexpr-vla3.C: Likewise.
* g++.dg/ubsan/pr63956.C: Likewise.
Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
---
gcc/cp/constexpr.cc | 31 ++++++++++++++++++-
gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C | 10 +++---
gcc/testsuite/g++.dg/cpp0x/constexpr-70323.C | 8 ++---
gcc/testsuite/g++.dg/cpp0x/constexpr-70323a.C | 8 ++---
.../g++.dg/cpp0x/constexpr-delete2.C | 5 +--
gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C | 2 +-
gcc/testsuite/g++.dg/cpp0x/constexpr-ice20.C | 1 +
.../g++.dg/cpp0x/constexpr-recursion.C | 6 ++--
gcc/testsuite/g++.dg/cpp0x/overflow1.C | 2 +-
gcc/testsuite/g++.dg/cpp1y/constexpr-89285.C | 5 +--
gcc/testsuite/g++.dg/cpp1y/constexpr-89481.C | 3 +-
.../g++.dg/cpp1y/constexpr-tracking-const14.C | 3 +-
.../g++.dg/cpp1y/constexpr-tracking-const16.C | 3 +-
.../g++.dg/cpp1y/constexpr-tracking-const18.C | 4 +--
.../g++.dg/cpp1y/constexpr-tracking-const19.C | 4 +--
.../g++.dg/cpp1y/constexpr-tracking-const21.C | 4 +--
.../g++.dg/cpp1y/constexpr-tracking-const22.C | 4 +--
.../g++.dg/cpp1y/constexpr-tracking-const3.C | 3 +-
.../g++.dg/cpp1y/constexpr-tracking-const4.C | 3 +-
.../g++.dg/cpp1y/constexpr-tracking-const7.C | 3 +-
gcc/testsuite/g++.dg/cpp1y/constexpr-union5.C | 4 +--
gcc/testsuite/g++.dg/cpp1y/pr68180.C | 4 +--
.../g++.dg/cpp1z/constexpr-lambda6.C | 4 +--
.../g++.dg/cpp1z/constexpr-lambda8.C | 5 ++-
gcc/testsuite/g++.dg/cpp2a/bit-cast11.C | 10 +++---
gcc/testsuite/g++.dg/cpp2a/bit-cast12.C | 10 +++---
gcc/testsuite/g++.dg/cpp2a/bit-cast14.C | 14 ++++-----
gcc/testsuite/g++.dg/cpp2a/constexpr-98122.C | 4 +--
.../g++.dg/cpp2a/constexpr-dynamic17.C | 5 ++-
gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C | 5 ++-
gcc/testsuite/g++.dg/cpp2a/constexpr-new12.C | 6 ++--
gcc/testsuite/g++.dg/cpp2a/constexpr-new3.C | 10 +++---
gcc/testsuite/g++.dg/cpp2a/constinit10.C | 5 ++-
.../g++.dg/cpp2a/is-corresponding-member4.C | 4 +--
gcc/testsuite/g++.dg/ext/constexpr-vla2.C | 4 +--
gcc/testsuite/g++.dg/ext/constexpr-vla3.C | 4 +--
gcc/testsuite/g++.dg/ubsan/pr63956.C | 23 +++++++-------
.../25_algorithms/equal/constexpr_neg.cc | 7 +++--
.../testsuite/26_numerics/gcd/105844.cc | 10 +++---
.../testsuite/26_numerics/lcm/105844.cc | 14 +++++----
40 files changed, 147 insertions(+), 117 deletions(-)
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc
index 6e8f1c2b61e..2bf2458c3cd 100644
--- a/gcc/cp/constexpr.cc
+++ b/gcc/cp/constexpr.cc
@@ -2160,7 +2160,33 @@ modifying_const_object_error (tree expr, tree obj)
auto_diagnostic_group d;
error_at (loc, "modifying a const object %qE is not allowed in "
"a constant expression", TREE_OPERAND (expr, 0));
- inform (location_of (obj), "originally declared %<const%> here");
+
+ /* Find the underlying object that was declared as const. */
+ location_t decl_loc = UNKNOWN_LOCATION;
+ for (tree probe = obj; decl_loc == UNKNOWN_LOCATION; )
+ switch (TREE_CODE (probe))
+ {
+ case BIT_FIELD_REF:
+ case COMPONENT_REF:
+ {
+ tree elt = TREE_OPERAND (probe, 1);
+ if (CP_TYPE_CONST_P (TREE_TYPE (elt)))
+ decl_loc = DECL_SOURCE_LOCATION (elt);
+ probe = TREE_OPERAND (probe, 0);
+ }
+ break;
+
+ case ARRAY_REF:
+ case REALPART_EXPR:
+ case IMAGPART_EXPR:
+ probe = TREE_OPERAND (probe, 0);
+ break;
+
+ default:
+ decl_loc = location_of (probe);
+ break;
+ }
+ inform (decl_loc, "originally declared %<const%> here");
}
/* Return true if FNDECL is a replaceable global allocation function that
@@ -6950,7 +6976,10 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
return t;
}
+ /* Change the input location to the currently processed expression for
+ better error messages when a subexpression has no location. */
location_t loc = cp_expr_loc_or_input_loc (t);
+ iloc_sentinel sentinel (loc);
STRIP_ANY_LOCATION_WRAPPER (t);
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C
index 4574eb83ff7..11630f26ffe 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C
@@ -10,11 +10,11 @@
// R() is well-formed because i is initialized before j.
struct s {
- constexpr s() : v(v) { }
+ constexpr s() : v(v) { } // { dg-error "accessing uninitialized member" }
int v;
};
-constexpr s bang; // { dg-error "|" }
+constexpr s bang; // { dg-message "in .constexpr. expansion" }
struct R {
int i,j;
@@ -26,14 +26,14 @@ constexpr R r; // { dg-bogus "" }
// Ill-formed (no diagnostic required)
struct T {
int i;
- constexpr int f() { return i; }
+ constexpr int f() { return i; } // { dg-error "accessing uninitialized member" }
constexpr T(): i(0) { }
- constexpr T(const T& t) : i(f()) { } // { dg-message "" }
+ constexpr T(const T& t) : i(f()) { } // { dg-message "in .constexpr. expansion" }
};
constexpr T t1;
// Ill-formed (diagnostic required)
-constexpr T t2(t1); // { dg-message "" }
+constexpr T t2(t1); // { dg-message "in .constexpr. expansion" }
// Well-formed
struct U {
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-70323.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-70323.C
index 272a225d967..bfb185f2fb5 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-70323.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-70323.C
@@ -1,10 +1,10 @@
// PR c++/70323
// { dg-do compile { target c++11 } }
-constexpr int overflow_if_0 (int i) { return __INT_MAX__ + !i; }
-constexpr int overflow_if_1 (int i) { return __INT_MAX__ + i; }
+constexpr int overflow_if_0 (int i) { return __INT_MAX__ + !i; } // { dg-error "overflow in constant expression" }
+constexpr int overflow_if_1 (int i) { return __INT_MAX__ + i; } // { dg-error "overflow in constant expression" }
-constexpr bool i0_0 = overflow_if_0 (0); // { dg-error "overflow in constant expression|in .constexpr. expansion of " }
+constexpr bool i0_0 = overflow_if_0 (0); // { dg-message "in .constexpr. expansion of " }
constexpr bool i0_1 = overflow_if_0 (1);
constexpr bool i1_0 = overflow_if_1 (0);
-constexpr bool i1_1 = overflow_if_1 (1); // { dg-error "overflow in constant expression|in .constexpr. expansion of " }
+constexpr bool i1_1 = overflow_if_1 (1); // { dg-message "in .constexpr. expansion of " }
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-70323a.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-70323a.C
index 1990ab6be2d..b5ed581e1c8 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-70323a.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-70323a.C
@@ -2,10 +2,10 @@
// { dg-do compile { target c++11 } }
// { dg-options "-Wall" }
-constexpr int overflow_if_0 (int i) { return __INT_MAX__ + !i; }
-constexpr int overflow_if_1 (int i) { return __INT_MAX__ + i; }
+constexpr int overflow_if_0 (int i) { return __INT_MAX__ + !i; } // { dg-error "overflow in constant expression" }
+constexpr int overflow_if_1 (int i) { return __INT_MAX__ + i; } // { dg-error "overflow in constant expression" }
-constexpr bool i0_0 = overflow_if_0 (0); // { dg-error "overflow in constant expression|in .constexpr. expansion of" }
+constexpr bool i0_0 = overflow_if_0 (0); // { dg-message "in .constexpr. expansion of" }
constexpr bool i0_1 = overflow_if_0 (1);
constexpr bool i1_0 = overflow_if_1 (0);
-constexpr bool i1_1 = overflow_if_1 (1); // { dg-error "overflow in constant expression|in .constexpr. expansion of" }
+constexpr bool i1_1 = overflow_if_1 (1); // { dg-message "in .constexpr. expansion of" }
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-delete2.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-delete2.C
index 999f9b7851e..f2b6df2509c 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-delete2.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-delete2.C
@@ -6,8 +6,9 @@ constexpr int f(int i) { return i; }
constexpr int g(A* ap)
{
return f((delete[] ap, 42)); // { dg-message "" "" { target c++17_down } }
+ // { dg-error "" "" { target c++2a } .-1 }
}
A a;
-constexpr int i = g(&a); // { dg-error "" }
- // { dg-message "in 'constexpr' expansion of" "" { target c++2a } .-1 }
+constexpr int i = g(&a); // { dg-error "" "" { target c++17_down } }
+ // { dg-message "in 'constexpr' expansion of" "" { target c++2a } .-1 }
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C
index 5eedf42ba36..50c676c56cd 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C
@@ -16,7 +16,7 @@ int main()
struct complex // { dg-message "no .constexpr. constructor" "" { target { ! implicit_constexpr } } }
{
complex(double r, double i) : re(r), im(i) { }
- constexpr double real() const { return re; } // { dg-error "not a literal type" "" { target c++11_only } }
+ constexpr double real() const { return re; } // { dg-error "not a literal type|not usable in a constant expression" "" { target { ! implicit_constexpr } } }
double imag() const { return im; }
private:
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-ice20.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-ice20.C
index e2d4853a284..43fa9a03c14 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-ice20.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-ice20.C
@@ -3,5 +3,6 @@
typedef bool (*Function)(int);
constexpr bool check(int x, Function p) { return p(x); } // { dg-message "in .constexpr. expansion of" }
+// { dg-error "not a constant expression" "" { target *-*-* } .-1 }
static_assert(check(2, check), ""); // { dg-error "conversion|constant|in .constexpr. expansion of" }
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-recursion.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-recursion.C
index 8c4201e1ec2..b00f8794d4c 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-recursion.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-recursion.C
@@ -1,6 +1,6 @@
// Test that we catch excessive recursion.
// { dg-do compile { target c++11 } }
// { dg-options "-fconstexpr-depth=5" }
-// { dg-prune-output "in constexpr expansion" }
-constexpr int f (int i) { return f (i-1); } // { dg-message "in .constexpr. expansion of " }
-constexpr int i = f(42); // { dg-error ".constexpr. evaluation depth|in .constexpr. expansion of " }
+// { dg-prune-output "in .constexpr. expansion" }
+constexpr int f (int i) { return f (i-1); } // { dg-error ".constexpr. evaluation depth" }
+constexpr int i = f(42);
diff --git a/gcc/testsuite/g++.dg/cpp0x/overflow1.C b/gcc/testsuite/g++.dg/cpp0x/overflow1.C
index b8591b4af41..e295355c88f 100644
--- a/gcc/testsuite/g++.dg/cpp0x/overflow1.C
+++ b/gcc/testsuite/g++.dg/cpp0x/overflow1.C
@@ -4,7 +4,7 @@ template <long long i>
struct Fib
{
static const long long value // { dg-error "overflow" }
- = Fib<i-1>::value + Fib<i-2>::value;
+ = Fib<i-1>::value + Fib<i-2>::value; // { dg-error "overflow" }
};
template <>
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-89285.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-89285.C
index fe0b8570ca2..efbf9bd15dd 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-89285.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-89285.C
@@ -13,8 +13,9 @@ struct B {
*c = reinterpret_cast<char *>(this) - reinterpret_cast<char *>(c); // { dg-error "reinterpret_cast" "" { target c++20_down } }
}
};
-struct C : A {
+struct C : A { // { dg-error "" "" { target c++14_down } }
B bar {this};
};
-constexpr C foo {}; // { dg-message "" }
+// error path changes in C++17 due to `C` becoming an aggregate
+constexpr C foo {}; // { dg-error "" "" { target c++17 } }
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-89481.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-89481.C
index 8ac4ef0fd36..6f8f6a8038e 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-89481.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-89481.C
@@ -6,7 +6,7 @@ foo ()
{
union U { long long a; int b[2]; } u { 5LL };
u.b[1] = 4; // { dg-error "change of the active member of a union from" "" { target c++17_down } }
- return u.b[0];
+ return u.b[0]; // { dg-error "accessing uninitialized array element" "" { target c++2a } }
}
constexpr int
@@ -19,6 +19,5 @@ bar ()
static_assert (foo () == 0, ""); // { dg-error "non-constant condition for static assertion" }
// { dg-message "in 'constexpr' expansion of" "" { target *-*-* } .-1 }
- // { dg-error "accessing uninitialized array element" "" { target c++2a } .-2 }
static_assert (bar () == 4, ""); // { dg-error "non-constant condition for static assertion" "" { target c++17_down } }
// { dg-message "in 'constexpr' expansion of" "" { target c++17_down } .-1 }
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const14.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const14.C
index 45c4fcf50be..0c77dd4934d 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const14.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const14.C
@@ -14,7 +14,7 @@ struct C {
struct A {
int r;
- const C c;
+ const C c; // { dg-message "originally declared" }
constexpr A() : r(11) { r = 14; const_cast<C &>(c).n = 42; } // { dg-error "modifying a const object" }
};
@@ -34,5 +34,4 @@ struct B {
};
constexpr B b(false); // { dg-message "in .constexpr. expansion of" }
-// { dg-message "originally declared" "" { target *-*-* } .-1 }
static_assert(b.e.d.a.c.n == 2, ""); // { dg-error "non-constant condition" }
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const16.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const16.C
index 5a5b92bc8cc..b5ccf3a4ea5 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const16.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const16.C
@@ -7,7 +7,7 @@ constexpr int& impl(const int (&array)[10], int index) {
struct A {
constexpr int& operator[](int i) { return impl(elems, i); }
- const int elems[10];
+ const int elems[10]; // { dg-message "originally declared" }
};
constexpr bool
@@ -19,4 +19,3 @@ f()
}
constexpr bool b = f(); // { dg-message "in .constexpr. expansion of " }
-// { dg-message "originally declared" "" { target *-*-* } .-1 }
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const18.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const18.C
index 11a680468c2..278628c121b 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const18.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const18.C
@@ -13,11 +13,11 @@ struct array
template <typename T>
struct S {
using U = array<T, 4>;
- const U m;
+ const U m; // { dg-message "originally declared" }
constexpr S(int) : m{}
{
const_cast<int &>(const_cast<const U &>(m)[0]) = 42; // { dg-error "modifying a const object" }
}
};
-constexpr S<int> p = { 10 }; // { dg-message "originally declared" }
+constexpr S<int> p = { 10 };
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const19.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const19.C
index c31222ffcdd..2d18c94537b 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const19.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const19.C
@@ -7,7 +7,7 @@ template <typename E, size_t N>
struct array
{
constexpr const E &operator[](size_t n) const noexcept { return elems[n]; }
- const E elems[N];
+ const E elems[N]; // { dg-message "originally declared" }
};
template <typename T>
@@ -20,4 +20,4 @@ struct S {
}
};
-constexpr S<int> p = { 10 }; // { dg-message "originally declared" }
+constexpr S<int> p = { 10 };
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const21.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const21.C
index 0b16193398e..d3bbcb116a6 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const21.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const21.C
@@ -18,11 +18,11 @@ struct array2 {
template <typename T>
struct S {
using U = array2<T, 4>;
- const U m;
+ const U m; // { dg-message "originally declared" }
constexpr S(int) : m{}
{
const_cast<int &>(m.a[0]) = 42; // { dg-error "modifying a const object" }
}
};
-constexpr S<int> p = { 10 }; // { dg-message "originally declared" }
+constexpr S<int> p = { 10 };
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const22.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const22.C
index 216cf1607a4..27522f86dbd 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const22.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const22.C
@@ -7,11 +7,11 @@ struct X {
template <typename T>
struct S {
- const X x;
+ const X x; // { dg-message "originally declared" }
constexpr S(int) : x{}
{
const_cast<X&>(x).i = 19; // { dg-error "modifying a const object" }
}
};
-constexpr S<int> p = { 10 }; // { dg-message "originally declared" }
+constexpr S<int> p = { 10 };
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const3.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const3.C
index 6853775c1e2..fc88dd05eef 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const3.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const3.C
@@ -7,7 +7,7 @@ struct A {
};
struct B {
- const A a;
+ const A a; // { dg-message "originally declared" }
constexpr B(bool b) {
if (b)
const_cast<A &>(a).n = 3; // { dg-error "modifying a const object" }
@@ -18,5 +18,4 @@ constexpr B b(false);
static_assert(b.a.n == 2, "");
constexpr B b2(true); // { dg-message "in .constexpr. expansion of " }
-// { dg-message "originally declared" "" { target *-*-* } .-1 }
static_assert((b2.a.n, 1), "");
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const4.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const4.C
index 8263a7cc505..27fede152c7 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const4.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const4.C
@@ -2,7 +2,7 @@
// { dg-do compile { target c++14 } }
struct A {
- const int n;
+ const int n; // { dg-message "originally declared" }
constexpr A() : n(1) { }
};
struct B {
@@ -13,5 +13,4 @@ struct B {
}
};
constexpr B b; // { dg-message "in .constexpr. expansion of " }
-// { dg-message "originally declared" "" { target *-*-* } .-1 }
static_assert((b.a.n, 1), "");
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const7.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const7.C
index 922e8ff126f..bea14b05602 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const7.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-tracking-const7.C
@@ -3,7 +3,7 @@
struct D { int n; };
-struct C { const D d; };
+struct C { const D d; }; // { dg-message "originally declared" }
struct A {
C c;
@@ -19,5 +19,4 @@ struct B {
};
constexpr B b{}; // { dg-message "in .constexpr. expansion of " }
-// { dg-message "originally declared" "" { target *-*-* } .-1 }
static_assert((b.a.c.d.n, 1), "");
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-union5.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-union5.C
index 55fe9fa2f0b..3d76345d564 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-union5.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-union5.C
@@ -8,8 +8,8 @@ union U {
};
constexpr int foo(U *up) {
- up->a++;
+ up->a++; // { dg-error "accessing uninitialized member" }
return {42};
}
-extern constexpr U u = {}; // { dg-error "accessing uninitialized member" }
+extern constexpr U u = {}; // { dg-message "in .constexpr. expansion" }
diff --git a/gcc/testsuite/g++.dg/cpp1y/pr68180.C b/gcc/testsuite/g++.dg/cpp1y/pr68180.C
index 9e6e5e984f9..8de1ef3936b 100644
--- a/gcc/testsuite/g++.dg/cpp1y/pr68180.C
+++ b/gcc/testsuite/g++.dg/cpp1y/pr68180.C
@@ -6,11 +6,11 @@ typedef float __attribute__( ( vector_size( 16 ) ) ) float32x4_t;
constexpr float32x4_t fill(float x) {
float32x4_t v{0};
constexpr auto vs = sizeof(v)/sizeof(v[0]);
- for (auto i=0U; i<vs; ++i) v[i]=i;
+ for (auto i=0U; i<vs; ++i) v[i]=i; // { dg-error "not a constant" }
return v+x;
}
float32x4_t foo(float32x4_t x) {
- constexpr float32x4_t v = fill(1.f); // { dg-error "not a constant||in .constexpr. expansion of " }
+ constexpr float32x4_t v = fill(1.f); // { dg-message "in .constexpr. expansion of " }
return x+v;
}
diff --git a/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda6.C b/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda6.C
index 214d3821299..c46c2d4c7fe 100644
--- a/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda6.C
+++ b/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda6.C
@@ -1,7 +1,7 @@
// Testcase from P0170R1
// { dg-do compile { target c++17 } }
-auto monoid = [](auto v) { return [=] { return v; }; };
+auto monoid = [](auto v) { return [=] { return v; }; }; // { dg-error "not usable in a constant expression" }
auto add = [](auto m1) constexpr {
auto ret = m1();
return [=](auto m2) mutable {
@@ -22,7 +22,7 @@ int main()
// member function call operator can not perform an lvalue-to-rvalue conversion
// on one of its subobjects (that represents its capture) in a constant
// expression.
- auto two = monoid(2);
+ auto two = monoid(2); // { dg-message "not declared .constexpr." }
if (!(two() == 2)) __builtin_abort(); // OK, not a constant expression.
static_assert(add(one)(one)() == two()); // { dg-error "|in .constexpr. expansion of " } two() is not a constant expression
static_assert(add(one)(one)() == monoid(2)()); // OK
diff --git a/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda8.C b/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda8.C
index 84be68ab7f0..82351ff0c54 100644
--- a/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda8.C
+++ b/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda8.C
@@ -4,11 +4,14 @@
auto Fwd = [](int (*fp)(int), auto a) { return fp(a); };
auto C = [](auto a) { return a; };
static_assert( Fwd(C ,3) == 3); // OK
+
// No specialization of the function call operator template can be constexpr
// (because of the local static).
auto NC = [](auto a) { static int s; return a; }; // { dg-error "static" }
-// { dg-message "operator int" "" { target *-*-* } .+1 }
+// { dg-error "called in a constant expression" "" { target *-*-* } .-1 }
+
static_assert( Fwd(NC ,3) == 3); // { dg-error "" }
+// { dg-message "operator int" "" { target *-*-* } .-1 }
// We look for the string "operator int" to check that we aren't trying to do
// template pretty-printing in an expression; that gets incredibly unwieldy
diff --git a/gcc/testsuite/g++.dg/cpp2a/bit-cast11.C b/gcc/testsuite/g++.dg/cpp2a/bit-cast11.C
index a3eb31bc6c7..760c9ca40b4 100644
--- a/gcc/testsuite/g++.dg/cpp2a/bit-cast11.C
+++ b/gcc/testsuite/g++.dg/cpp2a/bit-cast11.C
@@ -28,7 +28,7 @@ f3 ()
{
T t = { 1, 2 };
S s = __builtin_bit_cast (S, t);
- return s.a[1] == 0;
+ return s.a[1] == 0; // { dg-error "accessing uninitialized array element" }
}
constexpr bool
@@ -52,12 +52,12 @@ f6 ()
{
W t = { 1, 2 };
V s = __builtin_bit_cast (V, t);
- return s.b.a[1] == 1;
+ return s.b.a[1] == 1; // { dg-error "accessing uninitialized array element" }
}
constexpr bool a = f1 ();
constexpr bool b = f2 ();
-constexpr bool c = f3 (); // { dg-error "accessing uninitialized array element" }
-constexpr bool d = f4 ();
+constexpr bool c = f3 (); // { dg-message "in .constexpr. expansion" }
+constexpr bool d = f4 (); // { dg-message "in .constexpr. expansion" }
constexpr bool e = f5 ();
-constexpr bool f = f6 (); // { dg-error "accessing uninitialized array element" }
+constexpr bool f = f6 (); // { dg-message "in .constexpr. expansion" }
diff --git a/gcc/testsuite/g++.dg/cpp2a/bit-cast12.C b/gcc/testsuite/g++.dg/cpp2a/bit-cast12.C
index 9c699dd55f0..e205bc6a8c1 100644
--- a/gcc/testsuite/g++.dg/cpp2a/bit-cast12.C
+++ b/gcc/testsuite/g++.dg/cpp2a/bit-cast12.C
@@ -33,7 +33,7 @@ f3 ()
{
T t = { 1, 2 };
S s = __builtin_bit_cast (S, t);
- return s.a[1] == 0;
+ return s.a[1] == 0; // { dg-error "accessing uninitialized array element" }
}
constexpr bool
@@ -57,12 +57,12 @@ f6 ()
{
W t = { 1, 2 };
V s = __builtin_bit_cast (V, t);
- return s.b.a[1] == 1;
+ return s.b.a[1] == 1; // { dg-error "accessing uninitialized array element" }
}
constexpr bool a = f1 ();
constexpr bool b = f2 ();
-constexpr bool c = f3 (); // { dg-error "accessing uninitialized array element" }
-constexpr bool d = f4 ();
+constexpr bool c = f3 (); // { dg-message "in .constexpr. expansion" }
+constexpr bool d = f4 (); // { dg-message "in .constexpr. expansion" }
constexpr bool e = f5 ();
-constexpr bool f = f6 (); // { dg-error "accessing uninitialized array element" }
+constexpr bool f = f6 (); // { dg-message "in .constexpr. expansion" }
diff --git a/gcc/testsuite/g++.dg/cpp2a/bit-cast14.C b/gcc/testsuite/g++.dg/cpp2a/bit-cast14.C
index 5e185919be4..e0cc9a39702 100644
--- a/gcc/testsuite/g++.dg/cpp2a/bit-cast14.C
+++ b/gcc/testsuite/g++.dg/cpp2a/bit-cast14.C
@@ -44,7 +44,7 @@ f5 ()
{
T1 t = { 0, 0, 0, 0, 0, 0, 0 };
S s = __builtin_bit_cast (S, t);
- unsigned char a = s.a;
+ unsigned char a = s.a; // { dg-error "accessing uninitialized member" }
return true;
}
@@ -53,7 +53,7 @@ f6 ()
{
T2 t = { 0, 0, 0, 0, 0, 0, 0 };
S s = __builtin_bit_cast (S, t);
- unsigned char b = s.b;
+ unsigned char b = s.b; // { dg-error "accessing uninitialized member" }
return true;
}
@@ -62,14 +62,14 @@ f7 ()
{
T3 t = { 0, 0, 0, 0, 0, 0, 0 };
S s = __builtin_bit_cast (S, t);
- unsigned char c = s.c;
+ unsigned char c = s.c; // { dg-error "accessing uninitialized member" }
return true;
}
constexpr bool a = f1 ();
constexpr bool b = f2 ();
constexpr bool c = f3 ();
-constexpr bool d = f4 ();
-constexpr bool e = f5 (); // { dg-error "accessing uninitialized member" }
-constexpr bool f = f6 (); // { dg-error "accessing uninitialized member" }
-constexpr bool g = f7 (); // { dg-error "accessing uninitialized member" }
+constexpr bool d = f4 (); // { dg-message "in .constexpr. expansion" }
+constexpr bool e = f5 (); // { dg-message "in .constexpr. expansion" }
+constexpr bool f = f6 (); // { dg-message "in .constexpr. expansion" }
+constexpr bool g = f7 (); // { dg-message "in .constexpr. expansion" }
diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-98122.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-98122.C
index 01bdfa5bd4d..b0c91d5ef97 100644
--- a/gcc/testsuite/g++.dg/cpp2a/constexpr-98122.C
+++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-98122.C
@@ -9,7 +9,7 @@ bar ()
{
V f { .b = 42 };
constexpr auto m = &V::a;
- return (f.*m) == 42;
+ return (f.*m) == 42; // { dg-error "accessing 'V::a' member instead of initialized 'V::b' member in constant expression" }
}
constexpr bool
@@ -21,5 +21,5 @@ baz ()
}
static_assert (bar (), ""); // { dg-error "non-constant condition for static assertion" }
- // { dg-error "accessing 'V::a' member instead of initialized 'V::b' member in constant expression" "" { target *-*-* } .-1 }
+ // { dg-message "in .constexpr. expansion" "" { target *-*-* } .-1 }
static_assert (baz (), "");
diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-dynamic17.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-dynamic17.C
index a26678e6ed7..28facf192df 100644
--- a/gcc/testsuite/g++.dg/cpp2a/constexpr-dynamic17.C
+++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-dynamic17.C
@@ -25,8 +25,7 @@ struct D : B, A {
constexpr B::B(V* v, A* a)
{
- dynamic_cast<B*>(a);
+ dynamic_cast<B*>(a); // { dg-error "accessing uninitialized member" }
}
-constexpr D d; // { dg-error "accessing uninitialized member" }
-// { dg-message "in 'constexpr' expansion of" "" { target *-*-* } .-1 }
+constexpr D d; // { dg-message "in 'constexpr' expansion of" }
diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
index e56ecfed48a..b4e39b6f928 100644
--- a/gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
+++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
@@ -52,11 +52,10 @@ constexpr int
fn5 ()
{
struct S { int a = 9; int b; } s;
- return s.b;
+ return s.b; // { dg-error "accessing uninitialized member" }
}
-constexpr int b = fn5 (); // { dg-error "accessing uninitialized member" }
-// { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-1 }
+constexpr int b = fn5 (); // { dg-message "in .constexpr. expansion of" }
constexpr int
fn6 ()
diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-new12.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-new12.C
index 5a3d06a5fab..832782e1427 100644
--- a/gcc/testsuite/g++.dg/cpp2a/constexpr-new12.C
+++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-new12.C
@@ -17,11 +17,11 @@ struct B : A {
constexpr int
foo ()
{
- A *a = new B ();
+ A *a = new B (); // { dg-message "allocated here" }
a->a = 4;
delete a;
- int r = a->foo ();
+ int r = a->foo (); // { dg-error "constant expression" }
return r;
}
-constexpr auto a = foo (); // { dg-error "constant expression" }
+constexpr auto a = foo (); // { dg-message "in .constexpr. expansion" }
diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-new3.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-new3.C
index 70b841208f8..3ba440fec53 100644
--- a/gcc/testsuite/g++.dg/cpp2a/constexpr-new3.C
+++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-new3.C
@@ -45,11 +45,10 @@ constexpr bool
f5 ()
{
int *p = new int; // { dg-message "allocated here" }
- return *p == 1;
+ return *p == 1; // { dg-error "the content of uninitialized storage is not usable in a constant expression" }
}
-constexpr auto v5 = f5 (); // { dg-error "the content of uninitialized storage is not usable in a constant expression" }
- // { dg-message "in 'constexpr' expansion of" "" { target *-*-* } .-1 }
+constexpr auto v5 = f5 (); // { dg-message "in 'constexpr' expansion of" }
constexpr bool
f6 ()
@@ -57,11 +56,10 @@ f6 ()
int *p = new int (2); // { dg-message "allocated here" }
int *q = p;
delete p;
- return *q == 2;
+ return *q == 2; // { dg-error "use of allocated storage after deallocation in a constant expression" }
}
-constexpr auto v6 = f6 (); // { dg-error "use of allocated storage after deallocation in a constant expression" }
- // { dg-message "in 'constexpr' expansion of" "" { target *-*-* } .-1 }
+constexpr auto v6 = f6 (); // { dg-message "in 'constexpr' expansion of" }
constexpr int *
f7 ()
diff --git a/gcc/testsuite/g++.dg/cpp2a/constinit10.C b/gcc/testsuite/g++.dg/cpp2a/constinit10.C
index b678788541e..d2c49c41f91 100644
--- a/gcc/testsuite/g++.dg/cpp2a/constinit10.C
+++ b/gcc/testsuite/g++.dg/cpp2a/constinit10.C
@@ -11,15 +11,14 @@ struct S1
struct alignas(64) S2
{
constexpr S2 ()
- : m_tabS1()
+ : m_tabS1() // { dg-error "used before its definition" }
{}
S1 m_tabS1[7];
};
constinit S2 objX; // { dg-error ".constinit. variable .objX. does not have a constant initializer" }
-// { dg-error "used before its definition" "" { target *-*-* } .-1 }
-// // { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-2 }
+// { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-1 }
constexpr S1::S1 ()
: m_i(14)
diff --git a/gcc/testsuite/g++.dg/cpp2a/is-corresponding-member4.C b/gcc/testsuite/g++.dg/cpp2a/is-corresponding-member4.C
index 6b74090306b..241e9976e8c 100644
--- a/gcc/testsuite/g++.dg/cpp2a/is-corresponding-member4.C
+++ b/gcc/testsuite/g++.dg/cpp2a/is-corresponding-member4.C
@@ -14,8 +14,8 @@ is_corresponding_member (M1 S1::*m1, M2 S2::*m2) noexcept
struct A { int a; };
struct B;
constexpr int B::*n = nullptr;
-constexpr auto a = std::is_corresponding_member (&A::a, n); // { dg-error "invalid use of incomplete type 'struct B'" }
-constexpr auto b = std::is_corresponding_member (n, &A::a); // { dg-error "invalid use of incomplete type 'struct B'" }
+constexpr auto a = std::is_corresponding_member (&A::a, n); // { dg-message "in .constexpr. expansion of" }
+constexpr auto b = std::is_corresponding_member (n, &A::a); // { dg-message "in .constexpr. expansion of" }
void
foo (int B::*m)
diff --git a/gcc/testsuite/g++.dg/ext/constexpr-vla2.C b/gcc/testsuite/g++.dg/ext/constexpr-vla2.C
index d4ea7c58c0d..e09a27af3de 100644
--- a/gcc/testsuite/g++.dg/ext/constexpr-vla2.C
+++ b/gcc/testsuite/g++.dg/ext/constexpr-vla2.C
@@ -4,7 +4,7 @@
constexpr int
fn_bad (int n)
{
- __extension__ int a [n] = { 0 };
+ __extension__ int a [n] = { 0 }; // { dg-error "array subscript" }
int z = a [0] + (n ? fn_bad (n - 1) : 0); // { dg-message "in .constexpr. expansion of " }
return z;
}
@@ -18,4 +18,4 @@ fn_ok (int n)
}
constexpr int i1 = fn_ok (3);
-constexpr int i2 = fn_bad (3); // { dg-error "array subscript|in .constexpr. expansion of " }
+constexpr int i2 = fn_bad (3); // { dg-message "in .constexpr. expansion of " }
diff --git a/gcc/testsuite/g++.dg/ext/constexpr-vla3.C b/gcc/testsuite/g++.dg/ext/constexpr-vla3.C
index 538b576a825..6f9daa1897f 100644
--- a/gcc/testsuite/g++.dg/ext/constexpr-vla3.C
+++ b/gcc/testsuite/g++.dg/ext/constexpr-vla3.C
@@ -4,11 +4,11 @@
constexpr int
foo (int n)
{
- __extension__ int a[n] = { 1, 2, 3, 4, 5, 6 };
+ __extension__ int a[n] = { 1, 2, 3, 4, 5, 6 }; // { dg-error "array subscript" }
int z = 0;
for (int i = 0; i <= n; ++i)
z += a[i];
return z;
}
-constexpr int n = foo (3); // { dg-error "array subscript|in .constexpr. expansion of " }
+constexpr int n = foo (3); // { dg-message "in .constexpr. expansion of " }
diff --git a/gcc/testsuite/g++.dg/ubsan/pr63956.C b/gcc/testsuite/g++.dg/ubsan/pr63956.C
index 3a1596e6e2e..6fd0b4f893e 100644
--- a/gcc/testsuite/g++.dg/ubsan/pr63956.C
+++ b/gcc/testsuite/g++.dg/ubsan/pr63956.C
@@ -56,12 +56,13 @@ fn3 (int a, int b)
{
if (b != 2)
a = a / b; // { dg-error "..7 / 0.. is not a constant expression" }
+ // { dg-error "overflow in constant expression" "" { target *-*-* } .-1 }
return a;
}
constexpr int k1 = fn3 (8, 4);
constexpr int k2 = fn3 (7, 0); // { dg-message "in .constexpr. expansion" }
-constexpr int k3 = fn3 (INT_MIN, -1); // { dg-error "overflow in constant expression|in .constexpr. expansion of " }
+constexpr int k3 = fn3 (INT_MIN, -1); // { dg-message "in .constexpr. expansion of " }
SA (k1 == 2);
@@ -100,13 +101,13 @@ constexpr int
fn7 (const int *a, int b)
{
if (b != 3)
- return fn6 (*a, b);
+ return fn6 (*a, b); // { dg-error "null pointer" }
return 7;
}
constexpr int n1 = 7;
constexpr int n2 = fn7 (&n1, 5);
-constexpr int n3 = fn7 ((const int *) 0, 8); // { dg-error "null pointer|in .constexpr. expansion of " }
+constexpr int n3 = fn7 ((const int *) 0, 8); // { dg-message "in .constexpr. expansion of " }
constexpr int
fn8 (int i)
@@ -122,15 +123,15 @@ constexpr int
fn9 (int a, int b)
{
if (b != 0)
- return a + b;
+ return a + b; // { dg-error "overflow in constant expression" }
return a;
}
constexpr int p1 = fn9 (42, 7);
-constexpr int p2 = fn9 (__INT_MAX__, 1); // { dg-error "overflow in constant expression|in .constexpr. expansion of " }
+constexpr int p2 = fn9 (__INT_MAX__, 1); // { dg-message "in .constexpr. expansion of " }
constexpr int p3 = fn9 (__INT_MAX__, -1);
constexpr int p4 = fn9 (INT_MIN, 1);
-constexpr int p5 = fn9 (INT_MIN, -1); // { dg-error "overflow in constant expression|in .constexpr. expansion of " }
+constexpr int p5 = fn9 (INT_MIN, -1); // { dg-message "in .constexpr. expansion of " }
SA (p1 == 49);
SA (p3 == __INT_MAX__ - 1);
@@ -140,13 +141,13 @@ constexpr int
fn10 (int a, int b)
{
if (b != 0)
- return a * b;
+ return a * b; // { dg-error "overflow in constant expression" }
return a;
}
constexpr int q1 = fn10 (10, 10);
-constexpr int q2 = fn10 (__INT_MAX__, 2); // { dg-error "overflow in constant expression|in .constexpr. expansion of " }
-constexpr int q3 = fn10 (INT_MIN, 2); // { dg-error "overflow in constant expression|in .constexpr. expansion of " }
+constexpr int q2 = fn10 (__INT_MAX__, 2); // { dg-message "in .constexpr. expansion of " }
+constexpr int q3 = fn10 (INT_MIN, 2); // { dg-message "in .constexpr. expansion of " }
constexpr int q4 = fn10 (-1, -1);
SA (q1 == 100);
@@ -155,14 +156,14 @@ SA (q4 == 1);
constexpr int
fn11 (double d)
{
- int i = d;
+ int i = d; // { dg-error "overflow in constant expression" }
if (i != 0)
return i;
return i * 2;
}
constexpr int r1 = fn11 (3.4);
-constexpr int r2 = fn11 (__builtin_inf ()); // { dg-error "overflow in constant expression|in .constexpr. expansion of " }
+constexpr int r2 = fn11 (__builtin_inf ()); // { dg-message "in .constexpr. expansion of " }
constexpr int
fn12 (int i)
diff --git a/libstdc++-v3/testsuite/25_algorithms/equal/constexpr_neg.cc b/libstdc++-v3/testsuite/25_algorithms/equal/constexpr_neg.cc
index 34ca5c4805c..fd89ac0e166 100644
--- a/libstdc++-v3/testsuite/25_algorithms/equal/constexpr_neg.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/equal/constexpr_neg.cc
@@ -32,7 +32,7 @@ test01()
return outa;
}
-static_assert(test01()); // { dg-error "outside the bounds" }
+static_assert(test01()); // { dg-error "non-constant condition" }
constexpr bool
test02()
@@ -44,7 +44,8 @@ test02()
return outa;
}
-static_assert(test02()); // { dg-error "outside the bounds" }
+static_assert(test02()); // { dg-error "non-constant condition" }
-// { dg-prune-output "non-constant condition" }
+// Errors occuring within <algorithm> internals:
+// { dg-error "outside the bounds of array" "" { target *-*-* } 0 }
// { dg-prune-output "in 'constexpr'" }
diff --git a/libstdc++-v3/testsuite/26_numerics/gcd/105844.cc b/libstdc++-v3/testsuite/26_numerics/gcd/105844.cc
index 5b6fea7b560..bc9b29bc39d 100644
--- a/libstdc++-v3/testsuite/26_numerics/gcd/105844.cc
+++ b/libstdc++-v3/testsuite/26_numerics/gcd/105844.cc
@@ -13,9 +13,11 @@ static_assert( std::gcd(LLONG_MIN, 2ull) == 2 );
static_assert( std::gcd(2ull, LLONG_MIN) == 2 );
// But |INT_MIN| cannot be represented in common_type<int, int> i.e. int.
-constexpr int a = std::gcd(INT_MIN, 1); // { dg-error "overflow" }
-constexpr int b = std::gcd(1, INT_MIN); // { dg-error "overflow" }
+constexpr int a = std::gcd(INT_MIN, 1); // { dg-error "in .constexpr." }
+constexpr int b = std::gcd(1, INT_MIN); // { dg-error "in .constexpr." }
// And |LLONG_MIN| cannot be represented in long.
-constexpr long long c = std::gcd(LLONG_MIN, 1); // { dg-error "overflow" }
-constexpr long long d = std::gcd(1, LLONG_MIN); // { dg-error "overflow" }
+constexpr long long c = std::gcd(LLONG_MIN, 1); // { dg-error "in .constexpr." }
+constexpr long long d = std::gcd(1, LLONG_MIN); // { dg-error "in .constexpr." }
+
+// { dg-error "overflow" "" { target *-*-* } 0 }
diff --git a/libstdc++-v3/testsuite/26_numerics/lcm/105844.cc b/libstdc++-v3/testsuite/26_numerics/lcm/105844.cc
index d0e032e03e0..d853974f77e 100644
--- a/libstdc++-v3/testsuite/26_numerics/lcm/105844.cc
+++ b/libstdc++-v3/testsuite/26_numerics/lcm/105844.cc
@@ -9,14 +9,16 @@ static_assert( std::lcm(INT_MIN, 1u) == INT_MAX+1u );
static_assert( std::lcm(1u, INT_MIN) == INT_MAX+1u );
// But |INT_MIN| cannot be represented in common_type<int, int> i.e. int.
-constexpr int a = std::lcm(INT_MIN, 1); // { dg-error "overflow" }
-constexpr int b = std::lcm(1, INT_MIN); // { dg-error "overflow" }
+constexpr int a = std::lcm(INT_MIN, 1); // { dg-error "in .constexpr." }
+constexpr int b = std::lcm(1, INT_MIN); // { dg-error "in .constexpr." }
// And the LCM of 50000 and 49999 cannot be represented in int.
-constexpr int c = std::lcm(50000, 49999); // { dg-error "overflow" }
-constexpr int d = std::lcm(49999, 50000); // { dg-error "overflow" }
+constexpr int c = std::lcm(50000, 49999); // { dg-error "in .constexpr." }
+constexpr int d = std::lcm(49999, 50000); // { dg-error "in .constexpr." }
// Similarly for unsigned, but the diagnostic is a failed assertion instead.
-constexpr int e = std::lcm(500000u, 499999); // { dg-error "in 'constexpr'" }
-constexpr int f = std::lcm(499999u, 500000); // { dg-error "in 'constexpr'" }
+constexpr int e = std::lcm(500000u, 499999); // { dg-error "in .constexpr." }
+constexpr int f = std::lcm(499999u, 500000); // { dg-error "in .constexpr." }
+
+// { dg-error "overflow" "" { target *-*-* } 0 }
// { dg-error "unreachable" "" { target *-*-* } 0 }
--
2.41.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v5 2/3] c++: Prevent dangling pointers from becoming nullptr in constexpr [PR110619]
2023-07-22 15:12 [PATCH v5 0/3] c++: Track lifetimes in constant evaluation [PR70331, ...] Nathaniel Shead
2023-07-22 15:13 ` [PATCH v5 1/3] c++: Improve location information in constant evaluation Nathaniel Shead
@ 2023-07-22 15:14 ` Nathaniel Shead
2023-07-22 15:15 ` [PATCH v5 3/3] c++: Track lifetimes in constant evaluation [PR70331,PR96630,PR98675] Nathaniel Shead
2023-07-26 1:53 ` [PATCH v5 0/3] c++: Track lifetimes in constant evaluation [PR70331, ...] Jason Merrill
3 siblings, 0 replies; 5+ messages in thread
From: Nathaniel Shead @ 2023-07-22 15:14 UTC (permalink / raw)
To: gcc-patches; +Cc: Jason Merrill, Patrick Palka
Currently, when typeck discovers that a return statement will refer to a
local variable it rewrites to return a null pointer. This causes the
error messages for using the return value in a constant expression to be
unhelpful, especially for reference return values, and is also a visible
change to otherwise valid code (as in the linked PR).
The transformation is nonetheless important, however, both as a safety
guard against attackers being able to gain a handle to other data on the
stack, and to prevent duplicate warnings from later null-dereference
warning passes.
As such, this patch just delays the transformation until cp_genericize,
after constexpr function definitions have been generated.
PR c++/110619
gcc/cp/ChangeLog:
* cp-gimplify.cc (cp_genericize_r): Transform RETURN_EXPRs to
not return dangling pointers.
* cp-tree.h (RETURN_EXPR_LOCAL_ADDR_P): New flag.
(check_return_expr): Add a new parameter.
* semantics.cc (finish_return_stmt): Set flag on RETURN_EXPR
when referring to dangling pointer.
* typeck.cc (check_return_expr): Disable transformation of
dangling pointers, instead pass this information to caller.
gcc/testsuite/ChangeLog:
* g++.dg/cpp1y/constexpr-110619.C: New test.
Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
---
gcc/cp/cp-gimplify.cc | 23 ++++++++++++++++---
gcc/cp/cp-tree.h | 8 ++++++-
gcc/cp/semantics.cc | 4 +++-
gcc/cp/typeck.cc | 9 ++++----
gcc/testsuite/g++.dg/cpp1y/constexpr-110619.C | 10 ++++++++
5 files changed, 45 insertions(+), 9 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-110619.C
diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc
index f5734197774..0a5d6300aca 100644
--- a/gcc/cp/cp-gimplify.cc
+++ b/gcc/cp/cp-gimplify.cc
@@ -1336,9 +1336,26 @@ cp_genericize_r (tree *stmt_p, int *walk_subtrees, void *data)
break;
case RETURN_EXPR:
- if (TREE_OPERAND (stmt, 0) && is_invisiref_parm (TREE_OPERAND (stmt, 0)))
- /* Don't dereference an invisiref RESULT_DECL inside a RETURN_EXPR. */
- *walk_subtrees = 0;
+ if (TREE_OPERAND (stmt, 0))
+ {
+ if (is_invisiref_parm (TREE_OPERAND (stmt, 0)))
+ /* Don't dereference an invisiref RESULT_DECL inside a RETURN_EXPR. */
+ *walk_subtrees = 0;
+ if (RETURN_EXPR_LOCAL_ADDR_P (stmt))
+ {
+ /* Don't return the address of a local variable. */
+ tree *p = &TREE_OPERAND (stmt, 0);
+ while (TREE_CODE (*p) == COMPOUND_EXPR)
+ p = &TREE_OPERAND (*p, 0);
+ if (TREE_CODE (*p) == INIT_EXPR)
+ {
+ tree op = TREE_OPERAND (*p, 1);
+ tree new_op = build2 (COMPOUND_EXPR, TREE_TYPE (op), op,
+ build_zero_cst (TREE_TYPE (op)));
+ TREE_OPERAND (*p, 1) = new_op;
+ }
+ }
+ }
break;
case OMP_CLAUSE:
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 3de0e154c12..e0c181d9aef 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -447,6 +447,7 @@ extern GTY(()) tree cp_global_trees[CPTI_MAX];
INIT_EXPR_NRV_P (in INIT_EXPR)
ATOMIC_CONSTR_MAP_INSTANTIATED_P (in ATOMIC_CONSTR)
contract_semantic (in ASSERTION_, PRECONDITION_, POSTCONDITION_STMT)
+ RETURN_EXPR_LOCAL_ADDR_P (in RETURN_EXPR)
1: IDENTIFIER_KIND_BIT_1 (in IDENTIFIER_NODE)
TI_PENDING_TEMPLATE_FLAG.
TEMPLATE_PARMS_FOR_INLINE.
@@ -4071,6 +4072,11 @@ struct GTY(()) lang_decl {
(LANG_DECL_FN_CHECK (FUNCTION_DECL_CHECK (NODE)) \
->u.saved_auto_return_type)
+/* In a RETURN_EXPR, whether the expression refers to the address
+ of a local variable. */
+#define RETURN_EXPR_LOCAL_ADDR_P(NODE) \
+ TREE_LANG_FLAG_0 (RETURN_EXPR_CHECK (NODE))
+
/* True if NODE is an implicit INDIRECT_REF from convert_from_reference. */
#define REFERENCE_REF_P(NODE) \
(INDIRECT_REF_P (NODE) \
@@ -8139,7 +8145,7 @@ extern tree composite_pointer_type (const op_location_t &,
tsubst_flags_t);
extern tree merge_types (tree, tree);
extern tree strip_array_domain (tree);
-extern tree check_return_expr (tree, bool *);
+extern tree check_return_expr (tree, bool *, bool *);
extern tree spaceship_type (tree, tsubst_flags_t = tf_warning_or_error);
extern tree genericize_spaceship (location_t, tree, tree, tree);
extern tree cp_build_binary_op (const op_location_t &,
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 8fb47fd179e..720521b7f1a 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -1240,8 +1240,9 @@ finish_return_stmt (tree expr)
{
tree r;
bool no_warning;
+ bool dangling;
- expr = check_return_expr (expr, &no_warning);
+ expr = check_return_expr (expr, &no_warning, &dangling);
if (error_operand_p (expr)
|| (flag_openmp && !check_omp_return ()))
@@ -1259,6 +1260,7 @@ finish_return_stmt (tree expr)
}
r = build_stmt (input_location, RETURN_EXPR, expr);
+ RETURN_EXPR_LOCAL_ADDR_P (r) = dangling;
if (no_warning)
suppress_warning (r, OPT_Wreturn_type);
r = maybe_cleanup_point_expr_void (r);
diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 859b133a18d..d5c0c85ed51 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -10920,10 +10920,11 @@ maybe_warn_pessimizing_move (tree expr, tree type, bool return_p)
change RETVAL into the function return type, and to assign it to
the DECL_RESULT for the function. Set *NO_WARNING to true if
code reaches end of non-void function warning shouldn't be issued
- on this RETURN_EXPR. */
+ on this RETURN_EXPR. Set *DANGLING to true if code returns the
+ address of a local variable. */
tree
-check_return_expr (tree retval, bool *no_warning)
+check_return_expr (tree retval, bool *no_warning, bool *dangling)
{
tree result;
/* The type actually returned by the function. */
@@ -10935,6 +10936,7 @@ check_return_expr (tree retval, bool *no_warning)
location_t loc = cp_expr_loc_or_input_loc (retval);
*no_warning = false;
+ *dangling = false;
/* A `volatile' function is one that isn't supposed to return, ever.
(This is a G++ extension, used to get better code for functions
@@ -11273,8 +11275,7 @@ check_return_expr (tree retval, bool *no_warning)
else if (!processing_template_decl
&& maybe_warn_about_returning_address_of_local (retval, loc)
&& INDIRECT_TYPE_P (valtype))
- retval = build2 (COMPOUND_EXPR, TREE_TYPE (retval), retval,
- build_zero_cst (TREE_TYPE (retval)));
+ *dangling = true;
}
/* A naive attempt to reduce the number of -Wdangling-reference false
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-110619.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-110619.C
new file mode 100644
index 00000000000..cca13302238
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-110619.C
@@ -0,0 +1,10 @@
+// { dg-do compile { target c++14 } }
+// { dg-options "-Wno-return-local-addr" }
+// PR c++/110619
+
+constexpr auto f() {
+ int i = 0;
+ return &i;
+};
+
+static_assert( f() != nullptr );
--
2.41.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v5 3/3] c++: Track lifetimes in constant evaluation [PR70331,PR96630,PR98675]
2023-07-22 15:12 [PATCH v5 0/3] c++: Track lifetimes in constant evaluation [PR70331, ...] Nathaniel Shead
2023-07-22 15:13 ` [PATCH v5 1/3] c++: Improve location information in constant evaluation Nathaniel Shead
2023-07-22 15:14 ` [PATCH v5 2/3] c++: Prevent dangling pointers from becoming nullptr in constexpr [PR110619] Nathaniel Shead
@ 2023-07-22 15:15 ` Nathaniel Shead
2023-07-26 1:53 ` [PATCH v5 0/3] c++: Track lifetimes in constant evaluation [PR70331, ...] Jason Merrill
3 siblings, 0 replies; 5+ messages in thread
From: Nathaniel Shead @ 2023-07-22 15:15 UTC (permalink / raw)
To: gcc-patches; +Cc: Jason Merrill, Patrick Palka
This adds rudimentary lifetime tracking in C++ constexpr contexts,
allowing the compiler to report errors with using values after their
backing has gone out of scope. We don't yet handle other ways of
accessing values outside their lifetime (e.g. following explicit
destructor calls).
PR c++/96630
PR c++/98675
PR c++/70331
gcc/cp/ChangeLog:
* constexpr.cc (constexpr_global_ctx::is_outside_lifetime): New
function.
(constexpr_global_ctx::get_value): Don't return expired values.
(constexpr_global_ctx::get_value_ptr): Likewise.
(constexpr_global_ctx::remove_value): Mark value outside
lifetime.
(outside_lifetime_error): New function.
(cxx_eval_call_expression): No longer track save_exprs.
(cxx_eval_loop_expr): Likewise.
(cxx_eval_constant_expression): Add checks for outside lifetime
values. Remove local variables at end of bind exprs, and
temporaries after cleanup points.
gcc/testsuite/ChangeLog:
* g++.dg/cpp1y/constexpr-lifetime1.C: New test.
* g++.dg/cpp1y/constexpr-lifetime2.C: New test.
* g++.dg/cpp1y/constexpr-lifetime3.C: New test.
* g++.dg/cpp1y/constexpr-lifetime4.C: New test.
* g++.dg/cpp1y/constexpr-lifetime5.C: New test.
* g++.dg/cpp1y/constexpr-lifetime6.C: New test.
Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
---
gcc/cp/constexpr.cc | 128 ++++++++++++------
.../g++.dg/cpp1y/constexpr-lifetime1.C | 13 ++
.../g++.dg/cpp1y/constexpr-lifetime2.C | 20 +++
.../g++.dg/cpp1y/constexpr-lifetime3.C | 13 ++
.../g++.dg/cpp1y/constexpr-lifetime4.C | 11 ++
.../g++.dg/cpp1y/constexpr-lifetime5.C | 11 ++
.../g++.dg/cpp1y/constexpr-lifetime6.C | 15 ++
7 files changed, 169 insertions(+), 42 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime1.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime2.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime3.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime4.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime5.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime6.C
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc
index 2bf2458c3cd..0ab77dcaf62 100644
--- a/gcc/cp/constexpr.cc
+++ b/gcc/cp/constexpr.cc
@@ -1148,7 +1148,8 @@ enum constexpr_switch_state {
class constexpr_global_ctx {
/* Values for any temporaries or local variables within the
- constant-expression. */
+ constant-expression. Objects outside their lifetime have
+ value 'void_node'. */
hash_map<tree,tree> values;
public:
/* Number of cxx_eval_constant_expression calls (except skipped ones,
@@ -1170,17 +1171,28 @@ public:
: constexpr_ops_count (0), cleanups (NULL), modifiable (nullptr),
heap_dealloc_count (0) {}
+ bool is_outside_lifetime (tree t)
+ {
+ if (tree *p = values.get (t))
+ if (*p == void_node)
+ return true;
+ return false;
+ }
tree get_value (tree t)
{
if (tree *p = values.get (t))
- return *p;
+ if (*p != void_node)
+ return *p;
return NULL_TREE;
}
tree *get_value_ptr (tree t)
{
if (modifiable && !modifiable->contains (t))
return nullptr;
- return values.get (t);
+ if (tree *p = values.get (t))
+ if (*p != void_node)
+ return p;
+ return nullptr;
}
void put_value (tree t, tree v)
{
@@ -1188,7 +1200,13 @@ public:
if (!already_in_map && modifiable)
modifiable->add (t);
}
- void remove_value (tree t) { values.remove (t); }
+ void remove_value (tree t)
+ {
+ if (DECL_P (t))
+ values.put (t, void_node);
+ else
+ values.remove (t);
+ }
};
/* Helper class for constexpr_global_ctx. In some cases we want to avoid
@@ -3111,12 +3129,9 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t,
gcc_assert (!DECL_BY_REFERENCE (res));
ctx->global->put_value (res, NULL_TREE);
- /* Track the callee's evaluated SAVE_EXPRs and TARGET_EXPRs so that
- we can forget their values after the call. */
- constexpr_ctx ctx_with_save_exprs = *ctx;
- auto_vec<tree, 10> save_exprs;
- ctx_with_save_exprs.save_exprs = &save_exprs;
- ctx_with_save_exprs.call = &new_call;
+ /* Remember the current call we're evaluating. */
+ constexpr_ctx call_ctx = *ctx;
+ call_ctx.call = &new_call;
unsigned save_heap_alloc_count = ctx->global->heap_vars.length ();
unsigned save_heap_dealloc_count = ctx->global->heap_dealloc_count;
@@ -3127,7 +3142,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t,
non_constant_p, overflow_p);
tree jump_target = NULL_TREE;
- cxx_eval_constant_expression (&ctx_with_save_exprs, body,
+ cxx_eval_constant_expression (&call_ctx, body,
vc_discard, non_constant_p, overflow_p,
&jump_target);
@@ -3183,15 +3198,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t,
cxx_set_object_constness (ctx, new_obj, /*readonly_p=*/true,
non_constant_p, overflow_p);
- /* Forget the saved values of the callee's SAVE_EXPRs and
- TARGET_EXPRs. */
- for (tree save_expr : save_exprs)
- ctx->global->remove_value (save_expr);
-
- /* Remove the parms/result from the values map. Is it worth
- bothering to do this when the map itself is only live for
- one constexpr evaluation? If so, maybe also clear out
- other vars from call, maybe in BIND_EXPR handling? */
+ /* Remove the parms/result from the values map. */
ctx->global->remove_value (res);
for (tree parm = parms; parm; parm = TREE_CHAIN (parm))
ctx->global->remove_value (parm);
@@ -5723,6 +5730,25 @@ cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t,
return r;
}
+/* Complain about R, a DECL that is accessed outside its lifetime. */
+
+static void
+outside_lifetime_error (location_t loc, tree r)
+{
+ if (DECL_NAME (r) == heap_deleted_identifier)
+ {
+ /* Provide a more accurate message for deleted variables. */
+ error_at (loc, "use of allocated storage after deallocation "
+ "in a constant expression");
+ inform (DECL_SOURCE_LOCATION (r), "allocated here");
+ }
+ else
+ {
+ error_at (loc, "accessing object outside its lifetime");
+ inform (DECL_SOURCE_LOCATION (r), "declared here");
+ }
+}
+
/* Complain about R, a VAR_DECL, not being usable in a constant expression.
FUNDEF_P is true if we're checking a constexpr function body.
Shared between potential_constant_expression and
@@ -6628,7 +6654,6 @@ cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t,
bool *non_constant_p, bool *overflow_p,
tree *jump_target)
{
- constexpr_ctx new_ctx = *ctx;
tree local_target;
if (!jump_target)
{
@@ -6666,14 +6691,12 @@ cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t,
default:
gcc_unreachable ();
}
- auto_vec<tree, 10> save_exprs;
- new_ctx.save_exprs = &save_exprs;
do
{
if (count != -1)
{
if (body)
- cxx_eval_constant_expression (&new_ctx, body, vc_discard,
+ cxx_eval_constant_expression (ctx, body, vc_discard,
non_constant_p, overflow_p,
jump_target);
if (breaks (jump_target))
@@ -6686,7 +6709,7 @@ cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t,
*jump_target = NULL_TREE;
if (expr)
- cxx_eval_constant_expression (&new_ctx, expr, vc_prvalue,
+ cxx_eval_constant_expression (ctx, expr, vc_prvalue,
non_constant_p, overflow_p,
jump_target);
}
@@ -6694,7 +6717,7 @@ cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t,
if (cond)
{
tree res
- = cxx_eval_constant_expression (&new_ctx, cond, vc_prvalue,
+ = cxx_eval_constant_expression (ctx, cond, vc_prvalue,
non_constant_p, overflow_p,
jump_target);
if (res)
@@ -6709,11 +6732,6 @@ cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t,
gcc_assert (*jump_target);
}
- /* Forget saved values of SAVE_EXPRs and TARGET_EXPRs. */
- for (tree save_expr : save_exprs)
- ctx->global->remove_value (save_expr);
- save_exprs.truncate (0);
-
if (++count >= constexpr_loop_limit)
{
if (!ctx->quiet)
@@ -6731,10 +6749,6 @@ cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t,
&& (!switches (jump_target) || count == 0)
&& !*non_constant_p);
- /* Forget saved values of SAVE_EXPRs and TARGET_EXPRs. */
- for (tree save_expr : save_exprs)
- ctx->global->remove_value (save_expr);
-
return NULL_TREE;
}
@@ -7079,11 +7093,20 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
else if (t == ctx->object)
return ctx->ctor;
if (VAR_P (t))
- if (tree v = ctx->global->get_value (t))
+ {
+ if (tree v = ctx->global->get_value (t))
{
r = v;
break;
}
+ if (ctx->global->is_outside_lifetime (t))
+ {
+ if (!ctx->quiet)
+ outside_lifetime_error (loc, t);
+ *non_constant_p = true;
+ break;
+ }
+ }
if (ctx->manifestly_const_eval == mce_true)
maybe_warn_about_constant_value (loc, t);
if (COMPLETE_TYPE_P (TREE_TYPE (t))
@@ -7128,6 +7151,13 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
r = v;
else if (lval)
/* Defer in case this is only used for its type. */;
+ else if (ctx->global->is_outside_lifetime (t))
+ {
+ if (!ctx->quiet)
+ outside_lifetime_error (loc, t);
+ *non_constant_p = true;
+ break;
+ }
else if (COMPLETE_TYPE_P (TREE_TYPE (t))
&& is_really_empty_class (TREE_TYPE (t), /*ignore_vptr*/false))
{
@@ -7367,17 +7397,28 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
auto_vec<tree, 2> cleanups;
vec<tree> *prev_cleanups = ctx->global->cleanups;
ctx->global->cleanups = &cleanups;
- r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0),
+
+ auto_vec<tree, 10> save_exprs;
+ constexpr_ctx new_ctx = *ctx;
+ new_ctx.save_exprs = &save_exprs;
+
+ r = cxx_eval_constant_expression (&new_ctx, TREE_OPERAND (t, 0),
lval,
non_constant_p, overflow_p,
jump_target);
+
ctx->global->cleanups = prev_cleanups;
unsigned int i;
tree cleanup;
/* Evaluate the cleanups. */
FOR_EACH_VEC_ELT_REVERSE (cleanups, i, cleanup)
- cxx_eval_constant_expression (ctx, cleanup, vc_discard,
+ cxx_eval_constant_expression (&new_ctx, cleanup, vc_discard,
non_constant_p, overflow_p);
+
+ /* Forget SAVE_EXPRs and TARGET_EXPRs created by this
+ full-expression. */
+ for (tree save_expr : save_exprs)
+ ctx->global->remove_value (save_expr);
}
break;
@@ -7893,10 +7934,13 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
non_constant_p, overflow_p, jump_target);
case BIND_EXPR:
- return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t),
- lval,
- non_constant_p, overflow_p,
- jump_target);
+ r = cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t),
+ lval,
+ non_constant_p, overflow_p,
+ jump_target);
+ for (tree decl = BIND_EXPR_VARS (t); decl; decl = DECL_CHAIN (decl))
+ ctx->global->remove_value (decl);
+ return r;
case PREINCREMENT_EXPR:
case POSTINCREMENT_EXPR:
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime1.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime1.C
new file mode 100644
index 00000000000..43aa7c974c1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime1.C
@@ -0,0 +1,13 @@
+// PR c++/96630
+// { dg-do compile { target c++14 } }
+
+struct S {
+ int x = 0;
+ constexpr const int& get() const { return x; }
+};
+
+constexpr const int& test() {
+ auto local = S{}; // { dg-message "note: declared here" }
+ return local.get();
+}
+constexpr int x = test(); // { dg-error "accessing object outside its lifetime" }
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime2.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime2.C
new file mode 100644
index 00000000000..2f5ae8db6d5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime2.C
@@ -0,0 +1,20 @@
+// PR c++/98675
+// { dg-do compile { target c++14 } }
+
+struct S {
+ int x = 0;
+ constexpr const int& get() const { return x; }
+};
+
+constexpr int error() {
+ const auto& local = S{}.get(); // { dg-message "note: declared here" }
+ return local; // { dg-error "accessing object outside its lifetime" }
+}
+constexpr int x = error(); // { dg-message "in .constexpr. expansion" }
+
+constexpr int ok() {
+ // temporary should only be destroyed after end of full-expression
+ auto local = S{}.get();
+ return local;
+}
+constexpr int y = ok();
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime3.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime3.C
new file mode 100644
index 00000000000..53785521d05
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime3.C
@@ -0,0 +1,13 @@
+// PR c++/70331
+// { dg-do compile { target c++14 } }
+
+constexpr int f(int i) {
+ int *p = &i;
+ if (i == 0) {
+ int j = 123; // { dg-message "note: declared here" }
+ p = &j;
+ }
+ return *p; // { dg-error "accessing object outside its lifetime" }
+}
+
+constexpr int i = f(0); // { dg-message "in .constexpr. expansion" }
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime4.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime4.C
new file mode 100644
index 00000000000..181a1201663
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime4.C
@@ -0,0 +1,11 @@
+// { dg-do compile { target c++14 } }
+
+constexpr const double& test() {
+ const double& local = 3.0; // { dg-message "note: declared here" }
+ return local;
+}
+
+static_assert(test() == 3.0, ""); // { dg-error "constant|accessing object outside its lifetime" }
+
+// no deference, shouldn't error
+static_assert((test(), true), "");
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime5.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime5.C
new file mode 100644
index 00000000000..e7e01fe99a7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime5.C
@@ -0,0 +1,11 @@
+// { dg-do compile { target c++14 } }
+// { dg-options "-Wno-return-local-addr" }
+
+constexpr const int& id(int x) { return x; }
+
+constexpr bool test() {
+ const int& y = id(3);
+ return y == 3; // { dg-error "outside its lifetime" }
+}
+
+constexpr bool x = test(); // { dg-message "in .constexpr. expansion" }
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime6.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime6.C
new file mode 100644
index 00000000000..45c11e8384e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime6.C
@@ -0,0 +1,15 @@
+// { dg-do compile { target c++14 } }
+// { dg-options "-Wno-return-local-addr" }
+
+struct Empty {};
+
+constexpr const Empty& empty() {
+ return Empty{}; // { dg-message "note: declared here" }
+}
+
+constexpr const Empty& empty_parm(Empty e) { // { dg-message "note: declared here" }
+ return e;
+}
+
+constexpr Empty a = empty(); // { dg-error "outside its lifetime" }
+constexpr Empty b = empty_parm({}); // { dg-error "outside its lifetime" }
--
2.41.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v5 0/3] c++: Track lifetimes in constant evaluation [PR70331, ...]
2023-07-22 15:12 [PATCH v5 0/3] c++: Track lifetimes in constant evaluation [PR70331, ...] Nathaniel Shead
` (2 preceding siblings ...)
2023-07-22 15:15 ` [PATCH v5 3/3] c++: Track lifetimes in constant evaluation [PR70331,PR96630,PR98675] Nathaniel Shead
@ 2023-07-26 1:53 ` Jason Merrill
3 siblings, 0 replies; 5+ messages in thread
From: Jason Merrill @ 2023-07-26 1:53 UTC (permalink / raw)
To: Nathaniel Shead, gcc-patches; +Cc: Patrick Palka
On 7/22/23 11:12, Nathaniel Shead wrote:
> This is an update of the patch series at
> https://gcc.gnu.org/pipermail/gcc-patches/2023-July/625050.html
I applied the patches, with an addition to the first patch to fix
constexpr-mutable3.C in C++11 mode, which was not part of the default
std set. And fixed the testsuite to run that test (and others that test
c++11_only behavior) in C++11 mode. Thanks!
FWIW, I test C++ patches with GXX_TESTSUITE_STDS=98,11,14,17,20,impcx
for more coverage.
> Changes since v4:
>
> - Reordered patches to be more independent from each other (they don't need
> to keep updating the new tests)
> - Removed workaround for better locations in cxx_eval_store_expression
> - Don't bother checking lifetime for CONST_DECLs
> - Rewrite patch for dangling pointers to keep the transformation to
> `return (&x, nullptr)`, but only perform it when genericising. It turns out
> that implementing this wasn't as hard as I thought it might be, at least for
> this specific case.
>
> Thanks very much for all the reviews and comments so far!
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu.
>
> Nathaniel Shead (3):
> c++: Improve location information in constant evaluation
> c++: Prevent dangling pointers from becoming nullptr in constexpr
> [PR110619]
> c++: Track lifetimes in constant evaluation [PR70331,PR96630,PR98675]
>
> gcc/cp/constexpr.cc | 159 +++++++++++++-----
> gcc/cp/cp-gimplify.cc | 23 ++-
> gcc/cp/cp-tree.h | 8 +-
> gcc/cp/semantics.cc | 4 +-
> gcc/cp/typeck.cc | 9 +-
> gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C | 10 +-
> gcc/testsuite/g++.dg/cpp0x/constexpr-70323.C | 8 +-
> gcc/testsuite/g++.dg/cpp0x/constexpr-70323a.C | 8 +-
> .../g++.dg/cpp0x/constexpr-delete2.C | 5 +-
> gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C | 2 +-
> gcc/testsuite/g++.dg/cpp0x/constexpr-ice20.C | 1 +
> .../g++.dg/cpp0x/constexpr-recursion.C | 6 +-
> gcc/testsuite/g++.dg/cpp0x/overflow1.C | 2 +-
> gcc/testsuite/g++.dg/cpp1y/constexpr-110619.C | 10 ++
> gcc/testsuite/g++.dg/cpp1y/constexpr-89285.C | 5 +-
> gcc/testsuite/g++.dg/cpp1y/constexpr-89481.C | 3 +-
> .../g++.dg/cpp1y/constexpr-lifetime1.C | 13 ++
> .../g++.dg/cpp1y/constexpr-lifetime2.C | 20 +++
> .../g++.dg/cpp1y/constexpr-lifetime3.C | 13 ++
> .../g++.dg/cpp1y/constexpr-lifetime4.C | 11 ++
> .../g++.dg/cpp1y/constexpr-lifetime5.C | 11 ++
> .../g++.dg/cpp1y/constexpr-lifetime6.C | 15 ++
> .../g++.dg/cpp1y/constexpr-tracking-const14.C | 3 +-
> .../g++.dg/cpp1y/constexpr-tracking-const16.C | 3 +-
> .../g++.dg/cpp1y/constexpr-tracking-const18.C | 4 +-
> .../g++.dg/cpp1y/constexpr-tracking-const19.C | 4 +-
> .../g++.dg/cpp1y/constexpr-tracking-const21.C | 4 +-
> .../g++.dg/cpp1y/constexpr-tracking-const22.C | 4 +-
> .../g++.dg/cpp1y/constexpr-tracking-const3.C | 3 +-
> .../g++.dg/cpp1y/constexpr-tracking-const4.C | 3 +-
> .../g++.dg/cpp1y/constexpr-tracking-const7.C | 3 +-
> gcc/testsuite/g++.dg/cpp1y/constexpr-union5.C | 4 +-
> gcc/testsuite/g++.dg/cpp1y/pr68180.C | 4 +-
> .../g++.dg/cpp1z/constexpr-lambda6.C | 4 +-
> .../g++.dg/cpp1z/constexpr-lambda8.C | 5 +-
> gcc/testsuite/g++.dg/cpp2a/bit-cast11.C | 10 +-
> gcc/testsuite/g++.dg/cpp2a/bit-cast12.C | 10 +-
> gcc/testsuite/g++.dg/cpp2a/bit-cast14.C | 14 +-
> gcc/testsuite/g++.dg/cpp2a/constexpr-98122.C | 4 +-
> .../g++.dg/cpp2a/constexpr-dynamic17.C | 5 +-
> gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C | 5 +-
> gcc/testsuite/g++.dg/cpp2a/constexpr-new12.C | 6 +-
> gcc/testsuite/g++.dg/cpp2a/constexpr-new3.C | 10 +-
> gcc/testsuite/g++.dg/cpp2a/constinit10.C | 5 +-
> .../g++.dg/cpp2a/is-corresponding-member4.C | 4 +-
> gcc/testsuite/g++.dg/ext/constexpr-vla2.C | 4 +-
> gcc/testsuite/g++.dg/ext/constexpr-vla3.C | 4 +-
> gcc/testsuite/g++.dg/ubsan/pr63956.C | 23 +--
> .../25_algorithms/equal/constexpr_neg.cc | 7 +-
> .../testsuite/26_numerics/gcd/105844.cc | 10 +-
> .../testsuite/26_numerics/lcm/105844.cc | 14 +-
> 51 files changed, 361 insertions(+), 168 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-110619.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime1.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime2.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime3.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime4.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime5.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-lifetime6.C
>
^ permalink raw reply [flat|nested] 5+ messages in thread
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Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2023-07-22 15:12 [PATCH v5 0/3] c++: Track lifetimes in constant evaluation [PR70331, ...] Nathaniel Shead
2023-07-22 15:13 ` [PATCH v5 1/3] c++: Improve location information in constant evaluation Nathaniel Shead
2023-07-22 15:14 ` [PATCH v5 2/3] c++: Prevent dangling pointers from becoming nullptr in constexpr [PR110619] Nathaniel Shead
2023-07-22 15:15 ` [PATCH v5 3/3] c++: Track lifetimes in constant evaluation [PR70331,PR96630,PR98675] Nathaniel Shead
2023-07-26 1:53 ` [PATCH v5 0/3] c++: Track lifetimes in constant evaluation [PR70331, ...] Jason Merrill
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