https://github.com/Sirraide created
https://github.com/llvm/llvm-project/pull/89420
This addresses two problems observed in #89407 wrt user-defined `static_assert`
messages:
1. In `Expr::EvaluateCharRangeAsString`, we were calling `getExtValue()`
instead of `getZExtValue()`, which would assert if a negative or very large
number was returned from `size()`.
2. If the value could not be converted to `std::size_t`, attempting to diagnose
that would crash because `ext_cce_narrowing` was missing two `%select` cases.
This fixes #89407.
>From a64b08503ae9f49d8b58ee92c226ba19c450ca27 Mon Sep 17 00:00:00 2001
From: Sirraide <aeternalm...@gmail.com>
Date: Fri, 19 Apr 2024 19:13:26 +0200
Subject: [PATCH] [Clang] Fix crash on invalid size in static_assert message
---
.../clang/Basic/DiagnosticSemaKinds.td | 6 +-
clang/lib/AST/ExprConstant.cpp | 4 +-
clang/test/SemaCXX/static-assert-cxx26.cpp | 74 +++++++++++++++++++
3 files changed, 79 insertions(+), 5 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 5ec0218aedfe86..85c0cf93ee732f 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -87,9 +87,9 @@ def err_expr_not_cce : Error<
"call to 'size()'|call to 'data()'}0 is not a constant expression">;
def ext_cce_narrowing : ExtWarn<
"%select{case value|enumerator value|non-type template argument|"
- "array size|explicit specifier argument|noexcept specifier argument}0 "
- "%select{cannot be narrowed from type %2 to %3|"
- "evaluates to %2, which cannot be narrowed to type %3}1">,
+ "array size|explicit specifier argument|noexcept specifier argument|"
+ "call to 'size()'|call to 'data()'}0 %select{cannot be narrowed from "
+ "type %2 to %3|evaluates to %2, which cannot be narrowed to type %3}1">,
InGroup<CXX11Narrowing>, DefaultError, SFINAEFailure;
def err_ice_not_integral : Error<
"%select{integer|integral}1 constant expression must have "
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 88c8eaf6ef9b6e..e1f060f77ccd9d 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -16853,13 +16853,13 @@ bool Expr::EvaluateCharRangeAsString(std::string
&Result,
if (!::EvaluateInteger(SizeExpression, SizeValue, Info))
return false;
- int64_t Size = SizeValue.getExtValue();
+ uint64_t Size = SizeValue.getZExtValue();
if (!::EvaluatePointer(PtrExpression, String, Info))
return false;
QualType CharTy = PtrExpression->getType()->getPointeeType();
- for (int64_t I = 0; I < Size; ++I) {
+ for (uint64_t I = 0; I < Size; ++I) {
APValue Char;
if (!handleLValueToRValueConversion(Info, PtrExpression, CharTy, String,
Char))
diff --git a/clang/test/SemaCXX/static-assert-cxx26.cpp
b/clang/test/SemaCXX/static-assert-cxx26.cpp
index f4ede74f9214a4..7d896d8b365b74 100644
--- a/clang/test/SemaCXX/static-assert-cxx26.cpp
+++ b/clang/test/SemaCXX/static-assert-cxx26.cpp
@@ -341,3 +341,77 @@ struct Callable {
} data;
};
static_assert(false, Callable{}); // expected-error {{static assertion failed:
hello}}
+
+namespace GH89407 {
+struct A {
+ constexpr __SIZE_TYPE__ size() const { return -1; }
+ constexpr const char* data() const { return ""; }
+};
+
+struct B {
+ constexpr long long size() const { return 18446744073709551615U; }
+ constexpr const char* data() const { return ""; }
+};
+
+struct C {
+ constexpr __int128 size() const { return -1; }
+ constexpr const char* data() const { return ""; }
+};
+
+struct D {
+ constexpr unsigned __int128 size() const { return -1; }
+ constexpr const char* data() const { return ""; }
+};
+
+struct E {
+ constexpr __SIZE_TYPE__ size() const { return 18446744073709551615U; }
+ constexpr const char* data() const { return ""; }
+};
+
+static_assert(true, A{}); // expected-error {{the message in this static
assertion is not a constant expression}}
+ // expected-note@-1 {{read of dereferenced
one-past-the-end pointer is not allowed in a constant expression}}
+static_assert(true, B{}); // expected-error {{call to 'size()' evaluates to
-1, which cannot be narrowed to type 'unsigned long'}}
+ // expected-error@-1 {{the message in this static
assertion is not a constant expression}}
+ // expected-note@-2 {{read of dereferenced
one-past-the-end pointer is not allowed in a constant expression}}
+static_assert(true, C{}); // expected-error {{call to 'size()' evaluates to
-1, which cannot be narrowed to type 'unsigned long'}}
+ // expected-error@-1 {{the message in this static
assertion is not a constant expression}}
+ // expected-note@-2 {{read of dereferenced
one-past-the-end pointer is not allowed in a constant expression}}
+static_assert(true, D{}); // expected-error {{call to 'size()' evaluates to
340282366920938463463374607431768211455, which cannot be narrowed to type
'unsigned long'}}
+ // expected-error@-1 {{the message in this static
assertion is not a constant expression}}
+ // expected-note@-2 {{read of dereferenced
one-past-the-end pointer is not allowed in a constant expression}}
+static_assert(true, E{}); // expected-error {{the message in this static
assertion is not a constant expression}}
+ // expected-note@-1 {{read of dereferenced
one-past-the-end pointer is not allowed in a constant expression}}
+
+static_assert(
+ false, // expected-error {{static assertion failed}}
+ A{} // expected-error {{the message in a static assertion must be produced
by a constant expression}}
+ // expected-note@-1 {{read of dereferenced one-past-the-end pointer is
not allowed in a constant expression}}
+);
+
+static_assert(
+ false, // expected-error {{static assertion failed}}
+ B{} // expected-error {{call to 'size()' evaluates to -1, which cannot be
narrowed to type 'unsigned long'}}
+ // expected-error@-1 {{the message in a static assertion must be
produced by a constant expression}}
+ // expected-note@-2 {{read of dereferenced one-past-the-end pointer is
not allowed in a constant expression}}
+);
+
+static_assert(
+ false, // expected-error {{static assertion failed}}
+ C{} // expected-error {{call to 'size()' evaluates to -1, which cannot be
narrowed to type 'unsigned long'}}
+ // expected-error@-1 {{the message in a static assertion must be
produced by a constant expression}}
+ // expected-note@-2 {{read of dereferenced one-past-the-end pointer is
not allowed in a constant expression}}
+);
+
+static_assert(
+ false, // expected-error {{static assertion failed}}
+ D{} // expected-error {{call to 'size()' evaluates to
340282366920938463463374607431768211455, which cannot be narrowed to type
'unsigned long'}}
+ // expected-error@-1 {{the message in a static assertion must be
produced by a constant expression}}
+ // expected-note@-2 {{read of dereferenced one-past-the-end pointer is
not allowed in a constant expression}}
+);
+
+static_assert(
+ false, // expected-error {{static assertion failed}}
+ E{} // expected-error {{the message in a static assertion must be produced
by a constant expression}}
+ // expected-note@-1 {{read of dereferenced one-past-the-end pointer is
not allowed in a constant expression}}
+);
+}
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