https://github.com/maramatias updated
https://github.com/llvm/llvm-project/pull/145053
>From f58ea201585cb1b0128f97b9edb07f35621d81b0 Mon Sep 17 00:00:00 2001
From: Mara Matias <mara.mati...@gmail.com>
Date: Wed, 18 Jun 2025 09:06:10 -0700
Subject: [PATCH] [clang] Avoid printing overly large integer/_BitInt numbers
in static assertion failure diagnostics #71675
---
clang/docs/ReleaseNotes.rst | 6 +++++-
clang/lib/Sema/SemaDeclCXX.cpp | 17 ++++++++++++++++-
clang/test/AST/ByteCode/intap.cpp | 8 ++++----
clang/test/Sema/enum.c | 2 +-
clang/test/SemaCXX/static-assert.cpp | 6 ++++++
5 files changed, 32 insertions(+), 7 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index bc8e157e2b1c0..9e48175700613 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -647,7 +647,11 @@ Improvements to Clang's diagnostics
#GH69470, #GH59391, #GH58172, #GH46215, #GH45915, #GH45891, #GH44490,
#GH36703, #GH32903, #GH23312, #GH69874.
-
+- Improved the performance of static assertions envolving large integers by
+ using hex format instead of string.
+
+ Fixes #GH71675
+
Improvements to Clang's time-trace
----------------------------------
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 16645ecf411e5..71bf5f60d6e1b 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -47,6 +47,7 @@
#include "clang/Sema/SemaOpenMP.h"
#include "clang/Sema/Template.h"
#include "clang/Sema/TemplateDeduction.h"
+#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
@@ -17575,7 +17576,21 @@ static bool ConvertAPValueToString(const APValue &V,
QualType T,
break;
}
}
- V.getInt().toString(Str);
+
+ llvm::APSInt vInt = V.getInt();
+ if (llvm::APSInt::compareValues(
+ vInt, llvm::APSInt::getUnsigned(
+ std::numeric_limits<uint64_t>::max())) >= 0 ||
+ vInt < std::numeric_limits<int64_t>::min()) {
+ // The value of cutSize is not special, it is just a number of
+ // characters that gives us enough info without losing readability.
+ const int cutSize = 20;
+ vInt.toString(Str, 16);
+ Str.erase(Str.begin() + cutSize, Str.end() - cutSize);
+ Str.insert(Str.begin() + cutSize, 3, '.');
+ } else {
+ vInt.toString(Str);
+ }
}
break;
diff --git a/clang/test/AST/ByteCode/intap.cpp
b/clang/test/AST/ByteCode/intap.cpp
index 68883871ffd26..1381bba5050a2 100644
--- a/clang/test/AST/ByteCode/intap.cpp
+++ b/clang/test/AST/ByteCode/intap.cpp
@@ -87,12 +87,12 @@ typedef unsigned __int128 uint128_t;
static const __uint128_t UINT128_MAX =__uint128_t(__int128_t(-1L));
static_assert(UINT128_MAX == -1, "");
static_assert(UINT128_MAX == 1, ""); // both-error {{static assertion failed}}
\
- // both-note
{{'340282366920938463463374607431768211455 == 1'}}
+ // both-note
{{'FFFFFFFFFFFFFFFFFFFF...FFFFFFFFFFFFFFFFFFFF == 1'}}
static const __int128_t INT128_MAX = UINT128_MAX >> (__int128_t)1;
static_assert(INT128_MAX != 0, "");
static_assert(INT128_MAX == 0, ""); // both-error {{failed}} \
- // both-note {{evaluates to
'170141183460469231731687303715884105727 == 0'}}
+ // both-note {{evaluates to
'7FFFFFFFFFFFFFFFFFFF...FFFFFFFFFFFFFFFFFFFF == 0'}}
static const __int128_t INT128_MIN = -INT128_MAX - 1;
@@ -113,14 +113,14 @@ namespace i128 {
static const __uint128_t UINT128_MAX =__uint128_t(__int128_t(-1L));
static_assert(UINT128_MAX == -1, "");
static_assert(UINT128_MAX == 1, ""); // both-error {{static assertion
failed}} \
- // both-note
{{'340282366920938463463374607431768211455 == 1'}}
+ // both-note
{{'FFFFFFFFFFFFFFFFFFFF...FFFFFFFFFFFFFFFFFFFF == 1'}}
constexpr uint128_t TooMuch = UINT128_MAX * 2;
static const __int128_t INT128_MAX = UINT128_MAX >> (__int128_t)1;
static_assert(INT128_MAX != 0, "");
static_assert(INT128_MAX == 0, ""); // both-error {{failed}} \
- // both-note {{evaluates to
'170141183460469231731687303715884105727 == 0'}}
+ // both-note {{evaluates to
'7FFFFFFFFFFFFFFFFFFF...FFFFFFFFFFFFFFFFFFFF == 0'}}
constexpr int128_t TooMuch2 = INT128_MAX * INT128_MAX; // both-error {{must
be initialized by a constant expression}} \
// both-note {{value
28948022309329048855892746252171976962977213799489202546401021394546514198529
is outside the range of representable}}
diff --git a/clang/test/Sema/enum.c b/clang/test/Sema/enum.c
index 01e41d4ebe956..80315a0c29b6a 100644
--- a/clang/test/Sema/enum.c
+++ b/clang/test/Sema/enum.c
@@ -196,7 +196,7 @@ enum GH59352 { // expected-warning {{enumeration values
exceed range of largest
BigVal = 66666666666666666666wb
};
_Static_assert(BigVal == 66666666666666666666wb); /* expected-error {{static
assertion failed due to requirement 'BigVal == 66666666666666666666wb'}}
- expected-note
{{expression evaluates to '11326434445538011818 == 66666666666666666666'}}
+ expected-note
{{expression evaluates to '11326434445538011818 ==
39D2F941E420AAAAA<U+0000><U+0000><U+0000>...<U+0000><U+0000><U+0000>39D2F941E420AAAAA'}}
*/
_Static_assert(
_Generic(BigVal, // expected-error {{static
assertion failed}}
diff --git a/clang/test/SemaCXX/static-assert.cpp
b/clang/test/SemaCXX/static-assert.cpp
index bf6a2eeb432a3..4b9d23cb8c808 100644
--- a/clang/test/SemaCXX/static-assert.cpp
+++ b/clang/test/SemaCXX/static-assert.cpp
@@ -255,6 +255,12 @@ int f() {
}
}
+namespace GH71675 {
+constexpr unsigned _BitInt(__BITINT_MAXWIDTH__ >> 6) F = ~0; //
expected-warning {{Clang extension}}
+static_assert(F == 1,""); // expected-error {{static assertion failed due to
requirement 'F == 1'}} \
+ // expected-note {{expression evaluates to
'FFFFFFFFFFFFFFFFFFFF...FFFFFFFFFFFFFFFFFFFF == 1'}}
+} // namespace GH71675
+
namespace Diagnostics {
/// No notes for literals.
static_assert(false, ""); // expected-error {{failed}}
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