[clang] Use separator for large numeric values in overflow diagnostic…

… (#80939)

Add functionality to APInt::toString() that allows it to insert
separators between groups of digits, using the C++ literal
separator ' between groups.

Fixes issue #58228

Reviewers:  @AaronBallman, @cjdb, @tbaederr

clang/docs/ReleaseNotes.rst

@@ -177,6 +177,9 @@ Improvements to Clang's diagnostics
 - The ``-Wshorten-64-to-32`` diagnostic is now grouped under ``-Wimplicit-int-conversion`` instead
    of ``-Wconversion``. Fixes #GH69444.
 
+- Clang now uses thousand separators when printing large numbers in integer overflow diagnostics.
+  Fixes #GH80939.
+
 - Clang now diagnoses friend declarations with an ``enum`` elaborated-type-specifier in language modes after C++98.
 
 - Added diagnostics for C11 keywords being incompatible with language standards

clang/lib/AST/ExprConstant.cpp

@@ -2778,7 +2778,9 @@ static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
     if (Info.checkingForUndefinedBehavior())
       Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
                                        diag::warn_integer_constant_overflow)
-          << toString(Result, 10) << E->getType() << E->getSourceRange();
+          << toString(Result, 10, Result.isSigned(), /*formatAsCLiteral=*/false,
+                      /*UpperCase=*/true, /*InsertSeparators=*/true)
+          << E->getType() << E->getSourceRange();
     return HandleOverflow(Info, E, Value, E->getType());
   }
   return true;
@@ -13910,7 +13912,9 @@ bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
       if (Info.checkingForUndefinedBehavior())
         Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
                                          diag::warn_integer_constant_overflow)
-            << toString(Value, 10) << E->getType() << E->getSourceRange();
+            << toString(Value, 10, Value.isSigned(), /*formatAsCLiteral=*/false,
+                        /*UpperCase=*/true, /*InsertSeparators=*/true)
+            << E->getType() << E->getSourceRange();
 
       if (!HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1),
                           E->getType()))

clang/lib/AST/Interp/Interp.h

@@ -287,7 +287,9 @@ bool AddSubMulHelper(InterpState &S, CodePtr OpPC, unsigned Bits, const T &LHS,
   QualType Type = E->getType();
   if (S.checkingForUndefinedBehavior()) {
     SmallString<32> Trunc;
-    Value.trunc(Result.bitWidth()).toString(Trunc, 10);
+    Value.trunc(Result.bitWidth())
+        .toString(Trunc, 10, Result.isSigned(), /*formatAsCLiteral=*/false,
+                  /*UpperCase=*/true, /*InsertSeparators=*/true);
     auto Loc = E->getExprLoc();
     S.report(Loc, diag::warn_integer_constant_overflow)
         << Trunc << Type << E->getSourceRange();
@@ -499,7 +501,9 @@ bool Neg(InterpState &S, CodePtr OpPC) {
 
   if (S.checkingForUndefinedBehavior()) {
     SmallString<32> Trunc;
-    NegatedValue.trunc(Result.bitWidth()).toString(Trunc, 10);
+    NegatedValue.trunc(Result.bitWidth())
+        .toString(Trunc, 10, Result.isSigned(), /*formatAsCLiteral=*/false,
+                  /*UpperCase=*/true, /*InsertSeparators=*/true);
     auto Loc = E->getExprLoc();
     S.report(Loc, diag::warn_integer_constant_overflow)
         << Trunc << Type << E->getSourceRange();
@@ -561,7 +565,9 @@ bool IncDecHelper(InterpState &S, CodePtr OpPC, const Pointer &Ptr) {
   QualType Type = E->getType();
   if (S.checkingForUndefinedBehavior()) {
     SmallString<32> Trunc;
-    APResult.trunc(Result.bitWidth()).toString(Trunc, 10);
+    APResult.trunc(Result.bitWidth())
+        .toString(Trunc, 10, Result.isSigned(), /*formatAsCLiteral=*/false,
+                  /*UpperCase=*/true, /*InsertSeparators=*/true);
     auto Loc = E->getExprLoc();
     S.report(Loc, diag::warn_integer_constant_overflow)
         << Trunc << Type << E->getSourceRange();

clang/test/AST/Interp/c.c

@@ -95,7 +95,7 @@ int chooseexpr[__builtin_choose_expr(1, 1, expr)];
 
 int somefunc(int i) {
   return (i, 65537) * 65537; // all-warning {{left operand of comma operator has no effect}} \
-                             // all-warning {{overflow in expression; result is 131073}}
+                             // all-warning {{overflow in expression; result is 131'073 with type 'int'}}
 }
 
 /// FIXME: The following test is incorrect in the new interpreter.

clang/test/C/drs/dr0xx.c

@@ -214,7 +214,7 @@ _Static_assert(__builtin_types_compatible_p(struct S { int a; }, union U { int a
  */
 void dr031(int i) {
   switch (i) {
-  case __INT_MAX__ + 1: break; /* expected-warning {{overflow in expression; result is -2147483648 with type 'int'}} */
+  case __INT_MAX__ + 1: break; /* expected-warning {{overflow in expression; result is -2'147'483'648 with type 'int'}} */
   #pragma clang diagnostic push
   #pragma clang diagnostic ignored "-Wswitch"
   /* Silence the targets which issue:

clang/test/C/drs/dr2xx.c

@@ -277,7 +277,7 @@ void dr258(void) {
 void dr261(void) {
   /* This is still an integer constant expression despite the overflow. */
   enum e1 {
-    ex1 = __INT_MAX__ + 1  /* expected-warning {{overflow in expression; result is -2147483648 with type 'int'}} */
+    ex1 = __INT_MAX__ + 1  /* expected-warning {{overflow in expression; result is -2'147'483'648 with type 'int'}} */
   };
 
   /* This is not an integer constant expression, because of the comma operator,

clang/test/Sema/integer-overflow.c

@@ -11,169 +11,169 @@ uint64_t f0(uint64_t);
 uint64_t f1(uint64_t, uint32_t);
 uint64_t f2(uint64_t, ...);
 
-static const uint64_t overflow = 1 * 4608 * 1024 * 1024; // expected-warning {{overflow in expression; result is 536870912 with type 'int'}}
+static const uint64_t overflow = 1 * 4608 * 1024 * 1024; // expected-warning {{overflow in expression; result is 536'870'912 with type 'int'}}
 
 uint64_t check_integer_overflows(int i) {
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   uint64_t overflow = 4608 * 1024 * 1024,
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
            overflow2 = (uint64_t)(4608 * 1024 * 1024),
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
            overflow3 = (uint64_t)(4608 * 1024 * 1024 * i),
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
            overflow4 =  (1ULL * ((4608) * ((1024) * (1024))) + 2ULL),
-// expected-warning@+1 2{{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 2{{overflow in expression; result is 536'870'912 with type 'int'}}
            multi_overflow = (uint64_t)((uint64_t)(4608 * 1024 * 1024) * (uint64_t)(4608 * 1024 * 1024));
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   overflow += overflow2 = overflow3 = (uint64_t)(4608 * 1024 * 1024);
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   overflow += overflow2 = overflow3 = 4608 * 1024 * 1024;
 
   uint64_t not_overflow = 4608 * 1024 * 1024ULL;
   uint64_t not_overflow2 = (1ULL * ((uint64_t)(4608) * (1024 * 1024)) + 2ULL);
 
-// expected-warning@+1 2{{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 2{{overflow in expression; result is 536'870'912 with type 'int'}}
   overflow = 4608 * 1024 * 1024 ?  4608 * 1024 * 1024 : 0;
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   overflow =  0 ? 0 : 4608 * 1024 * 1024;
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   if (4608 * 1024 * 1024)
     return 0;
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   if ((uint64_t)(4608 * 1024 * 1024))
     return 1;
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   if ((uint64_t)(4608 * 1024 * 1024))
     return 2;
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   if ((uint64_t)(4608 * 1024 * 1024 * i))
     return 3;
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   if ((1ULL * ((4608) * ((1024) * (1024))) + 2ULL))
     return 4;
 
-// expected-warning@+1 2{{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 2{{overflow in expression; result is 536'870'912 with type 'int'}}
   if ((uint64_t)((uint64_t)(4608 * 1024 * 1024) * (uint64_t)(4608 * 1024 * 1024)))
     return 5;
 
   switch (i) {
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   case 4608 * 1024 * 1024:
     return 6;
-// expected-warning@+1 {{overflow in expression; result is 537919488 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 537'919'488 with type 'int'}}
   case (uint64_t)(4609 * 1024 * 1024):
     return 7;
 // expected-error@+1 {{expression is not an integer constant expression}}
   case ((uint64_t)(4608 * 1024 * 1024 * i)):
     return 8;
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   case ((1ULL * ((4608) * ((1024) * (1024))) + 2ULL)):
     return 9;
-// expected-warning@+2 2{{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+2 2{{overflow in expression; result is 536'870'912 with type 'int'}}
 // expected-warning@+1 {{overflow converting case value to switch condition type (288230376151711744 to 0)}}
   case ((uint64_t)((uint64_t)(4608 * 1024 * 1024) * (uint64_t)(4608 * 1024 * 1024))):
     return 10;
   }
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   while (4608 * 1024 * 1024);
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   while ((uint64_t)(4608 * 1024 * 1024));
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   while ((uint64_t)(4608 * 1024 * 1024));
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   while ((uint64_t)(4608 * 1024 * 1024 * i));
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   while ((1ULL * ((4608) * ((1024) * (1024))) + 2ULL));
 
-// expected-warning@+1 2{{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 2{{overflow in expression; result is 536'870'912 with type 'int'}}
   while ((uint64_t)((uint64_t)(4608 * 1024 * 1024) * (uint64_t)(4608 * 1024 * 1024)));
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   do { } while (4608 * 1024 * 1024);
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   do { } while ((uint64_t)(4608 * 1024 * 1024));
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   do { } while ((uint64_t)(4608 * 1024 * 1024));
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   do { } while ((uint64_t)(4608 * 1024 * 1024 * i));
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   do { } while ((1ULL * ((4608) * ((1024) * (1024))) + 2ULL));
 
-// expected-warning@+1 2{{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 2{{overflow in expression; result is 536'870'912 with type 'int'}}
   do { } while ((uint64_t)((uint64_t)(4608 * 1024 * 1024) * (uint64_t)(4608 * 1024 * 1024)));
 
-// expected-warning@+3 {{overflow in expression; result is 536870912 with type 'int'}}
-// expected-warning@+3 {{overflow in expression; result is 536870912 with type 'int'}}
-// expected-warning@+3 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+3 {{overflow in expression; result is 536'870'912 with type 'int'}}
+// expected-warning@+3 {{overflow in expression; result is 536'870'912 with type 'int'}}
+// expected-warning@+3 {{overflow in expression; result is 536'870'912 with type 'int'}}
   for (uint64_t i = 4608 * 1024 * 1024;
        (uint64_t)(4608 * 1024 * 1024);
        i += (uint64_t)(4608 * 1024 * 1024 * i));
 
-// expected-warning@+3 {{overflow in expression; result is 536870912 with type 'int'}}
-// expected-warning@+3 2{{overflow in expression; result is 536870912 with type 'int'}}
-// expected-warning@+3 2{{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+3 {{overflow in expression; result is 536'870'912 with type 'int'}}
+// expected-warning@+3 2{{overflow in expression; result is 536'870'912 with type 'int'}}
+// expected-warning@+3 2{{overflow in expression; result is 536'870'912 with type 'int'}}
   for (uint64_t i = (1ULL * ((4608) * ((1024) * (1024))) + 2ULL);
        ((uint64_t)((uint64_t)(4608 * 1024 * 1024) * (uint64_t)(4608 * 1024 * 1024)));
        i = ((4608 * 1024 * 1024) + ((uint64_t)(4608 * 1024 * 1024))));
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   _Complex long long x = 4608 * 1024 * 1024;
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   (__real__ x) = 4608 * 1024 * 1024;
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   (__imag__ x) = 4608 * 1024 * 1024;
 
-// expected-warning@+4 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+4 {{overflow in expression; result is 536'870'912 with type 'int'}}
 // expected-warning@+3 {{array index 536870912 is past the end of the array (that has type 'uint64_t[10]' (aka 'unsigned long long[10]'))}}
 // expected-note@+1 {{array 'a' declared here}}
   uint64_t a[10];
   a[4608 * 1024 * 1024] = 1i;
 
-// expected-warning@+2 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+2 {{overflow in expression; result is 536'870'912 with type 'int'}}
   uint64_t *b;
   uint64_t b2 = b[4608 * 1024 * 1024] + 1;
 
-// expected-warning@+1 2{{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 2{{overflow in expression; result is 536'870'912 with type 'int'}}
   (void)((i ? (4608 * 1024 * 1024) : (4608 * 1024 * 1024)) + 1);
 
-// expected-warning@+1 2{{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 2{{overflow in expression; result is 536'870'912 with type 'int'}}
   return ((4608 * 1024 * 1024) + ((uint64_t)(4608 * 1024 * 1024)));
 }
 
 void check_integer_overflows_in_function_calls(void) {
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   (void)f0(4608 * 1024 * 1024);
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   uint64_t x = f0(4608 * 1024 * 1024);
 
-// expected-warning@+2 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+2 {{overflow in expression; result is 536'870'912 with type 'int'}}
   uint64_t (*f0_ptr)(uint64_t) = &f0;
   (void)(*f0_ptr)(4608 * 1024 * 1024);
 
-// expected-warning@+1 {{overflow in expression; result is 536870912 with type 'int'}}
+// expected-warning@+1 {{overflow in expression; result is 536'870'912 with type 'int'}}
   (void)f2(0, f0(4608 * 1024 * 1024));
 }
 void check_integer_overflows_in_array_size(void) {
-  int arr[4608 * 1024 * 1024]; // expected-warning {{overflow in expression; result is 536870912 with type 'int'}}
+  int arr[4608 * 1024 * 1024]; // expected-warning {{overflow in expression; result is 536'870'912 with type 'int'}}
 }
 
 struct s {

clang/test/Sema/switch-1.c

@@ -7,7 +7,7 @@ int f(int i) {
   switch (i) {
     case 2147483647 + 2:
 #if (__cplusplus <= 199711L) // C or C++03 or earlier modes
-    // expected-warning@-2 {{overflow in expression; result is -2147483647 with type 'int'}}
+    // expected-warning@-2 {{overflow in expression; result is -2'147'483'647 with type 'int'}}
 #else
     // expected-error@-4 {{case value is not a constant expression}} \
     // expected-note@-4 {{value 2147483649 is outside the range of representable values of type 'int'}}
@@ -23,7 +23,7 @@ int f(int i) {
       return 2;
     case (123456 *789012) + 1:
 #if (__cplusplus <= 199711L)
-    // expected-warning@-2 {{overflow in expression; result is -1375982336 with type 'int'}}
+    // expected-warning@-2 {{overflow in expression; result is -1'375'982'336 with type 'int'}}
 #else
     // expected-error@-4 {{case value is not a constant expression}} \
     // expected-note@-4 {{value 97408265472 is outside the range of representable values of type 'int'}}
@@ -47,7 +47,7 @@ int f(int i) {
     case 2147483647:
       return 0;
   }
-  return (i, 65537) * 65537; // expected-warning {{overflow in expression; result is 131073 with type 'int'}} \
+  return (i, 65537) * 65537; // expected-warning {{overflow in expression; result is 131'073 with type 'int'}} \
 			     // expected-warning {{left operand of comma operator has no effect}}
 }
 

clang/test/SemaCXX/enum.cpp

@@ -103,7 +103,7 @@ enum { overflow = 123456 * 234567 };
 // expected-warning@-2 {{not an integral constant expression}}
 // expected-note@-3 {{value 28958703552 is outside the range of representable values}}
 #else 
-// expected-warning@-5 {{overflow in expression; result is -1106067520 with type 'int'}}
+// expected-warning@-5 {{overflow in expression; result is -1'106'067'520 with type 'int'}}
 #endif
 
 // FIXME: This is not consistent with the above case.
@@ -112,7 +112,7 @@ enum NoFold : int { overflow2 = 123456 * 234567 };
 // expected-error@-2 {{enumerator value is not a constant expression}}
 // expected-note@-3 {{value 28958703552 is outside the range of representable values}}
 #else
-// expected-warning@-5 {{overflow in expression; result is -1106067520 with type 'int'}}
+// expected-warning@-5 {{overflow in expression; result is -1'106'067'520 with type 'int'}}
 // expected-warning@-6 {{extension}}
 #endif