C23 keywords by kroening · Pull Request #8623 · diffblue/cbmc

kroening · 2025-04-09T17:16:31Z

This adds scanner, parser and typechecker support for the new C23 keywords.

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tautschnig · 2025-04-09T17:37:41Z

Asking here so as not to delay #8621 any further:

In loc(); return conditional_keyword(...); the use of loc(); is unnecessary, we should clean that up.
In make_identifier and also MSC_cpp_keyword we have if(PARSER.cpp98 ... - which seems insufficient as it would not cover the case of PARSER.cpp11 being set instead.

tautschnig · 2025-04-09T17:41:24Z

Also, while working on this piece of code we might fix #8308?

kroening · 2025-04-09T18:09:38Z

Also, while working on this piece of code we might fix #8308?

#8624

kroening · 2025-04-09T18:12:28Z

In loc(); return conditional_keyword(...); the use of loc(); is unnecessary, we should clean that up.

Yes, some tokens come with an IREP and some don't -- and it's prone to error to keep that in sync. I am minded to give an IREP to all identifier-like tokens to remove that ambiguity.

In make_identifier and also MSC_cpp_keyword we have if(PARSER.cpp98 ... - which seems insufficient as it would not cover the case of PARSER.cpp11 being set instead.

For clarity, could be renamed to cpp98_or_above, but more verbose, or could write cpp98 || cpp11 || ....

tautschnig · 2025-04-09T18:35:35Z

In loc(); return conditional_keyword(...); the use of loc(); is unnecessary, we should clean that up.

Yes, some tokens come with an IREP and some don't -- and it's prone to error to keep that in sync. I am minded to give an IREP to all identifier-like tokens to remove that ambiguity.

Yes, but not what I was after: conditional_keyword invokes loc() on the if branch, or else make_identifier, which in turn invokes loc() right away. So doing loc(); return conditional_keyword(...) makes that first loc(); call redundant.

kroening · 2025-04-09T21:13:57Z

Yes, but not what I was after: conditional_keyword invokes loc() on the if branch, or else make_identifier, which in turn invokes loc() right away. So doing loc(); return conditional_keyword(...) makes that first loc(); call redundant.

#8626

codecov · 2025-04-09T23:09:49Z

Codecov Report

Attention: Patch coverage is 78.06452% with 34 lines in your changes missing coverage. Please review.

Project coverage is 80.37%. Comparing base (0b000a3) to head (b1808c3).
Report is 2 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/ansi-c/expr2c.cpp	40.00%	12 Missing ⚠️
src/ansi-c/scanner.l	70.83%	7 Missing ⚠️
src/ansi-c/c_typecheck_type.cpp	78.57%	6 Missing ⚠️
src/ansi-c/parser.y	76.92%	6 Missing ⚠️
src/ansi-c/gcc_version.cpp	50.00%	2 Missing ⚠️
src/util/config.cpp	75.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #8623      +/-   ##
===========================================
- Coverage    80.38%   80.37%   -0.02%     
===========================================
  Files         1686     1686              
  Lines       206764   206872     +108     
  Branches        75       73       -2     
===========================================
+ Hits        166207   166268      +61     
- Misses       40557    40604      +47

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tautschnig · 2025-04-10T10:46:25Z

+// C23 introduces the "static_assert" keyword.
+
+struct S
+{
+  // Visual Studio does not support static_assert in compound bodies.
+#ifndef _MSC_VER
+  static_assert(1, "in struct");
+#endif
+  int x;
+} asd;
+
+static_assert(1, "global scope");
+
+int main()
+{
+  static_assert(1, "in function");
+}


Shouldn't this go in the ansi-c regression test folder instead of cbmc?

Yes, that was my first attempt. But we run various compilers over that folder, and they don't do C23.

tautschnig · 2025-04-10T10:47:03Z

+typedef int INTTYPE;
+
+int func1();
+
+// C23 typeof
+typeof(int) v1;
+typeof(INTTYPE) v2;
+typeof(v2) v3;
+typeof(1 + 1) v4;
+typeof(1 + 1 + func1()) v5;
+const typeof(int) v6;
+typeof(int) const v7;
+static typeof(int) const v8;
+static typeof(int) const *v9;
+static volatile typeof(int) const *v10;
+
+void func2(typeof(int) *some_arg)
+{
+}
+
+int main()
+{
+}


Should probably go in ansi-c?

tautschnig · 2025-04-10T10:51:12Z

+      return integer2string(binary2integer(binary, false));
+    }
+    else
+      return convert_norep(src, precedence);


I think previously this would handle __CPROVER_bitvector in some way?

Those map to signedbv/unsignedv.

This adds scanner, parser and typechecker support for the new C23 keywords.

tautschnig · 2025-04-10T22:17:47Z

    INVARIANT_WITH_DIAGNOSTICS(
      !assertion.is_false(),
-      "static assertion " + id2string(get_string_constant(code.op1())),
+      "static assertion is false",


Hmm, shouldn't we keep the message when there is one?

This should never be executed, and is presumably dead code.

This release adds C17 and C23 support to our C front-end (via diffblue#8620, diffblue#8623). We have no longer provide Ubuntu 20.04 pre-built binaries as security support for that distribution has ended.

kroening added enhancement C Front End labels Apr 9, 2025

kroening requested review from peterschrammel, remi-delmas-3000 and tautschnig as code owners April 9, 2025 17:16

kroening force-pushed the c23-2 branch 2 times, most recently from cbba9f8 to b949d48 Compare April 9, 2025 17:25

kroening force-pushed the c23-2 branch from b949d48 to c8613ad Compare April 9, 2025 18:05

kroening force-pushed the c23-2 branch 2 times, most recently from 67cd3f5 to 1de6619 Compare April 9, 2025 18:27

kroening force-pushed the c23-2 branch 3 times, most recently from 54026f1 to 7c8b661 Compare April 9, 2025 22:20

kroening force-pushed the c23-2 branch 4 times, most recently from ddec5f3 to a556e81 Compare April 10, 2025 01:51

tautschnig reviewed Apr 10, 2025

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Comment thread regression/cbmc/_BitInt/_BitInt1.c Outdated

tautschnig reviewed Apr 10, 2025

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kroening force-pushed the c23-2 branch 4 times, most recently from 45c3fe6 to 5a39bdd Compare April 10, 2025 14:22

kroening requested review from TGWDB and jimgrundy as code owners April 10, 2025 14:22

kroening force-pushed the c23-2 branch 2 times, most recently from 669e233 to 0c3d48c Compare April 10, 2025 14:43

tautschnig reviewed Apr 10, 2025

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Comment thread doc/man/cbmc.1

kroening force-pushed the c23-2 branch 4 times, most recently from 6ee8f9d to d070209 Compare April 10, 2025 18:44

C23 keywords

b1808c3

This adds scanner, parser and typechecker support for the new C23 keywords.

kroening force-pushed the c23-2 branch from d070209 to b1808c3 Compare April 10, 2025 19:32

tautschnig approved these changes Apr 10, 2025

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kroening merged commit 5dc709d into develop Apr 11, 2025
39 of 41 checks passed

kroening deleted the c23-2 branch April 11, 2025 14:24

tautschnig mentioned this pull request Apr 28, 2025

Release CBMC 6.6.0 #8632

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