Re: [PATCH 1/2] testsuite: Fix analyzer errors for newlib-errno

[Hans-Peter Nilsson <hp@axis.com>]

> From: David Malcolm <dmalcolm@redhat.com>
> Cc: gcc-patches@gcc.gnu.org
> Date: Wed, 01 Mar 2023 08:32:13 -0500

> Also, the analyzer uses region_model::set_errno in various
> known_function implementations, e.g. for functions that can succeed or
> fail, to set errno on the "failure" execution path to a new symbolic
> value that tests as > 0.

Ha, there's indeed errno-analyzing magic. :)

(That's the level you get when your first impression of
source code is by tracing through failing test-cases...)

> > So, how's this instead, pending full testing (only
> > analyzer.exp spot-tested)?
> 
> Looks good, though how about adding a mention of newlib to the comment
> immediately above (the one that talks about Solaris and OS X)?

I deliberately didn't, as the format of that comment seemed
to ask for redundantly repeating the definition for each
system (telling exactly how the #define looks etc.), and I
thought the heading "Other implementations of C standard
library" should have been sufficient, assuming access to the
git log when there's interest in more than the first lines.

But I hear you so this is what I intend to commit later
today, just keeping the added comment as brief as
reasonable:

"analyzer: Support errno for newlib

Without this definition, the errno definition for newlib
isn't recognized as such, and these tests fail for newlib
targets:

FAIL: gcc.dg/analyzer/call-summaries-errno.c  (test for warnings, line 16)
FAIL: gcc.dg/analyzer/call-summaries-errno.c (test for excess errors)
FAIL: gcc.dg/analyzer/errno-1.c  (test for warnings, line 20)
FAIL: gcc.dg/analyzer/errno-1.c (test for excess errors)
FAIL: gcc.dg/analyzer/isatty-1.c  (test for warnings, line 31)
FAIL: gcc.dg/analyzer/isatty-1.c  (test for warnings, line 35)
FAIL: gcc.dg/analyzer/isatty-1.c  (test for warnings, line 46)
FAIL: gcc.dg/analyzer/isatty-1.c  (test for warnings, line 56)
FAIL: gcc.dg/analyzer/isatty-1.c (test for excess errors)

gcc/analyzer:
	* kf.cc (register_known_functions): Add __errno function for newlib.
---
 gcc/analyzer/kf.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gcc/analyzer/kf.cc b/gcc/analyzer/kf.cc
index 3a91b6bd6ebb..ed5f70398e1d 100644
--- a/gcc/analyzer/kf.cc
+++ b/gcc/analyzer/kf.cc
@@ -1033,9 +1033,11 @@ register_known_functions (known_function_manager &kfm)
        and OS X like this:
 	 extern int * __error(void);
 	 #define errno (*__error())
+       and similarly __errno for newlib.
        Add these as synonyms for "__errno_location".  */
     kfm.add ("___errno", make_unique<kf_errno_location> ());
     kfm.add ("__error", make_unique<kf_errno_location> ());
+    kfm.add ("__errno", make_unique<kf_errno_location> ());
   }
 
   /* Language-specific support functions.  */
-- 
2.30.2

> Thanks for fixing this

Thank *you* for the review!

brgds, H-P