[PATCH 2/4] cgcc: avoid passing a sparse-only option to cc

[Ramsay Jones <ramsay@xxxxxxxxxxxxxxxxxxx>]

Passing the '-Wsparse-error' to cgcc can cause that option to be
passed to the C compiler (usually gcc), if the given source file
does not provoke any sparse warnings, which in turn results in
a failure to compile that file.

In order to avoid passing this sparse option to the compiler, we
add the '-Wsparse-error' option to the regular expression check
in the 'check_only_option' function.

In addition, we replace the plain call to 'die' when sparse exits
with non-zero status (maybe due to -Wsparse-error), with a simple
'exit 1'. This suppresses an 'Died at ./cgcc line 86.' message on
exit from cgcc.

Signed-off-by: Ramsay Jones <ramsay@xxxxxxxxxxxxxxxxxxx>
---

Hi Chris,

The following shows the error/fix:

    $ pwd
    /home/ramsay/sparse
    $ cat -n hello.c
         1	#include <stdio.h>
         2	
         3	int main(void)
         4	{
         5		printf("Hello, world!\n");
         6		return 0;
         7	}
    $ CHECK=./sparse ./cgcc hello.c
    $ echo $?
    0
    $ CHECK=./sparse ./cgcc -Wsparse-error hello.c
    cc: error: unrecognized command line option ‘-Wsparse-error’
    $ echo $?
    1
    $ 

Note gcc complaining about the unknown option.
Now edit hello.c so that we generate a sparse warning ...

    $ cat -n hello.c
         1	#include <stdio.h>
         2	
         3	int f(void)
         4	{
         5		return 42;
         6	}
         7	
         8	int main(void)
         9	{
        10		printf("Hello, world!\n");
        11		return 0;
        12	}
    $ CHECK=./sparse ./cgcc hello.c
    hello.c:3:5: warning: symbol 'f' was not declared. Should it be static?
    $ echo $?
    0
    $ CHECK=./sparse ./cgcc -Wsparse-error hello.c
    hello.c:3:5: error: symbol 'f' was not declared. Should it be static?
    Died at ./cgcc line 86.
    $ echo $?
    1
    $ 

After this patch:

    with the original hello.c ...

    $ CHECK=./sparse ./cgcc hello.c
    $ echo $?
    0
    $ CHECK=./sparse ./cgcc -Wsparse-error hello.c
    $ echo $?
    0
    $ 

    with the modified hello.c ...

    $ CHECK=./sparse ./cgcc hello.c
    hello.c:3:5: warning: symbol 'f' was not declared. Should it be static?
    $ echo $?
    0
    $ CHECK=./sparse ./cgcc -Wsparse-error hello.c
    hello.c:3:5: error: symbol 'f' was not declared. Should it be static?
    $ echo $?
    1
    $ 

ATB,
Ramsay Jones


 cgcc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cgcc b/cgcc
index 8ee8da1..8e38174 100755
--- a/cgcc
+++ b/cgcc
@@ -83,7 +83,7 @@ if ($do_check) {
 
     print "$check\n" if $verbose;
     if ($do_compile) {
-	system ($check) == 0 or die;
+	system ($check) == 0 or exit 1;
     } else {
 	exec ($check);
     }
@@ -101,7 +101,7 @@ exit 0;
 
 sub check_only_option {
     my ($arg) = @_;
-    return 1 if $arg =~ /^-W(no-?)?(default-bitfield-sign|one-bit-signed-bitfield|cast-truncate|bitwise|typesign|context|undef|ptr-subtraction-blows|cast-to-as|decl|transparent-union|address-space|enum-mismatch|do-while|old-initializer|non-pointer-null|paren-string|return-void|designated-init|sparse-all)$/;
+    return 1 if $arg =~ /^-W(no-?)?(default-bitfield-sign|one-bit-signed-bitfield|cast-truncate|bitwise|typesign|context|undef|ptr-subtraction-blows|cast-to-as|decl|transparent-union|address-space|enum-mismatch|do-while|old-initializer|non-pointer-null|paren-string|return-void|designated-init|sparse-all|sparse-error)$/;
     return 1 if $arg =~ /^-v(no-?)?(entry|dead)$/;
     return 0;
 }
-- 
2.1.0
--
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