Some versions of gcc (e.g. v4.8.2) complain about ignoring the return
value of a call to 'write(2)' on line 735, since it is marked with
the warn_unused_result attribute. (see also lines 745-747).
Note that this code is mixing calls to 'write' on STDOUT_FILENO with
calls to stdio functions on the stdout file handle. So, in order to
suppress the compiler warnings, we replace both calls to 'write' with
equivalent calls to stdio functions.
Signed-off-by: Ramsay Jones <ramsay@xxxxxxxxxxxxxxxxxxx>
---
Hi Chris,
Since there are no tests for the compile program, I ran the old version
(from commit 748b856) and this version over all of the .c files in the
sparse directory, saving the output to file and diff-ing the result.
Unfortunately, compile segfaults on most files and the diff shows that
this patch leads to a change in behaviour, caused by the lack of I/O
buffer flushing prior to the segfault (all of the diffs showed missing
text at the end of each new output file).
Just to confirm, I added back the 'fflush(stdout); ...' line that I
removed in the third hunk below _and_ duplicated that line and placed
it after the call to 'emit_atom_list(f);'. This version of compile
produced (almost) exactly the same output as the original.
The reason for the almost is that three files showed a non-empty diff
which seemed to indicate (a possible bug?) that a label name was being
generated from a memory address. The actual addresses/label name
generated in each file was different, but they were used consistently
in each file. For example, the complete diff for sort.c is:
--- sort.c.out-old 2014-08-04 17:32:32.399744973 +0100
+++ sort.c.out-new 2014-08-04 17:37:04.189092702 +0100
@@ -742,7 +742,7 @@
addl $744, %esp
ret
.size merge_block_seqs, .-merge_block_seqs
-.L0xb740550c:
+.L0xb748068c:
.globl sort_list
.type sort_list, @function
sort_list:
@@ -837,7 +837,7 @@
movl %eax, 68(%esp) # .... end copy
jmp .L72
.L87: # end if
- jmp .LS0xb740550c
+ jmp .LS0xb748068c
.L86: # end if
movl 44(%esp), %eax # begin copy ..
movl %eax, 72(%esp) # .... end copy
ATB,
Ramsay Jones
compile-i386.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/compile-i386.c b/compile-i386.c
index 88169ec..f89b6ca 100644
--- a/compile-i386.c
+++ b/compile-i386.c
@@ -732,7 +732,7 @@ static void emit_insn_atom(struct function *f, struct atom *atom)
atom->insn,
comment[0] ? "\t\t" : "", comment);
- write(STDOUT_FILENO, s, strlen(s));
+ printf("%s", s);
}
static void emit_atom_list(struct function *f)
@@ -742,9 +742,7 @@ static void emit_atom_list(struct function *f)
FOR_EACH_PTR(f->atom_list, atom) {
switch (atom->type) {
case ATOM_TEXT: {
- ssize_t rc = write(STDOUT_FILENO, atom->text,
- atom->text_len);
- (void) rc; /* FIXME */
+ printf("%.*s", (int)atom->text_len, atom->text);
break;
}
case ATOM_INSN:
@@ -886,7 +884,6 @@ static void emit_func_post(struct symbol *sym)
insn("ret", NULL, NULL, NULL);
/* output everything to stdout */
- fflush(stdout); /* paranoia; needed? */
emit_atom_list(f);
/* function footer */
--
2.0.0
--
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