mjit.c: eliminate -save-temps flag

in a new variable cc_common_args.

`cflags=-save-temps=obj` makes MJIT fail like:
https://rubyci.org/logs/www.rubyist.net/~akr/chkbuild/debian/ruby-trunk/log/20181203T095000Z.log.html.gz

This rubyci specifies -save-temps=obj in CFLAGS to use update-deps, and
the flag is harmful when we want to use -pipe flag.

mjit_worker.c: prefer cc_common_args over CC_COMMON_ARGS

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66164 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

mjit.c

@@ -640,6 +640,19 @@ mjit_init(struct mjit_options *opts)
 #endif
     cc_path = CC_COMMON_ARGS[0];
     verbose(2, "MJIT: CC defaults to %s", cc_path);
+    cc_common_args = xmalloc(sizeof(CC_COMMON_ARGS));
+    memcpy(cc_common_args, CC_COMMON_ARGS, sizeof(CC_COMMON_ARGS));
+#if MJIT_CFLAGS_PIPE
+    { /* eliminate a flag incompatible with `-pipe` */
+        size_t i, j;
+        for (i = 0, j = 0; i < sizeof(CC_COMMON_ARGS) / sizeof(char *); i++) {
+            if (CC_COMMON_ARGS[i] && strncmp("-save-temps", CC_COMMON_ARGS[i], strlen("-save-temps")) == 0)
+                continue; /* skip -save-temps flag */
+            cc_common_args[j] = CC_COMMON_ARGS[i];
+            j++;
+        }
+    }
+#endif
 
     tmp_dir = system_tmpdir();
     verbose(2, "MJIT: tmp_dir is %s", tmp_dir);
@@ -826,6 +839,7 @@ mjit_finish(int close_handle_p)
 
     xfree(header_file); header_file = NULL;
 #endif
+    xfree(cc_common_args); cc_common_args = NULL;
     xfree(tmp_dir); tmp_dir = NULL;
     xfree(pch_file); pch_file = NULL;
 

mjit_worker.c

@@ -215,6 +215,8 @@ static VALUE valid_class_serials;
 
 /* Used C compiler path.  */
 static const char *cc_path;
+/* Used C compiler flags. */
+static const char **cc_common_args;
 /* Name of the precompiled header file.  */
 static char *pch_file;
 /* The process id which should delete the pch_file on mjit_finish. */
@@ -238,10 +240,11 @@ static char *libruby_pathflag;
 #if defined(__GNUC__) && \
      (!defined(__clang__) || \
       (defined(__clang__) && (defined(__FreeBSD__) || defined(__GLIBC__))))
-#define GCC_PIC_FLAGS "-Wfatal-errors", "-fPIC", "-shared", "-w", \
-    "-pipe",
+# define GCC_PIC_FLAGS "-Wfatal-errors", "-fPIC", "-shared", "-w", "-pipe",
+# define MJIT_CFLAGS_PIPE 1
 #else
-#define GCC_PIC_FLAGS /* empty */
+# define GCC_PIC_FLAGS /* empty */
+# define MJIT_CFLAGS_PIPE 0
 #endif
 
 static const char *const CC_COMMON_ARGS[] = {
@@ -741,7 +744,7 @@ make_pch(void)
     rest_args[len - 2] = header_file;
     rest_args[len - 3] = pch_file;
     verbose(2, "Creating precompiled header");
-    args = form_args(3, CC_COMMON_ARGS, CC_CODEFLAG_ARGS, rest_args);
+    args = form_args(3, cc_common_args, CC_CODEFLAG_ARGS, rest_args);
     if (args == NULL) {
         mjit_warning("making precompiled header failed on forming args");
         CRITICAL_SECTION_START(3, "in make_pch");
@@ -785,7 +788,7 @@ compile_c_to_o(const char *c_file, const char *o_file)
 # ifdef __clang__
     files[4] = pch_file;
 # endif
-    args = form_args(5, CC_COMMON_ARGS, CC_CODEFLAG_ARGS, files, CC_LIBS, CC_DLDFLAGS_ARGS);
+    args = form_args(5, cc_common_args, CC_CODEFLAG_ARGS, files, CC_LIBS, CC_DLDFLAGS_ARGS);
     if (args == NULL)
         return FALSE;