Add -O[0123s] gcc optimization flags for gcc pass 4 speedup.

* session.h (struct systemtap_session): Add gcc_flags string field.
* main.cxx (usage): Document -O[0123s].
  (main): Default gcc_flags to -O0. Add O:: to getopt_long. Handle case
  'O' to set gcc_flags.
* buildrun.cxx (compile_pass): Add gcc_flags to EXTRA_CFLAGS.
* stap1.in: Add -O[0123s] documentation.
* testsuite/systemtap.base/cache.exp: Add tests for -O[0123s].

1 files changed, 26 insertions, 1 deletions

diff --git a/main.cxx b/main.cxx
index 9dc658ff..2aeff580 100644
--- a/main.cxx
+++ b/main.cxx
@@ -111,6 +111,14 @@ usage (systemtap_session& s, int exitcode)
     << "              " << s.module_name << endl
     << "   -o FILE    send script output to file, instead of stdout. This supports" << endl
     << "              strftime(3) formats for FILE" << endl
+    << "   -O[0123s]  optimization to use for C code. Passed to gcc in pass 4." << endl
+    << "              -O  Alias for -O1" << endl
+    << "              -O0 Fast compilation" << endl
+    << "              -O1 Optimize, takes a bit more time" << endl
+    << "              -O2 Optimize more, takes more time" << endl
+    << "              -O3 Optimize even more, takes even more time" << endl
+    << "              -Os Optimize for size, like -O2 but tuned for small code size" << endl
+    << "              Default is -O0." << endl
     << "   -c CMD     start the probes, run CMD, and exit when it finishes" << endl
     << "   -x PID     sets target() to PID" << endl
     << "   -F         run as on-file flight recorder with -o." << endl
@@ -403,6 +411,7 @@ main (int argc, char * const argv [])
   s.ignore_dwarf = false;
   s.load_only = false;
   s.skip_badvars = false;
+  s.gcc_flags = "-O0";
 
   // Location of our signing certificate.
   // If we're root, use the database in SYSCONFDIR, otherwise
@@ -487,7 +496,7 @@ main (int argc, char * const argv [])
         { "vp", 1, &long_opt, LONG_OPT_VERBOSE_PASS },
         { NULL, 0, NULL, 0 }
       };
-      int grc = getopt_long (argc, argv, "hVMvtp:I:e:o:R:r:m:kgPc:x:D:bs:uqwl:d:L:FS:",
+      int grc = getopt_long (argc, argv, "hVMvtp:I:e:o:O::R:r:m:kgPc:x:D:bs:uqwl:d:L:FS:",
                                                           long_options, NULL);
       if (grc < 0)
         break;
@@ -551,6 +560,22 @@ main (int argc, char * const argv [])
           s.output_file = string (optarg);
           break;
 
+        case 'O':
+	  if (optarg == NULL)
+	    s.gcc_flags = "-O1";
+	  else
+	    s.gcc_flags = "-O" + string (optarg);
+
+	  if (s.gcc_flags != "-O0" && s.gcc_flags != "-O1"
+	      && s.gcc_flags != "-O2" && s.gcc_flags != "-O3"
+	      && s.gcc_flags != "-Os")
+	    {
+	      cerr << "'" << s.gcc_flags << "'"
+		   << " isn't a valid optimization option." << endl;
+	      usage (s, 1);
+	    }
+          break;
+
         case 'R':
           s.runtime_path = string (optarg);
           break;