Re: [PATCH, driver specs][1] Put -flto-partition= on the collect2 c/l

[Iain Sandoe <iain at sandoe dot co dot uk>]

> On 20 Aug 2018, at 11:01, Richard Biener <richard.guenther@gmail.com> wrote:
> 
> On Sat, Aug 18, 2018 at 9:00 PM Iain Sandoe <iain@sandoe.co.uk> wrote:

>> While working on the Darwin LTO issues I noticed that collect2 looks for "-flto-partition=none” in its command line option, but it doesn’t get passed.
>> 
>> So - is the attached patch the right idea, or should collect2 be looking in the COLLECT_GCC_OPTIONS as the lto-wrapper does?
> 
> Looking at COLLECT_GCC_OPTIONS is probably better.

So I bootstrapped and tested the following on Darwin and Linux (both with a 32b multilib)

It’s kinda odd that we really have to look in two places for the union of the options to be handled, although the reasoning is clear enough.

Comments?
thanks
Iain

gcc/

	* collect2.c (main): Combine flags from both the command line and
	COLLECT_GCC_OPTIONS to determine the set in force.

---
 gcc/collect2.c | 55 +++++++++++++++++++++++++++++---------------------
 1 file changed, 32 insertions(+), 23 deletions(-)

diff --git a/gcc/collect2.c b/gcc/collect2.c
index a96af137a4..9ead5a6a1d 100644
--- a/gcc/collect2.c
+++ b/gcc/collect2.c
@@ -979,13 +979,14 @@ main (int argc, char **argv)
   object = CONST_CAST2 (const char **, char **, object_lst);
 
 #ifdef DEBUG
-  debug = 1;
+  debug = true;
 #endif
 
-  /* Parse command line early for instances of -debug.  This allows
-     the debug flag to be set before functions like find_a_file()
-     are called.  We also look for the -flto or -flto-partition=none flag to know
-     what LTO mode we are in.  */
+  save_temps = false;
+  verbose = false;
+  /* Parse command line / environment for flags we want early.
+     This allows the debug flag to be set before functions like find_a_file()
+     are called. */
   {
     bool no_partition = false;
 
@@ -993,8 +994,6 @@ main (int argc, char **argv)
       {
 	if (! strcmp (argv[i], "-debug"))
 	  debug = true;
-        else if (! strcmp (argv[i], "-flto-partition=none"))
-	  no_partition = true;
 	else if (!strncmp (argv[i], "-fno-lto", 8))
 	  lto_mode = LTO_MODE_NONE;
         else if (! strcmp (argv[i], "-plugin"))
@@ -1027,13 +1026,6 @@ main (int argc, char **argv)
 	    aixlazy_flag = 1;
 #endif
       }
-    verbose = debug;
-    find_file_set_debug (debug);
-    if (use_plugin)
-      lto_mode = LTO_MODE_NONE;
-    if (no_partition && lto_mode == LTO_MODE_WHOPR)
-      lto_mode = LTO_MODE_LTO;
-  }
 
 #ifndef DEFAULT_A_OUT_NAME
   output_file = "a.out";
@@ -1041,20 +1033,37 @@ main (int argc, char **argv)
   output_file = DEFAULT_A_OUT_NAME;
 #endif
 
-  obstack_begin (&temporary_obstack, 0);
-  temporary_firstobj = (char *) obstack_alloc (&temporary_obstack, 0);
+    obstack_begin (&temporary_obstack, 0);
+    temporary_firstobj = (char *) obstack_alloc (&temporary_obstack, 0);
 
 #ifndef HAVE_LD_DEMANGLE
   current_demangling_style = auto_demangling;
 #endif
-  p = getenv ("COLLECT_GCC_OPTIONS");
-  while (p && *p)
-    {
-      const char *q = extract_string (&p);
-      if (*q == '-' && (q[1] == 'm' || q[1] == 'f'))
-	num_c_args++;
+
+    /* Now pick up any flags we want early from COLLECT_GCC_OPTIONS
+       The LTO options are passed here as are other options that might
+       be unsuitable for ld (e.g. -save-temps).  */
+    p = getenv ("COLLECT_GCC_OPTIONS");
+    while (p && *p)
+      {
+	const char *q = extract_string (&p);
+	if (*q == '-' && (q[1] == 'm' || q[1] == 'f'))
+	  num_c_args++;
+	if (strncmp (q, "-flto-partition=none", 20) == 0)
+	  no_partition = true;
+	else if (strncmp (q, "-fno-lto", 8) == 0)
+	  lto_mode = LTO_MODE_NONE;
     }
-  obstack_free (&temporary_obstack, temporary_firstobj);
+    obstack_free (&temporary_obstack, temporary_firstobj);
+
+    verbose |= debug;
+    save_temps |= debug;
+    find_file_set_debug (debug);
+    if (use_plugin)
+      lto_mode = LTO_MODE_NONE;
+    if (no_partition && lto_mode == LTO_MODE_WHOPR)
+      lto_mode = LTO_MODE_LTO;
+  }
 
   /* -fno-profile-arcs -fno-test-coverage -fno-branch-probabilities
      -fno-exceptions -w -fno-whole-program */
-- 
2.17.1