[gcc r11-6965] gccgo driver: always act as though -g is passed

[Ian Lance Taylor <ian@gcc.gnu.org>]

https://gcc.gnu.org/g:e6bce7fe17bf32ce969abc6f77f07acd352f6977

commit r11-6965-ge6bce7fe17bf32ce969abc6f77f07acd352f6977
Author: Ian Lance Taylor <iant@golang.org>
Date:   Thu Jan 28 15:46:59 2021 -0800

    gccgo driver: always act as though -g is passed
    
    The go1 compiler always turns on debugging, to support Go stack traces
    and functions like runtime.Callers.  With the recent switch to turn on
    DWARF 5 by default, this caused failures with some versions of gas,
    such as 2.35.1, because the assembly code would assume DWARF 5 but the
    driver would not pass --gdwarf-5 to gas.  gas would then give an
    error: "file number less than one".
    
    This change avoids that problem by having the gccgo driver spec add a
    -g option to the command line if no other -g option is present.  The
    newly added -g option is passed to the assembler as --gdwarf-5.
    
            * gospec.c (lang_specific_driver): Add -g if no debugging options
            were passed.

Diff:
---
 gcc/go/gospec.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/gcc/go/gospec.c b/gcc/go/gospec.c
index aaf64e73949..cf8d0f2b60e 100644
--- a/gcc/go/gospec.c
+++ b/gcc/go/gospec.c
@@ -127,6 +127,9 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
   /* The first input file with an extension of .go.  */
   const char *first_go_file = NULL;  
 
+  /* Whether we saw any -g option.  */
+  bool saw_opt_g = false;
+
   argc = *in_decoded_options_count;
   decoded_options = *in_decoded_options;
   added_libraries = *in_added_libraries;
@@ -208,6 +211,18 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
 	  saw_opt_o = true;
 	  break;
 
+	case OPT_g:
+	case OPT_gdwarf:
+	case OPT_gdwarf_:
+	case OPT_ggdb:
+	case OPT_gstabs:
+	case OPT_gstabs_:
+	case OPT_gvms:
+	case OPT_gxcoff:
+	case OPT_gxcoff_:
+	  saw_opt_g = true;
+	  break;
+
 	case OPT_static:
 	  static_link = 1;
 	  break;
@@ -271,6 +286,15 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
       j++;
     }
 
+  /* The go1 compiler is going to enable debug info by default.  If we
+     don't see any -g options, force -g, so that we invoke the
+     assembler with the right debug option.  */
+  if (!saw_opt_g)
+    {
+      generate_option (OPT_g, "1", 0, CL_DRIVER, &new_decoded_options[j]);
+      j++;
+    }
+
   /* NOTE: We start at 1 now, not 0.  */
   while (i < argc)
     {