From 072f20c555907cce38a424da47b6c1baa8330169 Mon Sep 17 00:00:00 2001
From: Kito Cheng <kito.cheng@sifive.com>
Date: Thu, 28 Jan 2021 18:29:53 +0800
Subject: [PATCH] PR target/98878 - Incorrect multilib list for riscv*-rtems

 - Multi-lib only check the default argument is appeared in the multilib
   flag list, but we didn't check the case that the flag is required but
   default argument didn't provide.

 - For example riscv*-rtems has a multilib set:

     rv32imafd/ilp32d;@march=rv32imafd@mabi=ilp32d

   And when we set the default argument of arch to rv32imafdc and ABI to
   ilp32d, gcc will check the ilp32d is matched, but it didn't check
   rv32imafd is not provided by default arguments, so it should not
   reuse default library.

 - The side effcet of this patch is csky-elf target will increase the
   number of multilib from 54 to 59, but it's because genmultilib didn't
   know the default argument for multilib, so I think it could be
   improved in future.

gcc/ChangeLog:

	* gcc.c (print_multilib_info): Check all required argument is provided
	by default arg.
---
 gcc/gcc.c | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/gcc/gcc.c b/gcc/gcc.c
index aa5774af7e7..76f1d422f9a 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -9909,12 +9909,14 @@ print_multilib_info (void)
 	  last_path_len = p - this_path;
 	}
 
-      /* If this directory requires any default arguments, we can skip
-	 it.  We will already have printed a directory identical to
-	 this one which does not require that default argument.  */
+      /* If all required arguments are default arguments, and no default
+	 arguments appear in the ! argument list, then we can skip it.
+	 We will already have printed a directory identical to this one
+	 which does not require that default argument.  */
       if (! skip)
 	{
 	  const char *q;
+	  bool default_arg_ok = false;
 
 	  q = p + 1;
 	  while (*q != ';')
@@ -9946,16 +9948,29 @@ print_multilib_info (void)
 		     list.  */
 		  if (not_arg)
 		    {
-		      skip = 0;
+		      default_arg_ok = false;
 		      break;
 		    }
-		  else
-		    skip = 1;
+
+		  default_arg_ok = true;
+		}
+	      else if (!not_arg)
+		{
+		  /* Stop checking if any required argument is not provided by
+		     default arguments.  */
+		  default_arg_ok = false;
+		  break;
 		}
 
 	      if (*q == ' ')
 		++q;
 	    }
+
+	  /* Make sure all default argument is OK for this multi-lib set.  */
+	  if (default_arg_ok)
+	    skip = 1;
+	  else
+	    skip = 0;
 	}
 
       if (! skip)
-- 
2.30.2