From: Yoshinori Sato <ysato@users.sourceforge.jp>
Date: Tue, 19 May 2020 17:33:08 +0000 (-0400)
Subject: gdb: fix -Wtautological-overlap-compare error in h8300-tdep.c
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1d6ce4d31257e1ea49b3a1b257055bf8f7ff16af;p=binutils-gdb.git

gdb: fix -Wtautological-overlap-compare error in h8300-tdep.c

Compiling with clang 11 gives us:

      CXX    h8300-tdep.o
    /home/smarchi/src/binutils-gdb/gdb/h8300-tdep.c:225:21: error: overlapping comparisons always evaluate to false [-Werror,-Wtautological-overlap-compare]
                  if (disp < 0 && disp > 0xffffff)
                      ~~~~~~~~~^~~~~~~~~~~~~~~~~~
    /home/smarchi/src/binutils-gdb/gdb/h8300-tdep.c:203:17: error: overlapping comparisons always evaluate to false [-Werror,-Wtautological-overlap-compare]
              if (disp < 0 && disp > 0xffffff)
                  ~~~~~~~~~^~~~~~~~~~~~~~~~~~
    /home/smarchi/src/binutils-gdb/gdb/h8300-tdep.c:184:17: error: overlapping comparisons always evaluate to false [-Werror,-Wtautological-overlap-compare]
              if (disp < 0 && disp > 0xffffff)
                  ~~~~~~~~~^~~~~~~~~~~~~~~~~~

Indeed, disp (of type LONGEST) can't be less than 0 and greater than
0xffffff.

Fix it by changing the way we check if disp is negative.  Check the sign
bit of disp, which is a 24-bit number.

gdb/ChangeLog:

	* h8300-tdep.c (h8300_is_argument_spill): Change how we check
	whether disp is negative.
---

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f086b5cf908..c4393182dd9 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2020-05-19  Yoshinori Sato  <ysato@users.sourceforge.jp>
+
+	* h8300-tdep.c (h8300_is_argument_spill): Change how we check
+	whether disp is negative.
+
 2020-05-19  Simon Marchi  <simon.marchi@efficios.com>
 
 	* symfile.h (struct symfile_segment_data)
diff --git a/gdb/h8300-tdep.c b/gdb/h8300-tdep.c
index 3c2f502a124..b569a23f263 100644
--- a/gdb/h8300-tdep.c
+++ b/gdb/h8300-tdep.c
@@ -178,10 +178,10 @@ h8300_is_argument_spill (struct gdbarch *gdbarch, CORE_ADDR pc)
       if (IS_MOVB_Rn24_SP (read_memory_unsigned_integer (pc + 2,
 							 2, byte_order)))
 	{
-	  LONGEST disp = read_memory_integer (pc + 4, 4, byte_order);
+	  ULONGEST disp = read_memory_unsigned_integer (pc + 4, 4, byte_order);
 
 	  /* ... and d:24 is negative.  */
-	  if (disp < 0 && disp > 0xffffff)
+	  if ((disp & 0x00800000) != 0)
 	    return 8;
 	}
     }
@@ -197,10 +197,10 @@ h8300_is_argument_spill (struct gdbarch *gdbarch, CORE_ADDR pc)
       if (IS_MOVW_Rn24_SP (read_memory_unsigned_integer (pc + 2,
 							 2, byte_order)))
 	{
-	  LONGEST disp = read_memory_integer (pc + 4, 4, byte_order);
+	  ULONGEST disp = read_memory_unsigned_integer (pc + 4, 4, byte_order);
 
 	  /* ... and d:24 is negative.  */
-	  if (disp < 0 && disp > 0xffffff)
+	  if ((disp & 0x00800000) != 0)
 	    return 8;
 	}
     }
@@ -219,10 +219,11 @@ h8300_is_argument_spill (struct gdbarch *gdbarch, CORE_ADDR pc)
 	{
 	  if (IS_MOVL_Rn24_SP (read_memory_integer (pc + 4, 2, byte_order)))
 	    {
-	      LONGEST disp = read_memory_integer (pc + 6, 4, byte_order);
+	      ULONGEST disp = read_memory_unsigned_integer (pc + 6, 4,
+							    byte_order);
 
 	      /* ... and d:24 is negative.  */
-	      if (disp < 0 && disp > 0xffffff)
+	      if ((disp & 0x00800000) != 0)
 		return 10;
 	    }
 	}