[PATCH v3] H8/300: sim: Fix simulator hang caused by qsort on Windows/MinGW

[PATCH v3] H8/300: sim: Fix simulator hang caused by qsort on Windows/MinGW

[Jan Dubiec]

On Windows, qsort() uses an unstable sorting algorithm, which results
in a "shuffled" opcode table rather than a properly sorted one, causing
the entire simulator to hang.

The simulator happens to work on Linux, but this behavior is not
guaranteed, because the glibc documentation clearly states that "If
two elements compare equal, their order after sorting is unpredictable."

This patch introduces two additional sort keys to the instruction
comparator function, making the resulting opcode table as close as
possible to the one that would be produced by a stable sorting algorithm.

---
  sim/h8300/compile.c | 41 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/sim/h8300/compile.c b/sim/h8300/compile.c
index 06988095228..82ce73a70f2 100644
--- a/sim/h8300/compile.c
+++ b/sim/h8300/compile.c
@@ -1586,6 +1586,7 @@ instruction_comparator (const void *p1_, const void *p2_)
 {
   struct h8_opcode *p1 = (struct h8_opcode *)p1_;
   struct h8_opcode *p2 = (struct h8_opcode *)p2_;
+  int cmp;
 
   /* The 1st sort key is based on whether or not the
      instruction is even available.  This reduces the
@@ -1605,7 +1606,45 @@ instruction_comparator (const void *p1_, const void *p2_)
     return p2_available - p1_available;
 
   /* Secondarily sort based on the first opcode nibble.  */
-  return p1->data.nib[0] - p2->data.nib[0];
+  if (p1->data.nib[0] != p2->data.nib[0])
+    return p1->data.nib[0] - p2->data.nib[0];
+
+  /* The 3rd sort key  */
+  cmp = strcmp (p1->name, p2->name);
+  if (cmp)
+    {
+      /* Two different opcodes  */
+      size_t l1 = strlen (p1->name);
+      size_t l2 = strlen (p2->name);
+      ptrdiff_t i1 = strchr (p1->name, '.') - p1->name;
+      ptrdiff_t i2 = strchr (p2->name, '.') - p2->name;
+      char c1, c2;
+
+      if ((l1 == l2) && (i1 == i2) && (i1 > 0))
+	{
+	  /* Check for different mnemonics of the same length,
+	     e.g. add.w vs. and.b  */
+	  cmp = strncmp (p1->name, p2->name, i1);
+	  if (cmp)
+	    return cmp;
+
+	  /* At this point we expect only b, w or l suffix,
+	     where b < w < l  */
+	  c1 = p1->name[i1+1];
+	  c2 = p2->name[i2+1];
+	  if (c1 == 'b')
+	    return -1;
+	  else if (c1 == 'w')
+	    return (c2 == 'b') ? 1 : -1;
+	  else
+	    return 1;
+	}
+
+      return cmp;
+    }
+
+  /* The 4th sort key  */
+  return p1->how - p2->how;
 }
 
 
-- 
2.55.0

Re: [PATCH v3] H8/300: sim: Fix simulator hang caused by qsort on Windows/MinGW

[Jan Dubiec]

Please do not apply this patch. After more thorough testing, it turned 
out that the patch introduces two regressions in the simulator testsuite:

PASS: h8300 stack.s
PASS: h8300h stack.s
FAIL: h8300s stack.s (execution)
FAIL: h8sx stack.s (execution)

I need some time to investigate this.

/J.D.