From 97ab0fdd9d053ee9201c74d4234fb68c74916548 Mon Sep 17 00:00:00 2001
From: "Maciej W. Rozycki" <macro@linux-mips.org>
Date: Thu, 20 Sep 2007 15:34:19 +0000
Subject: * mips-tdep.c (mips32_in_function_epilogue_p): New function.
 (mips16_in_function_epilogue_p): Likewise. (mips_in_function_epilogue_p):
 Likewise. (mips_gdbarch_init): Register mips_in_function_epilogue_p().

---
 gdb/ChangeLog   |  7 +++++
 gdb/mips-tdep.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 98 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c8486c5..833ef75 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2007-09-20  Maciej W. Rozycki  <macro@mips.com>
+
+	* mips-tdep.c (mips32_in_function_epilogue_p): New function.
+	(mips16_in_function_epilogue_p): Likewise.
+	(mips_in_function_epilogue_p): Likewise.
+	(mips_gdbarch_init): Register mips_in_function_epilogue_p().
+
 2007-09-19  Joel Brobecker  <brobecker@adacore.com>
 
 	* configure.ac: Add check for "etext".
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index ff81651..2384e12 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -4404,6 +4404,95 @@ mips_skip_prologue (CORE_ADDR pc)
     return mips32_scan_prologue (pc, limit_pc, NULL, NULL);
 }
 
+/* Check whether the PC is in a function epilogue (32-bit version).
+   This is a helper function for mips_in_function_epilogue_p.  */
+static int
+mips32_in_function_epilogue_p (CORE_ADDR pc)
+{
+  CORE_ADDR func_addr = 0, func_end = 0;
+
+  if (find_pc_partial_function (pc, NULL, &func_addr, &func_end))
+    {
+      /* The MIPS epilogue is max. 12 bytes long.  */
+      CORE_ADDR addr = func_end - 12;
+
+      if (addr < func_addr + 4)
+        addr = func_addr + 4;
+      if (pc < addr)
+        return 0;
+
+      for (; pc < func_end; pc += MIPS_INSN32_SIZE)
+	{
+	  unsigned long high_word;
+	  unsigned long inst;
+
+	  inst = mips_fetch_instruction (pc);
+	  high_word = (inst >> 16) & 0xffff;
+
+	  if (high_word != 0x27bd	/* addiu $sp,$sp,offset */
+	      && high_word != 0x67bd	/* daddiu $sp,$sp,offset */
+	      && inst != 0x03e00008	/* jr $ra */
+	      && inst != 0x00000000)	/* nop */
+	    return 0;
+	}
+
+      return 1;
+    }
+
+  return 0;
+}
+
+/* Check whether the PC is in a function epilogue (16-bit version).
+   This is a helper function for mips_in_function_epilogue_p.  */
+static int
+mips16_in_function_epilogue_p (CORE_ADDR pc)
+{
+  CORE_ADDR func_addr = 0, func_end = 0;
+
+  if (find_pc_partial_function (pc, NULL, &func_addr, &func_end))
+    {
+      /* The MIPS epilogue is max. 12 bytes long.  */
+      CORE_ADDR addr = func_end - 12;
+
+      if (addr < func_addr + 4)
+        addr = func_addr + 4;
+      if (pc < addr)
+        return 0;
+
+      for (; pc < func_end; pc += MIPS_INSN16_SIZE)
+	{
+	  unsigned short inst;
+
+	  inst = mips_fetch_instruction (pc);
+
+	  if ((inst & 0xf800) == 0xf000)	/* extend */
+	    continue;
+
+	  if (inst != 0x6300		/* addiu $sp,offset */
+	      && inst != 0xfb00		/* daddiu $sp,$sp,offset */
+	      && inst != 0xe820		/* jr $ra */
+	      && inst != 0xe8a0		/* jrc $ra */
+	      && inst != 0x6500)	/* nop */
+	    return 0;
+	}
+
+      return 1;
+    }
+
+  return 0;
+}
+
+/* The epilogue is defined here as the area at the end of a function,
+   after an instruction which destroys the function's stack frame.  */
+static int
+mips_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc)
+{
+  if (mips_pc_is_mips16 (pc))
+    return mips16_in_function_epilogue_p (pc);
+  else
+    return mips32_in_function_epilogue_p (pc);
+}
+
 /* Root of all "set mips "/"show mips " commands. This will eventually be
    used for all MIPS-specific commands.  */
 
@@ -5485,6 +5574,8 @@ mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   set_gdbarch_skip_prologue (gdbarch, mips_skip_prologue);
 
+  set_gdbarch_in_function_epilogue_p (gdbarch, mips_in_function_epilogue_p);
+
   set_gdbarch_pointer_to_address (gdbarch, signed_pointer_to_address);
   set_gdbarch_address_to_pointer (gdbarch, address_to_signed_pointer);
   set_gdbarch_integer_to_address (gdbarch, mips_integer_to_address);
-- 
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