http://sourceware.org/ml/gdb-patches/2016-10/msg00287.html
Subject: Re: aarch64 regression: gdb.cp/nextoverthrow.exp [Re: [PATCH master+7.12] [AArch64] Match instruction "STP with base register" in prologue]

Jan Kratochvil <jan.kratochvil@redhat.com> writes:

>> Could you open a ticket in bugzilla for this error?  I am testing a patch.
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=20682

Thanks, here is the patch...

-- 
Yao (齐尧)

>From 5794d10bcda63da8fc47d0a76c29669af83ed48b Mon Sep 17 00:00:00 2001
From: Yao Qi <yao.qi@linaro.org>
Date: Tue, 11 Oct 2016 12:12:46 +0100
Subject: [PATCH] [AArch64] Track FP registers in prologue analyzer

We don't track FP registers in aarch64 prologue analyzer, so this causes
an internal error when FP registers are saved by "stp" instruction in
prologue (stp	d8, d9, [sp,#128]),

 tbreak _Unwind_RaiseException^M
 aarch64-tdep.c:335: internal-error: CORE_ADDR aarch64_analyze_prologue(gdbarch*, CORE_ADDR, CORE_ADDR, aarch64_prologue_cache*): Assertion `inst.operands[0].type == AARCH64_OPND_Rt' failed.^M
 A problem internal to GDB has been detected,

This patch teaches GDB to track FP registers (D registers) in prologue
analyzer.

gdb:

2016-10-12  Yao Qi  <yao.qi@linaro.org>

	PR tdep/20682
	* aarch64-tdep.c: Replace 32 with AARCH64_D_REGISTER_COUNT.
	(aarch64_analyze_prologue): Extend array 'regs' for D registers.
	Assert that operand 0 and 1 can be X or D registers.  Update
	register number for D registers.  Update registers in frame
	cache.
	* aarch64-tdep.h (AARCH64_D_REGISTER_COUNT): New macro.

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 16dd365..be72785 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -68,7 +68,7 @@
 
 /* Pseudo register base numbers.  */
 #define AARCH64_Q0_REGNUM 0
-#define AARCH64_D0_REGNUM (AARCH64_Q0_REGNUM + 32)
+#define AARCH64_D0_REGNUM (AARCH64_Q0_REGNUM + AARCH64_D_REGISTER_COUNT)
 #define AARCH64_S0_REGNUM (AARCH64_D0_REGNUM + 32)
 #define AARCH64_H0_REGNUM (AARCH64_S0_REGNUM + 32)
 #define AARCH64_B0_REGNUM (AARCH64_H0_REGNUM + 32)
@@ -206,11 +206,12 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
 {
   enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
   int i;
-  pv_t regs[AARCH64_X_REGISTER_COUNT];
+  /* Track X registers and D registers in prologue.  */
+  pv_t regs[AARCH64_X_REGISTER_COUNT + AARCH64_D_REGISTER_COUNT];
   struct pv_area *stack;
   struct cleanup *back_to;
 
-  for (i = 0; i < AARCH64_X_REGISTER_COUNT; i++)
+  for (i = 0; i < AARCH64_X_REGISTER_COUNT + AARCH64_D_REGISTER_COUNT; i++)
     regs[i] = pv_register (i, 0);
   stack = make_pv_area (AARCH64_SP_REGNUM, gdbarch_addr_bit (gdbarch));
   back_to = make_cleanup_free_pv_area (stack);
@@ -328,13 +329,15 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
 	       && strcmp ("stp", inst.opcode->name) == 0)
 	{
 	  /* STP with addressing mode Pre-indexed and Base register.  */
-	  unsigned rt1 = inst.operands[0].reg.regno;
-	  unsigned rt2 = inst.operands[1].reg.regno;
+	  unsigned rt1;
+	  unsigned rt2;
 	  unsigned rn = inst.operands[2].addr.base_regno;
 	  int32_t imm = inst.operands[2].addr.offset.imm;
 
-	  gdb_assert (inst.operands[0].type == AARCH64_OPND_Rt);
-	  gdb_assert (inst.operands[1].type == AARCH64_OPND_Rt2);
+	  gdb_assert (inst.operands[0].type == AARCH64_OPND_Rt
+		      || inst.operands[0].type == AARCH64_OPND_Ft);
+	  gdb_assert (inst.operands[1].type == AARCH64_OPND_Rt2
+		      || inst.operands[1].type == AARCH64_OPND_Ft2);
 	  gdb_assert (inst.operands[2].type == AARCH64_OPND_ADDR_SIMM7);
 	  gdb_assert (!inst.operands[2].addr.offset.is_reg);
 
@@ -349,6 +352,17 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
 					 pv_add_constant (regs[rn], imm + 8)))
 	    break;
 
+	  rt1 = inst.operands[0].reg.regno;
+	  rt2 = inst.operands[1].reg.regno;
+	  if (inst.operands[0].type == AARCH64_OPND_Ft)
+	    {
+	      /* Only bottom 64-bit of each V register (D register) need
+		 to be preserved.  */
+	      gdb_assert (inst.operands[0].qualifier == AARCH64_OPND_QLF_S_D);
+	      rt1 += AARCH64_X_REGISTER_COUNT;
+	      rt2 += AARCH64_X_REGISTER_COUNT;
+	    }
+
 	  pv_area_store (stack, pv_add_constant (regs[rn], imm), 8,
 			 regs[rt1]);
 	  pv_area_store (stack, pv_add_constant (regs[rn], imm + 8), 8,
@@ -408,6 +422,16 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
 	cache->saved_regs[i].addr = offset;
     }
 
+  for (i = 0; i < AARCH64_D_REGISTER_COUNT; i++)
+    {
+      int regnum = gdbarch_num_regs (gdbarch);
+      CORE_ADDR offset;
+
+      if (pv_area_find_reg (stack, gdbarch, i + AARCH64_X_REGISTER_COUNT,
+			    &offset))
+	cache->saved_regs[i + regnum + AARCH64_D0_REGNUM].addr = offset;
+    }
+
   do_cleanups (back_to);
   return start;
 }
diff --git a/gdb/aarch64-tdep.h b/gdb/aarch64-tdep.h
index a95b613..6252820 100644
--- a/gdb/aarch64-tdep.h
+++ b/gdb/aarch64-tdep.h
@@ -68,6 +68,8 @@ enum aarch64_regnum
 
 /* Total number of general (X) registers.  */
 #define AARCH64_X_REGISTER_COUNT 32
+/* Total number of D registers.  */
+#define AARCH64_D_REGISTER_COUNT 32
 
 /* The maximum number of modified instructions generated for one
    single-stepped instruction.  */