gdb/arm: Fix prologue analysis to support vpush

While working on adding support for Non-secure/Secure modes unwinding,
I noticed that the prologue analysis lacked support for vpush, which
is used for instance in the CMSE stub routine.

This patch updates thumb_analyze_prologue accordingly, adding support
for vpush of D-registers.

Signed-off-by: Christophe Lyon <christophe.lyon@foss.st.com>
Signed-off-by: Christophe Lyon <christophe.lyon@arm.com>

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index cc7773914d728e188413c9dbd7fa2619cdf35d3c..66e26e6e2126e9583515fea2293a0ce9a7652381 100644 (file)
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -902,6 +902,35 @@ thumb_analyze_prologue (struct gdbarch *gdbarch,
                regs[bits (insn, 0, 3)] = addr;
            }
 
+         /* vstmdb Rn{!}, { D-registers } (aka vpush).  */
+         else if ((insn & 0xff20) == 0xed20
+                  && (inst2 & 0x0f00) == 0x0b00
+                  && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM))
+           {
+             /* Address SP points to.  */
+             pv_t addr = regs[bits (insn, 0, 3)];
+
+             /* Number of registers saved.  */
+             unsigned int number = bits (inst2, 0, 7) >> 1;
+
+             /* First register to save.  */
+             int vd = bits (inst2, 12, 15) | (bits (insn, 6, 6) << 4);
+
+             if (stack.store_would_trash (addr))
+               break;
+
+             /* Calculate offsets of saved registers.  */
+             for (; number > 0; number--)
+               {
+                 addr = pv_add_constant (addr, -8);
+                 stack.store (addr, 8, pv_register (ARM_D0_REGNUM
+                                                    + vd + number, 0));
+               }
+
+             /* Writeback SP to account for the saved registers.  */
+             regs[bits (insn, 0, 3)] = addr;
+           }
+
          else if ((insn & 0xff50) == 0xe940    /* strd Rt, Rt2,
                                                   [Rn, #+/-imm]{!} */
                   && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM))