[binutils-gdb] Add support for simulating big-endian AArch64 binaries.

[Nick Clifton <nickc at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=c7be441465094e5ffce2f4205ea887676965d0be

commit c7be441465094e5ffce2f4205ea887676965d0be
Author: Jim Wilson <jim.wilson@linaro.org>
Date:   Thu Jun 30 09:10:41 2016 +0100

    Add support for simulating big-endian AArch64 binaries.
    
    	* cpustate.h: Include config.h.
    	(union GRegisterValue): Add WORDS_BIGENDIAN check.  For big endian code
    	use anonymous structs to align members.
    	* simulator.c (aarch64_step): Use sim_core_read_buffer and
    	endian_le2h_4 to read instruction from pc.

Diff:
---
 sim/aarch64/ChangeLog   |  8 ++++++++
 sim/aarch64/cpustate.h  | 25 +++++++++++++++++--------
 sim/aarch64/simulator.c |  6 +++++-
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/sim/aarch64/ChangeLog b/sim/aarch64/ChangeLog
index 90e501a..2d9a9d2 100644
--- a/sim/aarch64/ChangeLog
+++ b/sim/aarch64/ChangeLog
@@ -1,3 +1,11 @@
+2016-06-30  Jim Wilson  <jim.wilson@linaro.org>
+
+	* cpustate.h: Include config.h.
+	(union GRegisterValue): Add WORDS_BIGENDIAN check.  For big endian code
+	use anonymous structs to align members.
+	* simulator.c (aarch64_step): Use sim_core_read_buffer and
+	endian_le2h_4 to read instruction from pc.
+
 2016-05-06  Nick Clifton  <nickc@redhat.com>
 
 	* simulator.c (do_FMLA_by_element): New function.
diff --git a/sim/aarch64/cpustate.h b/sim/aarch64/cpustate.h
index 07446a2..fc0c68b 100644
--- a/sim/aarch64/cpustate.h
+++ b/sim/aarch64/cpustate.h
@@ -22,6 +22,7 @@
 #ifndef _CPU_STATE_H
 #define _CPU_STATE_H
 
+#include "config.h"
 #include <sys/types.h>
 #include <stdint.h>
 #include <inttypes.h>
@@ -123,16 +124,14 @@ typedef enum VReg
 } VReg;
 
 /* All the different integer bit patterns for the components of a
-   general register are overlaid here using a union so as to allow all
-   reading and writing of the desired bits.
-
-   N.B. the ARM spec says that when you write a 32 bit register you
-   are supposed to write the low 32 bits and zero the high 32
-   bits. But we don't actually have to care about this because Java
-   will only ever consume the 32 bits value as a 64 bit quantity after
-   an explicit extend.  */
+   general register are overlaid here using a union so as to allow
+   all reading and writing of the desired bits.  Note that we have
+   to take care when emulating a big-endian AArch64 as we are
+   running on a little endian host.  */
+
 typedef union GRegisterValue
 {
+#if !WORDS_BIGENDIAN
   int8_t   s8;
   int16_t  s16;
   int32_t  s32;
@@ -141,6 +140,16 @@ typedef union GRegisterValue
   uint16_t u16;
   uint32_t u32;
   uint64_t u64;
+#else
+  struct { int64_t :56; int8_t s8; };
+  struct { int64_t :48; int16_t s16; };
+  struct { int64_t :32; int32_t s32; };
+  int64_t s64;
+  struct { uint64_t :56; uint8_t u8; };
+  struct { uint64_t :48; uint16_t u16; };
+  struct { uint64_t :32; uint32_t u32; };
+  uint64_t u64;
+#endif
 } GRegister;
 
 /* Float registers provide for storage of a single, double or quad
diff --git a/sim/aarch64/simulator.c b/sim/aarch64/simulator.c
index 88cb03d..7c15e7a 100644
--- a/sim/aarch64/simulator.c
+++ b/sim/aarch64/simulator.c
@@ -14083,7 +14083,11 @@ aarch64_step (sim_cpu *cpu)
     return FALSE;
 
   aarch64_set_next_PC (cpu, pc + 4);
-  aarch64_get_instr (cpu) = aarch64_get_mem_u32 (cpu, pc);
+
+  /* Code is always little-endian.  */
+  sim_core_read_buffer (CPU_STATE (cpu), cpu, read_map,
+			& aarch64_get_instr (cpu), pc, 4);
+  aarch64_get_instr (cpu) = endian_le2h_4 (aarch64_get_instr (cpu));
 
   TRACE_INSN (cpu, " pc = %" PRIx64 " instr = %08x", pc,
 	      aarch64_get_instr (cpu));