[Lightning] x86_64 (System V AMD64 ABI): %r12

[Marc Nieper-Wißkirchen]

GNU lightning defines the register %r12 as a caller-saved register:

http://git.savannah.gnu.org/cgit/lightning.git/tree/include/lightning/jit_x86.h#n128

However, this is not correct. According to the System V AMD64 ABI, %r12 is a callee-saved register: https://uclibc.org/docs/psABI-x86_64.pdf.

Here is a patch (passes all tests):

diff --git a/ChangeLog b/ChangeLog
index 97263f7..9495b31 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-09-04 Marc Nieper-Wisskirchen <address@hidden>
+
+    * include/lightning/jit_x86.h, lib/jit_x86.c: Correct x86_64
+    backend, made %r12 a callee-save register as dictated by the
+    System V AMD64 ABI.
+
 2017-06-09 Paulo Andrade <address@hidden>
 
     * include/lightning/jit_private.h, lib/lightning.c: Add a
diff --git a/doc/version.texi b/doc/version.texi
index 7a9127c..99cd7b0 100644
--- a/doc/version.texi
+++ b/doc/version.texi
@@ -1,4 +1,4 @@
address@hidden UPDATED 7 February 2015
address@hidden UPDATED-MONTH February 2015
address@hidden UPDATED 30 August 2017
address@hidden UPDATED-MONTH August 2017
address@hidden EDITION 2.1.0
address@hidden VERSION 2.1.0
diff --git a/include/lightning/jit_x86.h b/include/lightning/jit_x86.h
index c0596b4..0a7af0b 100644
--- a/include/lightning/jit_x86.h
+++ b/include/lightning/jit_x86.h
@@ -117,21 +117,21 @@ typedef enum {
 #    define jit_sse_reg_p(reg)    ((reg) >= _XMM4 && (reg) <= _XMM0)
 #  else
 #    define jit_r(i)        (_RAX + (i))
-#    define jit_r_num()        4
+#    define jit_r_num()        3
 #    define jit_v(i)        (_RBX + (i))
-#    define jit_v_num()        4
+#    define jit_v_num()        5
 #    define jit_f(index)    (_XMM8 + (index))
 #    define jit_f_num()        8
 #    define JIT_R0        _RAX
 #    define JIT_R1        _R10
 #    define JIT_R2        _R11
-#    define JIT_R3        _R12
-    _RAX,    _R10,    _R11,    _R12,
+    _RAX,    _R10,    _R11,
 #    define JIT_V0        _RBX
-#    define JIT_V1        _R13
-#    define JIT_V2        _R14
-#    define JIT_V3        _R15
-    _RBX,    _R13,    _R14,    _R15,
+#    define JIT_V1              _R12
+#    define JIT_V2        _R13
+#    define JIT_V3        _R14
+#    define JIT_V4        _R15
+    _RBX,    _R12,   _R13,    _R14,    _R15,
     _R9,    _R8,    _RCX,    _RDX,    _RSI,    _RDI,
     _RSP,    _RBP,
 #    define JIT_F0        _XMM8
diff --git a/lib/jit_x86.c b/lib/jit_x86.c
index 2e3ba80..649c639 100644
--- a/lib/jit_x86.c
+++ b/lib/jit_x86.c
@@ -185,8 +185,8 @@ jit_register_t        _rvs[] = {
     { rc(arg) | rc(gpr) | rc(rg8) | 0,    "%rax" },
     { rc(gpr) | rc(rg8) | 10,        "%r10" },
     { rc(gpr) | rc(rg8) | 11,        "%r11" },
-    { rc(gpr) | rc(rg8) | 12,        "%r12" },
     { rc(sav) | rc(rg8) | rc(gpr) | 3,    "%rbx" },
+    { rc(sav) | rc(rg8) | rc(gpr) | 12,    "%r12" },
     { rc(sav) | rc(rg8) | rc(gpr) | 13,    "%r13" },
     { rc(sav) | rc(rg8) | rc(gpr) | 14,    "%r14" },
     { rc(sav) | rc(rg8) | rc(gpr) | 15,    "%r15" },

Marc