Implement s390x LLVM backend.

This patch adds support for the s390x architecture for the LLVM code
generator. The patch includes a register mapping of STG registers onto
s390x machine registers which enables a registerised build.

3 files changed, 82 insertions, 0 deletions

diff --git a/includes/stg/MachRegs.h b/includes/stg/MachRegs.h
index 0afc88152e..ea1125bbf8 100644
--- a/includes/stg/MachRegs.h
+++ b/includes/stg/MachRegs.h
@@ -589,6 +589,78 @@ the stack. See Note [Overlapping global registers] for implications.
 #define REG_D3          d14
 #define REG_D4          d15
 
+/* -----------------------------------------------------------------------------
+   The s390x register mapping
+
+   Register    | Role(s)                                 | Call effect
+   ------------+-------------------------------------+-----------------
+   r0,r1       | -                                       | caller-saved
+   r2          | Argument / return value                 | caller-saved
+   r3,r4,r5    | Arguments                               | caller-saved
+   r6          | Argument                                | callee-saved
+   r7...r11    | -                                       | callee-saved
+   r12         | (Commonly used as GOT pointer)          | callee-saved
+   r13         | (Commonly used as literal pool pointer) | callee-saved
+   r14         | Return address                          | caller-saved
+   r15         | Stack pointer                           | callee-saved
+   f0          | Argument / return value                 | caller-saved
+   f2,f4,f6    | Arguments                               | caller-saved
+   f1,f3,f5,f7 | -                                       | caller-saved
+   f8...f15    | -                                       | callee-saved
+   v0...v31    | -                                       | caller-saved
+
+   Each general purpose register r0 through r15 as well as each floating-point
+   register f0 through f15 is 64 bits wide. Each vector register v0 through v31
+   is 128 bits wide.
+
+   Note, the vector registers v0 through v15 overlap with the floating-point
+   registers f0 through f15.
+
+   -------------------------------------------------------------------------- */
+
+#elif defined(MACHREGS_s390x)
+
+#define REG(x) __asm__("%" #x)
+
+#define REG_Base        r7
+#define REG_Sp          r8
+#define REG_Hp          r10
+#define REG_R1          r11
+#define REG_R2          r12
+#define REG_R3          r13
+#define REG_R4          r6
+#define REG_R5          r2
+#define REG_R6          r3
+#define REG_R7          r4
+#define REG_R8          r5
+#define REG_SpLim       r9
+#define REG_MachSp      r15
+
+#define REG_F1          f8
+#define REG_F2          f9
+#define REG_F3          f10
+#define REG_F4          f11
+#define REG_F5          f0
+#define REG_F6          f1
+
+#define REG_D1          f12
+#define REG_D2          f13
+#define REG_D3          f14
+#define REG_D4          f15
+#define REG_D5          f2
+#define REG_D6          f3
+
+#define CALLER_SAVES_R5
+#define CALLER_SAVES_R6
+#define CALLER_SAVES_R7
+#define CALLER_SAVES_R8
+
+#define CALLER_SAVES_F5
+#define CALLER_SAVES_F6
+
+#define CALLER_SAVES_D5
+#define CALLER_SAVES_D6
+
 #else
 
 #error Cannot find platform to give register info for
diff --git a/includes/stg/MachRegsForHost.h b/includes/stg/MachRegsForHost.h
index 135c7974bd..3597b2be90 100644
--- a/includes/stg/MachRegsForHost.h
+++ b/includes/stg/MachRegsForHost.h
@@ -67,6 +67,10 @@
 #define MACHREGS_darwin   1
 #endif
 
+#if defined(s390x_HOST_ARCH)
+#define MACHREGS_s390x    1
+#endif
+
 #endif
 
 #include "MachRegs.h"
diff --git a/includes/stg/SMP.h b/includes/stg/SMP.h
index 4be11d1f64..2d6a220a9e 100644
--- a/includes/stg/SMP.h
+++ b/includes/stg/SMP.h
@@ -336,6 +336,8 @@ write_barrier(void) {
 #elif defined(powerpc_HOST_ARCH) || defined(powerpc64_HOST_ARCH) \
     || defined(powerpc64le_HOST_ARCH)
     __asm__ __volatile__ ("lwsync" : : : "memory");
+#elif defined(s390x_HOST_ARCH)
+    __asm__ __volatile__ ("" : : : "memory");
 #elif defined(sparc_HOST_ARCH)
     /* Sparc in TSO mode does not require store/store barriers. */
     __asm__ __volatile__ ("" : : : "memory");
@@ -357,6 +359,8 @@ store_load_barrier(void) {
 #elif defined(powerpc_HOST_ARCH) || defined(powerpc64_HOST_ARCH) \
     || defined(powerpc64le_HOST_ARCH)
     __asm__ __volatile__ ("sync" : : : "memory");
+#elif defined(s390x_HOST_ARCH)
+    __asm__ __volatile__ ("bcr 14,0" : : : "memory");
 #elif defined(sparc_HOST_ARCH)
     __asm__ __volatile__ ("membar #StoreLoad" : : : "memory");
 #elif defined(arm_HOST_ARCH)
@@ -379,6 +383,8 @@ load_load_barrier(void) {
 #elif defined(powerpc_HOST_ARCH) || defined(powerpc64_HOST_ARCH) \
     || defined(powerpc64le_HOST_ARCH)
     __asm__ __volatile__ ("lwsync" : : : "memory");
+#elif defined(s390x_HOST_ARCH)
+    __asm__ __volatile__ ("" : : : "memory");
 #elif defined(sparc_HOST_ARCH)
     /* Sparc in TSO mode does not require load/load barriers. */
     __asm__ __volatile__ ("" : : : "memory");