Hello,
I've tried to add TCG backend support for Mac OS X ppc64 with limited success. It seems the linkage area and LR offset are the same as on Linux, so the main difference I could find was the register usage.
This brought up two questions:
i) In ppc/tcg-target.c TCG_REG_R2 is listed twice in tcg_target_reg_alloc_order for __APPLE__. I assume this is not intended? It does so far work with or without this patch eliminating the second use:
diff --git a/tcg/ppc/tcg-target.c b/tcg/ppc/tcg-target.c
index 23f94a8..7607d85 100644
--- a/tcg/ppc/tcg-target.c
+++ b/tcg/ppc/tcg-target.c
@@ -114,7 +114,9 @@ static const int tcg_target_reg_alloc_order[] = {
#endif
TCG_REG_R0,
TCG_REG_R1,
+#ifndef __APPLE__
TCG_REG_R2,
+#endif
TCG_REG_R24,
TCG_REG_R25,
TCG_REG_R26,
Alternatively, if the order of r2 does not matter too much, we could remove the initial __APPLE__ section instead for simplicity.
ii) In ppc64/tcg-target.c tcg_target_call_oarg_regs is declared with a length of 2 but only contains one register. Intended?
diff --git a/tcg/ppc64/tcg-target.c b/tcg/ppc64/tcg-target.c
index a96314c..2a8eaec 100644
--- a/tcg/ppc64/tcg-target.c
+++ b/tcg/ppc64/tcg-target.c
@@ -125,11 +134,15 @@ static const int tcg_target_call_iarg_regs[] = {
TCG_REG_R10
};
-static const int tcg_target_call_oarg_regs[2] = {
+static const int tcg_target_call_oarg_regs[1] = {
TCG_REG_R3
};
Then for the real OSX/ppc64 changes, I have marked r11 and r13 callee-saved, like for OSX/ppc.
Reference:
http://developer.apple.com/documentation/DeveloperTools/Conceptual/LowLevelABI/110-64-bit_PowerPC_Function_Calling_Conventions/64bitPowerPC.htmlTo my knowledge in ppc64 mode (at least on the G5) the lmw and stmw instructions are illegal. We should probably remove their definitions, they are not currently being used in the ppc64 backend.
Unfortunately qemu-system-ppc still crashes immediately, any hints welcome.
Program received signal EXC_BAD_INSTRUCTION, Illegal instruction/operand.
0x00000000005a9680 in code_gen_prologue ()
(gdb) bt
#0 0x00000000005a9680 in code_gen_prologue ()
#1 0x00000000000c5ba0 in cpu_ppc_exec (env1=<value temporarily unavailable, due to optimizations>) at /Users/andreas/Q/qemu/cpu-exec.c:622
#2 0x000000000000a208 in qemu_main (argc=<value temporarily unavailable, due to optimizations>, argv=<value temporarily unavailable, due to optimizations>, envp=<value temporarily unavailable, due to optimizations>) at /Users/andreas/Q/qemu/vl.c:3828
#3 0x00000000000b2788 in -[QemuCocoaAppController startEmulationWithArgc:argv:] (self=<value temporarily unavailable, due to optimizations>, _cmd=<value temporarily unavailable, due to optimizations>, argc=<value temporarily unavailable, due to optimizations>, argv=<value temporarily unavailable, due to optimizations>) at /Users/andreas/Q/qemu/cocoa.m:780
#4 0x00007fff81b3ff08 in _nsnote_callback ()
#5 0x00007fff8104fd34 in _CFXNotificationPostNotification ()
#6 0x00007fff81b3c970 in -[NSNotificationCenter postNotificationName:object:userInfo:] ()
#7 0x00007fff81b476e0 in -[NSNotificationCenter postNotificationName:object:] ()
#8 0x00007fff81f58e24 in -[NSApplication _postDidFinishNotification] ()
#9 0x00007fff81f58ce4 in -[NSApplication _sendFinishLaunchingNotification] ()
#10 0x00007fff81eaf02c in -[NSApplication(NSAppleEventHandling) _handleAEOpen:] ()
#11 0x00007fff81eae51c in -[NSApplication(NSAppleEventHandling) _handleCoreEvent:withReplyEvent:] ()
#12 0x00007fff81b6bbe0 in -[NSAppleEventManager dispatchRawAppleEvent:withRawReply:handlerRefCon:] ()
#13 0x00007fff81b6b974 in _NSAppleEventManagerGenericHandler ()
#14 0x000000010067708c in aeDispatchAppleEvent ()
#15 0x000000010065f810 in dispatchEventAndSendReply ()
#16 0x000000010065f5cc in aeProcessAppleEvent ()
#17 0x00007fff843962dc in AEProcessAppleEvent ()
#18 0x00007fff81eaaf68 in _DPSNextEvent ()
#19 0x00007fff81eaa49c in -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] ()
#20 0x00007fff81ea185c in -[NSApplication run] ()
#21 0x00000000000b346c in main (argc=<value temporarily unavailable, due to optimizations>, argv=<value temporarily unavailable, due to optimizations>) at /Users/andreas/Q/qemu/cocoa.m:905
(gdb) q