Ruby31: add support for Darwin ppc/ppc64 (#5927)

* add coroutines for ppc & ppc64

* fix universal coroutine to include ppc & ppc64

* add powerpc*-darwin to configure.ac

* fix thread_pthread for older systems

2 files changed, 127 insertions, 0 deletions

diff --git a/coroutine/ppc64/Context.S b/coroutine/ppc64/Context.S
new file mode 100644
index 0000000000..1bd9268f93
--- /dev/null
+++ b/coroutine/ppc64/Context.S
@@ -0,0 +1,70 @@
+#define TOKEN_PASTE(x,y) x##y
+#define PREFIXED_SYMBOL(prefix,name) TOKEN_PASTE(prefix,name)
+
+.text
+.align 3
+
+.globl PREFIXED_SYMBOL(SYMBOL_PREFIX,coroutine_transfer)
+PREFIXED_SYMBOL(SYMBOL_PREFIX,coroutine_transfer):
+	# Make space on the stack for caller registers
+	addi r1,r1,-152
+
+	# Save caller registers
+	std r14,0(r1)
+	std r15,8(r1)
+	std r16,16(r1)
+	std r17,24(r1)
+	std r18,32(r1)
+	std r19,40(r1)
+	std r20,48(r1)
+	std r21,56(r1)
+	std r22,64(r1)
+	std r23,72(r1)
+	std r24,80(r1)
+	std r25,88(r1)
+	std r26,96(r1)
+	std r27,104(r1)
+	std r28,112(r1)
+	std r29,120(r1)
+	std r30,128(r1)
+	std r31,136(r1)
+
+	# Save return address
+	mflr r0
+	std r0,144(r1)
+
+	# Save stack pointer to first argument
+	std r1,0(r3)
+
+	# Load stack pointer from second argument
+	ld r1,0(r4)
+
+	# Restore caller registers
+	ld r14,0(r1)
+	ld r15,8(r1)
+	ld r16,16(r1)
+	ld r17,24(r1)
+	ld r18,32(r1)
+	ld r19,40(r1)
+	ld r20,48(r1)
+	ld r21,56(r1)
+	ld r22,64(r1)
+	ld r23,72(r1)
+	ld r24,80(r1)
+	ld r25,88(r1)
+	ld r26,96(r1)
+	ld r27,104(r1)
+	ld r28,112(r1)
+	ld r29,120(r1)
+	ld r30,128(r1)
+	ld r31,136(r1)
+
+	# Load return address
+	ld r0,144(r1)
+	mtlr r0
+
+	# Pop stack frame
+	addi r1,r1,152
+
+	# Jump to return address
+	blr
diff --git a/coroutine/ppc64/Context.h b/coroutine/ppc64/Context.h
new file mode 100644
index 0000000000..5b47511b9c
--- /dev/null
+++ b/coroutine/ppc64/Context.h
@@ -0,0 +1,57 @@
+#ifndef COROUTINE_PPC64_CONTEXT_H
+#define COROUTINE_PPC64_CONTEXT_H 1
+
+#pragma once
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+#define COROUTINE __attribute__((noreturn)) void
+
+enum {
+  COROUTINE_REGISTERS =
+  19  /* 18 general purpose registers (r14–r31) and 1 return address */
+  + 4  /* space for fiber_entry() to store the link register */
+};
+
+struct coroutine_context
+{
+    void **stack_pointer;
+    void *argument;
+};
+
+typedef COROUTINE(* coroutine_start)(struct coroutine_context *from, struct coroutine_context *self);
+
+static inline void coroutine_initialize_main(struct coroutine_context * context) {
+    context->stack_pointer = NULL;
+}
+
+static inline void coroutine_initialize(
+    struct coroutine_context *context,
+    coroutine_start start,
+    void *stack,
+    size_t size
+) {
+    assert(start && stack && size >= 1024);
+
+    // Stack grows down. Force 16-byte alignment.
+    char * top = (char*)stack + size;
+    context->stack_pointer = (void**)((uintptr_t)top & ~0xF);
+
+    context->stack_pointer -= COROUTINE_REGISTERS;
+    memset(context->stack_pointer, 0, sizeof(void*) * COROUTINE_REGISTERS);
+
+    /* Skip a global prologue that sets the TOC register */
+    context->stack_pointer[18] = ((char*)start) + 8;
+}
+
+struct coroutine_context * coroutine_transfer(struct coroutine_context * current, struct coroutine_context * target);
+
+static inline void coroutine_destroy(struct coroutine_context * context)
+{
+    context->stack_pointer = NULL;
+}
+
+#endif /* COROUTINE_PPC64_CONTEXT_H */