Drop support for Darwin on PowerPC

The last Mac OS X release for PowerPC Macs is 10.5, and nothing else runs this code.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

configure.ac

@@ -2079,22 +2079,7 @@ AS_IF([test $rb_cv_stack_end_address != no], [
 
 dnl Checks for library functions.
 AC_TYPE_GETGROUPS
-AS_CASE(["${target_cpu}-${target_os}:${target_archs}"],
-[powerpc*-darwin*], [
-  AC_LIBSOURCES(alloca.c)
-  AC_SUBST([ALLOCA], [\${LIBOBJDIR}alloca.${ac_objext}])
-  AC_DEFINE(C_ALLOCA)
-  AC_DEFINE_UNQUOTED(alloca, alloca)
-  ],
-[universal-darwin*:*ppc*], [
-  AC_LIBSOURCES(alloca.c)
-  AC_SUBST([ALLOCA], [\${LIBOBJDIR}alloca.${ac_objext}])
-  RUBY_DEFINE_IF([defined __POWERPC__], C_ALLOCA, 1) # Darwin defines __POWERPC__ for ppc and ppc64 both
-  RUBY_DEFINE_IF([defined __POWERPC__], alloca, alloca)
-  ],
-[
-  AC_FUNC_ALLOCA
-  ])
+AC_FUNC_ALLOCA
 AS_IF([test "x$ALLOCA" = "x"], [
     AC_CACHE_CHECK([for dynamic size alloca], rb_cv_dynamic_alloca, [
     for chk in ok __chkstk; do
@@ -2748,15 +2733,6 @@ AS_CASE([$coroutine_type], [yes|''], [
         [arm64-darwin*], [
             coroutine_type=arm64
         ],
-        # Correct target name is powerpc*-, but Ruby seems to prefer ppc*-.
-        # Notice that Darwin PPC ABI differs from AIX and ELF.
-        # Adding PPC targets for AIX, *BSD and *Linux will require separate implementations.
-        [powerpc-darwin*|ppc-darwin*], [
-            coroutine_type=ppc
-        ],
-        [powerpc64-darwin*|ppc64-darwin*], [
-            coroutine_type=ppc64
-        ],
         [x*64-linux*], [
             AS_CASE(["$ac_cv_sizeof_voidp"],
                 [8], [ coroutine_type=amd64 ],

coroutine/ppc/Context.S

@@ -1,96 +0,0 @@
-; Based on the code by Samuel Williams. Created by Sergey Fedorov on 04/06/2022.
-; Credits to Samuel Williams, Rei Odaira and Iain Sandoe. Errors, if any, are mine.
-; Some relevant examples: https://github.com/gcc-mirror/gcc/blob/master/libphobos/libdruntime/config/powerpc/switchcontext.S
-; https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/rs6000/darwin-gpsave.S
-; https://www.ibm.com/docs/en/aix/7.2?topic=epilogs-saving-gprs-only
-; ppc32 version may be re-written compactly with stmw/lwm, but the code won't be faster, see: https://github.com/ruby/ruby/pull/5927#issuecomment-1139730541
-
-; Notice that this code is only for Darwin (macOS). Darwin ABI differs from AIX and ELF.
-; To add support for AIX, *BSD or *Linux, please make separate implementations.
-
-#define TOKEN_PASTE(x,y) x##y
-
-.machine ppc7400 ; = G4, Rosetta
-.text
-
-.globl PREFIXED_SYMBOL(coroutine_transfer)
-.align 2
-
-PREFIXED_SYMBOL(coroutine_transfer):
-	; Make space on the stack for caller registers
-	; (Should we rather use red zone? See libphobos example.)
-	subi r1,r1,80
-
-	; Get LR
-	mflr r0
-
-	; Save caller registers
-	stw r31,0(r1)
-	stw r30,4(r1)
-	stw r29,8(r1)
-	stw r28,12(r1)
-	stw r27,16(r1)
-	stw r26,20(r1)
-	stw r25,24(r1)
-	stw r24,28(r1)
-	stw r23,32(r1)
-	stw r22,36(r1)
-	stw r21,40(r1)
-	stw r20,44(r1)
-	stw r19,48(r1)
-	stw r18,52(r1)
-	stw r17,56(r1)
-	stw r16,60(r1)
-	stw r15,64(r1)
-	stw r14,68(r1)
-	stw r13,72(r1)
-
-	; Save return address
-	stw r0,76(r1)
-
-	; Save nonvolatile CR fields in the caller linkage area
-	mfcr r0
-	stw r0,84(r1)
-
-	; Save stack pointer to first argument
-	stw r1,0(r3)
-
-	; Load stack pointer from second argument
-	lwz r1,0(r4)
-
-	; Load return address
-	lwz r0,76(r1)
-
-	; Restore caller registers
-	lwz r13,72(r1)
-	lwz r14,68(r1)
-	lwz r15,64(r1)
-	lwz r16,60(r1)
-	lwz r17,56(r1)
-	lwz r18,52(r1)
-	lwz r19,48(r1)
-	lwz r20,44(r1)
-	lwz r21,40(r1)
-	lwz r22,36(r1)
-	lwz r23,32(r1)
-	lwz r24,28(r1)
-	lwz r25,24(r1)
-	lwz r26,20(r1)
-	lwz r27,16(r1)
-	lwz r28,12(r1)
-	lwz r29,8(r1)
-	lwz r30,4(r1)
-	lwz r31,0(r1)
-
-	; Set LR
-	mtlr r0
-
-	; Restore nonvolatile CR2-CR4
-	lwz r0,84(r1)
-	mtcrf 56,r0
-
-	; Pop stack frame
-	addi r1,r1,80
-
-	; Jump to return address
-	blr

coroutine/ppc/Context.h

@@ -1,58 +0,0 @@
-#ifndef COROUTINE_PPC_CONTEXT_H
-#define COROUTINE_PPC_CONTEXT_H 1
-
-#pragma once
-
-#include <assert.h>
-#include <stddef.h>
-#include <stdint.h>
-#include <string.h>
-
-#define COROUTINE __attribute__((noreturn)) void
-#define COROUTINE_LIMITED_ADDRESS_SPACE
-
-enum {
-  COROUTINE_REGISTERS =
-  20  /* 19 general purpose registers (r13-r31) and 1 return address */
-  + 4  /* caller linkage area, including the condition register save slot */
-};
-
-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[19] = ((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_PPC_CONTEXT_H */

coroutine/ppc64/Context.S

@@ -1,95 +0,0 @@
-; Based on the code by Samuel Williams. Created by Sergey Fedorov on 04/06/2022.
-; Credits to Samuel Williams, Rei Odaira and Iain Sandoe. Errors, if any, are mine.
-; Some relevant examples: https://github.com/gcc-mirror/gcc/blob/master/libphobos/libdruntime/config/powerpc/switchcontext.S
-; https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/rs6000/darwin-gpsave.S
-; https://www.ibm.com/docs/en/aix/7.2?topic=epilogs-saving-gprs-only
-
-; Notice that this code is only for Darwin (macOS). Darwin ABI differs from AIX and ELF.
-; To add support for AIX, *BSD or *Linux, please make separate implementations.
-
-#define TOKEN_PASTE(x,y) x##y
-
-.machine ppc64 ; = G5
-.text
-
-.globl PREFIXED_SYMBOL(coroutine_transfer)
-.align 2
-
-PREFIXED_SYMBOL(coroutine_transfer):
-	; Make space on the stack for caller registers
-	; (Should we rather use red zone? See libphobos example.)
-	subi r1,r1,160
-
-	; Get LR
-	mflr r0
-
-	; Save caller registers
-	std r31,0(r1)
-	std r30,8(r1)
-	std r29,16(r1)
-	std r28,24(r1)
-	std r27,32(r1)
-	std r26,40(r1)
-	std r25,48(r1)
-	std r24,56(r1)
-	std r23,64(r1)
-	std r22,72(r1)
-	std r21,80(r1)
-	std r20,88(r1)
-	std r19,96(r1)
-	std r18,104(r1)
-	std r17,112(r1)
-	std r16,120(r1)
-	std r15,128(r1)
-	std r14,136(r1)
-	std r13,144(r1)
-
-	; Save return address
-	std r0,152(r1)
-
-	; Save nonvolatile CR fields in the caller linkage area
-	mfcr r0
-	std r0,168(r1)
-
-	; Save stack pointer to first argument
-	std r1,0(r3)
-
-	; Load stack pointer from second argument
-	ld r1,0(r4)
-
-	; Load return address
-	ld r0,152(r1)
-
-	; Restore caller registers
-	ld r13,144(r1)
-	ld r14,136(r1)
-	ld r15,128(r1)
-	ld r16,120(r1)
-	ld r17,112(r1)
-	ld r18,104(r1)
-	ld r19,96(r1)
-	ld r20,88(r1)
-	ld r21,80(r1)
-	ld r22,72(r1)
-	ld r23,64(r1)
-	ld r24,56(r1)
-	ld r25,48(r1)
-	ld r26,40(r1)
-	ld r27,32(r1)
-	ld r28,24(r1)
-	ld r29,16(r1)
-	ld r30,8(r1)
-	ld r31,0(r1)
-
-	; Set LR
-	mtlr r0
-
-	; Restore nonvolatile CR2-CR4
-	ld r0,168(r1)
-	mtcrf 56,r0
-
-	; Pop stack frame
-	addi r1,r1,160
-
-	; Jump to return address
-	blr

coroutine/ppc64/Context.h

@@ -1,57 +0,0 @@
-#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 =
-  20  /* 19 general purpose registers (r13-r31) and 1 return address */
-  + 4  /* caller linkage area, including the condition register save slot */
-};
-
-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[19] = ((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 */

coroutine/universal/Context.S

@@ -3,12 +3,6 @@
 # include "coroutine/amd64/Context.S"
 #elif defined __i386__
 # include "coroutine/x86/Context.S"
-#elif defined __ppc__
-# include "coroutine/ppc/Context.S"
-#elif defined __ppc64__ && defined(WORDS_BIGENDIAN)
-# include "coroutine/ppc64/Context.S"
-#elif defined __ppc64__ && !defined(WORDS_BIGENDIAN)
-# include "coroutine/ppc64le/Context.S"
 #elif defined __arm64__
 # include "coroutine/arm64/Context.S"
 #else

coroutine/universal/Context.h

@@ -6,12 +6,6 @@
 # include "coroutine/amd64/Context.h"
 #elif defined __i386__
 # include "coroutine/x86/Context.h"
-#elif defined __ppc__
-# include "coroutine/ppc/Context.h"
-#elif defined __ppc64__ && defined(WORDS_BIGENDIAN)
-# include "coroutine/ppc64/Context.h"
-#elif defined __ppc64__ && !defined(WORDS_BIGENDIAN)
-# include "coroutine/ppc64le/Context.h"
 #elif defined __arm64__
 # include "coroutine/arm64/Context.h"
 #else

error.c

@@ -966,7 +966,7 @@ bug_important_message(FILE *out, const char *const msg, size_t len)
 
 #undef CRASH_REPORTER_MAY_BE_CREATED
 #if defined(__APPLE__) && \
-    (!defined(MAC_OS_X_VERSION_10_6) || MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_6 || defined(__POWERPC__)) /* 10.6 PPC case */
+    (!defined(MAC_OS_X_VERSION_10_6) || MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_6)
 # define CRASH_REPORTER_MAY_BE_CREATED
 #endif
 static void

gc/default/default.c

@@ -1690,27 +1690,6 @@ tick(void)
     return val;
 }
 
-#elif defined(__POWERPC__) && defined(__APPLE__)
-/* Implementation for macOS PPC by @nobu
- * See: https://github.com/ruby/ruby/pull/5975#discussion_r890045558
- */
-typedef unsigned long long tick_t;
-#define PRItick "llu"
-
-static __inline__ tick_t
-tick(void)
-{
-    unsigned long int upper, lower, tmp;
-    # define mftbu(r) __asm__ volatile("mftbu   %0" : "=r"(r))
-    # define mftb(r)  __asm__ volatile("mftb    %0" : "=r"(r))
-        do {
-            mftbu(upper);
-            mftb(lower);
-            mftbu(tmp);
-        } while (tmp != upper);
-    return ((tick_t)upper << 32) | lower;
-}
-
 #elif defined(__aarch64__) &&  defined(__GNUC__)
 typedef unsigned long tick_t;
 #define PRItick "lu"

internal/gc.h

@@ -26,12 +26,10 @@ struct rb_gc_zjit_fastpath;
 #define SET_MACHINE_STACK_END(p) __asm__ __volatile__ ("movq\t%%rsp, %0" : "=r" (*(p)))
 #elif defined(__i386) && defined(__GNUC__)
 #define SET_MACHINE_STACK_END(p) __asm__ __volatile__ ("movl\t%%esp, %0" : "=r" (*(p)))
-#elif (defined(__powerpc__) || defined(__powerpc64__)) && defined(__GNUC__) && !defined(_AIX) && !defined(__APPLE__) // Not Apple is NEEDED to unbreak ppc64 build on Darwin. Don't ask.
+#elif (defined(__powerpc__) || defined(__powerpc64__)) && defined(__GNUC__) && !defined(_AIX)
 #define SET_MACHINE_STACK_END(p) __asm__ __volatile__ ("mr\t%0, %%r1" : "=r" (*(p)))
 #elif (defined(__powerpc__) || defined(__powerpc64__)) && defined(__GNUC__) && defined(_AIX)
 #define SET_MACHINE_STACK_END(p) __asm__ __volatile__ ("mr %0,1" : "=r" (*(p)))
-#elif defined(__POWERPC__) && defined(__APPLE__) // Darwin ppc and ppc64
-#define SET_MACHINE_STACK_END(p) __asm__ volatile("mr %0, r1" : "=r" (*(p)))
 #elif defined(__aarch64__) && defined(__GNUC__)
 #define SET_MACHINE_STACK_END(p) __asm__ __volatile__ ("mov\t%0, sp" : "=r" (*(p)))
 #else

thread_pthread.c

@@ -1126,12 +1126,10 @@ native_thread_native_thread_id(rb_thread_t *target_th)
 #elif defined(__APPLE__)
     uint64_t tid;
 /* The first condition is needed because MAC_OS_X_VERSION_10_6
-    is not defined on 10.5, and while __POWERPC__ takes care of ppc/ppc64,
-    i386 will be broken without this. Note, 10.5 is supported with GCC upstream,
+    is not defined on 10.5. Note, 10.5 is supported with GCC upstream,
     so it has C++17 and everything needed to build modern Ruby. */
 # if (!defined(MAC_OS_X_VERSION_10_6) || \
-      (MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6) || \
-      defined(__POWERPC__) /* never defined for PowerPC platforms */)
+      (MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6))
     const bool no_pthread_threadid_np = true;
 #   define NO_PTHREAD_MACH_THREAD_NP 1
 # elif MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_6

tool/m4/ruby_universal_arch.m4

@@ -60,12 +60,6 @@ AS_IF([test ${target_archs+set}], [
 #ifdef __i386__
 "processor-name=i386"
 #endif
-#ifdef __ppc__
-"processor-name=powerpc"
-#endif
-#ifdef __ppc64__
-"processor-name=powerpc64"
-#endif
 #ifdef __arm64__
 "processor-name=arm64"
 #endif

vm_core.h

@@ -886,7 +886,7 @@ extern bool ruby_vm_during_cleanup;
 #define RUBY_VM_FIBER_VM_STACK_SIZE           (  16 * 1024 * sizeof(VALUE)) /*   64 KB or  128 KB */
 #define RUBY_VM_FIBER_VM_STACK_SIZE_MIN       (   2 * 1024 * sizeof(VALUE)) /*    8 KB or   16 KB */
 #define RUBY_VM_FIBER_MACHINE_STACK_SIZE      (  64 * 1024 * sizeof(VALUE)) /*  256 KB or  512 KB */
-#if defined(__powerpc64__) || defined(__ppc64__) // macOS has __ppc64__
+#if defined(__powerpc64__)
 #define RUBY_VM_FIBER_MACHINE_STACK_SIZE_MIN  (  32 * 1024 * sizeof(VALUE)) /*  128 KB or  256 KB */
 #else
 #define RUBY_VM_FIBER_MACHINE_STACK_SIZE_MIN  (  16 * 1024 * sizeof(VALUE)) /*   64 KB or  128 KB */

vm_dump.c

@@ -778,7 +778,7 @@ rb_vmdebug_thread_dump_state(FILE *errout, VALUE self)
 #  include <sys/mman.h>
 #  undef backtrace
 
-#  if defined(__arm64__) || defined(__POWERPC__)
+#  if defined(__arm64__)
 static bool
 is_coroutine_start(unw_word_t ip)
 {
@@ -891,22 +891,19 @@ darwin_sigtramp:
     }
     return n;
 
-#  elif defined(__arm64__) || defined(__POWERPC__)
+#  elif defined(__arm64__)
     /* Since Darwin arm64's _sigtramp is implemented as normal function,
      * unwind can unwind frames without special code.
      * https://github.com/apple/darwin-libplatform/blob/215b09856ab5765b7462a91be7076183076600df/src/setjmp/generic/sigtramp.c
      */
     while (n < size && unw_step(&cursor) > 0) {
         unw_get_reg(&cursor, UNW_REG_IP, &ip);
-#   if defined(__arm64__)
         // Strip Arm64's pointer authentication.
         // https://developer.apple.com/documentation/security/preparing_your_app_to_work_with_pointer_authentication
         // I wish I could use "ptrauth_strip()" but I get an error:
         // "this target does not support pointer authentication"
         trace[n++] = (void *)(ip & 0x7fffffffffffull);
-#   else
-        trace[n++] = (void *)ip;
-#   endif
+
         // Apple's libunwind can't handle our coroutine switching code
         if (is_coroutine_start(ip)) break;
     }