Add iOS support

src/arm/ffi.c

@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------
-   ffi.c - Copyright (c) 1998, 2008  Red Hat, Inc.
+   ffi.c - Copyright (c) 1998, 2008, 2011  Red Hat, Inc.
    
    ARM Foreign Function Interface 
 
@@ -337,6 +337,220 @@ ffi_prep_incoming_args_SYSV(char *stack, void **rvalue,
 
 /* How to make a trampoline.  */
 
+#if FFI_EXEC_TRAMPOLINE_TABLE
+
+#include <mach/mach.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+extern void *ffi_closure_trampoline_table_page;
+
+typedef struct ffi_trampoline_table ffi_trampoline_table;
+typedef struct ffi_trampoline_table_entry ffi_trampoline_table_entry;
+
+struct ffi_trampoline_table {
+  /* contigious writable and executable pages */
+  vm_address_t config_page;
+  vm_address_t trampoline_page;
+
+  /* free list tracking */
+  uint16_t free_count;
+  ffi_trampoline_table_entry *free_list;
+  ffi_trampoline_table_entry *free_list_pool;
+
+  ffi_trampoline_table *prev;
+  ffi_trampoline_table *next;
+};
+
+struct ffi_trampoline_table_entry {
+  void *(*trampoline)();
+  ffi_trampoline_table_entry *next;
+};
+
+/* Override the standard architecture trampoline size */
+// XXX TODO - Fix
+#undef FFI_TRAMPOLINE_SIZE
+#define FFI_TRAMPOLINE_SIZE 12
+
+/* The trampoline configuration is placed at 4080 bytes prior to the trampoline's entry point */
+#define FFI_TRAMPOLINE_CODELOC_CONFIG(codeloc) ((void **) (((uint8_t *) codeloc) - 4080));
+
+/* The first 16 bytes of the config page are unused, as they are unaddressable from the trampoline page. */
+#define FFI_TRAMPOLINE_CONFIG_PAGE_OFFSET 16
+
+/* Total number of trampolines that fit in one trampoline table */
+#define FFI_TRAMPOLINE_COUNT ((PAGE_SIZE - FFI_TRAMPOLINE_CONFIG_PAGE_OFFSET) / FFI_TRAMPOLINE_SIZE)
+
+static pthread_mutex_t ffi_trampoline_lock = PTHREAD_MUTEX_INITIALIZER;
+static ffi_trampoline_table *ffi_trampoline_tables = NULL;
+
+static ffi_trampoline_table *
+ffi_trampoline_table_alloc ()
+{
+  ffi_trampoline_table *table = NULL;
+
+  /* Loop until we can allocate two contigious pages */
+  while (table == NULL) {
+    vm_address_t config_page = 0x0;
+    kern_return_t kt;
+
+    /* Try to allocate two pages */
+    kt = vm_allocate (mach_task_self (), &config_page, PAGE_SIZE*2, VM_FLAGS_ANYWHERE);
+    if (kt != KERN_SUCCESS) {
+      fprintf(stderr, "vm_allocate() failure: %d at %s:%d\n", kt, __FILE__, __LINE__);
+      break;
+    }
+
+    /* Now drop the second half of the allocation to make room for the trampoline table */
+    vm_address_t trampoline_page = config_page+PAGE_SIZE;
+    kt = vm_deallocate (mach_task_self (), trampoline_page, PAGE_SIZE);
+    if (kt != KERN_SUCCESS) {
+      fprintf(stderr, "vm_deallocate() failure: %d at %s:%d\n", kt, __FILE__, __LINE__);
+      break;
+    }
+
+    /* Remap the trampoline table to directly follow the config page */
+    vm_prot_t cur_prot;
+    vm_prot_t max_prot;
+
+    kt = vm_remap (mach_task_self (), &trampoline_page, PAGE_SIZE, 0x0, FALSE, mach_task_self (), (vm_address_t) &ffi_closure_trampoline_table_page, FALSE, &cur_prot, &max_prot, VM_INHERIT_SHARE);
+
+    /* If we lost access to the destination trampoline page, drop our config allocation mapping and retry */
+    if (kt != KERN_SUCCESS) {
+      /* Log unexpected failures */
+      if (kt != KERN_NO_SPACE) {
+        fprintf(stderr, "vm_remap() failure: %d at %s:%d\n", kt, __FILE__, __LINE__);
+      }
+
+      vm_deallocate (mach_task_self (), config_page, PAGE_SIZE);
+      continue;
+    }
+
+    /* We have valid trampoline and config pages */
+    table = calloc (1, sizeof(ffi_trampoline_table));
+    table->free_count = FFI_TRAMPOLINE_COUNT;
+    table->config_page = config_page;
+    table->trampoline_page = trampoline_page;
+
+    /* Create and initialize the free list */
+    table->free_list_pool = calloc(FFI_TRAMPOLINE_COUNT, sizeof(ffi_trampoline_table_entry));
+
+    uint16_t i;
+    for (i = 0; i < table->free_count; i++) {
+      ffi_trampoline_table_entry *entry = &table->free_list_pool[i];
+      entry->trampoline = (void *) (table->trampoline_page + (i * FFI_TRAMPOLINE_SIZE));
+
+      if (i < table->free_count - 1)
+        entry->next = &table->free_list_pool[i+1];
+    }
+
+    table->free_list = table->free_list_pool;
+  }
+
+  return table;
+}
+
+void *
+ffi_closure_alloc (size_t size, void **code)
+{
+  /* Create the closure */
+  ffi_closure *closure = malloc(size);
+  if (closure == NULL)
+    return NULL;
+
+  pthread_mutex_lock(&ffi_trampoline_lock);
+
+  /* Check for an active trampoline table with available entries. */
+  ffi_trampoline_table *table = ffi_trampoline_tables;
+  if (table == NULL || table->free_list == NULL) {
+    table = ffi_trampoline_table_alloc ();
+    if (table == NULL) {
+      free(closure);
+      return NULL;
+    }
+
+    /* Insert the new table at the top of the list */
+    table->next = ffi_trampoline_tables;
+    if (table->next != NULL)
+        table->next->prev = table;
+
+    ffi_trampoline_tables = table;
+  }
+
+  /* Claim the free entry */
+  ffi_trampoline_table_entry *entry = ffi_trampoline_tables->free_list;
+  ffi_trampoline_tables->free_list = entry->next;
+  ffi_trampoline_tables->free_count--;
+  entry->next = NULL;
+
+  pthread_mutex_unlock(&ffi_trampoline_lock);
+
+  /* Initialize the return values */
+  *code = entry->trampoline;
+  closure->trampoline_table = table;
+  closure->trampoline_table_entry = entry;
+
+  return closure;
+}
+
+void
+ffi_closure_free (void *ptr)
+{
+  ffi_closure *closure = ptr;
+
+  pthread_mutex_lock(&ffi_trampoline_lock);
+
+  /* Fetch the table and entry references */
+  ffi_trampoline_table *table = closure->trampoline_table;
+  ffi_trampoline_table_entry *entry = closure->trampoline_table_entry;
+
+  /* Return the entry to the free list */
+  entry->next = table->free_list;
+  table->free_list = entry;
+  table->free_count++;
+
+  /* If all trampolines within this table are free, and at least one other table exists, deallocate
+   * the table */
+  if (table->free_count == FFI_TRAMPOLINE_COUNT && ffi_trampoline_tables != table) {
+    /* Remove from the list */
+    if (table->prev != NULL)
+      table->prev->next = table->next;
+
+    if (table->next != NULL)
+      table->next->prev = table->prev;
+
+    /* Deallocate pages */
+    kern_return_t kt;
+    kt = vm_deallocate (mach_task_self (), table->config_page, PAGE_SIZE);
+    if (kt != KERN_SUCCESS)
+      fprintf(stderr, "vm_deallocate() failure: %d at %s:%d\n", kt, __FILE__, __LINE__);
+
+    kt = vm_deallocate (mach_task_self (), table->trampoline_page, PAGE_SIZE);
+    if (kt != KERN_SUCCESS)
+      fprintf(stderr, "vm_deallocate() failure: %d at %s:%d\n", kt, __FILE__, __LINE__);
+
+    /* Deallocate free list */
+    free (table->free_list_pool);
+    free (table);
+  } else if (ffi_trampoline_tables != table) {
+    /* Otherwise, bump this table to the top of the list */
+    table->prev = NULL;
+    table->next = ffi_trampoline_tables;
+    if (ffi_trampoline_tables != NULL)
+      ffi_trampoline_tables->prev = table;
+
+    ffi_trampoline_tables = table;
+  }
+
+  pthread_mutex_unlock (&ffi_trampoline_lock);
+
+  /* Free the closure */
+  free (closure);
+}
+
+#else
+
 #define FFI_INIT_TRAMPOLINE(TRAMP,FUN,CTX)				\
 ({ unsigned char *__tramp = (unsigned char*)(TRAMP);			\
    unsigned int  __fun = (unsigned int)(FUN);				\
@@ -349,6 +563,7 @@ ffi_prep_incoming_args_SYSV(char *stack, void **rvalue,
    __clear_cache((&__tramp[0]), (&__tramp[19]));			\
  })
 
+#endif
 
 /* the cif must already be prep'ed */
 
@@ -368,10 +583,16 @@ ffi_prep_closure_loc (ffi_closure* closure,
   else
     FFI_ASSERT (0);
     
+#if FFI_EXEC_TRAMPOLINE_TABLE
+  void **config = FFI_TRAMPOLINE_CODELOC_CONFIG(codeloc);
+  config[0] = closure;
+  config[1] = closure_func;
+#else
   FFI_INIT_TRAMPOLINE (&closure->tramp[0], \
 		       closure_func,  \
 		       codeloc);
-    
+#endif
+
   closure->cif  = cif;
   closure->user_data = user_data;
   closure->fun  = fun;

src/arm/gentramp.sh

@@ -0,0 +1,118 @@
+#!/bin/sh
+
+# -----------------------------------------------------------------------
+#  gentramp.sh - Copyright (c) 2010, Plausible Labs Cooperative, Inc.
+#  
+#  ARM Trampoline Page Generator
+#
+#  Permission is hereby granted, free of charge, to any person obtaining
+#  a copy of this software and associated documentation files (the
+#  ``Software''), to deal in the Software without restriction, including
+#  without limitation the rights to use, copy, modify, merge, publish,
+#  distribute, sublicense, and/or sell copies of the Software, and to
+#  permit persons to whom the Software is furnished to do so, subject to
+#  the following conditions:
+#
+#  The above copyright notice and this permission notice shall be included
+#  in all copies or substantial portions of the Software.
+#
+#  THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND,
+#  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+#  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+#  NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+#  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+#  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+#  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+#  DEALINGS IN THE SOFTWARE.
+#  -----------------------------------------------------------------------
+
+PROGNAME=$0
+
+# Each trampoline is exactly 3 instructions, or 12 bytes. If any of these values change,
+# the entire arm trampoline implementation must be updated to match, too.
+
+# Size of an individual trampoline, in bytes
+TRAMPOLINE_SIZE=12
+
+# Page size, in bytes
+PAGE_SIZE=4096
+
+# Compute the size of the reachable config page; The first 16 bytes of the config page
+# are unreachable due to our maximum pc-relative ldr offset.
+PAGE_AVAIL=`expr $PAGE_SIZE - 16`
+
+# Compute the number of of available trampolines. 
+TRAMPOLINE_COUNT=`expr $PAGE_AVAIL / $TRAMPOLINE_SIZE`
+
+header () {
+    echo "# GENERATED CODE - DO NOT EDIT"
+    echo "# This file was generated by $PROGNAME"
+    echo ""
+
+    # Write out the license header
+cat << EOF
+#  Copyright (c) 2010, Plausible Labs Cooperative, Inc.
+#  
+#  Permission is hereby granted, free of charge, to any person obtaining
+#  a copy of this software and associated documentation files (the
+#  ``Software''), to deal in the Software without restriction, including
+#  without limitation the rights to use, copy, modify, merge, publish,
+#  distribute, sublicense, and/or sell copies of the Software, and to
+#  permit persons to whom the Software is furnished to do so, subject to
+#  the following conditions:
+#
+#  The above copyright notice and this permission notice shall be included
+#  in all copies or substantial portions of the Software.
+#
+#  THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND,
+#  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+#  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+#  NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+#  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+#  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+#  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+#  DEALINGS IN THE SOFTWARE.
+#  -----------------------------------------------------------------------
+
+EOF
+
+    # Write out the trampoline table, aligned to the page boundary
+    echo ".text"
+    echo ".align 12"
+    echo ".globl _ffi_closure_trampoline_table_page"
+    echo "_ffi_closure_trampoline_table_page:"
+}
+
+
+# WARNING - Don't modify the trampoline code size without also updating the relevent libffi code
+trampoline () {
+    cat << END
+
+    // trampoline
+    // Save to stack
+    stmfd sp!, {r0-r3}
+
+    // Load the context argument from the config page.
+    // This places the first usable config value at _ffi_closure_trampoline_table-4080
+    // This accounts for the above 4-byte stmfd instruction, plus 8 bytes constant when loading from pc.
+    ldr r0, [pc, #-4092]
+
+    // Load the jump address from the config page.
+    ldr pc, [pc, #-4092]
+
+END
+}
+
+main () {
+    # Write out the header
+    header
+
+    # Write out the trampolines
+    local i=0
+    while [ $i -lt ${TRAMPOLINE_COUNT} ]; do
+        trampoline
+        local i=`expr $i + 1`
+    done
+}
+
+main

src/arm/sysv.S

@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------
-   sysv.S - Copyright (c) 1998, 2008 Red Hat, Inc.
+   sysv.S - Copyright (c) 1998, 2008, 2011 Red Hat, Inc.
    
    ARM Foreign Function Interface 
 
@@ -39,7 +39,11 @@
 #else
 #define CNAME(x) x
 #endif
+#ifdef __APPLE__
+#define ENTRY(x) .globl CNAME(x); CNAME(x):
+#else
 #define ENTRY(x) .globl CNAME(x); .type CNAME(x),%function; CNAME(x):
+#endif /* __APPLE__ */
 #endif
 
 #ifdef __ELF__
@@ -48,6 +52,12 @@
 #define LSYM(x) x
 #endif
 
+/* Use the SOFTFP return value ABI on Mac OS X, as per the iOS ABI
+  Function Call Guide */
+#ifdef __APPLE__
+#define __SOFTFP__
+#endif
+
 /* We need a better way of testing for this, but for now, this is all 
    we can do.  */
 @ This selects the minimum architecture level required.
@@ -105,21 +115,33 @@
 	.align 0
 	.thumb
 	.thumb_func
+#ifdef __APPLE__
+	ENTRY($0)
+#else
 	ENTRY(\name)
+#endif
 	bx	pc
 	nop
 	.arm
 	UNWIND .fnstart
 /* A hook to tell gdb that we've switched to ARM mode.  Also used to call
    directly from other local arm routines.  */
-_L__\name:		
+#ifdef __APPLE__
+_L__$0:
+#else
+_L__\name:
+#endif
 .endm
 #else
 .macro	ARM_FUNC_START name
 	.text
 	.align 0
 	.arm
+#ifdef __APPLE__
+	ENTRY($0)
+#else
 	ENTRY(\name)
+#endif
 	UNWIND .fnstart
 .endm
 #endif
@@ -141,8 +163,7 @@ _L__\name:
 #endif
 .endm
 
-
-	@ r0:   fn
+	@ r0:   ffi_prep_args
 	@ r1:   &ecif
 	@ r2:   cif->bytes
 	@ r3:   fig->flags
@@ -222,11 +243,18 @@ ARM_FUNC_START ffi_call_SYSV
 #endif
 
 LSYM(Lepilogue):
-	RETLDM	"r0-r3,fp"
+#if defined (__INTERWORKING__)
+	ldmia   sp!, {r0-r3,fp, lr}
+	bx	lr
+#else
+	ldmia   sp!, {r0-r3,fp, pc}
+#endif
 
 .ffi_call_SYSV_end:
 	UNWIND .fnend
+#ifdef __ELF__
         .size    CNAME(ffi_call_SYSV),.ffi_call_SYSV_end-CNAME(ffi_call_SYSV)
+#endif
 
 
 /*
@@ -247,7 +275,7 @@ ARM_FUNC_START ffi_closure_SYSV
 	sub	sp, sp, #16
 	str	sp, [sp, #8]
 	add	r1, sp, #8
-	bl	ffi_closure_SYSV_inner
+	bl	CNAME(ffi_closure_SYSV_inner)
 	cmp	r0, #FFI_TYPE_INT
 	beq	.Lretint
 
@@ -299,7 +327,9 @@ ARM_FUNC_START ffi_closure_SYSV
 
 .ffi_closure_SYSV_end:
 	UNWIND .fnend
+#ifdef __ELF__
         .size    CNAME(ffi_closure_SYSV),.ffi_closure_SYSV_end-CNAME(ffi_closure_SYSV)
+#endif
 
 
 /* Below are VFP hard-float ABI call and closure implementations.
@@ -371,7 +401,7 @@ LSYM(Lbase_args):
 	@ assume no return value.
 	cmp	r2, #0
 	beq	LSYM(Lepilogue_vfp)
-	
+
 	cmp	r3, #FFI_TYPE_INT
 	streq	r0, [r2]
 	beq	LSYM(Lepilogue_vfp)

src/closures.c

@@ -32,7 +32,7 @@
 #include <ffi.h>
 #include <ffi_common.h>
 
-#ifndef FFI_MMAP_EXEC_WRIT
+#if !FFI_MMAP_EXEC_WRIT && !FFI_EXEC_TRAMPOLINE_TABLE
 # if __gnu_linux__
 /* This macro indicates it may be forbidden to map anonymous memory
    with both write and execute permission.  Code compiled when this
@@ -63,7 +63,11 @@
 
 #if FFI_CLOSURES
 
-# if FFI_MMAP_EXEC_WRIT
+# if FFI_EXEC_TRAMPOLINE_TABLE
+
+// Per-target implementation; It's unclear what can reasonable be shared between two OS/architecture implementations.
+
+# elif FFI_MMAP_EXEC_WRIT /* !FFI_EXEC_TRAMPOLINE_TABLE */
 
 #define USE_LOCKS 1
 #define USE_DL_PREFIX 1