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210 lines
6.1 KiB
C
210 lines
6.1 KiB
C
#ifdef WIN32_THREADS
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#include "gc_priv.h"
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#define STRICT
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#include <windows.h>
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#define MAX_THREADS 64
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struct thread_entry {
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LONG in_use;
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DWORD id;
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HANDLE handle;
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void *stack; /* The cold end of the stack. */
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/* 0 ==> entry not valid. */
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/* !in_use ==> stack == 0 */
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CONTEXT context;
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GC_bool suspended;
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};
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volatile GC_bool GC_please_stop = FALSE;
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volatile struct thread_entry thread_table[MAX_THREADS];
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void GC_stop_world()
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{
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DWORD thread_id = GetCurrentThreadId();
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int i;
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GC_please_stop = TRUE;
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for (i = 0; i < MAX_THREADS; i++)
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if (thread_table[i].stack != 0
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&& thread_table[i].id != thread_id) {
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if (SuspendThread(thread_table[i].handle) == (DWORD)-1)
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ABORT("SuspendThread failed");
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thread_table[i].suspended = TRUE;
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}
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}
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void GC_start_world()
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{
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DWORD thread_id = GetCurrentThreadId();
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int i;
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for (i = 0; i < MAX_THREADS; i++)
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if (thread_table[i].stack != 0 && thread_table[i].suspended
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&& thread_table[i].id != thread_id) {
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if (ResumeThread(thread_table[i].handle) == (DWORD)-1)
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ABORT("ResumeThread failed");
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thread_table[i].suspended = FALSE;
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}
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GC_please_stop = FALSE;
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}
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ptr_t GC_current_stackbottom()
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{
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DWORD thread_id = GetCurrentThreadId();
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int i;
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for (i = 0; i < MAX_THREADS; i++)
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if (thread_table[i].stack && thread_table[i].id == thread_id)
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return thread_table[i].stack;
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ABORT("no thread table entry for current thread");
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}
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ptr_t GC_get_lo_stack_addr(ptr_t s)
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{
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ptr_t bottom;
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MEMORY_BASIC_INFORMATION info;
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VirtualQuery(s, &info, sizeof(info));
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do {
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bottom = info.BaseAddress;
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VirtualQuery(bottom - 1, &info, sizeof(info));
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} while ((info.Protect & PAGE_READWRITE) && !(info.Protect & PAGE_GUARD));
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return(bottom);
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}
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void GC_push_all_stacks()
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{
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DWORD thread_id = GetCurrentThreadId();
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int i;
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for (i = 0; i < MAX_THREADS; i++)
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if (thread_table[i].stack) {
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ptr_t bottom = GC_get_lo_stack_addr(thread_table[i].stack);
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if (thread_table[i].id == thread_id)
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GC_push_all(&i, thread_table[i].stack);
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else {
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thread_table[i].context.ContextFlags
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= (CONTEXT_INTEGER|CONTEXT_CONTROL);
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if (!GetThreadContext(thread_table[i].handle,
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&thread_table[i].context))
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ABORT("GetThreadContext failed");
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if (thread_table[i].context.Esp >= (DWORD)thread_table[i].stack
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|| thread_table[i].context.Esp < (DWORD)bottom)
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ABORT("Thread stack pointer out of range");
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GC_push_one ((word) thread_table[i].context.Edi);
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GC_push_one ((word) thread_table[i].context.Esi);
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GC_push_one ((word) thread_table[i].context.Ebx);
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GC_push_one ((word) thread_table[i].context.Edx);
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GC_push_one ((word) thread_table[i].context.Ecx);
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GC_push_one ((word) thread_table[i].context.Eax);
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GC_push_all_stack(thread_table[i].context.Esp, thread_table[i].stack);
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}
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}
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}
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void GC_get_next_stack(char *start, char **lo, char **hi)
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{
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int i;
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# define ADDR_LIMIT (char *)(-1L)
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char * current_min = ADDR_LIMIT;
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for (i = 0; i < MAX_THREADS; i++) {
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char * s = (char *)thread_table[i].stack;
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if (0 != s && s > start && s < current_min) {
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current_min = s;
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}
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}
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*hi = current_min;
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if (current_min == ADDR_LIMIT) {
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*lo = ADDR_LIMIT;
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return;
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}
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*lo = GC_get_lo_stack_addr(current_min);
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if (*lo < start) *lo = start;
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}
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LONG WINAPI GC_write_fault_handler(struct _EXCEPTION_POINTERS *exc_info);
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/*
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* This isn't generally safe, since DllMain is not premptible.
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* If another thread holds the lock while this runs we're in trouble.
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* Pontus Rydin suggests wrapping the thread start routine instead.
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*/
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BOOL WINAPI DllMain(HINSTANCE inst, ULONG reason, LPVOID reserved)
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{
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switch (reason) {
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case DLL_PROCESS_ATTACH:
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InitializeCriticalSection(&GC_allocate_ml);
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GC_init(); /* Force initialization before thread attach. */
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/* fall through */
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case DLL_THREAD_ATTACH:
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{
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int i;
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/* It appears to be unsafe to acquire a lock here, since this */
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/* code is apparently not preeemptible on some systems. */
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/* (This is based on complaints, not on Microsoft's official */
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/* documentation, which says this should perform "only simple */
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/* inititalization tasks".) */
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/* Hence we make do with nonblocking synchronization. */
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/* The following should be a noop according to the win32 */
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/* documentation. There is empirical evidence that it */
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/* isn't. - HB */
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# ifndef SMALL_CONFIG
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if (GC_incremental) SetUnhandledExceptionFilter(GC_write_fault_handler);
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# endif
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for (i = 0; InterlockedExchange(&thread_table[i].in_use,1) != 0; i++) {
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/* Compare-and-swap would make this cleaner, but that's not */
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/* supported before Windows 98 and NT 4.0. In Windows 2000, */
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/* InterlockedExchange is supposed to be replaced by */
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/* InterlockedExchangePointer, but that's not really what I */
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/* want here. */
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if (i == MAX_THREADS - 1)
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ABORT("too many threads");
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}
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thread_table[i].id = GetCurrentThreadId();
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if (!DuplicateHandle(GetCurrentProcess(),
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GetCurrentThread(),
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GetCurrentProcess(),
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&thread_table[i].handle,
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0,
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0,
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DUPLICATE_SAME_ACCESS)) {
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DWORD last_error = GetLastError();
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GC_printf1("Last error code: %lx\n", last_error);
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ABORT("DuplicateHandle failed");
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}
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thread_table[i].stack = GC_get_stack_base();
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/* If this thread is being created while we are trying to stop */
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/* the world, wait here. Hopefully this can't happen on any */
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/* systems that don't allow us to block here. */
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while (GC_please_stop) Sleep(20);
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}
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break;
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case DLL_PROCESS_DETACH:
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case DLL_THREAD_DETACH:
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{
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int i;
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DWORD thread_id = GetCurrentThreadId();
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LOCK();
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for (i = 0;
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thread_table[i].stack == 0 || thread_table[i].id != thread_id;
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i++) {
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if (i == MAX_THREADS - 1)
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ABORT("thread not found on detach");
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}
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thread_table[i].stack = 0;
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thread_table[i].in_use = FALSE;
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CloseHandle(thread_table[i].handle);
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BZERO(&thread_table[i].context, sizeof(CONTEXT));
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UNLOCK();
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}
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break;
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}
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return TRUE;
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}
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#endif /* WIN32_THREADS */
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