vm: implement frame-based SEH for 64-bit Windows

Nmakefile

@@ -11,6 +11,7 @@ ML_FLAGS = /nologo /safeseh
 EXE_OBJS = vm\main-windows-nt.obj vm\factor.res
 
 DLL_OBJS = vm\os-windows-nt.obj \
+	vm\os-windows-nt-x86.32.obj \
 	vm\os-windows.obj \
 	vm\aging_collector.obj \
 	vm\alien.obj \

vm/Config.windows.nt.x86.32

@@ -1,3 +1,4 @@
+PLAF_DLL_OBJS += vm/os-windows-nt-x86.32.o
 DLL_PATH=http://factorcode.org/dlls
 WINDRES=windres
 include vm/Config.windows.nt

vm/Config.windows.nt.x86.64

@@ -1,3 +1,4 @@
+PLAF_DLL_OBJS += vm/os-windows-nt-x86.64.o
 DLL_PATH=http://factorcode.org/dlls/64
 CC=$(WIN64_PATH)-gcc.exe
 WINDRES=$(WIN64_PATH)-windres.exe

vm/code_heap.cpp

@@ -7,8 +7,14 @@ code_heap::code_heap(cell size)
 {
 	if(size > ((u64)1 << (sizeof(cell) * 8 - 6))) fatal_error("Heap too large",size);
 	seg = new segment(align_page(size),true);
-	if(!seg) fatal_error("Out of memory in heap allocator",size);
+	if(!seg) fatal_error("Out of memory in code_heap constructor",size);
-	allocator = new free_list_allocator<code_block>(size,seg->start);
+
+	cell start = seg->start + seh_area_size;
+
+	allocator = new free_list_allocator<code_block>(seg->end - start,start);
+
+	/* See os-windows-nt-x86.64.cpp for seh_area usage */
+	seh_area = (char *)seg->start;
 }
 
 code_heap::~code_heap()

vm/code_heap.hpp

@@ -1,10 +1,19 @@
 namespace factor
 {
 
+#if defined(WINDOWS) && defined(FACTOR_64)
+	const cell seh_area_size = 1024;
+#else
+	const cell seh_area_size = 0;
+#endif
+
 struct code_heap {
 	/* The actual memory area */
 	segment *seg;
 
+	/* Memory area reserved for SEH. Only used on Windows */
+	char *seh_area;
+
 	/* Memory allocator */
 	free_list_allocator<code_block> *allocator;
 

vm/image.cpp

@@ -258,7 +258,7 @@ void factor_vm::load_image(vm_parameters *p)
 	init_objects(&h);
 
 	cell data_offset = data->tenured->start - h.data_relocation_base;
-	cell code_offset = code->seg->start - h.code_relocation_base;
+	cell code_offset = code->allocator->start - h.code_relocation_base;
 
 	fixup_data(data_offset,code_offset);
 	fixup_code(data_offset,code_offset);
@@ -285,7 +285,7 @@ bool factor_vm::save_image(const vm_char *saving_filename, const vm_char *filena
 	h.version = image_version;
 	h.data_relocation_base = data->tenured->start;
 	h.data_size = data->tenured->occupied_space();
-	h.code_relocation_base = code->seg->start;
+	h.code_relocation_base = code->allocator->start;
 	h.code_size = code->allocator->occupied_space();
 
 	h.true_object = true_object;

vm/os-windows-nt-x86.32.cpp

@@ -0,0 +1,12 @@
+#include "master.hpp"
+
+namespace factor
+{
+
+void factor_vm::c_to_factor_toplevel(cell quot)
+{
+	/* 32-bit Windows SEH is set up in basis/cpu/x86/32/winnt/bootstrap.factor */
+	c_to_factor(quot);
+}
+
+}

vm/os-windows-nt-x86.64.cpp

@@ -0,0 +1,85 @@
+#include "master.hpp"
+
+namespace factor {
+
+typedef unsigned char UBYTE;
+
+const UBYTE UNW_FLAG_EHANDLER = 0x1;
+
+struct UNWIND_INFO {
+	UBYTE Version:3;
+	UBYTE Flags:5;
+	UBYTE SizeOfProlog;
+	UBYTE CountOfCodes;
+	UBYTE FrameRegister:4;
+	UBYTE FrameOffset:4;
+	ULONG ExceptionHandler;
+	ULONG ExceptionData[1];
+};
+
+struct seh_data {
+	UNWIND_INFO unwind_info;
+	RUNTIME_FUNCTION func;
+	UBYTE handler[32];
+};
+
+void factor_vm::c_to_factor_toplevel(cell quot)
+{
+	/* The annoying thing about Win64 SEH is that the offsets in
+	 * function tables are 32-bit integers, and the exception handler
+	 * itself must reside between the start and end pointers, so
+	 * we stick everything at the beginning of the code heap and
+	 * generate a small trampoline that jumps to the real
+	 * exception handler. */
+
+	seh_data *seh_area = (seh_data *)code->seh_area;
+	cell base = code->seg->start;
+
+	/* Should look at generating this with the Factor assembler */
+
+	/* mov rax,0 */
+	seh_area->handler[0] = 0x48;
+	seh_area->handler[1] = 0xb8;
+	seh_area->handler[2] = 0x0;
+	seh_area->handler[3] = 0x0;
+	seh_area->handler[4] = 0x0;
+	seh_area->handler[5] = 0x0;
+	seh_area->handler[6] = 0x0;
+	seh_area->handler[7] = 0x0;
+	seh_area->handler[8] = 0x0;
+	seh_area->handler[9] = 0x0;
+
+	/* jmp rax */
+	seh_area->handler[10] = 0x48;
+	seh_area->handler[11] = 0xff;
+	seh_area->handler[12] = 0xe0;
+
+	/* Store address of exception handler in the operand of the 'mov' */
+	cell handler = (cell)&factor::exception_handler;
+	memcpy(&seh_area->handler[2],&handler,sizeof(cell));
+
+	UNWIND_INFO *unwind_info = &seh_area->unwind_info;
+	unwind_info->Version = 1;
+	unwind_info->Flags = UNW_FLAG_EHANDLER;
+	unwind_info->SizeOfProlog = 0;
+	unwind_info->CountOfCodes = 0;
+	unwind_info->FrameRegister = 0;
+	unwind_info->FrameOffset = 0;
+	unwind_info->ExceptionHandler = (DWORD)((cell)&seh_area->handler[0] - base);
+	unwind_info->ExceptionData[0] = 0;
+
+	RUNTIME_FUNCTION *func = &seh_area->func;
+	func->BeginAddress = 0;
+	func->EndAddress = (DWORD)(code->seg->end - base);
+	func->UnwindData = (DWORD)((cell)&seh_area->unwind_info - base);
+
+	if(!RtlAddFunctionTable(func,1,base))
+		fatal_error("RtlAddFunctionTable() failed",0);
+
+	c_to_factor(quot);
+
+	if(!RtlDeleteFunctionTable(func))
+		fatal_error("RtlDeleteFunctionTable() failed",0);
+}
+
+}

vm/os-windows-nt.cpp

@@ -92,11 +92,6 @@ VM_C_API LONG exception_handler(PEXCEPTION_RECORD e, void *frame, PCONTEXT c, vo
 	return current_vm()->exception_handler(e,frame,c,dispatch);
 }
 
-void factor_vm::c_to_factor_toplevel(cell quot)
-{
-	c_to_factor(quot);
-}
-
 void factor_vm::open_console()
 {
 }