win32-os.c: Split up handle_exception
authorDavid Lichteblau <david@lichteblau.com>
Mon, 3 Sep 2012 11:31:46 +0000 (13:31 +0200)
committerDavid Lichteblau <david@lichteblau.com>
Tue, 11 Sep 2012 09:21:22 +0000 (11:21 +0200)
In preparation for various changes to exception handling, split up
handle_exception into separate functions for each kind of exception.

This change is entirely cosmetic in nature.

src/runtime/win32-os.c

index 3d27f78..b3e22ca 100644 (file)
@@ -313,108 +313,110 @@ is_valid_lisp_addr(os_vm_address_t addr)
 /* A tiny bit of interrupt.c state we want our paws on. */
 extern boolean internal_errors_enabled;
 
+#if defined(LISP_FEATURE_X86)
+static int
+handle_single_step(os_context_t *ctx)
+{
+    if (!single_stepping)
+        return -1;
+
+    /* We are doing a displaced instruction. At least function
+     * end breakpoints use this. */
+    restore_breakpoint_from_single_step(ctx);
+
+    return 0;
+}
+#endif
+
 #ifdef LISP_FEATURE_UD2_BREAKPOINTS
-#define IS_TRAP_EXCEPTION(exception_record, context) \
-    (((exception_record)->ExceptionCode == EXCEPTION_ILLEGAL_INSTRUCTION) && \
-     (((unsigned short *)((context)->Eip))[0] == 0x0b0f))
+#define SBCL_EXCEPTION_BREAKPOINT EXCEPTION_ILLEGAL_INSTRUCTION
 #define TRAP_CODE_WIDTH 2
 #else
-#define IS_TRAP_EXCEPTION(exception_record, context) \
-    ((exception_record)->ExceptionCode == EXCEPTION_BREAKPOINT)
+#define SBCL_EXCEPTION_BREAKPOINT EXCEPTION_BREAKPOINT
 #define TRAP_CODE_WIDTH 1
 #endif
 
-/*
- * A good explanation of the exception handling semantics is
- * http://win32assembly.online.fr/Exceptionhandling.html .
- */
-
-EXCEPTION_DISPOSITION
-handle_exception(EXCEPTION_RECORD *exception_record,
-                 struct lisp_exception_frame *exception_frame,
-                 CONTEXT *context,
-                 void *dispatcher_context)
+static int
+handle_breakpoint_trap(os_context_t *ctx)
 {
-    if (exception_record->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND)) {
-        /* If we're being unwound, be graceful about it. */
+#ifdef LISP_FEATURE_UD2_BREAKPOINTS
+    if (((unsigned short *)((ctx->win32_context)->Eip))[0] != 0x0b0f)
+        return -1;
+#endif
 
-        /* Undo any dynamic bindings. */
-        unbind_to_here(exception_frame->bindstack_pointer,
-                       arch_os_get_current_thread());
+    /* Unlike some other operating systems, Win32 leaves EIP
+     * pointing to the breakpoint instruction. */
+    ctx->Eip += TRAP_CODE_WIDTH;
 
-        return ExceptionContinueSearch;
-    }
+    /* Now EIP points just after the INT3 byte and aims at the
+     * 'kind' value (eg trap_Cerror). */
+    unsigned char trap = *(unsigned char *)(*os_context_pc_addr(ctx));
 
-    /* For EXCEPTION_ACCESS_VIOLATION only. */
-    void *fault_address = (void *)exception_record->ExceptionInformation[1];
+    /* This is just for info in case the monitor wants to print an
+     * approximation. */
+    current_control_stack_pointer =
+        (lispobj *)*os_context_sp_addr(ctx);
 
-    if (single_stepping &&
-        exception_record->ExceptionCode == EXCEPTION_SINGLE_STEP) {
-        /* We are doing a displaced instruction. At least function
-         * end breakpoints uses this. */
-        restore_breakpoint_from_single_step(context);
-        return ExceptionContinueExecution;
-    }
+    handle_trap(ctx, trap);
 
-    if (IS_TRAP_EXCEPTION(exception_record, context)) {
-        unsigned char trap;
-        /* This is just for info in case the monitor wants to print an
-         * approximation. */
-        current_control_stack_pointer =
-            (lispobj *)*os_context_sp_addr(context);
-        /* Unlike some other operating systems, Win32 leaves EIP
-         * pointing to the breakpoint instruction. */
-        context->Eip += TRAP_CODE_WIDTH;
-        /* Now EIP points just after the INT3 byte and aims at the
-         * 'kind' value (eg trap_Cerror). */
-        trap = *(unsigned char *)(*os_context_pc_addr(context));
-        handle_trap(context, trap);
-        /* Done, we're good to go! */
-        return ExceptionContinueExecution;
-    }
-    else if (exception_record->ExceptionCode == EXCEPTION_ACCESS_VIOLATION &&
-             (is_valid_lisp_addr(fault_address) ||
-              is_linkage_table_addr(fault_address))) {
-        /* Pick off GC-related memory fault next. */
-        MEMORY_BASIC_INFORMATION mem_info;
+    /* Done, we're good to go! */
+    return 0;
+}
 
-        if (!VirtualQuery(fault_address, &mem_info, sizeof mem_info)) {
-            fprintf(stderr, "VirtualQuery: 0x%lx.\n", GetLastError());
-            lose("handle_exception: VirtualQuery failure");
-        }
+static int
+handle_access_violation(os_context_t *ctx,
+                        EXCEPTION_RECORD *exception_record,
+                        void *fault_address)
+{
+    if (!(is_valid_lisp_addr(fault_address)
+          || is_linkage_table_addr(fault_address)))
+        return -1;
+
+    /* Pick off GC-related memory fault next. */
+    MEMORY_BASIC_INFORMATION mem_info;
 
-        if (mem_info.State == MEM_RESERVE) {
-            /* First use new page, lets get some memory for it. */
-            if (!VirtualAlloc(mem_info.BaseAddress, os_vm_page_size,
-                              MEM_COMMIT, PAGE_EXECUTE_READWRITE)) {
-                fprintf(stderr, "VirtualAlloc: 0x%lx.\n", GetLastError());
-                lose("handle_exception: VirtualAlloc failure");
-
-            } else {
-                /*
-                 * Now, if the page is supposedly write-protected and this
-                 * is a write, tell the gc that it's been hit.
-                 *
-                 * FIXME: Are we supposed to fall-through to the Lisp
-                 * exception handler if the gc doesn't take the wp violation?
-                 */
-                if (exception_record->ExceptionInformation[0]) {
-                    page_index_t index = find_page_index(fault_address);
-                    if ((index != -1) && (page_table[index].write_protected)) {
-                        gencgc_handle_wp_violation(fault_address);
-                    }
+    if (!VirtualQuery(fault_address, &mem_info, sizeof mem_info)) {
+        fprintf(stderr, "VirtualQuery: 0x%lx.\n", GetLastError());
+        lose("handle_exception: VirtualQuery failure");
+    }
+
+    if (mem_info.State == MEM_RESERVE) {
+        /* First use new page, lets get some memory for it. */
+        if (!VirtualAlloc(mem_info.BaseAddress, os_vm_page_size,
+                          MEM_COMMIT, PAGE_EXECUTE_READWRITE)) {
+            fprintf(stderr, "VirtualAlloc: 0x%lx.\n", GetLastError());
+            lose("handle_exception: VirtualAlloc failure");
+
+        } else {
+            /*
+             * Now, if the page is supposedly write-protected and this
+             * is a write, tell the gc that it's been hit.
+             *
+             * FIXME: Are we supposed to fall-through to the Lisp
+             * exception handler if the gc doesn't take the wp violation?
+             */
+            if (exception_record->ExceptionInformation[0]) {
+                page_index_t index = find_page_index(fault_address);
+                if ((index != -1) && (page_table[index].write_protected)) {
+                    gencgc_handle_wp_violation(fault_address);
                 }
-                return ExceptionContinueExecution;
             }
-
-        } else if (gencgc_handle_wp_violation(fault_address)) {
-            /* gc accepts the wp violation, so resume where we left off. */
-            return ExceptionContinueExecution;
+            return 0;
         }
 
-        /* All else failed, drop through to the lisp-side exception handler. */
+    } else if (gencgc_handle_wp_violation(fault_address)) {
+        /* gc accepts the wp violation, so resume where we left off. */
+        return 0;
     }
 
+    return -1;
+}
+
+static void
+signal_internal_error_or_lose(os_context_t *ctx,
+                              EXCEPTION_RECORD *exception_record,
+                              void *fault_address)
+{
     /*
      * If we fall through to here then we need to either forward
      * the exception to the lisp-side exception handler if it's
@@ -431,11 +433,11 @@ handle_exception(EXCEPTION_RECORD *exception_record,
          * aren't supposed to happen during cold init or reinit
          * anyway. */
 
-        fake_foreign_function_call(context);
+        fake_foreign_function_call(ctx);
 
         /* Allocate the SAP objects while the "interrupts" are still
          * disabled. */
-        context_sap = alloc_sap(context);
+        context_sap = alloc_sap(ctx);
         exception_record_sap = alloc_sap(exception_record);
 
         /* The exception system doesn't automatically clear pending
@@ -448,10 +450,10 @@ handle_exception(EXCEPTION_RECORD *exception_record,
                  exception_record_sap);
 
         /* If Lisp doesn't nlx, we need to put things back. */
-        undo_fake_foreign_function_call(context);
+        undo_fake_foreign_function_call(ctx);
 
         /* FIXME: HANDLE-WIN32-EXCEPTION should be allowed to decline */
-        return ExceptionContinueExecution;
+        return;
     }
 
     fprintf(stderr, "Exception Code: 0x%lx.\n", exception_record->ExceptionCode);
@@ -470,11 +472,67 @@ handle_exception(EXCEPTION_RECORD *exception_record,
 
     fflush(stderr);
 
-    fake_foreign_function_call(context);
+    fake_foreign_function_call(ctx);
     lose("Exception too early in cold init, cannot continue.");
+}
+
+/*
+ * A good explanation of the exception handling semantics is
+ * http://win32assembly.online.fr/Exceptionhandling.html .
+ */
+
+EXCEPTION_DISPOSITION
+handle_exception(EXCEPTION_RECORD *exception_record,
+                 struct lisp_exception_frame *exception_frame,
+                 CONTEXT *ctx,
+                 void *dispatcher_context)
+{
+    if (exception_record->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND)) {
+        /* If we're being unwound, be graceful about it. */
+
+        /* Undo any dynamic bindings. */
+        unbind_to_here(exception_frame->bindstack_pointer,
+                       arch_os_get_current_thread());
+
+        return ExceptionContinueSearch;
+    }
+
+    DWORD code = exception_record->ExceptionCode;
+
+    /* For EXCEPTION_ACCESS_VIOLATION only. */
+    void *fault_address = (void *)exception_record->ExceptionInformation[1];
+
+    /* This function will become unwieldy.  Let's cut it down into
+     * pieces based on the different exception codes.  Each exception
+     * code handler gets the chance to decline by returning non-zero if it
+     * isn't happy: */
+
+    int rc;
+    switch (code) {
+    case EXCEPTION_ACCESS_VIOLATION:
+        rc = handle_access_violation(
+            ctx, exception_record, fault_address);
+        break;
+
+    case SBCL_EXCEPTION_BREAKPOINT:
+        rc = handle_breakpoint_trap(ctx);
+        break;
+
+#if defined(LISP_FEATURE_X86)
+    case EXCEPTION_SINGLE_STEP:
+        rc = handle_single_step(ctx);
+        break;
+#endif
+
+    default:
+        rc = -1;
+    }
+
+    if (rc)
+        /* All else failed, drop through to the lisp-side exception handler. */
+        signal_internal_error_or_lose(ctx, exception_record, fault_address);
 
-    /* FIXME: WTF? How are we supposed to end up here? */
-    return ExceptionContinueSearch;
+    return ExceptionContinueExecution;
 }
 
 void