* This is a platform-independent interface for unwinding through stack frames
* based on the Dwarf unwinding interface.
* See http://dwarfstd.org/Dwarf3.pdf, section "Call Frame Information".
- * Currently, this is only used for emitting unwind info in AOT files.
*/
-/* CFA = Canonical Frame Address */
+/*
+ * CFA = Canonical Frame Address. By convention, this is the value of the stack pointer
+ * prior to the execution of the call instruction in the caller. I.e. on x86, it is
+ * esp + 4 on entry to a function. The value of the CFA does not change during execution
+ * of a function. There are two kinds of unwind directives:
+ * - those that describe how to compute the CFA at a given pc offset inside a function
+ * - those that describe where a given register is saved relative to the CFA.
+ */
/* Unwind ops */
#define DW_CFA_lo_user 0x1c
#define DW_CFA_hi_user 0x3f
+/*
+ * Mono extension, advance loc to a location stored outside the unwind info.
+ * This is required to make the unwind descriptors sharable, since otherwise each one would contain
+ * an advance_loc with a different offset just before the unwind ops for the epilog.
+ */
+#define DW_CFA_mono_advance_loc DW_CFA_lo_user
+
/* Represents one unwind instruction */
typedef struct {
guint8 op; /* One of DW_CFA_... */
*/
/* Set cfa to reg+offset */
-#define mono_emit_unwind_op_def_cfa(cfg,ip,reg,offset) do { mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_def_cfa, (reg), (offset)); (cfg)->cfa_reg = (reg); (cfg)->cfa_offset = (offset); } while (0)
+#define mono_emit_unwind_op_def_cfa(cfg,ip,reg,offset) do { mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_def_cfa, (reg), (offset)); (cfg)->cur_cfa_reg = (reg); (cfg)->cur_cfa_offset = (offset); } while (0)
/* Set cfa to reg+existing offset */
-#define mono_emit_unwind_op_def_cfa_reg(cfg,ip,reg) do { mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_def_cfa_register, (reg), (0)); (cfg)->cfa_reg = (reg); } while (0)
+#define mono_emit_unwind_op_def_cfa_reg(cfg,ip,reg) do { mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_def_cfa_register, (reg), (0)); (cfg)->cur_cfa_reg = (reg); } while (0)
/* Set cfa to existing reg+offset */
-#define mono_emit_unwind_op_def_cfa_offset(cfg,ip,offset) do { mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_def_cfa_offset, (0), (offset)); (cfg)->cfa_offset = (offset); } while (0)
+#define mono_emit_unwind_op_def_cfa_offset(cfg,ip,offset) do { mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_def_cfa_offset, (0), (offset)); (cfg)->cur_cfa_offset = (offset); } while (0)
/* Reg is the same as it was on enter to the function */
#define mono_emit_unwind_op_same_value(cfg,ip,reg) mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_same_value, (reg), 0)
/* Reg is saved at cfa+offset */
#define mono_emit_unwind_op_offset(cfg,ip,reg,offset) mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_offset, (reg), (offset))
+/* Save the unwind state into an implicit stack */
+#define mono_emit_unwind_op_remember_state(cfg,ip) mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_remember_state, 0, 0)
+/* Restore the unwind state from the state stack */
+#define mono_emit_unwind_op_restore_state(cfg,ip) mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_restore_state, 0, 0)
+/*
+ * Mark the current location as a location stored outside the unwind info, which will be passed
+ * explicitly to mono_unwind_frame () in the MARK_LOCATIONS argument. This allows the unwind info
+ * to be shared among multiple methods.
+ */
+#define mono_emit_unwind_op_mark_loc(cfg,ip,n) mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_mono_advance_loc, 0, (n))
/* Similar macros usable when a cfg is not available, like for trampolines */
#define mono_add_unwind_op_def_cfa(op_list,code,buf,reg,offset) do { (op_list) = g_slist_append ((op_list), mono_create_unwind_op ((code) - (buf), DW_CFA_def_cfa, (reg), (offset))); } while (0)
#define mono_add_unwind_op_same_value(op_list,code,buf,reg) do { (op_list) = g_slist_append ((op_list), mono_create_unwind_op ((code) - (buf), DW_CFA_same_value, (reg), 0)); } while (0)
#define mono_add_unwind_op_offset(op_list,code,buf,reg,offset) do { (op_list) = g_slist_append ((op_list), mono_create_unwind_op ((code) - (buf), DW_CFA_offset, (reg), (offset))); } while (0)
+/* Pointer Encoding in the .eh_frame */
+enum {
+ DW_EH_PE_absptr = 0x00,
+ DW_EH_PE_omit = 0xff,
+
+ DW_EH_PE_udata4 = 0x03,
+ DW_EH_PE_sdata4 = 0x0b,
+ DW_EH_PE_sdata8 = 0x0c,
+
+ DW_EH_PE_pcrel = 0x10,
+ DW_EH_PE_textrel = 0x20,
+ DW_EH_PE_datarel = 0x30,
+ DW_EH_PE_funcrel = 0x40,
+ DW_EH_PE_aligned = 0x50,
+
+ DW_EH_PE_indirect = 0x80
+};
+
int
mono_hw_reg_to_dwarf_reg (int reg) MONO_INTERNAL;
void
mono_unwind_frame (guint8 *unwind_info, guint32 unwind_info_len,
- guint8 *start_ip, guint8 *end_ip, guint8 *ip, mgreg_t *regs,
- int nregs, guint8 **out_cfa) MONO_INTERNAL;
+ guint8 *start_ip, guint8 *end_ip, guint8 *ip, guint8 **mark_locations,
+ mgreg_t *regs, int nregs,
+ mgreg_t **save_locations, int save_locations_len,
+ guint8 **out_cfa) MONO_INTERNAL;
void mono_unwind_init (void) MONO_INTERNAL;
GSList* mono_unwind_get_cie_program (void) MONO_INTERNAL;
+void mono_print_unwind_info (guint8 *unwind_info, int unwind_info_len) MONO_LLVM_INTERNAL;
+
#endif
projects / mono.git / blobdiff