split dwarf2_fetch_cfa_info from dwarf2_compile_expr_to_ax

This removes dwarf2_compile_expr_to_ax, replacing it with a utility
function that fetches the CFA data and adding the code to actually
compile to an agent expression directly into
dwarf2_compile_expr_to_ax.  This refactoring lets a later patch reuse
the new dwarf2_fetch_cfa_info.

gdb/ChangeLog
2014-12-12  Tom Tromey  <tromey@redhat.com>

	* dwarf2loc.c (dwarf2_compile_expr_to_ax) <DW_OP_call_frame_cfa>:
	Update.
	* dwarf2-frame.c (dwarf2_fetch_cfa_info): New function, based on
	dwarf2_compile_cfa_to_ax.
	(dwarf2_compile_cfa_to_ax): Remove.
	* dwarf2-frame.h (dwarf2_fetch_cfa_info): Declare.
	(dwarf2_compile_cfa_to_ax): Remove.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index df93995..ff001eb 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+2014-12-12  Tom Tromey  <tromey@redhat.com>
+
+       * dwarf2loc.c (dwarf2_compile_expr_to_ax) <DW_OP_call_frame_cfa>:
+       Update.
+       * dwarf2-frame.c (dwarf2_fetch_cfa_info): New function, based on
+       dwarf2_compile_cfa_to_ax.
+       (dwarf2_compile_cfa_to_ax): Remove.
+       * dwarf2-frame.h (dwarf2_fetch_cfa_info): Declare.
+       (dwarf2_compile_cfa_to_ax): Remove.
+
 2014-12-12  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
        * infcall.h (call_function_by_hand_dummy): Declare.

diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c
index 8747f4c..199ccea 100644 (file)
--- a/gdb/dwarf2-frame.c
+++ b/gdb/dwarf2-frame.c
@@ -882,11 +882,15 @@ dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
 }
 \f
 
-void
-dwarf2_compile_cfa_to_ax (struct agent_expr *expr, struct axs_value *loc,
-                         struct gdbarch *gdbarch,
-                         CORE_ADDR pc,
-                         struct dwarf2_per_cu_data *data)
+/* See dwarf2-frame.h.  */
+
+int
+dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc,
+                      struct dwarf2_per_cu_data *data,
+                      int *regnum_out, LONGEST *offset_out,
+                      CORE_ADDR *text_offset_out,
+                      const gdb_byte **cfa_start_out,
+                      const gdb_byte **cfa_end_out)
 {
   struct dwarf2_fde *fde;
   CORE_ADDR text_offset;
@@ -932,26 +936,20 @@ dwarf2_compile_cfa_to_ax (struct agent_expr *expr, struct axs_value *loc,
        if (regnum == -1)
          error (_("Unable to access DWARF register number %d"),
                 (int) fs.regs.cfa_reg); /* FIXME */
-       ax_reg (expr, regnum);
 
-       if (fs.regs.cfa_offset != 0)
-         {
-           if (fs.armcc_cfa_offsets_reversed)
-             ax_const_l (expr, -fs.regs.cfa_offset);
-           else
-             ax_const_l (expr, fs.regs.cfa_offset);
-           ax_simple (expr, aop_add);
-         }
+       *regnum_out = regnum;
+       if (fs.armcc_cfa_offsets_reversed)
+         *offset_out = -fs.regs.cfa_offset;
+       else
+         *offset_out = fs.regs.cfa_offset;
+       return 1;
       }
-      break;
 
     case CFA_EXP:
-      ax_const_l (expr, text_offset);
-      dwarf2_compile_expr_to_ax (expr, loc, gdbarch, addr_size,
-                                fs.regs.cfa_exp,
-                                fs.regs.cfa_exp + fs.regs.cfa_exp_len,
-                                data);
-      break;
+      *text_offset_out = text_offset;
+      *cfa_start_out = fs.regs.cfa_exp;
+      *cfa_end_out = fs.regs.cfa_exp + fs.regs.cfa_exp_len;
+      return 0;
 
     default:
       internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));

diff --git a/gdb/dwarf2-frame.h b/gdb/dwarf2-frame.h
index 0470cac..5ccf0c8 100644 (file)
--- a/gdb/dwarf2-frame.h
+++ b/gdb/dwarf2-frame.h
@@ -120,15 +120,26 @@ extern const struct frame_base *
 
 CORE_ADDR dwarf2_frame_cfa (struct frame_info *this_frame);
 
-/* Update the agent expression EXPR with code to compute the CFA for a
-   frame at PC.  GDBARCH is the architecture of the function at PC.
-   This function may call dwarf2_compile_expr_to_ax; DATA is passed
-   through to that function if needed.  */
-
-extern void dwarf2_compile_cfa_to_ax (struct agent_expr *expr,
-                                     struct axs_value *loc,
-                                     struct gdbarch *gdbarch,
-                                     CORE_ADDR pc,
-                                     struct dwarf2_per_cu_data *data);
+/* Find the CFA information for PC.
+
+   Return 1 if a register is used for the CFA, or 0 if another
+   expression is used.  Throw an exception on error.
+
+   GDBARCH is the architecture to use.
+   DATA is the per-CU data.
+
+   REGNUM_OUT is an out parameter that is set to the register number.
+   OFFSET_OUT is the offset to use from this register.
+   These are only filled in when 1 is returned.
+
+   TEXT_OFFSET_OUT, CFA_START_OUT, and CFA_END_OUT describe the CFA
+   in other cases.  These are only used when 0 is returned.  */
+
+extern int dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc,
+                                 struct dwarf2_per_cu_data *data,
+                                 int *regnum_out, LONGEST *offset_out,
+                                 CORE_ADDR *text_offset_out,
+                                 const gdb_byte **cfa_start_out,
+                                 const gdb_byte **cfa_end_out);
 
 #endif /* dwarf2-frame.h */

diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index fbaa7d3..bbe4568 100644 (file)
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -3282,8 +3282,34 @@ dwarf2_compile_expr_to_ax (struct agent_expr *expr, struct axs_value *loc,
          break;
 
        case DW_OP_call_frame_cfa:
-         dwarf2_compile_cfa_to_ax (expr, loc, arch, expr->scope, per_cu);
-         loc->kind = axs_lvalue_memory;
+         {
+           int regnum;
+           CORE_ADDR text_offset;
+           LONGEST off;
+           const gdb_byte *cfa_start, *cfa_end;
+
+           if (dwarf2_fetch_cfa_info (arch, expr->scope, per_cu,
+                                      &regnum, &off,
+                                      &text_offset, &cfa_start, &cfa_end))
+             {
+               /* Register.  */
+               ax_reg (expr, regnum);
+               if (off != 0)
+                 {
+                   ax_const_l (expr, off);
+                   ax_simple (expr, aop_add);
+                 }
+             }
+           else
+             {
+               /* Another expression.  */
+               ax_const_l (expr, text_offset);
+               dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size,
+                                          cfa_start, cfa_end, per_cu);
+             }
+
+           loc->kind = axs_lvalue_memory;
+         }
          break;
 
        case DW_OP_GNU_push_tls_address: