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Diffstat (limited to 'verilog/Stacklayout.v')
| -rw-r--r-- | verilog/Stacklayout.v | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/verilog/Stacklayout.v b/verilog/Stacklayout.v new file mode 100644 index 00000000..d375febf --- /dev/null +++ b/verilog/Stacklayout.v @@ -0,0 +1,148 @@ +(* *********************************************************************) +(* *) +(* The Compcert verified compiler *) +(* *) +(* Xavier Leroy, INRIA Paris *) +(* *) +(* Copyright Institut National de Recherche en Informatique et en *) +(* Automatique. All rights reserved. This file is distributed *) +(* under the terms of the INRIA Non-Commercial License Agreement. *) +(* *) +(* *********************************************************************) + +(** Machine- and ABI-dependent layout information for activation records. *) + +Require Import Coqlib. +Require Import AST Memory Separation. +Require Import Bounds. + +Local Open Scope sep_scope. + +(** The general shape of activation records is as follows, + from bottom (lowest offsets) to top: +- Space for outgoing arguments to function calls. +- Back link to parent frame +- Saved values of integer callee-save registers used by the function. +- Saved values of float callee-save registers used by the function. +- Local stack slots. +- Space for the stack-allocated data declared in Cminor +- Return address. +*) + +Definition fe_ofs_arg := 0. + +Definition make_env (b: bounds) : frame_env := + let w := if Archi.ptr64 then 8 else 4 in + let olink := align (4 * b.(bound_outgoing)) w in (* back link *) + let ocs := olink + w in (* callee-saves *) + let ol := align (size_callee_save_area b ocs) 8 in (* locals *) + let ostkdata := align (ol + 4 * b.(bound_local)) 8 in (* stack data *) + let oretaddr := align (ostkdata + b.(bound_stack_data)) w in (* return address *) + let sz := oretaddr + w in (* total size *) + {| fe_size := sz; + fe_ofs_link := olink; + fe_ofs_retaddr := oretaddr; + fe_ofs_local := ol; + fe_ofs_callee_save := ocs; + fe_stack_data := ostkdata; + fe_used_callee_save := b.(used_callee_save) |}. + +Lemma frame_env_separated: + forall b sp m P, + let fe := make_env b in + m |= range sp 0 (fe_stack_data fe) ** range sp (fe_stack_data fe + bound_stack_data b) (fe_size fe) ** P -> + m |= range sp (fe_ofs_local fe) (fe_ofs_local fe + 4 * bound_local b) + ** range sp fe_ofs_arg (fe_ofs_arg + 4 * bound_outgoing b) + ** range sp (fe_ofs_link fe) (fe_ofs_link fe + size_chunk Mptr) + ** range sp (fe_ofs_retaddr fe) (fe_ofs_retaddr fe + size_chunk Mptr) + ** range sp (fe_ofs_callee_save fe) (size_callee_save_area b (fe_ofs_callee_save fe)) + ** P. +Proof. +Local Opaque Z.add Z.mul sepconj range. + intros; simpl. + set (w := if Archi.ptr64 then 8 else 4). + set (olink := align (4 * b.(bound_outgoing)) w). + set (ocs := olink + w). + set (ol := align (size_callee_save_area b ocs) 8). + set (ostkdata := align (ol + 4 * b.(bound_local)) 8). + set (oretaddr := align (ostkdata + b.(bound_stack_data)) w). + replace (size_chunk Mptr) with w by (rewrite size_chunk_Mptr; auto). + assert (0 < w) by (unfold w; destruct Archi.ptr64; omega). + generalize b.(bound_local_pos) b.(bound_outgoing_pos) b.(bound_stack_data_pos); intros. + assert (0 <= 4 * b.(bound_outgoing)) by omega. + assert (4 * b.(bound_outgoing) <= olink) by (apply align_le; omega). + assert (olink + w <= ocs) by (unfold ocs; omega). + assert (ocs <= size_callee_save_area b ocs) by (apply size_callee_save_area_incr). + assert (size_callee_save_area b ocs <= ol) by (apply align_le; omega). + assert (ol + 4 * b.(bound_local) <= ostkdata) by (apply align_le; omega). + assert (ostkdata + bound_stack_data b <= oretaddr) by (apply align_le; omega). +(* Reorder as: + outgoing + back link + callee-save + local + retaddr *) + rewrite sep_swap12. + rewrite sep_swap23. + rewrite sep_swap45. + rewrite sep_swap34. +(* Apply range_split and range_split2 repeatedly *) + unfold fe_ofs_arg. + apply range_split_2. fold olink. omega. omega. + apply range_split. omega. + apply range_split_2. fold ol. omega. omega. + apply range_drop_right with ostkdata. omega. + rewrite sep_swap. + apply range_drop_left with (ostkdata + bound_stack_data b). omega. + rewrite sep_swap. + exact H. +Qed. + +Lemma frame_env_range: + forall b, + let fe := make_env b in + 0 <= fe_stack_data fe /\ fe_stack_data fe + bound_stack_data b <= fe_size fe. +Proof. + intros; simpl. + set (w := if Archi.ptr64 then 8 else 4). + set (olink := align (4 * b.(bound_outgoing)) w). + set (ocs := olink + w). + set (ol := align (size_callee_save_area b ocs) 8). + set (ostkdata := align (ol + 4 * b.(bound_local)) 8). + set (oretaddr := align (ostkdata + b.(bound_stack_data)) w). + assert (0 < w) by (unfold w; destruct Archi.ptr64; omega). + generalize b.(bound_local_pos) b.(bound_outgoing_pos) b.(bound_stack_data_pos); intros. + assert (0 <= 4 * b.(bound_outgoing)) by omega. + assert (4 * b.(bound_outgoing) <= olink) by (apply align_le; omega). + assert (olink + w <= ocs) by (unfold ocs; omega). + assert (ocs <= size_callee_save_area b ocs) by (apply size_callee_save_area_incr). + assert (size_callee_save_area b ocs <= ol) by (apply align_le; omega). + assert (ol + 4 * b.(bound_local) <= ostkdata) by (apply align_le; omega). + assert (ostkdata + bound_stack_data b <= oretaddr) by (apply align_le; omega). + split. omega. omega. +Qed. + +Lemma frame_env_aligned: + forall b, + let fe := make_env b in + (8 | fe_ofs_arg) + /\ (8 | fe_ofs_local fe) + /\ (8 | fe_stack_data fe) + /\ (align_chunk Mptr | fe_ofs_link fe) + /\ (align_chunk Mptr | fe_ofs_retaddr fe). +Proof. + intros; simpl. + set (w := if Archi.ptr64 then 8 else 4). + set (olink := align (4 * b.(bound_outgoing)) w). + set (ocs := olink + w). + set (ol := align (size_callee_save_area b ocs) 8). + set (ostkdata := align (ol + 4 * b.(bound_local)) 8). + set (oretaddr := align (ostkdata + b.(bound_stack_data)) w). + assert (0 < w) by (unfold w; destruct Archi.ptr64; omega). + replace (align_chunk Mptr) with w by (rewrite align_chunk_Mptr; auto). + split. apply Z.divide_0_r. + split. apply align_divides; omega. + split. apply align_divides; omega. + split. apply align_divides; omega. + apply align_divides; omega. +Qed. |