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Diffstat (limited to 'mppa_k1c/Asmblockgenproof0.v')
-rw-r--r-- | mppa_k1c/Asmblockgenproof0.v | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/mppa_k1c/Asmblockgenproof0.v b/mppa_k1c/Asmblockgenproof0.v new file mode 100644 index 00000000..374ae0d1 --- /dev/null +++ b/mppa_k1c/Asmblockgenproof0.v @@ -0,0 +1,95 @@ +Require Import Coqlib. +Require Intv. +Require Import AST. +Require Import Errors. +Require Import Integers. +Require Import Floats. +Require Import Values. +Require Import Memory. +Require Import Globalenvs. +Require Import Events. +Require Import Smallstep. +Require Import Locations. +Require Import Machblock. +Require Import Asmblock. +Require Import Asmblockgen. + +Module MB:=Machblock. +Module AB:=Asmblock. + +(* inspired from Mach *) + +Lemma find_label_tail: + forall lbl c c', MB.find_label lbl c = Some c' -> is_tail c' c. +Proof. + induction c; simpl; intros. discriminate. + destruct (MB.is_label lbl a). inv H. auto with coqlib. eauto with coqlib. +Qed. + +(* inspired from Asmgenproof0 *) + +(* ... skip ... *) + +(** The ``code tail'' of an instruction list [c] is the list of instructions + starting at PC [pos]. *) + +Inductive code_tail: Z -> bblocks -> bblocks -> Prop := + | code_tail_0: forall c, + code_tail 0 c c + | code_tail_S: forall pos bi c1 c2, + code_tail pos c1 c2 -> + code_tail (pos + (size bi)) (bi :: c1) c2. + +Lemma code_tail_pos: + forall pos c1 c2, code_tail pos c1 c2 -> pos >= 0. +Proof. + induction 1. omega. generalize (size_positive bi); intros; omega. +Qed. + +Lemma find_bblock_tail: + forall c1 bi c2 pos, + code_tail pos c1 (bi :: c2) -> + find_bblock pos c1 = Some bi. +Proof. + induction c1; simpl; intros. + inversion H. + destruct (zlt pos 0). generalize (code_tail_pos _ _ _ H); intro; omega. + destruct (zeq pos 0). subst pos. + inv H. auto. generalize (size_positive a) (code_tail_pos _ _ _ H4). intro; omega. + inv H. congruence. replace (pos0 + size a - size a) with pos0 by omega. + eauto. +Qed. + +(* ... skip ... *) + + +(** Predictor for return addresses in generated Asm code. + + The [return_address_offset] predicate defined here is used in the + semantics for Mach to determine the return addresses that are + stored in activation records. *) + +(** Consider a Mach function [f] and a sequence [c] of Mach instructions + representing the Mach code that remains to be executed after a + function call returns. The predicate [return_address_offset f c ofs] + holds if [ofs] is the integer offset of the PPC instruction + following the call in the Asm code obtained by translating the + code of [f]. Graphically: +<< + Mach function f |--------- Mcall ---------| + Mach code c | |--------| + | \ \ + | \ \ + | \ \ + Asm code | |--------| + Asm function |------------- Pcall ---------| + + <-------- ofs -------> +>> +*) + +Definition return_address_offset (f: MB.function) (c: MB.code) (ofs: ptrofs) : Prop := + forall tf tc, + transf_function f = OK tf -> + transl_blocks f c = OK tc -> + code_tail (Ptrofs.unsigned ofs) (fn_blocks tf) tc. |