Coloring: allow to exclude user-specified registers from allocation.

CPragmas (PPC/EABI only): add #pragma reserve_register


git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1314 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e

3 files changed, 89 insertions, 3 deletions

diff --git a/powerpc/Machregsaux.ml b/powerpc/Machregsaux.ml
new file mode 100644
index 0000000..b729d10
--- /dev/null
+++ b/powerpc/Machregsaux.ml
@@ -0,0 +1,45 @@
+(* *********************************************************************)
+(*                                                                     *)
+(*              The Compcert verified compiler                         *)
+(*                                                                     *)
+(*          Xavier Leroy, INRIA Paris-Rocquencourt                     *)
+(*                                                                     *)
+(*  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.     *)
+(*                                                                     *)
+(* *********************************************************************)
+
+(** Auxiliary functions on machine registers *)
+
+open Machregs
+
+let register_names = [
+  ("R3", R3);  ("R4", R4);  ("R5", R5);  ("R6", R6);
+  ("R7", R7);  ("R8", R8);  ("R9", R9);  ("R10", R10);
+  ("R14", R14); ("R15", R15); ("R16", R16);
+  ("R17", R17); ("R18", R18); ("R19", R19); ("R20", R20);
+  ("R21", R21); ("R22", R22); ("R23", R23); ("R24", R24);
+  ("R25", R25); ("R26", R26); ("R27", R27); ("R28", R28);
+  ("R29", R29); ("R30", R30); ("R31", R31);
+  ("F1", F1);  ("F2", F2);  ("F3", F3);  ("F4", F4);
+  ("F5", F5);  ("F6", F6);  ("F7", F7);  ("F8", F8);
+  ("F9", F9);  ("F10", F10); ("F14", F14); ("F15", F15);
+  ("F16", F16); ("F17", F17); ("F18", F18); ("F19", F19);
+  ("F20", F20); ("F21", F21); ("F22", F22); ("F23", F23);
+  ("F24", F24); ("F25", F25); ("F26", F26); ("F27", F27);
+  ("F28", F28); ("F29", F29); ("F30", F30); ("F31", F31);
+  ("R11", IT1); ("R0", IT2);
+  ("F11", FT1); ("F12", FT2); ("F0", FT3)
+]
+
+let register_by_name s =
+  try
+    Some(List.assoc (String.uppercase s) register_names)
+  with Not_found ->
+    None
+
+let can_reserve_register r =
+  List.mem r Conventions.int_callee_save_regs
+  || List.mem r Conventions.float_callee_save_regs
+
diff --git a/powerpc/Machregsaux.mli b/powerpc/Machregsaux.mli
new file mode 100644
index 0000000..6d81988
--- /dev/null
+++ b/powerpc/Machregsaux.mli
@@ -0,0 +1,16 @@
+(* *********************************************************************)
+(*                                                                     *)
+(*              The Compcert verified compiler                         *)
+(*                                                                     *)
+(*          Xavier Leroy, INRIA Paris-Rocquencourt                     *)
+(*                                                                     *)
+(*  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.     *)
+(*                                                                     *)
+(* *********************************************************************)
+
+(** Auxiliary functions on machine registers *)
+
+val register_by_name: string -> Machregs.mreg option
+val can_reserve_register: Machregs.mreg -> bool
diff --git a/powerpc/eabi/CPragmas.ml b/powerpc/eabi/CPragmas.ml
index 4bb7786..3104cc8 100644
--- a/powerpc/eabi/CPragmas.ml
+++ b/powerpc/eabi/CPragmas.ml
@@ -68,6 +68,8 @@ let _ =
                sec_near_access = false}
   ]
 
+(* #pragma section *)
+
 let process_section_pragma classname istring ustring addrmode accmode =
   let old_si =
     try Hashtbl.find section_table classname
@@ -85,6 +87,7 @@ let process_section_pragma classname istring ustring addrmode accmode =
         else (addrmode = "near-code") || (addrmode = "near-data") } in
   Hashtbl.add section_table classname si
 
+(* #pragma use_section *)
 
 let use_section_table : (AST.ident, section_info) Hashtbl.t =
   Hashtbl.create 51
@@ -122,6 +125,19 @@ let define_variable id d =
       if is_small !Clflags.option_small_data then "SDATA" else "DATA" in
   default_use_section id sect
 
+(* #pragma reserve_register *)
+
+let process_reserve_register_pragma name =
+  match Machregsaux.register_by_name name with
+  | None ->
+      C2Clight.error "unknown register in `reserve_register' pragma"
+  | Some r ->
+      if Machregsaux.can_reserve_register r then
+        Coloringaux.reserved_registers :=
+          r :: !Coloringaux.reserved_registers
+      else
+        C2Clight.error "cannot reserve this register (not a callee-save)"
+
 (* Parsing of pragmas using regexps *)
 
 let re_start_pragma_section = Str.regexp "section\\b"
@@ -144,6 +160,11 @@ let re_pragma_use_section = Str.regexp
 
 let re_split_idents = Str.regexp "[ \t,]+"
 
+let re_start_pragma_reserve_register = Str.regexp "reserve_register\\b"
+
+let re_pragma_reserve_register = Str.regexp
+  "reserve_register[ \t]+\\([A-Za-z0-9]+\\)"
+
 let process_pragma name =
   if Str.string_match re_pragma_section name 0 then begin
     process_section_pragma
@@ -162,9 +183,13 @@ let process_pragma name =
     if identlist = [] then C2Clight.warning "vacuous `use_section' pragma";
     List.iter (process_use_section_pragma classname) identlist;
     true
-  end else if Str.string_match re_start_pragma_use_section name 0 then
-    (C2Clight.error "ill-formed `use_section' pragma"; true)
-  else
+  end else if Str.string_match re_start_pragma_use_section name 0 then begin
+    C2Clight.error "ill-formed `use_section' pragma"; true
+  end else if Str.string_match re_pragma_reserve_register name 0 then begin
+    process_reserve_register_pragma (Str.matched_group 1 name); true
+  end else if Str.string_match re_start_pragma_reserve_register name 0 then begin
+    C2Clight.error "ill-formed `reserve_register' pragma"; true
+  end else
     false
 
 let initialize () =