From 270fc3943295580f298f74359661950fb9beb49d Mon Sep 17 00:00:00 2001
From: sergei <gorelkin@nanoreflex.ru>
Date: Tue, 6 Dec 2011 19:44:24 +0000
Subject: [PATCH] * An open array/array of const parameter passed by value and
 requiring a local copy on heap (currently all targets except non-Darwin i386
 ones) should not be placed into register and should force procedure to have
 an implicit finally block. * At the same time, allow non-value parameters to
 be placed into registers even if they have managed type (it is ok because
 they don't participate in implicit exception handing; explicit exception
 handling still forces them to memory due to logic in
 tabstractvarsym.is_regvar). + Added tparavarsym.needs_finalization method to
 handle this logic in a single place. + Added tparamanager.use_stackalloc
 method to determine if local copies should be allocated on heap.

git-svn-id: trunk@19762 -
---
 compiler/paramgr.pas |  9 +++++++++
 compiler/pdecsub.pas |  2 +-
 compiler/psub.pas    |  3 +--
 compiler/symsym.pas  | 12 ++++++++++++
 4 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/compiler/paramgr.pas b/compiler/paramgr.pas
index 0f01b74e3c..13d149b641 100644
--- a/compiler/paramgr.pas
+++ b/compiler/paramgr.pas
@@ -134,6 +134,8 @@ unit paramgr;
 
           { allocate room for parameters on the stack in the entry code? }
           function use_fixed_stack: boolean;
+          { whether stack pointer can be changed in the middle of procedure }
+          function use_stackalloc: boolean;
        end;
 
 
@@ -467,6 +469,13 @@ implementation
 {$endif i386}
       end;
 
+    { This is a separate function because at least win64 allows stack allocations
+      despite of fixed stack semantics (actually supporting it requires generating
+      a compliant stack frame, not yet possible) }
+    function tparamanager.use_stackalloc: boolean;
+      begin
+        result:=not use_fixed_stack;
+      end;
 
 initialization
   ;
diff --git a/compiler/pdecsub.pas b/compiler/pdecsub.pas
index 299481be93..b34e3d045d 100644
--- a/compiler/pdecsub.pas
+++ b/compiler/pdecsub.pas
@@ -488,7 +488,7 @@ implementation
          exit;
         with tparavarsym(p) do
          begin
-           if not is_managed_type(vardef) and
+           if (not needs_finalization) and
               paramanager.push_addr_param(varspez,vardef,tprocdef(arg).proccalloption) then
              varregable:=vr_intreg;
          end;
diff --git a/compiler/psub.pas b/compiler/psub.pas
index 3e9b15c28c..55283fd4a8 100644
--- a/compiler/psub.pas
+++ b/compiler/psub.pas
@@ -144,8 +144,7 @@ implementation
     procedure check_finalize_paras(p:TObject;arg:pointer);
       begin
         if (tsym(p).typ=paravarsym) and
-           (tparavarsym(p).varspez=vs_value) and
-           is_managed_type(tparavarsym(p).vardef) then
+           tparavarsym(p).needs_finalization then
           include(current_procinfo.flags,pi_needs_implicit_finally);
       end;
 
diff --git a/compiler/symsym.pas b/compiler/symsym.pas
index a8512892a7..ef7cb21a30 100644
--- a/compiler/symsym.pas
+++ b/compiler/symsym.pas
@@ -206,6 +206,7 @@ interface
           constructor ppuload(ppufile:tcompilerppufile);
           destructor destroy;override;
           procedure ppuwrite(ppufile:tcompilerppufile);override;
+          function needs_finalization: boolean;
       end;
 
       tstaticvarsym = class(tabstractnormalvarsym)
@@ -1592,6 +1593,17 @@ implementation
          ppufile.writeentry(ibparavarsym);
       end;
 
+    function tparavarsym.needs_finalization:boolean;
+      begin
+        result:=(varspez=vs_value) and
+          (is_managed_type(vardef) or
+            (
+              (not (tabstractprocdef(owner.defowner).proccalloption in cdecl_pocalls)) and
+              (not paramanager.use_stackalloc) and
+              (is_open_array(vardef) or is_array_of_const(vardef))
+            )
+          );
+      end;
 
 {****************************************************************************
                                TABSOLUTEVARSYM