system-linux-ia64.ads, [...] (Functions_Return_By_DSP_On_Target): Removed

2007-04-06  Robert Dewar  <dewar@adacore.com>

	* system-linux-ia64.ads, system-freebsd-x86.ads, system-lynxos-ppc.ads,
	system-lynxos-x86.ads, system-linux-x86_64.ads, system-tru64.ads,
	system-vxworks-sparcv9.ads, system-solaris-x86.ads, system-irix-o32.ads,
	system-irix-n32.ads, system-hpux.ads, system-vxworks-m68k.ads,
	system-linux-x86.ads, system-vxworks-mips.ads, system-interix.ads,
	system-solaris-sparc.ads, system-solaris-sparcv9.ads, system-vms.ads,
	system-mingw.ads, system-vms-zcx.ads, system-vxworks-ppc.ads,
	system-vxworks-alpha.ads, system-vms_64.ads, system-darwin-ppc.ads,
	system-vxworks-x86.ads, system-linux-ppc.ads, system-linux-hppa.ads,
        system-hpux-ia64.ads, targparm.adb,
	targparm.ads (Functions_Return_By_DSP_On_Target): Removed

	* system.ads: Move Functions_Return_By_DSP to obsolete section,
	kept for bootstrap purposes only.

From-SVN: r123539

gcc/ada/system-darwin-ppc.ads

@@ -153,7 +153,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-freebsd-x86.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-hpux-ia64.ads

@@ -127,14 +127,13 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;
    Preallocated_Stacks       : constant Boolean := False;
    Signed_Zeros              : constant Boolean := True;
    Stack_Check_Default       : constant Boolean := False;
-   Stack_Check_Probes        : constant Boolean := False;
+   Stack_Check_Probes        : constant Boolean := True;
    Support_64_Bit_Divides    : constant Boolean := True;
    Support_Aggregates        : constant Boolean := True;
    Support_Composite_Assign  : constant Boolean := True;

gcc/ada/system-hpux.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-interix.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-irix-n32.ads

@@ -139,7 +139,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-irix-o32.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-linux-hppa.ads

@@ -126,7 +126,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-linux-ia64.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-linux-ppc.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-linux-x86.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-linux-x86_64.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-lynxos-ppc.ads

@@ -141,7 +141,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-lynxos-x86.ads

@@ -141,7 +141,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-mingw.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-solaris-sparc.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-solaris-sparcv9.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-solaris-x86.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-tru64.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-vms-zcx.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := True;

gcc/ada/system-vms.ads

@@ -127,7 +127,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := True;

gcc/ada/system-vms_64.ads

@@ -146,7 +146,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := True;

gcc/ada/system-vxworks-alpha.ads

@@ -135,7 +135,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-vxworks-m68k.ads

@@ -135,7 +135,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-vxworks-mips.ads

@@ -135,7 +135,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-vxworks-ppc.ads

@@ -135,7 +135,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-vxworks-sparcv9.ads

@@ -137,7 +137,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system-vxworks-x86.ads

@@ -135,7 +135,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;

gcc/ada/system.ads

@@ -139,7 +139,6 @@ private
    Exit_Status_Supported     : constant Boolean := True;
    Fractional_Fixed_Ops      : constant Boolean := False;
    Frontend_Layout           : constant Boolean := False;
-   Functions_Return_By_DSP   : constant Boolean := False;
    Machine_Overflows         : constant Boolean := False;
    Machine_Rounds            : constant Boolean := True;
    OpenVMS                   : constant Boolean := False;
@@ -162,5 +161,6 @@ private
 
    High_Integrity_Mode       : constant Boolean := False;
    Long_Shifts_Inlined       : constant Boolean := True;
+   Functions_Return_By_DSP   : constant Boolean := False;
 
 end System;

gcc/ada/targparm.adb

@@ -48,7 +48,6 @@ package body Targparm is
       CSV,  --   Compiler_System_Version
       D32,  --   Duration_32_Bits
       DEN,  --   Denorm
-      DSP,  --   Functions_Return_By_DSP
       EXS,  --   Exit_Status_Supported
       FEL,  --   Frontend_Layout
       FFO,  --   Fractional_Fixed_Ops
@@ -85,7 +84,6 @@ package body Targparm is
    CSV_Str : aliased constant Source_Buffer := "Compiler_System_Version";
    D32_Str : aliased constant Source_Buffer := "Duration_32_Bits";
    DEN_Str : aliased constant Source_Buffer := "Denorm";
-   DSP_Str : aliased constant Source_Buffer := "Functions_Return_By_DSP";
    EXS_Str : aliased constant Source_Buffer := "Exit_Status_Supported";
    FEL_Str : aliased constant Source_Buffer := "Frontend_Layout";
    FFO_Str : aliased constant Source_Buffer := "Fractional_Fixed_Ops";
@@ -119,7 +117,6 @@ package body Targparm is
       CSV_Str'Access,
       D32_Str'Access,
       DEN_Str'Access,
-      DSP_Str'Access,
       EXS_Str'Access,
       FEL_Str'Access,
       FFO_Str'Access,
@@ -556,7 +553,6 @@ package body Targparm is
                      when CSV => Compiler_System_Version             := Result;
                      when D32 => Duration_32_Bits_On_Target          := Result;
                      when DEN => Denorm_On_Target                    := Result;
-                     when DSP => Functions_Return_By_DSP_On_Target   := Result;
                      when EXS => Exit_Status_Supported_On_Target     := Result;
                      when FEL => Frontend_Layout_On_Target           := Result;
                      when FFO => Fractional_Fixed_Ops_On_Target      := Result;

gcc/ada/targparm.ads

@@ -553,46 +553,6 @@ package Targparm is
    --  2 ** (-(T'Object_Size - 1)) and whose values have an absolute
    --  value less than 1.0.
 
-   --------------------------------------------------------------
-   -- Handling of Unconstrained Values Returned from Functions --
-   --------------------------------------------------------------
-
-   --  Functions that return variable length objects, notably unconstrained
-   --  arrays are a special case, because there is no simple obvious way of
-   --  implementing this feature. Furthermore, this capability is not present
-   --  in C++ or C, so typically the system ABI does not handle this case.
-
-   --  GNAT uses two different approaches
-
-   --    The Secondary Stack
-
-   --      The secondary stack is a special storage pool that is used for
-   --      this purpose. The called function places the result on the
-   --      secondary stack, and the caller uses or copies the value from
-   --      the secondary stack, and pops the secondary stack after the
-   --      value is consumed. The secondary stack is outside the system
-   --      ABI, and the important point is that although generally it is
-   --      handled in a stack like manner corresponding to the subprogram
-   --      call structure, a return from a function does NOT pop the stack.
-
-   --    DSP (Depressed Stack Pointer)
-
-   --      Some targets permit the implementation of a function call/return
-   --      protocol in which the function does not pop the main stack pointer
-   --      on return, but rather returns with the stack pointer depressed.
-   --      This is not generally permitted by any ABI, but for at least some
-   --      targets, the implementation of alloca provides a model for this
-   --      approach. If return-with-DSP is implemented, then functions that
-   --      return variable length objects do it by returning with the stack
-   --      pointer depressed, and the returned object is a pointer to the
-   --      area within the stack frame of the called procedure that contains
-   --      the returned value. The caller must then pop the main stack when
-   --      this value is consumed.
-
-   Functions_Return_By_DSP_On_Target : Boolean := False;
-   --  Set to True if target permits functions to return with using the
-   --  DSP (depressed stack pointer) approach.
-
    -----------------
    -- Data Layout --
    -----------------