------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- SYSTEM.MACHINE_STATE_OPERATIONS -- -- -- -- B o d y -- -- (Version for IRIX/MIPS) -- -- -- -- Copyright (C) 1999-2004 Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- This version of Ada.Exceptions.Machine_State_Operations is for use on -- SGI Irix systems. By means of compile time conditional calculations, it -- can handle both n32/n64 and o32 modes. with System.Machine_Code; use System.Machine_Code; with System.Memory; with System.Soft_Links; use System.Soft_Links; with Unchecked_Conversion; package body System.Machine_State_Operations is use System.Storage_Elements; use System.Exceptions; -- The exc_unwind function in libexc operats on a Sigcontext -- Type sigcontext_t is defined in /usr/include/sys/signal.h. -- We define an equivalent Ada type here. From the comments in -- signal.h: -- sigcontext is not part of the ABI - so this version is used to -- handle 32 and 64 bit applications - it is a constant size regardless -- of compilation mode, and always returns 64 bit register values type Uns32 is mod 2 ** 32; type Uns64 is mod 2 ** 64; type Uns32_Ptr is access all Uns32; type Uns64_Array is array (Integer range <>) of Uns64; type Reg_Array is array (0 .. 31) of Uns64; type Sigcontext is record SC_Regmask : Uns32; -- 0 SC_Status : Uns32; -- 4 SC_PC : Uns64; -- 8 SC_Regs : Reg_Array; -- 16 SC_Fpregs : Reg_Array; -- 272 SC_Ownedfp : Uns32; -- 528 SC_Fpc_Csr : Uns32; -- 532 SC_Fpc_Eir : Uns32; -- 536 SC_Ssflags : Uns32; -- 540 SC_Mdhi : Uns64; -- 544 SC_Mdlo : Uns64; -- 552 SC_Cause : Uns64; -- 560 SC_Badvaddr : Uns64; -- 568 SC_Triggersave : Uns64; -- 576 SC_Sigset : Uns64; -- 584 SC_Fp_Rounded_Result : Uns64; -- 592 SC_Pancake : Uns64_Array (0 .. 5); SC_Pad : Uns64_Array (0 .. 26); end record; type Sigcontext_Ptr is access all Sigcontext; SC_Regs_Pos : constant String := "16"; SC_Fpregs_Pos : constant String := "272"; -- Byte offset of the Integer and Floating Point register save areas -- within the Sigcontext. function To_Sigcontext_Ptr is new Unchecked_Conversion (Machine_State, Sigcontext_Ptr); type Addr_Int is mod 2 ** Long_Integer'Size; -- An unsigned integer type whose size is the same as System.Address. -- We rely on the fact that Long_Integer'Size = System.Address'Size in -- all ABIs. Type Addr_Int can be converted to Uns64. function To_Code_Loc is new Unchecked_Conversion (Addr_Int, Code_Loc); function To_Addr_Int is new Unchecked_Conversion (System.Address, Addr_Int); function To_Uns32_Ptr is new Unchecked_Conversion (Addr_Int, Uns32_Ptr); -------------------------------- -- ABI-Dependent Declarations -- -------------------------------- o32 : constant Boolean := System.Word_Size = 32; n32 : constant Boolean := System.Word_Size = 64; o32n : constant Natural := Boolean'Pos (o32); n32n : constant Natural := Boolean'Pos (n32); -- Flags to indicate which ABI is in effect for this compilation. For the -- purposes of this unit, the n32 and n64 ABI's are identical. LSC : constant Character := Character'Val (o32n * Character'Pos ('w') + n32n * Character'Pos ('d')); -- This is 'w' for o32, and 'd' for n32/n64, used for constructing the -- load/store instructions used to save/restore machine instructions. Roff : constant Character := Character'Val (o32n * Character'Pos ('4') + n32n * Character'Pos ('0')); -- Offset from first byte of a __uint64 register save location where -- the register value is stored. For n32/64 we store the entire 64 -- bit register into the uint64. For o32, only 32 bits are stored -- at an offset of 4 bytes. This is used as part of expressions with -- '+' signs on both sides, so a null offset has to be '0' and not ' ' -- to avoid assembler syntax errors on "X + + Y" in the latter case. procedure Update_GP (Scp : Sigcontext_Ptr); --------------- -- Update_GP -- --------------- procedure Update_GP (Scp : Sigcontext_Ptr) is type F_op is mod 2 ** 6; type F_reg is mod 2 ** 5; type F_imm is new Short_Integer; type I_Type is record op : F_op; rs : F_reg; rt : F_reg; imm : F_imm; end record; pragma Pack (I_Type); for I_Type'Size use 32; type I_Type_Ptr is access all I_Type; LW : constant F_op := 2#100011#; Reg_GP : constant := 28; type Address_Int is mod 2 ** Standard'Address_Size; function To_I_Type_Ptr is new Unchecked_Conversion (Address_Int, I_Type_Ptr); Ret_Ins : constant I_Type_Ptr := To_I_Type_Ptr (Address_Int (Scp.SC_PC)); GP_Ptr : Uns32_Ptr; begin if Ret_Ins.op = LW and then Ret_Ins.rt = Reg_GP then GP_Ptr := To_Uns32_Ptr (Addr_Int (Scp.SC_Regs (Integer (Ret_Ins.rs))) + Addr_Int (Ret_Ins.imm)); Scp.SC_Regs (Reg_GP) := Uns64 (GP_Ptr.all); end if; end Update_GP; ---------------------------- -- Allocate_Machine_State -- ---------------------------- function Allocate_Machine_State return Machine_State is begin return Machine_State (Memory.Alloc (Sigcontext'Max_Size_In_Storage_Elements)); end Allocate_Machine_State; ------------------- -- Enter_Handler -- ------------------- procedure Enter_Handler (M : Machine_State; Handler : Handler_Loc) is pragma Warnings (Off, M); pragma Warnings (Off, Handler); LOADI : constant String (1 .. 2) := 'l' & LSC; -- This is "lw" in o32 mode, and "ld" in n32/n64 mode LOADF : constant String (1 .. 4) := 'l' & LSC & "c1"; -- This is "lwc1" in o32 mode and "ldc1" in n32/n64 mode begin -- Restore integer registers from machine state. Note that we know -- that $4 points to M, and $5 points to Handler, since this is -- the standard calling sequence Asm (LOADI & " $16, 16*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $17, 17*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $18, 18*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $19, 19*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $20, 20*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $21, 21*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $22, 22*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $23, 23*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $24, 24*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $25, 25*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $26, 26*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $27, 27*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $28, 28*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $29, 29*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $30, 30*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (LOADI & " $31, 31*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); -- Restore floating-point registers from machine state Asm (LOADF & " $f16, 16*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f17, 17*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f18, 18*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f19, 19*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f20, 20*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f21, 21*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f22, 22*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f23, 23*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f24, 24*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f25, 25*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f26, 26*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f27, 27*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f28, 28*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f29, 29*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f30, 30*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (LOADF & " $f31, 31*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); -- Jump directly to the handler Asm ("jr $5"); end Enter_Handler; ---------------- -- Fetch_Code -- ---------------- function Fetch_Code (Loc : Code_Loc) return Code_Loc is begin return Loc; end Fetch_Code; ------------------------ -- Free_Machine_State -- ------------------------ procedure Free_Machine_State (M : in out Machine_State) is begin Memory.Free (Address (M)); M := Machine_State (Null_Address); end Free_Machine_State; ------------------ -- Get_Code_Loc -- ------------------ function Get_Code_Loc (M : Machine_State) return Code_Loc is SC : constant Sigcontext_Ptr := To_Sigcontext_Ptr (M); begin return To_Code_Loc (Addr_Int (SC.SC_PC)); end Get_Code_Loc; -------------------------- -- Machine_State_Length -- -------------------------- function Machine_State_Length return Storage_Offset is begin return Sigcontext'Max_Size_In_Storage_Elements; end Machine_State_Length; --------------- -- Pop_Frame -- --------------- procedure Pop_Frame (M : Machine_State; Info : Subprogram_Info_Type) is pragma Warnings (Off, Info); Scp : constant Sigcontext_Ptr := To_Sigcontext_Ptr (M); procedure Exc_Unwind (Scp : Sigcontext_Ptr; Fde : Long_Integer := 0); pragma Import (C, Exc_Unwind, "exc_unwind"); -- ??? Calling exc_unwind in the current setup does not work and -- triggers the emission of system warning messages. Why it does -- not work remains to be investigated. Part of the problem is -- probably a section naming issue (e.g. .eh_frame/.debug_frame). -- Instead of letting the call take place for nothing and emit -- messages we don't expect, we just arrange things to pretend it -- occurred and failed. -- ??? Until this is fixed, we shall document that the backtrace -- computation facility does not work, and we inhibit the pragma below -- because we arrange for the call not to be emitted and the linker -- complains when a library is linked in but resolves nothing. -- pragma Linker_Options ("-lexc"); begin -- exc_unwind is apparently not thread-safe under IRIX, so protect it -- against race conditions within the GNAT run time. -- ??? Note that we might want to use a fine grained lock here since -- Lock_Task is used in many other places. Lock_Task.all; if False then Exc_Unwind (Scp); else Scp.SC_PC := 0; end if; Unlock_Task.all; if Scp.SC_PC = 0 or else Scp.SC_PC = 1 then -- A return value of 0 or 1 means exc_unwind couldn't find a parent -- frame. Propagate_Exception expects a zero return address to -- indicate TOS. Scp.SC_PC := 0; else -- Set the GP to restore to the caller value (not callee value) -- This is done only in o32 mode. In n32/n64 mode, GP is a normal -- callee save register if o32 then Update_GP (Scp); end if; -- Adjust the return address to the call site, not the -- instruction following the branch delay slot. This may -- be necessary if the last instruction of a pragma No_Return -- subprogram is a call. The first instruction following the -- delay slot may be the start of another subprogram. We back -- off the address by 8, which points safely into the middle -- of the generated subprogram code, avoiding end effects. Scp.SC_PC := Scp.SC_PC - 8; end if; end Pop_Frame; ----------------------- -- Set_Machine_State -- ----------------------- procedure Set_Machine_State (M : Machine_State) is STOREI : constant String (1 .. 2) := 's' & LSC; -- This is "sw" in o32 mode, and "sd" in n32 mode STOREF : constant String (1 .. 4) := 's' & LSC & "c1"; -- This is "swc1" in o32 mode and "sdc1" in n32 mode Scp : Sigcontext_Ptr; begin -- Save the integer registers. Note that we know that $4 points -- to M, since that is where the first parameter is passed. -- Restore integer registers from machine state. Note that we know -- that $4 points to M since this is the standard calling sequence <> Asm (STOREI & " $16, 16*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $17, 17*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $18, 18*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $19, 19*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $20, 20*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $21, 21*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $22, 22*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $23, 23*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $24, 24*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $25, 25*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $26, 26*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $27, 27*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $28, 28*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $29, 29*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $30, 30*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); Asm (STOREI & " $31, 31*8+" & Roff & "+" & SC_Regs_Pos & "($4)"); -- Restore floating-point registers from machine state Asm (STOREF & " $f16, 16*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f17, 17*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f18, 18*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f19, 19*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f20, 20*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f21, 21*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f22, 22*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f23, 23*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f24, 24*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f25, 25*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f26, 26*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f27, 27*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f28, 28*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f29, 29*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f30, 30*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); Asm (STOREF & " $f31, 31*8+" & Roff & "+" & SC_Fpregs_Pos & "($4)"); -- Set the PC value for the context to a location after the -- prolog has been executed. Scp := To_Sigcontext_Ptr (M); Scp.SC_PC := Uns64 (To_Addr_Int (Past_Prolog'Address)); -- We saved the state *inside* this routine, but what we want is -- the state at the call site. So we need to do one pop operation. -- This pop operation will properly set the PC value in the machine -- state, so there is no need to save PC in the above code. Pop_Frame (M, Set_Machine_State'Address); end Set_Machine_State; ------------------------------ -- Set_Signal_Machine_State -- ------------------------------ procedure Set_Signal_Machine_State (M : Machine_State; Context : System.Address) is pragma Warnings (Off, M); pragma Warnings (Off, Context); begin null; end Set_Signal_Machine_State; end System.Machine_State_Operations;