| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT RUN-TIME COMPONENTS -- |
| -- -- |
| -- T A R G P A R M -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1999-2005, 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, 51 Franklin Street, Fifth Floor, -- |
| -- Boston, MA 02110-1301, 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 package obtains parameters from the target runtime version of |
| -- System, to indicate parameters relevant to the target environment. |
| |
| -- Conceptually, these parameters could be obtained using rtsfind, but |
| -- we do not do this for four reasons: |
| |
| -- 1. Compiling System for every compilation wastes time |
| |
| -- 2. This compilation impedes debugging by adding extra compile steps |
| |
| -- 3. There are recursion problems coming from compiling System itself |
| -- or any of its children. |
| |
| -- 4. The binder also needs the parameters, and we do not want to have |
| -- to drag a lot of front end stuff into the binder. |
| |
| -- For all these reasons, we read in the source of System, and then scan |
| -- it at the text level to extract the parameter values. |
| |
| -- Note however, that later on, when the ali file is written, we make sure |
| -- that the System file is at least parsed, so that the checksum is properly |
| -- computed and set in the ali file. This partially negates points 1 and 2 |
| -- above although just parsing is quick and does not impact debugging much. |
| |
| -- The parameters acquired by this routine from system.ads fall into four |
| -- categories: |
| |
| -- 1. Configuration pragmas, that must appear at the start of the file. |
| -- Any such pragmas automatically apply to any unit compiled in the |
| -- presence of this system file. Only a limited set of such pragmas |
| -- may appear as documented in the corresponding section below, |
| |
| -- 2. Target parameters. These are boolean constants that are defined |
| -- in the private part of the package giving fixed information |
| -- about the target architecture, and the capabilities of the |
| -- code generator and run-time library. |
| |
| -- 3. Identification information. This is an optional string constant |
| -- that gives the name of the run-time library configuration. This |
| -- line may be ommitted for a version of system.ads to be used with |
| -- the full Ada 95 run time. |
| |
| -- 4. Other characterisitics of package System. At the current time the |
| -- only item in this category is whether type Address is private. |
| |
| with Rident; use Rident; |
| with Types; use Types; |
| |
| package Targparm is |
| |
| --------------------------- |
| -- Configuration Pragmas -- |
| --------------------------- |
| |
| -- The following switches get set if the corresponding configuration |
| -- pragma is scanned from the source of system.ads. No other pragmas |
| -- are permitted to appear at the start of the system.ads source file. |
| |
| -- If a pragma Discard_Names appears, then Opt.Global_Discard_Names is |
| -- set to True to indicate that all units must be compiled in this mode. |
| |
| -- If a pragma Locking_Policy appears, then Opt.Locking_Policy is set |
| -- to the first character of the policy name, and Opt.Locking_Policy_Sloc |
| -- is set to System_Location. |
| |
| -- If a pragma Normalize_Scalars appears, then Opt.Normalize_Scalars |
| -- is set True, as well as Opt.Init_Or_Norm_Scalars. |
| |
| -- If a pragma Queuing_Policy appears, then Opt.Queuing_Policy is set |
| -- to the first character of the policy name, and Opt.Queuing_Policy_Sloc |
| -- is set to System_Location. |
| |
| -- If a pragma Task_Dispatching_Policy appears, then the flag |
| -- Opt.Task_Dispatching_Policy is set to the first character of the |
| -- policy name, and Opt.Task_Dispatching_Policy_Sloc is set to |
| -- System_Location. |
| |
| -- If a pragma Polling (On) appears, then the flag Opt.Polling_Required |
| -- is set to True. |
| |
| -- If a pragma Detect_Blocking appears, then the flag Opt.Detect_Blocking |
| -- is set to True. |
| |
| -- if a pragma Suppress_Exception_Locations appears, then the flag |
| -- Opt.Exception_Locations_Suppressed is set to True. |
| |
| -- If a pragma Profile with a valid profile argument appears, then |
| -- the appropriate restrictions and policy flags are set. |
| |
| -- The only other pragma allowed is a pragma Restrictions that specifies |
| -- a restriction that will be imposed on all units in the partition. Note |
| -- that in this context, only one restriction can be specified in a single |
| -- pragma, and the pragma must appear on its own on a single source line. |
| |
| -- If package System contains exactly the line "type Address is private;" |
| -- then the flag Opt.Address_Is_Private is set True, otherwise this flag |
| -- is set False. |
| |
| Restrictions_On_Target : Restrictions_Info; |
| -- Records restrictions specified by system.ads. Only the Set and Value |
| -- members are modified. The Violated and Count fields are never modified. |
| -- Note that entries can be set either by a pragma Restrictions or by |
| -- a pragma Profile. |
| |
| ------------------- |
| -- Run Time Name -- |
| ------------------- |
| |
| -- This parameter should be regarded as read only by all clients of |
| -- of package. The only way they get modified is by calling the |
| -- Get_Target_Parameters routine which reads the values from a provided |
| -- text buffer containing the source of the system package. |
| |
| -- The corresponding string constant is placed immediately at the start |
| -- of the private part of system.ads if is present, e.g. in the form: |
| |
| -- Run_Time_Name : constant String := "Zero Footprint Run Time"; |
| |
| -- the corresponding messages will look something like |
| |
| -- xxx not supported (Zero Footprint Run Time) |
| |
| Run_Time_Name_On_Target : Name_Id := No_Name; |
| -- Set to appropriate names table entry Id value if a Run_Time_Name |
| -- string constant is defined in system.ads. This name is used only |
| -- for the configurable run-time case, and is used to parametrize |
| -- messages that complain about non-supported run-time features. |
| -- The name should contain only letters A-Z, digits 1-9, spaces, |
| -- and underscores. |
| |
| ----------------------- |
| -- Target Parameters -- |
| ----------------------- |
| |
| -- The following parameters correspond to the variables defined in the |
| -- private part of System (without the terminating _On_Target). Note |
| -- that it is required that all parameters defined here be specified |
| -- in the target specific version of system.ads (there are no defaults). |
| |
| -- All these parameters should be regarded as read only by all clients |
| -- of the package. The only way they get modified is by calling the |
| -- Get_Target_Parameters routine which reads the values from a provided |
| -- text buffer containing the source of the system package. |
| |
| -- The default values here are used if no value is found in system.ads. |
| -- This should normally happen only if the special version of system.ads |
| -- used by the compiler itself is in use. The default values are suitable |
| -- for use by the compiler itself in normal environments. This approach |
| -- allows the possibility of new versions of the compiler (possibly with |
| -- new system parameters added) being used to compile older versions of |
| -- the compiler sources. This is not guaranteed to work, but often will |
| -- and by setting appropriate default values, we make it more likely that |
| -- this can succeed. |
| |
| Compiler_System_Version : Boolean := True; |
| -- This is set False in all target dependent versions of System. In the |
| -- compiler default version, it is omitted entirely, meaning that the |
| -- above default value of True will be set. If the flag is False, then |
| -- the scanning circuits in the body of this package do an error check to |
| -- ensure that all parameters other than this one are specified and not |
| -- defaulted. If the parameter is set True, then this check is omitted, |
| -- and any parameters not present in system.ads are left set to their |
| -- default value as described above. |
| |
| ---------------------------- |
| -- Special Target Control -- |
| ---------------------------- |
| |
| -- The great majority of GNAT ports are based on GCC. The switches in |
| -- This section indicate the use of some non-standard target back end |
| -- or other special targetting requirements. |
| |
| AAMP_On_Target : Boolean := False; |
| -- Set to True if target is AAMP |
| |
| OpenVMS_On_Target : Boolean := False; |
| -- Set to True if target is OpenVMS |
| |
| ------------------------------- |
| -- Backend Arithmetic Checks -- |
| ------------------------------- |
| |
| -- Divide and overflow checks are either done in the front end or |
| -- back end. The front end will generate checks when required unless |
| -- the corresponding parameter here is set to indicate that the back |
| -- end will generate the required checks (or that the checks are |
| -- automatically performed by the hardware in an appropriate form). |
| |
| Backend_Divide_Checks_On_Target : Boolean := False; |
| -- Set True if the back end generates divide checks, or if the hardware |
| -- checks automatically. Set False if the front end must generate the |
| -- required tests using explicit expanded code. |
| |
| Backend_Overflow_Checks_On_Target : Boolean := False; |
| -- Set True if the back end generates arithmetic overflow checks, or if |
| -- the hardware checks automatically. Set False if the front end must |
| -- generate the required tests using explicit expanded code. |
| |
| ----------------------------------- |
| -- Control of Exception Handling -- |
| ----------------------------------- |
| |
| -- GNAT implements three methods of implementing exceptions: |
| |
| -- Front-End Longjmp/Setjmp Exceptions |
| |
| -- This approach uses longjmp/setjmp to handle exceptions. It |
| -- uses less storage, and can often propagate exceptions faster, |
| -- at the expense of (sometimes considerable) overhead in setting |
| -- up an exception handler. This approach is available on all |
| -- targets, and is the default where it is the only approach. |
| |
| -- The generation of the setjmp and longjmp calls is handled by |
| -- the front end of the compiler (this includes gigi in the case |
| -- of the standard GCC back end). It does not use any back end |
| -- suport (such as the GCC3 exception handling mechanism). When |
| -- this approach is used, the compiler generates special exception |
| -- handlers for handling cleanups when an exception is raised. |
| |
| -- Front-End Zero Cost Exceptions |
| |
| -- This approach uses separate exception tables. These use extra |
| -- storage, and exception propagation can be quite slow, but there |
| -- is no overhead in setting up an exception handler (it is to this |
| -- latter operation that the phrase zero-cost refers). This approach |
| -- is only available on some targets, and is the default where it is |
| -- available. |
| |
| -- The generation of the exception tables is handled by the front |
| -- end of the compiler. It does not use any back end support (such |
| -- as the GCC3 exception handling mechanism). When this approach |
| -- is used, the compiler generates special exception handlers for |
| -- handling cleanups when an exception is raised. |
| |
| -- Back-End Zero Cost Exceptions |
| |
| -- With this approach, the back end handles the generation and |
| -- handling of exceptions. For example, the GCC3 exception handling |
| -- mechanisms are used in this mode. The front end simply generates |
| -- code for explicit exception handlers, and AT END cleanup handlers |
| -- are simply passed unchanged to the backend for generating cleanups |
| -- both in the exceptional and non-exceptional cases. |
| |
| -- As the name implies, this approach generally uses a zero-cost |
| -- mechanism with tables, but the tables are generated by the back |
| -- end. However, since the back-end is entirely responsible for the |
| -- handling of exceptions, another mechanism might be used. In the |
| -- case of GCC3 for instance, it might be the case that the compiler |
| -- is configured for setjmp/longjmp handling, then everything will |
| -- work correctly. However, it is definitely preferred that the |
| -- back end provide zero cost exception handling. |
| |
| -- Controlling the selection of methods |
| |
| -- On most implementations, back-end zero-cost exceptions are used. |
| -- Otherwise, Front-End Longjmp/Setjmp approach is used. |
| -- Note that there is a requirement that all Ada units in a partition |
| -- be compiled with the same exception model. |
| |
| -- Control of Available Methods and Defaults |
| |
| -- The following switches specify whether ZCX is available, and |
| -- whether it is enabled by default. |
| |
| ZCX_By_Default_On_Target : Boolean := False; |
| -- Indicates if zero cost exceptions are active by default. If this |
| -- variable is False, then the only possible exception method is the |
| -- front-end setjmp/longjmp approach, and this is the default. If |
| -- this variable is True, then GCC ZCX is used. |
| |
| GCC_ZCX_Support_On_Target : Boolean := False; |
| -- Indicates that the target supports GCC Exceptions |
| |
| ------------------------------------ |
| -- Run-Time Library Configuration -- |
| ------------------------------------ |
| |
| -- In configurable run-time mode, the system run-time may not support |
| -- the full Ada language. The effect of setting this switch is to let |
| -- the compiler know that it is not surprising (i.e. the system is not |
| -- misconfigured) if run-time library units or entities within units are |
| -- not present in the run-time. |
| |
| Configurable_Run_Time_On_Target : Boolean := False; |
| -- Indicates that the system.ads file is for a configurable run-time |
| -- |
| -- This has some specific effects as follows |
| -- |
| -- The binder generates the gnat_argc/argv/envp variables in the |
| -- binder file instead of being imported from the run-time library. |
| -- If Command_Line_Args_On_Target is set to False, then the |
| -- generation of these variables is suppressed completely. |
| -- |
| -- The binder generates the gnat_exit_status variable in the binder |
| -- file instead of being imported from the run-time library. If |
| -- Exit_Status_Supported_On_Target is set to False, then the |
| -- generation of this variable is suppressed entirely. |
| -- |
| -- The routine __gnat_break_start is defined within the binder file |
| -- instead of being imported from the run-time library. |
| -- |
| -- The variable __gnat_exit_status is generated within the binder file |
| -- instead of being imported from the run-time library. |
| |
| Suppress_Standard_Library_On_Target : Boolean := False; |
| -- If this flag is True, then the standard library is not included by |
| -- default in the executable (see unit System.Standard_Library in file |
| -- s-stalib.ads for details of what this includes). This is for example |
| -- set True for the zero foot print case, where these files should not |
| -- be included by default. |
| -- |
| -- This flag has some other related effects: |
| -- |
| -- The generation of global variables in the bind file is suppressed, |
| -- with the exception of the priority of the environment task, which |
| -- is needed by the Ravenscar run-time. |
| -- |
| -- The calls to __gnat_initialize and __gnat_finalize are omitted |
| -- |
| -- All finalization and initialization (controlled types) is omitted |
| -- |
| -- The routine __gnat_handler_installed is not imported |
| |
| Preallocated_Stacks_On_Target : Boolean := False; |
| -- If this flag is True, then the expander preallocates all task stacks |
| -- at compile time. If the flag is False, then task stacks are not pre- |
| -- allocated, and task stack allocation is the responsibility of the |
| -- run-time (which typically delegates the task to the underlying |
| -- operating system environment). |
| |
| --------------------- |
| -- Duration Format -- |
| --------------------- |
| |
| -- By default, type Duration is a 64-bit fixed-point type with a delta |
| -- and small of 10**(-9) (i.e. it is a count in nanoseconds. This flag |
| -- allows that standard format to be modified. |
| |
| Duration_32_Bits_On_Target : Boolean := False; |
| -- If True, then Duration is represented in 32 bits and the delta and |
| -- small values are set to 20.0*(10**(-3)) (i.e. it is a count in units |
| -- of 20 milliseconds. |
| |
| ------------------------------------ |
| -- Back-End Code Generation Flags -- |
| ------------------------------------ |
| |
| -- These flags indicate possible limitations in what the code generator |
| -- can handle. They will all be True for a full run-time, but one or more |
| -- of these may be false for a configurable run-time, and if a feature is |
| -- used at the source level, and the corresponding flag is false, then an |
| -- error message will be issued saying the feature is not supported. |
| |
| Support_64_Bit_Divides_On_Target : Boolean := True; |
| -- If True, the back end supports 64-bit divide operations. If False, then |
| -- the source program may not contain 64-bit divide operations. This is |
| -- specifically useful in the zero foot-print case, where the issue is |
| -- whether there is a hardware divide instruction for 64-bits so that |
| -- no run-time support is required. It should always be set True if the |
| -- necessary run-time support is present. |
| |
| Support_Aggregates_On_Target : Boolean := True; |
| -- In the general case, the use of aggregates may generate calls |
| -- to run-time routines in the C library, including memset, memcpy, |
| -- memmove, and bcopy. This flag is set to True if these routines |
| -- are available. If any of these routines is not available, then |
| -- this flag is False, and the use of aggregates is not permitted. |
| |
| Support_Composite_Assign_On_Target : Boolean := True; |
| -- The assignment of composite objects other than small records and |
| -- arrays whose size is 64-bits or less and is set by an explicit |
| -- size clause may generate calls to memcpy, memmove, and bcopy. |
| -- If versions of all these routines are available, then this flag |
| -- is set to True. If any of these routines is not available, then |
| -- the flag is set False, and composite assignments are not allowed. |
| |
| Support_Composite_Compare_On_Target : Boolean := True; |
| -- If this flag is True, then the back end supports bit-wise comparison |
| -- of composite objects for equality, either generating inline code or |
| -- calling appropriate (and available) run-time routines. If this flag |
| -- is False, then the back end does not provide this support, and the |
| -- front end uses component by component comparison for composites. |
| |
| Support_Long_Shifts_On_Target : Boolean := True; |
| -- If True, the back end supports 64-bit shift operations. If False, then |
| -- the source program may not contain explicit 64-bit shifts. In addition, |
| -- the code generated for packed arrays will avoid the use of long shifts. |
| |
| ------------------------------- |
| -- Control of Stack Checking -- |
| ------------------------------- |
| |
| -- GNAT provides two methods of implementing exceptions: |
| |
| -- GCC Probing Mechanism |
| |
| -- This approach uses the standard GCC mechanism for |
| -- stack checking. The method assumes that accessing |
| -- storage immediately beyond the end of the stack |
| -- will result in a trap that is converted to a storage |
| -- error by the runtime system. This mechanism has |
| -- minimal overhead, but requires complex hardware, |
| -- operating system and run-time support. Probing is |
| -- the default method where it is available. The stack |
| -- size for the environment task depends on the operating |
| -- system and cannot be set in a system-independent way. |
| |
| -- GNAT Stack-limit Checking |
| |
| -- This method relies on comparing the stack pointer |
| -- with per-task stack limits. If the check fails, an |
| -- exception is explicitly raised. The advantage is |
| -- that the method requires no extra system dependent |
| -- runtime support and can be used on systems without |
| -- memory protection as well, but at the cost of more |
| -- overhead for doing the check. This method is the |
| -- default on systems that lack complete support for |
| -- probing. |
| |
| Stack_Check_Probes_On_Target : Boolean := False; |
| -- Indicates if stack check probes are used, as opposed to the standard |
| -- target independent comparison method. |
| |
| Stack_Check_Default_On_Target : Boolean := False; |
| -- Indicates if stack checking is on by default |
| |
| ---------------------------- |
| -- Command Line Arguments -- |
| ---------------------------- |
| |
| -- For most ports of GNAT, command line arguments are supported. The |
| -- following flag is set to False for targets that do not support |
| -- command line arguments (VxWorks and AAMP). Note that support of |
| -- command line arguments is not required on such targets (RM A.15(13)). |
| |
| Command_Line_Args_On_Target : Boolean := True; |
| -- Set False if no command line arguments on target. Note that if this |
| -- is False in with Configurable_Run_Time_On_Target set to True, then |
| -- this causes suppression of generation of the argv/argc variables |
| -- used to record command line arguments. |
| |
| -- Similarly, most ports support the use of an exit status, but AAMP |
| -- is an exception (as allowed by RM A.15(18-20)) |
| |
| Exit_Status_Supported_On_Target : Boolean := True; |
| -- Set False if returning of an exit status is not supported on target. |
| -- Note that if this False in with Configurable_Run_Time_On_Target |
| -- set to True, then this causes suppression of the gnat_exit_status |
| -- variable used to record the exit status. |
| |
| ----------------------- |
| -- Main Program Name -- |
| ----------------------- |
| |
| -- When the binder generates the main program to be used to create the |
| -- executable, the main program name is main by default (to match the |
| -- usual Unix practice). If this parameter is set to True, then the |
| -- name is instead by default taken from the actual Ada main program |
| -- name (just the name of the child if the main program is a child unit). |
| -- In either case, this value can be overridden using -M name. |
| |
| Use_Ada_Main_Program_Name_On_Target : Boolean := False; |
| -- Set True to use the Ada main program name as the main name |
| |
| ---------------------------------------------- |
| -- Boolean-Valued Floating-Point Attributes -- |
| ---------------------------------------------- |
| |
| -- The constants below give the values for representation oriented |
| -- floating-point attributes that are the same for all float types |
| -- on the target. These are all boolean values. |
| |
| -- A value is only True if the target reliably supports the corresponding |
| -- feature. Reliably here means that support is guaranteed for all |
| -- possible settings of the relevant compiler switches (like -mieee), |
| -- since we cannot control the user setting of those switches. |
| |
| -- The attributes cannot dependent on the current setting of compiler |
| -- switches, since the values must be static and consistent throughout |
| -- the partition. We probably should add such consistency checks in future, |
| -- but for now we don't do this. |
| |
| -- Note: the compiler itself does not use floating-point, so the |
| -- settings of the defaults here are not really relevant. |
| |
| -- Note: in some cases, proper support of some of these floating point |
| -- features may require a specific switch (e.g. -mieee on the Alpha) |
| -- to be used to obtain full RM compliant support. |
| |
| Denorm_On_Target : Boolean := False; |
| -- Set to False on targets that do not reliably support denormals |
| |
| Machine_Rounds_On_Target : Boolean := True; |
| -- Set to False for targets where S'Machine_Rounds is False |
| |
| Machine_Overflows_On_Target : Boolean := False; |
| -- Set to True for targets where S'Machine_Overflows is True |
| |
| Signed_Zeros_On_Target : Boolean := True; |
| -- Set to False on targets that do not reliably support signed zeros |
| |
| ------------------------------------------- |
| -- Boolean-Valued Fixed-Point Attributes -- |
| ------------------------------------------- |
| |
| Fractional_Fixed_Ops_On_Target : Boolean := False; |
| -- Set to True for targets that support fixed-by-fixed multiplication |
| -- and division for fixed-point types with a small value equal to |
| -- 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 -- |
| ----------------- |
| |
| -- Normally when using the GCC backend, Gigi and GCC perform much of the |
| -- data layout using the standard layout capabilities of GCC. If the |
| -- parameter Backend_Layout is set to False, then the front end must |
| -- perform all data layout. For further details see the package Layout. |
| |
| Frontend_Layout_On_Target : Boolean := False; |
| -- Set True if front end does layout |
| |
| ----------------- |
| -- Subprograms -- |
| ----------------- |
| |
| -- These subprograms are used to initialize the target parameter values |
| -- from the system.ads file. Note that this is only done once, so if more |
| -- than one call is made to either routine, the second and subsequent |
| -- calls are ignored. |
| |
| procedure Get_Target_Parameters |
| (System_Text : Source_Buffer_Ptr; |
| Source_First : Source_Ptr; |
| Source_Last : Source_Ptr); |
| -- Called at the start of execution to obtain target parameters from |
| -- the source of package System. The parameters provide the source |
| -- text to be scanned (in System_Text (Source_First .. Source_Last)). |
| |
| procedure Get_Target_Parameters; |
| -- This version reads in system.ads using Osint. The idea is that the |
| -- caller uses the first version if they have to read system.ads anyway |
| -- (e.g. the compiler) and uses this simpler interface if system.ads is |
| -- not otherwise needed. |
| |
| end Targparm; |
