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Diffstat (limited to 'gcc-4.7/gcc/ada/expander.ads')
-rw-r--r-- | gcc-4.7/gcc/ada/expander.ads | 167 |
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diff --git a/gcc-4.7/gcc/ada/expander.ads b/gcc-4.7/gcc/ada/expander.ads deleted file mode 100644 index df5944218..000000000 --- a/gcc-4.7/gcc/ada/expander.ads +++ /dev/null @@ -1,167 +0,0 @@ ------------------------------------------------------------------------------- --- -- --- GNAT COMPILER COMPONENTS -- --- -- --- E X P A N D E R -- --- -- --- S p e c -- --- -- --- Copyright (C) 1992-2008, 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 3, 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 COPYING3. If not, go to -- --- http://www.gnu.org/licenses for a complete copy of the license. -- --- -- --- GNAT was originally developed by the GNAT team at New York University. -- --- Extensive contributions were provided by Ada Core Technologies Inc. -- --- -- ------------------------------------------------------------------------------- - --- This procedure performs any required expansion for the specified node. --- The argument is the node that is a candidate for possible expansion. --- If no expansion is required, then Expand returns without doing anything. - --- If the node does need expansion, then the subtree is replaced by the --- tree corresponding to the required rewriting. This tree is a syntactic --- tree, except that all Entity fields must be correctly set on all --- direct names, since the expander presumably knows what it wants, and in --- any case it doesn't work to have the semantic analyzer perform visibility --- analysis on these trees (they may have references to non-visible runtime --- routines etc.) There are a few exceptions to this rule in special cases, --- but they must be documented clearly. - --- Expand is called in two different situations: - --- Nodes that are not subexpressions (Nkind not in N_Subexpr) - --- In this case, Expand is called from the body of Sem, immediately --- after completing semantic analysis by calling the corresponding --- Analyze_N_xxx procedure. If expansion occurs, the given node must --- be replaced with another node that is also not a subexpression. --- This seems naturally to be the case, since it is hard to imagine any --- situation in which it would make sense to replace a non-expression --- subtree with an expression. Once the substitution is completed, the --- Expand routine must call Analyze on the resulting node to do any --- required semantic analysis. Note that references to children copied --- from the old tree won't be reanalyzed, since their Analyzed flag --- is set. - --- Nodes that are subexpressions (Nkind in N_Subexpr) - --- In this case, Expand is called from Sem_Res.Resolve after completing --- the resolution of the subexpression (this means that the expander sees --- the fully typed subtree). If expansion occurs, the given node must be --- replaced by a node that is also a subexpression. Again it is hard --- to see how this restriction could possibly be violated. Once the --- substitution is completed, the Expand routine must first call Analyze --- on the resulting node to do any required semantic analysis, and then --- call Resolve on the node to set the type (typically the type will be --- the same as the original type of the input node, but this is not --- always the case). - --- In both these cases, Replace or Rewrite must be used to achieve the --- of the node, since the Expander routine is only passed the Node_Id --- of the node to be expanded, and the resulting expanded Node_Id must --- be the same (the parameter to Expand is mode in, not mode in-out). - --- For nodes other than subexpressions, it is not necessary to preserve the --- original tree in the Expand routines, unlike the case for modifications --- to the tree made in the semantic analyzer. This is because anyone who is --- interested in working with the original tree (like ASIS) is required to --- compile in semantics checks only mode. Thus Replace may be freely used --- in such instances. - --- For subexpressions, preservation of the original tree is required because --- of the need for conformance checking of default expressions, which occurs --- on expanded trees. This means that Replace should not ever be used on --- on subexpression nodes. Instead use Rewrite. - --- Note: the front end avoids calls to any of the expand routines if code --- is not being generated. This is done for three reasons: - --- 1. Make sure tree does not get mucked up by the expander if no --- code is being generated, and is thus usable by ASIS etc. - --- 2. Save time, since expansion is not needed if a compilation is --- being done only to check the semantics, or if code generation --- has been canceled due to previously detected errors. - --- 3. Allow the expand routines to assume that the tree is error free. --- This results from the fact that code generation mode is always --- cancelled when any error occurs. - --- If we ever decide to implement a feature allowing object modules to be --- generated even if errors have been detected, then point 3 will no longer --- hold, and the expand routines will have to be modified to operate properly --- in the presence of errors (for many reasons this is not currently true). - --- Note: a consequence of this approach is that error messages must never --- be generated in the expander, since this would mean that such error --- messages are not generated when the expander is not being called. - --- Expansion is the last stage of analyzing a node, so Expand sets the --- Analyzed flag of the node being analyzed as its last action. This is --- done even if expansion is off (in this case, the only effect of the --- call to Expand is to set the Analyzed flag to True). - -with Types; use Types; - -package Expander is - - -- The flag Opt.Expander_Active controls whether expansion is active - -- (True) or deactivated (False). When expansion is deactivated all - -- calls to expander routines have no effect. To temporarily disable - -- expansion, always call the routines defined below, do NOT change - -- Expander_Active directly. - -- - -- You should not use this flag to test if you are currently processing - -- a generic spec or body. Use the flag Inside_A_Generic instead (see - -- the spec of package Sem). - -- - -- There is no good reason for permanently changing the value of this flag - -- except after detecting a syntactic or semantic error. In this event - -- this flag is set to False to disable all subsequent expansion activity. - -- - -- In general this flag should be used as a read only value. The only - -- exceptions where it makes sense to temporarily change its value are: - -- - -- (a) when starting/completing the processing of a generic definition - -- or declaration (see routines Start_Generic_Processing and - -- End_Generic_Processing in Sem_Ch12) - -- - -- (b) when starting/completing the pre-analysis of an expression - -- (see the spec of package Sem for more info on pre-analysis.) - -- - -- Note that when processing a spec expression (In_Spec_Expression - -- is True) or performing semantic analysis of a generic spec or body - -- (Inside_A_Generic) or when performing pre-analysis (Full_Analysis is - -- False) the Expander_Active flag is False. - - procedure Expand (N : Node_Id); - -- Expand node N, as described above - - procedure Expander_Mode_Save_And_Set (Status : Boolean); - -- Saves the current setting of the Expander_Active flag on an internal - -- stack and then sets the flag to the given value. - -- - -- Note: this routine has no effect in ASIS_Mode. In ASIS_Mode, all - -- expansion activity is always off, since we want the original semantic - -- tree for ASIS purposes without any expansion. This is achieved by - -- setting Expander_Active False in ASIS_Mode. In situations such as - -- the call to Instantiate_Bodies in Frontend, Expander_Mode_Save_And_Set - -- may be called to temporarily turn the expander on, but this will have - -- no effect in ASIS mode. - - procedure Expander_Mode_Restore; - -- Restores the setting of the Expander_Active flag using the top entry - -- pushed onto the stack by Expander_Mode_Save_And_Reset, popping the - -- stack, except that if any errors have been detected, then the state - -- of the flag is left set to False. Disabled for ASIS_Mode (see above). - -end Expander; |