diff options
Diffstat (limited to 'gcc/ada/sem_elab.adb')
| -rw-r--r-- | gcc/ada/sem_elab.adb | 172 |
1 files changed, 118 insertions, 54 deletions
diff --git a/gcc/ada/sem_elab.adb b/gcc/ada/sem_elab.adb index a57a477..c84d04b 100644 --- a/gcc/ada/sem_elab.adb +++ b/gcc/ada/sem_elab.adb @@ -184,7 +184,11 @@ package body Sem_Elab is -- E is the entity of the called subprogram, or instantiated generic unit, -- or subprogram referenced by 'Access. -- - -- The flag Outer_Scope is the outer level scope for the original call. + -- In SPARK mode, N can also be a variable reference, since in SPARK this + -- also triggers a requirement for Elaborate_All, and in this case E is the + -- entity being referenced. + -- + -- Outer_Scope is the outer level scope for the original reference. -- Inter_Unit_Only is set if the call is only to be checked in the -- case where it is to another unit (and skipped if within a unit). -- Generate_Warnings is set to False to suppress warning messages about @@ -194,6 +198,11 @@ package body Sem_Elab is -- procedure (since the referenced subprogram may be called later -- indirectly). Flag In_Init_Proc should be set whenever the current -- context is a type init proc. + -- + -- Note: this might better be called Check_A_Reference to recognize the + -- variable case for SPARK, but we prefer to retain the historical name + -- since in practice this is mostly about checking calls for the possible + -- occurrence of an access-before-elaboration exception. procedure Check_Bad_Instantiation (N : Node_Id); -- N is a node for an instantiation (if called with any other node kind, @@ -287,6 +296,9 @@ package body Sem_Elab is -- this is a call to a protected subprogram, the entity is a selected -- component. The callable entity may be absent, in which case Empty is -- returned. This happens with non-analyzed calls in nested generics. + -- + -- If SPARK_Mode is On, then N can also be a reference to an E_Variable + -- entity, in which case, the value returned is simply this entity. procedure Set_Elaboration_Constraint (Call : Node_Id; @@ -601,45 +613,60 @@ package body Sem_Elab is return; end if; - -- Go to parent for derived subprogram, or to original subprogram in the - -- case of a renaming (Alias covers both these cases). - Ent := E; - loop - if (Suppress_Elaboration_Warnings (Ent) - or else Elaboration_Checks_Suppressed (Ent)) - and then (Inst_Case or else No (Alias (Ent))) - then - return; - end if; - -- Nothing to do for imported entities + -- For a variable reference, just set Body_Acts_As_Spec to False - if Is_Imported (Ent) then - return; - end if; + if Nkind (N) in N_Has_Entity + and then Present (Entity (N)) + and then Ekind (Entity (N)) = E_Variable + then + Body_Acts_As_Spec := False; - exit when Inst_Case or else No (Alias (Ent)); - Ent := Alias (Ent); - end loop; + -- Additional checks for all other cases - Decl := Unit_Declaration_Node (Ent); + else + -- Go to parent for derived subprogram, or to original subprogram in + -- the case of a renaming (Alias covers both these cases). - if Nkind (Decl) = N_Subprogram_Body then - Body_Acts_As_Spec := True; + loop + if (Suppress_Elaboration_Warnings (Ent) + or else Elaboration_Checks_Suppressed (Ent)) + and then (Inst_Case or else No (Alias (Ent))) + then + return; + end if; - elsif Nkind_In (Decl, N_Subprogram_Declaration, N_Subprogram_Body_Stub) - or else Inst_Case - then - Body_Acts_As_Spec := False; + -- Nothing to do for imported entities - -- If we have none of an instantiation, subprogram body or subprogram - -- declaration, then it is not a case that we want to check. (One case - -- is a call to a generic formal subprogram, where we do not want the - -- check in the template). + if Is_Imported (Ent) then + return; + end if; - else - return; + exit when Inst_Case or else No (Alias (Ent)); + Ent := Alias (Ent); + end loop; + + Decl := Unit_Declaration_Node (Ent); + + if Nkind (Decl) = N_Subprogram_Body then + Body_Acts_As_Spec := True; + + elsif Nkind_In (Decl, N_Subprogram_Declaration, + N_Subprogram_Body_Stub) + or else Inst_Case + then + Body_Acts_As_Spec := False; + + -- If we have none of an instantiation, subprogram body or subprogram + -- declaration, or in the SPARK case, a variable reference, then + -- it is not a case that we want to check. (One case is a call to a + -- generic formal subprogram, where we do not want the check in the + -- template). + + else + return; + end if; end if; E_Scope := Ent; @@ -941,6 +968,16 @@ package body Sem_Elab is Elab_Warning ("", "info: access to & during elaboration?$?", Ent); + -- Variable reference in SPARK mode + + elsif SPARK_Mode = On + and then Nkind (N) in N_Has_Entity + and then Present (Entity (N)) + and then Ekind (Entity (N)) = E_Variable + then + Error_Msg_NE + ("reference to & during elaboration in SPARK", N, Ent); + -- Subprogram call case else @@ -1207,9 +1244,9 @@ package body Sem_Elab is P : Node_Id; begin - -- If the call does not come from the main unit, there is nothing to - -- check. Elaboration call from units in the context of the main unit - -- will lead to semantic dependencies when those units are compiled. + -- If the reference is not in the main unit, there is nothing to check. + -- Elaboration call from units in the context of the main unit will lead + -- to semantic dependencies when those units are compiled. if not In_Extended_Main_Code_Unit (N) then return; @@ -1222,15 +1259,22 @@ package body Sem_Elab is then Check_Restriction (No_Entry_Calls_In_Elaboration_Code, N); - -- Nothing to do if this is not a call or attribute reference (happens + -- Nothing to do if this is not an expected type of reference (happens -- in some error conditions, and in some cases where rewriting occurs). elsif Nkind (N) not in N_Subprogram_Call and then Nkind (N) /= N_Attribute_Reference + and then (SPARK_Mode /= On + or else Nkind (N) not in N_Has_Entity + or else No (Entity (N)) + or else Ekind (Entity (N)) /= E_Variable) then return; - -- Nothing to do if this is a call already rewritten for elab checking + -- Nothing to do if this is a call already rewritten for elab checking. + -- Such calls appear as the targets of If_Expressions. + + -- This check MUST be wrong, it catches far too much elsif Nkind (Parent (N)) = N_If_Expression then return; @@ -1260,10 +1304,10 @@ package body Sem_Elab is return; end if; - -- Here we have a call at elaboration time which must be checked + -- Here we have a reference at elaboration time which must be checked if Debug_Flag_LL then - Write_Str (" Check_Elab_Call: "); + Write_Str (" Check_Elab_Ref: "); if Nkind (N) = N_Attribute_Reference then if not Is_Entity_Name (Prefix (N)) then @@ -1271,6 +1315,7 @@ package body Sem_Elab is else Write_Name (Chars (Entity (Prefix (N)))); end if; + Write_Str ("'Access"); elsif No (Name (N)) or else not Is_Entity_Name (Name (N)) then @@ -1280,20 +1325,21 @@ package body Sem_Elab is Write_Name (Chars (Entity (Name (N)))); end if; - Write_Str (" call at "); + Write_Str (" reference at "); Write_Location (Sloc (N)); Write_Eol; end if; -- Climb up the tree to make sure we are not inside default expression -- of a parameter specification or a record component, since in both - -- these cases, we will be doing the actual call later, not now, and it - -- is at the time of the actual call (statically speaking) that we must - -- do our static check, not at the time of its initial analysis). + -- these cases, we will be doing the actual reference later, not now, + -- and it is at the time of the actual reference (statically speaking) + -- that we must do our static check, not at the time of its initial + -- analysis). - -- However, we have to check calls within component definitions (e.g. - -- a function call that determines an array component bound), so we - -- terminate the loop in that case. + -- However, we have to check references within component definitions + -- (e.g. a function call that determines an array component bound), + -- so we terminate the loop in that case. P := Parent (N); while Present (P) loop @@ -1302,7 +1348,7 @@ package body Sem_Elab is then return; - -- The call occurs within the constraint of a component, + -- The reference occurs within the constraint of a component, -- so it must be checked. elsif Nkind (P) = N_Component_Definition then @@ -1333,7 +1379,7 @@ package body Sem_Elab is if From_Elab_Code then - -- Complain if call that comes from source in preelaborated unit + -- Complain if ref that comes from source in preelaborated unit -- and we are not inside a subprogram (i.e. we are in elab code). if Comes_From_Source (N) @@ -1415,8 +1461,8 @@ package body Sem_Elab is -- We are not in elaboration code, but we are doing -- dynamic elaboration checks, in this case, we still - -- need to do the call, since the subprogram we are in - -- could be called from another unit, also in dynamic + -- need to do the reference, since the subprogram we are + -- in could be called from another unit, also in dynamic -- elaboration check mode, at elaboration time. elsif Dynamic_Elaboration_Checks then @@ -1482,23 +1528,23 @@ package body Sem_Elab is end if; end loop; - -- See if we need to analyze this call. We analyze it if either of + -- See if we need to analyze this reference. We analyze it if either of -- the following conditions is met: -- It is an inner level call (since in this case it was triggered -- by an outer level call from elaboration code), but only if the -- call is within the scope of the original outer level call. - -- It is an outer level call from elaboration code, or the called - -- entity is in the same elaboration scope. + -- It is an outer level reference from elaboration code, or a call to + -- an entity is in the same elaboration scope. -- And in these cases, we will check both inter-unit calls and -- intra-unit (within a single unit) calls. C_Scope := Current_Scope; - -- If not outer level call, then we follow it if it is within the - -- original scope of the outer call. + -- If not outer level reference, then we follow it if it is within the + -- original scope of the outer reference. if Present (Outer_Scope) and then Within (Scope (Ent), Outer_Scope) @@ -2088,6 +2134,17 @@ package body Sem_Elab is Check_Elab_Call (N, Outer_Scope); return OK; + -- In SPARK mode, if we have an entity reference to a variable, then + -- check it. For now we consider any reference. + + elsif SPARK_Mode = On + and then Nkind (N) in N_Has_Entity + and then Present (Entity (N)) + and then Ekind (Entity (N)) = E_Variable + then + Check_Elab_Call (N, Outer_Scope); + return OK; + -- If we have a generic instantiation, check it elsif Nkind (N) in N_Generic_Instantiation then @@ -2760,6 +2817,13 @@ package body Sem_Elab is Nam : Node_Id; begin + if Nkind (N) in N_Has_Entity + and then Present (Entity (N)) + and then Ekind (Entity (N)) = E_Variable + then + return Entity (N); + end if; + if Nkind (N) = N_Attribute_Reference then Nam := Prefix (N); else |