+2017-09-06 Hristian Kirtchev <kirtchev@adacore.com>
+
+ * a-comlin.adb, exp_aggr.adb, exp_ch6.adb, frontend.adb, gnatbind.adb,
+ sem_ch3.adb, sem_util.adb: Minor reformatting.
+
+2017-09-06 Yannick Moy <moy@adacore.com>
+
+ * freeze.adb (Check_Inherited_Conditions): Rewriting
+ of inherited preconditions and postconditions should only occur
+ in GNATprove mode, that is, when GNATprove_Mode is True, not to
+ be confused with SPARK_Mode being On.
+
+2017-09-06 Yannick Moy <moy@adacore.com>
+
+ * sem_warn.adb (Check_References): Take into
+ account possibility of attribute reference as original node.
+
+2017-09-06 Yannick Moy <moy@adacore.com>
+
+ * exp_attr.adb (Expand_N_Attribute_Reference): Protect against invalid
+ use of attribute.
+
+2017-09-06 Eric Botcazou <ebotcazou@adacore.com>
+
+ * inline.adb (Split_Unconstrained_Function): Also set Is_Inlined
+ on the procedure created to encapsulate the body.
+ * sem_ch7.adb: Add with clause for GNAT.HTable.
+ (Entity_Table_Size): New constant.
+ (Entity_Hash): New function.
+ (Subprogram_Table): New instantiation of GNAT.Htable.Simple_HTable.
+ (Is_Subprogram_Ref): Rename into...
+ (Scan_Subprogram_Ref): ...this. Record references to subprograms in
+ the table instead of bailing out on them. Scan the value of constants
+ if it is not known at compile time.
+ (Contains_Subprograms_Refs): Rename into...
+ (Scan_Subprogram_Refs): ...this.
+ (Has_Referencer): Scan the body of all inlined subprograms. Reset the
+ Is_Public flag on subprograms if they are not actually referenced.
+ (Hide_Public_Entities): Beef up comment on the algorithm.
+ Reset the table of subprograms on entry.
+
2017-09-06 Yannick Moy <moy@adacore.com>
* inline.adb: Add comments to Can_Be_Inlined_In_GNATprove_Mode.
with Style;
with Uintp; use Uintp;
+with GNAT.HTable;
+
package body Sem_Ch7 is
-----------------------------------
end if;
end Analyze_Package_Body;
+ ------------------------------------------------------
+ -- Analyze_Package_Body_Helper Data and Subprograms --
+ ------------------------------------------------------
+
+ Entity_Table_Size : constant := 4096;
+ -- Number of headers in hash table
+
+ subtype Entity_Header_Num is Integer range 0 .. Entity_Table_Size - 1;
+ -- Range of headers in hash table
+
+ function Entity_Hash (Id : Entity_Id) return Entity_Header_Num;
+ -- Simple hash function for Entity_Ids
+
+ package Subprogram_Table is new GNAT.Htable.Simple_HTable
+ (Header_Num => Entity_Header_Num,
+ Element => Boolean,
+ No_Element => False,
+ Key => Entity_Id,
+ Hash => Entity_Hash,
+ Equal => "=");
+ -- Hash table to record which subprograms are referenced. It is declared
+ -- at library level to avoid elaborating it for every call to Analyze.
+
+ -----------------
+ -- Entity_Hash --
+ -----------------
+
+ function Entity_Hash (Id : Entity_Id) return Entity_Header_Num is
+ begin
+ return Entity_Header_Num (Id mod Entity_Table_Size);
+ end Entity_Hash;
+
---------------------------------
-- Analyze_Package_Body_Helper --
---------------------------------
-- Attempt to hide all public entities found in declarative list Decls
-- by resetting their Is_Public flag to False depending on whether the
-- entities are not referenced by inlined or generic bodies. This kind
- -- of processing is a conservative approximation and may still leave
- -- certain entities externally visible.
+ -- of processing is a conservative approximation and will still leave
+ -- entities externally visible if the package is not simple enough.
procedure Install_Composite_Operations (P : Entity_Id);
-- Composite types declared in the current scope may depend on types
--------------------------
procedure Hide_Public_Entities (Decls : List_Id) is
- function Contains_Subprograms_Refs (N : Node_Id) return Boolean;
- -- Subsidiary to routine Has_Referencer. Determine whether a node
- -- contains a reference to a subprogram.
- -- WARNING: this is a very expensive routine as it performs a full
- -- tree traversal.
function Has_Referencer
(Decls : List_Id;
-- in the range Last (Decls) .. Referencer are hidden from external
-- visibility.
- -------------------------------
- -- Contains_Subprograms_Refs --
- -------------------------------
-
- function Contains_Subprograms_Refs (N : Node_Id) return Boolean is
- Reference_Seen : Boolean := False;
-
- function Is_Subprogram_Ref (N : Node_Id) return Traverse_Result;
- -- Determine whether a node denotes a reference to a subprogram
-
- -----------------------
- -- Is_Subprogram_Ref --
- -----------------------
-
- function Is_Subprogram_Ref
- (N : Node_Id) return Traverse_Result
- is
- Val : Node_Id;
-
- begin
- -- Detect a reference of the form
- -- Subp_Call
-
- if Nkind (N) in N_Subprogram_Call
- and then Is_Entity_Name (Name (N))
- then
- Reference_Seen := True;
- return Abandon;
-
- -- Detect a reference of the form
- -- Subp'Some_Attribute
-
- elsif Nkind (N) = N_Attribute_Reference
- and then Is_Entity_Name (Prefix (N))
- and then Present (Entity (Prefix (N)))
- and then Is_Subprogram (Entity (Prefix (N)))
- then
- Reference_Seen := True;
- return Abandon;
-
- -- Constants can be substituted by their value in gigi, which
- -- may contain a reference, so be conservative for them.
-
- elsif Is_Entity_Name (N)
- and then Present (Entity (N))
- and then Ekind (Entity (N)) = E_Constant
- then
- Val := Constant_Value (Entity (N));
-
- if Present (Val)
- and then not Compile_Time_Known_Value (Val)
- then
- Reference_Seen := True;
- return Abandon;
- end if;
- end if;
+ function Scan_Subprogram_Ref (N : Node_Id) return Traverse_Result;
+ -- Determine whether a node denotes a reference to a subprogram
- return OK;
- end Is_Subprogram_Ref;
-
- procedure Find_Subprograms_Ref is
- new Traverse_Proc (Is_Subprogram_Ref);
-
- -- Start of processing for Contains_Subprograms_Refs
-
- begin
- Find_Subprograms_Ref (N);
-
- return Reference_Seen;
- end Contains_Subprograms_Refs;
+ procedure Scan_Subprogram_Refs is
+ new Traverse_Proc (Scan_Subprogram_Ref);
+ -- Subsidiary to routine Has_Referencer. Determine whether a node
+ -- contains references to a subprogram and record them.
+ -- WARNING: this is a very expensive routine as it performs a full
+ -- tree traversal.
--------------------
-- Has_Referencer --
Spec : Node_Id;
Has_Non_Subprograms_Referencer : Boolean := False;
- -- Flag set if a subprogram body was detected as a referencer but
- -- does not contain references to other subprograms. In this case,
- -- if we still are top level, we do not return True immediately,
- -- but keep hiding subprograms from external visibility.
+ -- Set if an inlined subprogram body was detected as a referencer.
+ -- In this case, we do not return True immediately but keep hiding
+ -- subprograms from external visibility.
begin
if No (Decls) then
if Is_Inlined (Decl_Id)
or else Has_Pragma_Inline (Decl_Id)
then
+ Has_Non_Subprograms_Referencer := True;
+
-- Inspect the statements of the subprogram body
-- to determine whether the body references other
-- subprograms.
- if Top_Level
- and then not Contains_Subprograms_Refs (Decl)
- then
- Has_Non_Subprograms_Referencer := True;
- else
- return True;
- end if;
+ Scan_Subprogram_Refs (Decl);
end if;
-- Otherwise this is a stand alone subprogram body
else
Decl_Id := Defining_Entity (Decl);
- -- An inlined body acts as a referencer, see above. Note
- -- that an inlined subprogram remains Is_Public as gigi
- -- requires the flag to be set.
+ -- An inlined subprogram body acts as a referencer
if Is_Inlined (Decl_Id)
or else Has_Pragma_Inline (Decl_Id)
then
- if Top_Level
- and then not Contains_Subprograms_Refs (Decl)
- then
- Has_Non_Subprograms_Referencer := True;
- else
- return True;
- end if;
- else
+ Has_Non_Subprograms_Referencer := True;
+
+ -- Inspect the statements of the subprogram body
+ -- to determine whether the body references other
+ -- subprograms.
+
+ Scan_Subprogram_Refs (Decl);
+
+ -- Otherwise we can reset Is_Public right away
+
+ elsif not Subprogram_Table.Get (Decl_Id) then
Set_Is_Public (Decl_Id, False);
end if;
end if;
-- if they are not followed by a construct which can reference
-- and export them. The Is_Public flag is reset on top level
-- entities only as anything nested is local to its context.
- -- Likewise for subprograms, but we work harder for them as
- -- their visibility can have a significant impact on inlining
- -- decisions in the back end.
+ -- Likewise for subprograms, but we work harder for them.
elsif Nkind_In (Decl, N_Exception_Declaration,
N_Object_Declaration,
and then No (Interface_Name (Decl_Id))
and then
(not Has_Non_Subprograms_Referencer
- or else Nkind (Decl) = N_Subprogram_Declaration)
+ or else (Nkind (Decl) = N_Subprogram_Declaration
+ and then not Subprogram_Table.Get (Decl_Id)))
then
Set_Is_Public (Decl_Id, False);
end if;
return Has_Non_Subprograms_Referencer;
end Has_Referencer;
+ -------------------------
+ -- Scan_Subprogram_Ref --
+ -------------------------
+
+ function Scan_Subprogram_Ref (N : Node_Id) return Traverse_Result is
+ begin
+ -- Detect a reference of the form
+ -- Subp_Call
+
+ if Nkind (N) in N_Subprogram_Call
+ and then Is_Entity_Name (Name (N))
+ and then Present (Entity (Name (N)))
+ and then Is_Subprogram (Entity (Name (N)))
+ then
+ Subprogram_Table.Set (Entity (Name (N)), True);
+
+ -- Detect a reference of the form
+ -- Subp'Some_Attribute
+
+ elsif Nkind (N) = N_Attribute_Reference
+ and then Is_Entity_Name (Prefix (N))
+ and then Present (Entity (Prefix (N)))
+ and then Is_Subprogram (Entity (Prefix (N)))
+ then
+ Subprogram_Table.Set (Entity (Prefix (N)), True);
+
+ -- Constants can be substituted by their value in gigi, which may
+ -- contain a reference, so scan the value recursively.
+
+ elsif Is_Entity_Name (N)
+ and then Present (Entity (N))
+ and then Ekind (Entity (N)) = E_Constant
+ then
+ declare
+ Val : constant Node_Id := Constant_Value (Entity (N));
+ begin
+ if Present (Val)
+ and then not Compile_Time_Known_Value (Val)
+ then
+ Scan_Subprogram_Refs (Val);
+ end if;
+ end;
+ end if;
+
+ return OK;
+ end Scan_Subprogram_Ref;
+
-- Local variables
Discard : Boolean := True;
-- not always be the case. The algorithm takes a conservative stance
-- and leaves entity External_Obj public.
+ -- This very conservative algorithm is supplemented by a more precise
+ -- processing for inlined bodies. For them, we traverse the syntactic
+ -- tree and record which subprograms are actually referenced from it.
+ -- This makes it possible to compute a much smaller set of externally
+ -- visible subprograms, which can have a significant impact on the
+ -- inlining decisions made in the back end. We do it only for inlined
+ -- bodies because they are supposed to be reasonably small and tree
+ -- traversal is very expensive.
+
+ -- Note that even this special processing is not optimal for inlined
+ -- bodies, because we treat all inlined subprograms alike. An optimal
+ -- algorithm would require computing the transitive closure of the
+ -- inlined subprograms that can really be referenced from other units
+ -- in the source code.
+
+ -- We could extend this processing for inlined bodies and record all
+ -- entities, not just subprograms, referenced from them, which would
+ -- make it possible to compute a much smaller set of all externally
+ -- visible entities in the absence of generic bodies. But this would
+ -- mean implementing a more thorough tree traversal of the bodies,
+ -- i.e. not just syntactic, and the gain would very likely be worth
+ -- neither the hassle nor the slowdown of the compiler.
+
+ Subprogram_Table.Reset;
Discard := Has_Referencer (Decls, Top_Level => True);
end Hide_Public_Entities;
projects / gcc.git / commitdiff