diff options
Diffstat (limited to 'gcc/ada/table.adb')
| -rw-r--r-- | gcc/ada/table.adb | 369 |
1 files changed, 362 insertions, 7 deletions
diff --git a/gcc/ada/table.adb b/gcc/ada/table.adb index 5d4522b..ed6f1f7 100644 --- a/gcc/ada/table.adb +++ b/gcc/ada/table.adb @@ -29,6 +29,9 @@ -- -- ------------------------------------------------------------------------------ +with Debug; use Debug; +with Opt; use Opt; +with Output; use Output; with System; use System; with Tree_IO; use Tree_IO; @@ -36,20 +39,370 @@ with System.Memory; use System.Memory; with Unchecked_Conversion; +pragma Elaborate_All (Output); + package body Table is package body Table is + Min : constant Int := Int (Table_Low_Bound); + -- Subscript of the minimum entry in the currently allocated table + + Length : Int := 0; + -- Number of entries in currently allocated table. The value of zero + -- ensures that we initially allocate the table. + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Reallocate; + -- Reallocate the existing table according to the current value stored + -- in Max. Works correctly to do an initial allocation if the table + -- is currently null. + function Tree_Get_Table_Address return Address; -- Return Null_Address if the table length is zero, -- Table (First)'Address if not. + pragma Warnings (Off); + -- Turn off warnings. The following unchecked conversions are only used + -- internally in this package, and cannot never result in any instances + -- of improperly aliased pointers for the client of the package. + + function To_Address is new Unchecked_Conversion (Table_Ptr, Address); + function To_Pointer is new Unchecked_Conversion (Address, Table_Ptr); + + pragma Warnings (On); + + ------------ + -- Append -- + ------------ + + procedure Append (New_Val : Table_Component_Type) is + begin + Set_Item (Table_Index_Type (Last_Val + 1), New_Val); + end Append; + + ---------------- + -- Append_All -- + ---------------- + + procedure Append_All (New_Vals : Table_Type) is + begin + for J in New_Vals'Range loop + Append (New_Vals (J)); + end loop; + end Append_All; + + -------------------- + -- Decrement_Last -- + -------------------- + + procedure Decrement_Last is + begin + Last_Val := Last_Val - 1; + end Decrement_Last; + + ---------- + -- Free -- + ---------- + + procedure Free is + begin + Free (To_Address (Table)); + Table := null; + Length := 0; + end Free; + + -------------------- + -- Increment_Last -- + -------------------- + + procedure Increment_Last is + begin + Last_Val := Last_Val + 1; + + if Last_Val > Max then + Reallocate; + end if; + end Increment_Last; + + ---------- + -- Init -- + ---------- + + procedure Init is + Old_Length : constant Int := Length; + + begin + Locked := False; + Last_Val := Min - 1; + Max := Min + (Table_Initial * Table_Factor) - 1; + Length := Max - Min + 1; + + -- If table is same size as before (happens when table is never + -- expanded which is a common case), then simply reuse it. Note + -- that this also means that an explicit Init call right after + -- the implicit one in the package body is harmless. + + if Old_Length = Length then + return; + + -- Otherwise we can use Reallocate to get a table of the right size. + -- Note that Reallocate works fine to allocate a table of the right + -- initial size when it is first allocated. + + else + Reallocate; + end if; + end Init; + + ---------- + -- Last -- + ---------- + + function Last return Table_Index_Type is + begin + return Table_Index_Type (Last_Val); + end Last; + + ---------------- + -- Reallocate -- + ---------------- + + procedure Reallocate is + New_Size : Memory.size_t; + New_Length : Long_Long_Integer; + + begin + if Max < Last_Val then + pragma Assert (not Locked); + + -- Make sure that we have at least the initial allocation. This + -- is needed in cases where a zero length table is written out. + + Length := Int'Max (Length, Table_Initial); + + -- Now increment table length until it is sufficiently large. Use + -- the increment value or 10, which ever is larger (the reason + -- for the use of 10 here is to ensure that the table does really + -- increase in size (which would not be the case for a table of + -- length 10 increased by 3% for instance). Do the intermediate + -- calculation in Long_Long_Integer to avoid overflow. + + while Max < Last_Val loop + New_Length := + Long_Long_Integer (Length) * + (100 + Long_Long_Integer (Table_Increment)) / 100; + Length := Int'Max (Int (New_Length), Length + 10); + Max := Min + Length - 1; + end loop; + + if Debug_Flag_D then + Write_Str ("--> Allocating new "); + Write_Str (Table_Name); + Write_Str (" table, size = "); + Write_Int (Max - Min + 1); + Write_Eol; + end if; + end if; + + -- Do the intermediate calculation in size_t to avoid signed overflow + + New_Size := + Memory.size_t (Max - Min + 1) * + (Table_Type'Component_Size / Storage_Unit); + + if Table = null then + Table := To_Pointer (Alloc (New_Size)); + + elsif New_Size > 0 then + Table := + To_Pointer (Realloc (Ptr => To_Address (Table), + Size => New_Size)); + end if; + + if Length /= 0 and then Table = null then + Set_Standard_Error; + Write_Str ("available memory exhausted"); + Write_Eol; + Set_Standard_Output; + raise Unrecoverable_Error; + end if; + end Reallocate; + + ------------- + -- Release -- + ------------- + + procedure Release is + Extra_Length : Int; + Size : Memory.size_t; + + begin + Length := Last_Val - Int (Table_Low_Bound) + 1; + Size := Memory.size_t (Length) * + (Table_Type'Component_Size / Storage_Unit); + + -- If the size of the table exceeds the release threshold then leave + -- space to store as many extra elements as 0.1% of the table length. + + if Release_Threshold > 0 + and then Size > Memory.size_t (Release_Threshold) + then + Extra_Length := Length / 1000; + Length := Length + Extra_Length; + Max := Int (Table_Low_Bound) + Length - 1; + + if Debug_Flag_D then + Write_Str ("--> Release_Threshold reached (length="); + Write_Int (Int (Size)); + Write_Str ("): leaving room space for "); + Write_Int (Extra_Length); + Write_Str (" components"); + Write_Eol; + end if; + else + Max := Last_Val; + end if; + + Reallocate; + end Release; + + ------------- + -- Restore -- + ------------- + + procedure Restore (T : Saved_Table) is + begin + Free (To_Address (Table)); + Last_Val := T.Last_Val; + Max := T.Max; + Table := T.Table; + Length := Max - Min + 1; + end Restore; + + ---------- + -- Save -- + ---------- + + function Save return Saved_Table is + Res : Saved_Table; + + begin + Res.Last_Val := Last_Val; + Res.Max := Max; + Res.Table := Table; + + Table := null; + Length := 0; + Init; + return Res; + end Save; + + -------------- + -- Set_Item -- + -------------- + + procedure Set_Item + (Index : Table_Index_Type; + Item : Table_Component_Type) + is + -- If Item is a value within the current allocation, and we are going + -- to reallocate, then we must preserve an intermediate copy here + -- before calling Increment_Last. Otherwise, if Table_Component_Type + -- is passed by reference, we are going to end up copying from + -- storage that might have been deallocated from Increment_Last + -- calling Reallocate. + + subtype Allocated_Table_T is + Table_Type (Table'First .. Table_Index_Type (Max + 1)); + -- A constrained table subtype one element larger than the currently + -- allocated table. + + Allocated_Table_Address : constant System.Address := + Table.all'Address; + -- Used for address clause below (we can't use non-static expression + -- Table.all'Address directly in the clause because some older + -- versions of the compiler do not allow it). + + Allocated_Table : Allocated_Table_T; + pragma Import (Ada, Allocated_Table); + pragma Suppress (Range_Check, On => Allocated_Table); + for Allocated_Table'Address use Allocated_Table_Address; + -- Allocated_Table represents the currently allocated array, plus one + -- element (the supplementary element is used to have a convenient + -- way of computing the address just past the end of the current + -- allocation). Range checks are suppressed because this unit + -- uses direct calls to System.Memory for allocation, and this can + -- yield misaligned storage (and we cannot rely on the bootstrap + -- compiler supporting specifically disabling alignment checks, so we + -- need to suppress all range checks). It is safe to suppress this + -- check here because we know that a (possibly misaligned) object + -- of that type does actually exist at that address. + -- ??? We should really improve the allocation circuitry here to + -- guarantee proper alignment. + + Need_Realloc : constant Boolean := Int (Index) > Max; + -- True if this operation requires storage reallocation (which may + -- involve moving table contents around). + + begin + -- If we're going to reallocate, check whether Item references an + -- element of the currently allocated table. + + if Need_Realloc + and then Allocated_Table'Address <= Item'Address + and then Item'Address < + Allocated_Table (Table_Index_Type (Max + 1))'Address + then + -- If so, save a copy on the stack because Increment_Last will + -- reallocate storage and might deallocate the current table. + + declare + Item_Copy : constant Table_Component_Type := Item; + begin + Set_Last (Index); + Table (Index) := Item_Copy; + end; + + else + -- Here we know that either we won't reallocate (case of Index < + -- Max) or that Item is not in the currently allocated table. + + if Int (Index) > Last_Val then + Set_Last (Index); + end if; + + Table (Index) := Item; + end if; + end Set_Item; + + -------------- + -- Set_Last -- + -------------- + + procedure Set_Last (New_Val : Table_Index_Type) is + begin + if Int (New_Val) < Last_Val then + Last_Val := Int (New_Val); + + else + Last_Val := Int (New_Val); + + if Last_Val > Max then + Reallocate; + end if; + end if; + end Set_Last; + ---------------------------- -- Tree_Get_Table_Address -- ---------------------------- function Tree_Get_Table_Address return Address is begin - if Is_Empty then + if Length = 0 then return Null_Address; else return Table (First)'Address; @@ -65,15 +418,15 @@ package body Table is -- does an implicit Release. procedure Tree_Read is - Last : Int; begin - Init; - Tree_Read_Int (Last); - Set_Last (Table_Last_Type (Last)); + Tree_Read_Int (Max); + Last_Val := Max; + Length := Max - Min + 1; + Reallocate; Tree_Read_Data (Tree_Get_Table_Address, - (Last - Int (First) + 1) * + (Last_Val - Int (First) + 1) * -- Note the importance of parenthesizing the following division -- to avoid the possibility of intermediate overflow. @@ -93,9 +446,11 @@ package body Table is Tree_Write_Int (Int (Last)); Tree_Write_Data (Tree_Get_Table_Address, - (Int (Last - First) + 1) * + (Last_Val - Int (First) + 1) * (Table_Type'Component_Size / Storage_Unit)); end Tree_Write; + begin + Init; end Table; end Table; |