From ae3a2b54d1a19f9ca4941645f71dddf675fbd19c Mon Sep 17 00:00:00 2001 From: Bob Duff Date: Wed, 14 Aug 2019 09:52:06 +0000 Subject: [PATCH] [Ada] Strengthen Locked flag This patch strengthens the Locked flag, by Asserting that it is False on operations that might cause reallocation. No change in behavior (except in the presence of compiler bugs), so no test. 2019-08-14 Bob Duff gcc/ada/ * table.adb: Assert that the table is not locked when increasing Last, even if it doesn't cause reallocation. In other words, assert that on operations that MIGHT cause reallocation. * table.ads: Fix comment accordingly. From-SVN: r274463 --- gcc/ada/ChangeLog | 7 +++++++ gcc/ada/table.adb | 4 ++++ gcc/ada/table.ads | 17 +++++++++-------- 3 files changed, 20 insertions(+), 8 deletions(-) diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog index b7bacdcd0ad..7c09cc0c32f 100644 --- a/gcc/ada/ChangeLog +++ b/gcc/ada/ChangeLog @@ -1,3 +1,10 @@ +2019-08-14 Bob Duff + + * table.adb: Assert that the table is not locked when increasing + Last, even if it doesn't cause reallocation. In other words, + assert that on operations that MIGHT cause reallocation. + * table.ads: Fix comment accordingly. + 2019-08-14 Arnaud Charlet * doc/gnat_ugn/gnat_and_program_execution.rst: Remove diff --git a/gcc/ada/table.adb b/gcc/ada/table.adb index ebbb8574da3..97940475bf1 100644 --- a/gcc/ada/table.adb +++ b/gcc/ada/table.adb @@ -80,6 +80,7 @@ package body Table is procedure Append (New_Val : Table_Component_Type) is begin + pragma Assert (not Locked); Set_Item (Table_Index_Type (Last_Val + 1), New_Val); end Append; @@ -120,6 +121,7 @@ package body Table is procedure Increment_Last is begin + pragma Assert (not Locked); Last_Val := Last_Val + 1; if Last_Val > Max then @@ -384,6 +386,8 @@ package body Table is procedure Set_Last (New_Val : Table_Index_Type) is begin + pragma Assert (Int (New_Val) <= Last_Val or else not Locked); + if Int (New_Val) < Last_Val then Last_Val := Int (New_Val); diff --git a/gcc/ada/table.ads b/gcc/ada/table.ads index a816c738430..5f03cf3ca19 100644 --- a/gcc/ada/table.ads +++ b/gcc/ada/table.ads @@ -130,14 +130,15 @@ package Table is -- First .. Last. Locked : Boolean := False; - -- Table expansion is permitted only if this switch is set to False. A - -- client may set Locked to True, in which case any attempt to expand - -- the table will cause an assertion failure. Note that while a table - -- is locked, its address in memory remains fixed and unchanging. This - -- feature is used to control table expansion during Gigi processing. - -- Gigi assumes that tables other than the Uint and Ureal tables do - -- not move during processing, which means that they cannot be expanded. - -- The Locked flag is used to enforce this restriction. + -- Increasing the value of Last is permitted only if this switch is set + -- to False. A client may set Locked to True, in which case any attempt + -- to increase the value of Last (which might expand the table) will + -- cause an assertion failure. Note that while a table is locked, its + -- address in memory remains fixed and unchanging. This feature is used + -- to control table expansion during Gigi processing. Gigi assumes that + -- tables other than the Uint and Ureal tables do not move during + -- processing, which means that they cannot be expanded. The Locked + -- flag is used to enforce this restriction. procedure Init; -- This procedure allocates a new table of size Initial (freeing any -- 2.30.2