From: Eric Botcazou Date: Wed, 18 Sep 2019 08:33:12 +0000 (+0000) Subject: [Ada] Fix sharing of expression in array aggregate with others choice X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=6951cbc9e7646bca1c99c973815e6838a6e1fe25;p=gcc.git [Ada] Fix sharing of expression in array aggregate with others choice This change fixes a long-standing issue in the compiler that is generally silent but may lead to wrong code generation in specific circumstances. When an others choice in an array aggregate spans multiple ranges, the compiler may generate multiple (groups of) assignments for the ranges. The problem is that it internally reuses the original expression for all the ranges, which is problematic if this expression gets rewritten during the processing of one of the ranges and typically causes a new temporary to be shared between different ranges. The solution is to duplicate the original expression for each range. 2019-09-18 Eric Botcazou gcc/ada/ * exp_aggr.adb (Build_Array_Aggr_Code): In STEP 1 (c), duplicate the expression and reset the Loop_Actions for each loop generated for an others choice. gcc/testsuite/ * gnat.dg/aggr28.adb: New testcase. From-SVN: r275859 --- diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog index 384f9820542..5c17f81e7c0 100644 --- a/gcc/ada/ChangeLog +++ b/gcc/ada/ChangeLog @@ -1,3 +1,9 @@ +2019-09-18 Eric Botcazou + + * exp_aggr.adb (Build_Array_Aggr_Code): In STEP 1 (c), duplicate + the expression and reset the Loop_Actions for each loop + generated for an others choice. + 2019-09-18 Justin Squirek * einfo.adb, einfo.ads (Minimum_Accessibility): Added new field. diff --git a/gcc/ada/exp_aggr.adb b/gcc/ada/exp_aggr.adb index 7f11b4105bd..5b2e0a554c0 100644 --- a/gcc/ada/exp_aggr.adb +++ b/gcc/ada/exp_aggr.adb @@ -2075,7 +2075,6 @@ package body Exp_Aggr is Choice := First (Choice_List (Assoc)); while Present (Choice) loop if Nkind (Choice) = N_Others_Choice then - Set_Loop_Actions (Assoc, New_List); Others_Assoc := Assoc; exit; end if; @@ -2122,7 +2121,8 @@ package body Exp_Aggr is if Present (Others_Assoc) then declare - First : Boolean := True; + First : Boolean := True; + Dup_Expr : Node_Id; begin for J in 0 .. Nb_Choices loop @@ -2160,9 +2160,19 @@ package body Exp_Aggr is or else not Empty_Range (Low, High) then First := False; + + -- Duplicate the expression in case we will be generating + -- several loops. As a result the expression is no longer + -- shared between the loops and is reevaluated for each + -- such loop. + + Expr := Get_Assoc_Expr (Others_Assoc); + Dup_Expr := New_Copy_Tree (Expr); + Set_Parent (Dup_Expr, Parent (Expr)); + + Set_Loop_Actions (Others_Assoc, New_List); Append_List - (Gen_Loop (Low, High, - Get_Assoc_Expr (Others_Assoc)), To => New_Code); + (Gen_Loop (Low, High, Dup_Expr), To => New_Code); end if; end loop; end; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index fd0efb176e6..32297d12789 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2019-09-18 Eric Botcazou + + * gnat.dg/aggr28.adb: New testcase. + 2019-09-18 Steve Baird * gnat.dg/ai12_0086_example.adb: New testcase. diff --git a/gcc/testsuite/gnat.dg/aggr28.adb b/gcc/testsuite/gnat.dg/aggr28.adb new file mode 100644 index 00000000000..3375b71346f --- /dev/null +++ b/gcc/testsuite/gnat.dg/aggr28.adb @@ -0,0 +1,29 @@ +-- { dg-do run } + +procedure Aggr28 is + + Count : Natural := 0; + + function Get (S: String) return String is + begin + Count := Count + 1; + return S; + end; + + Max_Error_Length : constant := 8; + subtype Error_Type is String (1 .. Max_Error_Length); + + type Rec is record + Text : Error_Type; + end record; + + type Arr is array (1 .. 16) of Rec; + + Table : constant Arr := + (3 => (Text => Get ("INVALID ")), others => (Text => Get ("OTHERS "))); + +begin + if Count /= Table'Length then + raise Program_Error; + end if; +end; \ No newline at end of file