From 6bc08721d027d10a2d9ea98c753a8bf0b4493e91 Mon Sep 17 00:00:00 2001 From: Javier Miranda Date: Wed, 18 Sep 2019 08:32:55 +0000 Subject: [PATCH] [Ada] Fix portability issues in access to subprograms This patch improves the portability of the code generated by the compiler for access to subprograms. Written by Richard Kenner. 2019-09-18 Javier Miranda gcc/ada/ * exp_ch4.adb (Expand_N_Op_Eq): The frontend assumes that we can do a bit-for-bit comparison of two access to protected subprogram pointers. However, there are two reasons why we may not be able to do that: (1) there may be padding bits for alignment before the access to subprogram, and (2) the access to subprogram itself may not be compared bit-for- bit because the activation record part is undefined: two pointers are equal iff the subprogram addresses are equal. This patch fixes it by forcing a field-by-field comparison. * bindgen.adb (Gen_Adainit): The type No_Param_Proc is defined in the library as having Favor_Top_Level, but when we create an object of that type in the binder file we don't have that pragma, so the types are different. This patch fixes this issue. * libgnarl/s-interr.adb, libgnarl/s-interr__hwint.adb, libgnarl/s-interr__sigaction.adb, libgnarl/s-interr__vxworks.adb (Is_Registered): This routine erroneously assumes that the access to protected subprogram is two addresses. We need to create the same record that the compiler makes to ensure that any padding is the same. Then we have to look at just the first word of the access to subprogram. This patch fixes this issue. From-SVN: r275856 --- gcc/ada/ChangeLog | 23 ++++++++++++++ gcc/ada/bindgen.adb | 1 + gcc/ada/exp_ch4.adb | 39 +++++++++++++++++++++++- gcc/ada/libgnarl/s-interr.adb | 6 ++-- gcc/ada/libgnarl/s-interr__hwint.adb | 7 +++-- gcc/ada/libgnarl/s-interr__sigaction.adb | 6 ++-- gcc/ada/libgnarl/s-interr__vxworks.adb | 7 +++-- 7 files changed, 80 insertions(+), 9 deletions(-) diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog index 561f6a845f2..07638f14a50 100644 --- a/gcc/ada/ChangeLog +++ b/gcc/ada/ChangeLog @@ -1,3 +1,26 @@ +2019-09-18 Javier Miranda + + * exp_ch4.adb (Expand_N_Op_Eq): The frontend assumes that we can + do a bit-for-bit comparison of two access to protected + subprogram pointers. However, there are two reasons why we may + not be able to do that: (1) there may be padding bits for + alignment before the access to subprogram, and (2) the access to + subprogram itself may not be compared bit-for- bit because the + activation record part is undefined: two pointers are equal iff + the subprogram addresses are equal. This patch fixes it by + forcing a field-by-field comparison. + * bindgen.adb (Gen_Adainit): The type No_Param_Proc is defined + in the library as having Favor_Top_Level, but when we create an + object of that type in the binder file we don't have that + pragma, so the types are different. This patch fixes this issue. + * libgnarl/s-interr.adb, libgnarl/s-interr__hwint.adb, + libgnarl/s-interr__sigaction.adb, libgnarl/s-interr__vxworks.adb + (Is_Registered): This routine erroneously assumes that the + access to protected subprogram is two addresses. We need to + create the same record that the compiler makes to ensure that + any padding is the same. Then we have to look at just the first + word of the access to subprogram. This patch fixes this issue. + 2019-09-18 Bob Duff * exp_ch5.adb (Expand_Assign_Array_Loop_Or_Bitfield): The call diff --git a/gcc/ada/bindgen.adb b/gcc/ada/bindgen.adb index 153043c8678..e60cb7a7590 100644 --- a/gcc/ada/bindgen.adb +++ b/gcc/ada/bindgen.adb @@ -524,6 +524,7 @@ package body Bindgen is and then not Configurable_Run_Time_On_Target then WBI (" type No_Param_Proc is access procedure;"); + WBI (" pragma Favor_Top_Level (No_Param_Proc);"); WBI (""); end if; diff --git a/gcc/ada/exp_ch4.adb b/gcc/ada/exp_ch4.adb index c288d6a79a7..0c96d8c2a4a 100644 --- a/gcc/ada/exp_ch4.adb +++ b/gcc/ada/exp_ch4.adb @@ -8221,6 +8221,32 @@ package body Exp_Ch4 is Insert_Actions (N, Bodies, Suppress => All_Checks); Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); end if; + + -- If unnesting, handle elementary types whose Equivalent_Types are + -- records because there may be padding or undefined fields. + + elsif Unnest_Subprogram_Mode + and then Ekind_In (Typl, E_Class_Wide_Type, + E_Class_Wide_Subtype, + E_Access_Subprogram_Type, + E_Access_Protected_Subprogram_Type, + E_Anonymous_Access_Protected_Subprogram_Type, + E_Access_Subprogram_Type, + E_Exception_Type) + and then Present (Equivalent_Type (Typl)) + and then Is_Record_Type (Equivalent_Type (Typl)) + then + Typl := Equivalent_Type (Typl); + Remove_Side_Effects (Lhs); + Remove_Side_Effects (Rhs); + Rewrite (N, + Expand_Record_Equality (N, Typl, + Unchecked_Convert_To (Typl, Lhs), + Unchecked_Convert_To (Typl, Rhs), + Bodies)); + + Insert_Actions (N, Bodies, Suppress => All_Checks); + Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); end if; -- Test if result is known at compile time @@ -9497,10 +9523,21 @@ package body Exp_Ch4 is Typ : constant Entity_Id := Etype (Left_Opnd (N)); begin - -- Case of elementary type with standard operator + -- Case of elementary type with standard operator. But if + -- unnesting, handle elementary types whose Equivalent_Types are + -- records because there may be padding or undefined fields. if Is_Elementary_Type (Typ) and then Sloc (Entity (N)) = Standard_Location + and then not (Ekind_In (Typ, E_Class_Wide_Type, + E_Class_Wide_Subtype, + E_Access_Subprogram_Type, + E_Access_Protected_Subprogram_Type, + E_Anonymous_Access_Protected_Subprogram_Type, + E_Access_Subprogram_Type, + E_Exception_Type) + and then Present (Equivalent_Type (Typ)) + and then Is_Record_Type (Equivalent_Type (Typ))) then Binary_Op_Validity_Checks (N); diff --git a/gcc/ada/libgnarl/s-interr.adb b/gcc/ada/libgnarl/s-interr.adb index 7106c5783d6..bb5defdca07 100644 --- a/gcc/ada/libgnarl/s-interr.adb +++ b/gcc/ada/libgnarl/s-interr.adb @@ -545,9 +545,11 @@ package body System.Interrupts is function Is_Registered (Handler : Parameterless_Handler) return Boolean is + type Acc_Proc is access procedure; + type Fat_Ptr is record Object_Addr : System.Address; - Handler_Addr : System.Address; + Handler_Addr : Acc_Proc; end record; function To_Fat_Ptr is new Ada.Unchecked_Conversion @@ -565,7 +567,7 @@ package body System.Interrupts is Ptr := Registered_Handler_Head; while Ptr /= null loop - if Ptr.H = Fat.Handler_Addr then + if Ptr.H = Fat.Handler_Addr.all'Address then return True; end if; diff --git a/gcc/ada/libgnarl/s-interr__hwint.adb b/gcc/ada/libgnarl/s-interr__hwint.adb index 50e2ec2a653..ff7fe05912d 100644 --- a/gcc/ada/libgnarl/s-interr__hwint.adb +++ b/gcc/ada/libgnarl/s-interr__hwint.adb @@ -561,9 +561,12 @@ package body System.Interrupts is ------------------- function Is_Registered (Handler : Parameterless_Handler) return Boolean is + + type Acc_Proc is access procedure; + type Fat_Ptr is record Object_Addr : System.Address; - Handler_Addr : System.Address; + Handler_Addr : Acc_Proc; end record; function To_Fat_Ptr is new Ada.Unchecked_Conversion @@ -581,7 +584,7 @@ package body System.Interrupts is Ptr := Registered_Handler_Head; while Ptr /= null loop - if Ptr.H = Fat.Handler_Addr then + if Ptr.H = Fat.Handler_Addr.all'Address then return True; end if; diff --git a/gcc/ada/libgnarl/s-interr__sigaction.adb b/gcc/ada/libgnarl/s-interr__sigaction.adb index d9ffe0cfdaa..d8fb7ba9712 100644 --- a/gcc/ada/libgnarl/s-interr__sigaction.adb +++ b/gcc/ada/libgnarl/s-interr__sigaction.adb @@ -487,9 +487,11 @@ package body System.Interrupts is function Is_Registered (Handler : Parameterless_Handler) return Boolean is Ptr : R_Link := Registered_Handlers; + type Acc_Proc is access procedure; + type Fat_Ptr is record Object_Addr : System.Address; - Handler_Addr : System.Address; + Handler_Addr : Acc_Proc; end record; function To_Fat_Ptr is new Ada.Unchecked_Conversion @@ -505,7 +507,7 @@ package body System.Interrupts is Fat := To_Fat_Ptr (Handler); while Ptr /= null loop - if Ptr.H = Fat.Handler_Addr then + if Ptr.H = Fat.Handler_Addr.all'Address then return True; end if; diff --git a/gcc/ada/libgnarl/s-interr__vxworks.adb b/gcc/ada/libgnarl/s-interr__vxworks.adb index b2c4eee671b..16d22a63556 100644 --- a/gcc/ada/libgnarl/s-interr__vxworks.adb +++ b/gcc/ada/libgnarl/s-interr__vxworks.adb @@ -578,9 +578,12 @@ package body System.Interrupts is ------------------- function Is_Registered (Handler : Parameterless_Handler) return Boolean is + + type Acc_Proc is access procedure; + type Fat_Ptr is record Object_Addr : System.Address; - Handler_Addr : System.Address; + Handler_Addr : Acc_Proc; end record; function To_Fat_Ptr is new Ada.Unchecked_Conversion @@ -598,7 +601,7 @@ package body System.Interrupts is Ptr := Registered_Handler_Head; while Ptr /= null loop - if Ptr.H = Fat.Handler_Addr then + if Ptr.H = Fat.Handler_Addr.all'Address then return True; end if; -- 2.30.2