# HG changeset patch
# User Christophe CURIS <[email protected]>
# Date 1392052434 -3600
# Mon Feb 10 18:13:54 2014 +0100
# Node ID 42aa510d7bc3b3c7c1685f2f84a6a3fa54329f37
# Parent 722467d0c45fb0e5b804e7eab88667265f531031
Add option to handle allocation check behaviour (ticket #5)
When ghdl_malloc was returning null, the old behaviour was to
ignore it and continue, which led to crash because the initialiser
mechanism would try to dereference this null pointer.
This was almost ok because in most cases OS are overcommiting
and thus malloc never returns null.
There are a few cases however where malloc may return null, so
now:
- we properly check that, and issue an appropriate allocation
failure message;
- if user explicitely wants it (optin -fno-check-allocation) then
we can also return a null access pointer to the VHDL code so the
case can be handled by user code
diff -r 722467d0c45f -r 42aa510d7bc3 doc/ghdl.texi
--- a/doc/ghdl.texi Mon Feb 10 01:43:01 2014 +0100
+++ b/doc/ghdl.texi Mon Feb 10 18:13:54 2014 +0100
@@ -863,6 +863,21 @@
@option{--workdir=} option, or in the current directory if the latter
option is not specified.
+@item -fno-check-allocation
+@cindex @option{-fcheck-allocation} switch
+@cindex @option{-fno-check-allocation} switch
+When allocating memory with the @samp{new} operator, the VHDL LRM states that
+the allocation cannot fail, so the default behaviour
(@option{-fcheck-allocation})
+is to raise an error if @samp{malloc} returns NULL.
+
+When @emph{compiling} with @option{-fno-check-allocation}, GHDL will generate
+the appropriate code so that the VHDL code will receive a NULL access pointer,
+to give your VHDL code the opportunity to handle the situation.
+
+Please note that on most OS the @emph{default} behaviour is to overcommit
+(@samp{malloc} never fail), so the program will crash anyway during the
+initialisation of the allocated data.
+
@item -fexplicit
@cindex @option{-fexplicit} switch
When two operators are overloaded, give preference to the explicit declaration.
diff -r 722467d0c45f -r 42aa510d7bc3 flags.ads
--- a/flags.ads Mon Feb 10 01:43:01 2014 +0100
+++ b/flags.ads Mon Feb 10 18:13:54 2014 +0100
@@ -109,6 +109,11 @@
-- If set, performs VITAL checks.
Flag_Vital_Checks : Boolean := True;
+ -- Specify how memory allocation failure are handled for the 'new' operator
+ -- The default is to report an error as VHDL LRM states that 'new' never
fails
+ -- When disabled, returns a null access pointer to the VHDL code
+ Flag_Allocation_Check : Boolean := True;
+
-- --time-resolution=X
-- Where X corresponds to:
-- fs => 'f'
diff -r 722467d0c45f -r 42aa510d7bc3 options.adb
--- a/options.adb Mon Feb 10 01:43:01 2014 +0100
+++ b/options.adb Mon Feb 10 18:13:54 2014 +0100
@@ -116,6 +116,10 @@
Flag_Explicit := True;
elsif Opt = "-frelaxed-rules" then
Flag_Relaxed_Rules := True;
+ elsif Opt = "-fcheck-allocation" then
+ Flag_Allocation_Check := True;
+ elsif Opt = "-fno-check-allocation" then
+ Flag_Allocation_Check := False;
elsif Opt = "--syn-binding" then
Flag_Syn_Binding := True;
elsif Opt = "--no-vital-checks" then
@@ -216,6 +220,7 @@
-- P (" simulation. LEVEL is note, warning, error,");
-- P (" failure or none");
P ("Extensions:");
+ P (" -fno-check-allocation do not raise error when allocation fail,
return a NULL access");
P (" -fexplicit give priority to explicitly declared operator");
P (" -frelaxed-rules relax some LRM rules");
P (" -C --mb-comments allow multi-bytes chars in a comment");
diff -r 722467d0c45f -r 42aa510d7bc3 ortho/gcc/lang.opt
--- a/ortho/gcc/lang.opt Mon Feb 10 01:43:01 2014 +0100
+++ b/ortho/gcc/lang.opt Mon Feb 10 18:13:54 2014 +0100
@@ -62,6 +62,10 @@
vhdl
Enable VITAL checks
+fcheck-allocation
+vhdl Driver Report
+-f[no-]check-allocation Specify how to handle out-of-memory with 'new'
operator
+
fexplicit
vhdl
Explicit function declarations override implicit one in use
diff -r 722467d0c45f -r 42aa510d7bc3 ortho/gcc/ortho-lang.c
--- a/ortho/gcc/ortho-lang.c Mon Feb 10 01:43:01 2014 +0100
+++ b/ortho/gcc/ortho-lang.c Mon Feb 10 18:13:54 2014 +0100
@@ -425,6 +425,8 @@
case OPT__anaelab:
/* Only a few options have a real arguments. */
return lang_handle_option (opt, arg) != 0;
+ case OPT_fcheck_allocation:
+ return lang_handle_option (value?opt:"-fno-check-allocation", NULL);
default:
/* The other options must have a joint argument. */
if (arg != NULL)
diff -r 722467d0c45f -r 42aa510d7bc3 translate/grt/grt-lib.adb
--- a/translate/grt/grt-lib.adb Mon Feb 10 01:43:01 2014 +0100
+++ b/translate/grt/grt-lib.adb Mon Feb 10 18:13:54 2014 +0100
@@ -145,6 +145,8 @@
Error_C ("block already configured");
when 3 =>
Error_C ("bad configuration");
+ when 6 =>
+ Error_C ("could not allocate memory");
when others =>
Error_C ("unknown error code ");
Error_C (Integer (Code));
diff -r 722467d0c45f -r 42aa510d7bc3 translate/translation.adb
--- a/translate/translation.adb Mon Feb 10 01:43:01 2014 +0100
+++ b/translate/translation.adb Mon Feb 10 18:13:54 2014 +0100
@@ -2181,6 +2181,7 @@
Prg_Err_Dummy_Config : constant Natural := 3;
Prg_Err_No_Choice : constant Natural := 4;
Prg_Err_Bad_Choice : constant Natural := 5;
+ Prg_Err_Alloc_NoMem : constant Natural := 6;
procedure Gen_Program_Error (Loc : Iir; Code : Natural);
-- Generate code to emit a failure if COND is TRUE, indicating an
@@ -8589,6 +8590,7 @@
Dinfo : Type_Info_Acc;
Length : O_Enode;
Kind : constant Object_Kind_Type := Get_Object_Kind (Res);
+ If_Blk : O_If_Block;
begin
Dinfo := Get_Info (Get_Base_Type (Arr_Type));
-- Compute array size.
@@ -8598,6 +8600,15 @@
(M2Lp (Chap3.Get_Array_Base (Res)),
Gen_Alloc (Alloc_Kind, Length, Dinfo.T.Base_Ptr_Type (Kind)));
+ if Alloc_Kind = Alloc_Heap then
+ -- Allocation can fail, so we include a check to handle the case
smoothly
+ Start_If_Stmt (If_Blk,
+ New_Compare_Op (On_Neq,
+ M2Addr (Chap3.Get_Array_Base (Res)),
+ New_Lit (New_Null_Access
(Dinfo.T.Base_Ptr_Type (Kind))),
+ Ghdl_Bool_Type));
+ end if;
+
if Is_Complex_Type (Dinfo)
and then Dinfo.C (Kind).Builder_Need_Func
then
@@ -8606,6 +8617,24 @@
Chap3.Gen_Call_Type_Builder (Res, Arr_Type);
Close_Temp;
end if;
+
+ if Alloc_Kind = Alloc_Heap then
+ New_Else_Stmt (If_Blk);
+ -- If we're here, the allocation failed for Array's data
+ if Flag_Allocation_Check then
+ Chap6.Gen_Program_Error (Arr_Type, Chap6.Prg_Err_Alloc_NoMem);
+ else
+ -- We release memory allocated for the bounds to make the
access variable
+ -- a valid looking NULL pointer to reflect that state of things
so it can
+ -- be properly handled in user's VHDL code
+ Chap3.Gen_Deallocate (M2Addr (Chap3.Get_Array_Bounds (Res)));
+ New_Assign_Stmt
+ (M2Lp (Chap3.Get_Array_Bounds (Res)),
+ New_Lit (New_Null_Access (Dinfo.T.Bounds_Ptr_Type)));
+ end if;
+
+ Finish_If_Stmt (If_Blk);
+ end if;
end Allocate_Fat_Array_Base;
procedure Create_Array_Subtype (Sub_Type : Iir; Transient : Boolean)
@@ -8724,6 +8753,7 @@
is
Dinfo : Type_Info_Acc;
Kind : Object_Kind_Type;
+ If_Blk : O_If_Block;
begin
Dinfo := Get_Info (Obj_Type);
Kind := Get_Object_Kind (Res);
@@ -8736,6 +8766,16 @@
Ghdl_Index_Type)),
Dinfo.T.Bounds_Ptr_Type));
+ if Alloc_Kind = Alloc_Heap then
+ -- Allocation can fail, so we include a check to avoid NULL
+ -- pointer dereference in generated code
+ Start_If_Stmt (If_Blk,
+ New_Compare_Op (On_Neq,
+ M2Addr (Chap3.Get_Array_Bounds
(Res)),
+ New_Lit (New_Null_Access
(Dinfo.T.Bounds_Ptr_Type)),
+ Ghdl_Bool_Type));
+ end if;
+
-- Copy bounds to the allocated area.
Gen_Memcpy
(M2Addr (Chap3.Get_Array_Bounds (Res)),
@@ -8744,6 +8784,22 @@
-- Allocate base.
Allocate_Fat_Array_Base (Alloc_Kind, Res, Obj_Type);
+
+ if Alloc_Kind = Alloc_Heap then
+ New_Else_Stmt (If_Blk);
+ -- If we're here, the allocation for Bounds failed (no more
memory)
+ if Flag_Allocation_Check then
+ Chap6.Gen_Program_Error (Obj_Type,
Chap6.Prg_Err_Alloc_NoMem);
+ else
+ -- We initialise the pointer as a valid-looking NULL pointer
+ New_Assign_Stmt
+ (M2Lp (Chap3.Get_Array_Base (Res)),
+ New_Lit (New_Null_Access (Dinfo.T.Base_Ptr_Type (Kind))));
+ end if;
+
+ Finish_If_Stmt (If_Blk);
+ end if;
+
else
New_Assign_Stmt
(M2Lp (Res),
@@ -8753,6 +8809,14 @@
Obj_Type),
Dinfo.Ortho_Ptr_Type (Kind)));
+ if Alloc_Kind = Alloc_Heap then
+ Start_If_Stmt (If_Blk,
+ New_Compare_Op (ON_Neq,
+ M2Addr (Res),
+ New_Lit (New_Null_Access
(Dinfo.Ortho_Ptr_Type (Kind))),
+ Ghdl_Bool_Type));
+ end if;
+
if Is_Complex_Type (Dinfo)
and then Dinfo.C (Kind).Builder_Need_Func
then
@@ -8762,6 +8826,13 @@
Close_Temp;
end if;
+ if Alloc_Kind = Alloc_Heap then
+ if Flag_Allocation_Check then
+ New_Else_Stmt (If_Blk);
+ Chap6.Gen_Program_Error (Obj_Type,
Chap6.Prg_Err_Alloc_NoMem);
+ end if;
+ Finish_If_Stmt (If_Blk);
+ end if;
end if;
end Translate_Object_Allocation;
@@ -16041,6 +16112,7 @@
D_Info : constant Type_Info_Acc := Get_Info (D_Type);
R : Mnode;
Rtype : O_Tnode;
+ If_Blk : O_If_Block;
begin
-- Compute the expression.
Val := Translate_Expression (Get_Expression (Expr), D_Type);
@@ -16064,7 +16136,33 @@
when others =>
raise Internal_Error;
end case;
+
+ if A_Info.Type_Mode = Type_Mode_Fat_Acc then
+ Start_If_Stmt (If_Blk,
+ New_Compare_Op (On_Neq,
+ M2Addr (Chap3.Get_Array_Base (R)),
+ New_Lit (New_Null_Access
+ (D_Info.T.Base_Ptr_Type
+ (Get_Object_Kind (R)))),
+ Ghdl_Bool_Type));
+ else
+ Start_If_Stmt (If_Blk,
+ New_Compare_Op (On_Neq,
+ M2Addr (R),
+ New_Lit (New_Null_Access
+ (D_Info.Ortho_Ptr_Type
+ (Get_Object_Kind (R)))),
+ Ghdl_Bool_Type));
+ end if;
+
Chap3.Translate_Object_Copy (R, Val, D_Type);
+
+ if Flag_Allocation_Check then
+ New_Else_Stmt (If_Blk);
+ Chap6.Gen_Program_Error (Expr, Chap6.Prg_Err_Alloc_NoMem);
+ end if;
+ Finish_If_Stmt (If_Blk);
+
return New_Convert_Ov (M2Addr (R), Rtype);
end Translate_Allocator_By_Expression;
@@ -16079,6 +16177,7 @@
P_Info : Type_Info_Acc;
D_Type : Iir;
D_Info : Type_Info_Acc;
+ If_Blk : O_If_Block;
begin
P_Type := Get_Type (Expr);
P_Info := Get_Info (P_Type);
@@ -16103,7 +16202,34 @@
raise Internal_Error;
end case;
Chap3.Translate_Object_Allocation (Res, Alloc_Heap, D_Type, Bounds);
+
+ if D_Info.Type_Mode = Type_Mode_Fat_Array then
+ -- the allocation may have failed, do not initialise a NULL pointer
+ Start_If_Stmt (If_Blk,
+ New_Compare_Op (ON_Neq,
+ M2Addr (Chap3.Get_Array_Base (Res)),
+ New_Lit (New_Null_Access
+ (D_Info.T.Base_Ptr_Type
+ (Get_Object_Kind (Res)))),
+ Ghdl_Bool_Type));
+ else
+ Start_If_Stmt (If_Blk,
+ New_Compare_Op (ON_Neq,
+ M2Addr (Res),
+ New_Lit (New_Null_Access
+ (D_Info.Ortho_Ptr_Type
+ (Get_Object_Kind (Res)))),
+ Ghdl_Bool_Type));
+ end if;
+
Chap4.Init_Object (Res, D_Type);
+
+ if Flag_Allocation_Check then
+ New_Else_Stmt (If_Blk);
+ Chap6.Gen_Program_Error (Expr, Chap6.Prg_Err_Alloc_NoMem);
+ end if;
+ Finish_If_Stmt (If_Blk);
+
return New_Convert_Ov (M2Addr (Res), Rtype);
end Translate_Allocator_By_Subtype;
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