[PATCH] DWARF reader: use size_t for DWARF expression length

[PATCH] DWARF reader: use size_t for DWARF expression length

[Giuliano Procida]

A recent change broke 32-bit builds due to an implicit assumption that
size_t == uint64_t. This appears in the elfutils dwarf_getlocation*
functions' types.

This commit updates callers and other functions to use size_t
consistently for such expression lengths and indexes.

	* src/abg-dwarf-reader.cc (die_location_expr): Change expr_len
	argument type to size_t*.
	(op_manipulates_stack): Change expr_len and index argument
	types to size_t; change next_index argument type to size_t&.
	(eval_last_constant_dwarf_sub_expr): Change expr_len argument
	and local variables index and next_index types to size_t.
	(die_member_offset): Change local variable expr_len type to
	size_t.
	(die_location_address): Likewise.
	(die_virtual_function_index): Likewise.

Fixes: 16207c4af7bc ("Bug 28191 - Interpret DWARF 5 addrx locations")
Signed-off-by: Giuliano Procida <gprocida@google.com>
---
 src/abg-dwarf-reader.cc | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/abg-dwarf-reader.cc b/src/abg-dwarf-reader.cc
index f125196d..7ee8c04a 100644
--- a/src/abg-dwarf-reader.cc
+++ b/src/abg-dwarf-reader.cc
@@ -7686,7 +7686,7 @@ static bool
 die_location_expr(const Dwarf_Die* die,
 		  unsigned attr_name,
 		  Dwarf_Op** expr,
-		  uint64_t* expr_len)
+		  size_t* expr_len)
 {
   if (!die)
     return false;
@@ -8022,9 +8022,9 @@ op_pushes_non_constant_value(Dwarf_Op* ops,
 /// DEVM stack, false otherwise.
 static bool
 op_manipulates_stack(Dwarf_Op* expr,
-		     uint64_t expr_len,
-		     uint64_t index,
-		     uint64_t& next_index,
+		     size_t expr_len,
+		     size_t index,
+		     size_t& next_index,
 		     dwarf_expr_eval_context& ctxt)
 {
   Dwarf_Op& op = expr[index];
@@ -8398,7 +8398,7 @@ eval_quickly(Dwarf_Op*	expr,
 /// to evaluate, false otherwise.
 static bool
 eval_last_constant_dwarf_sub_expr(Dwarf_Op*	expr,
-				  uint64_t	expr_len,
+				  size_t	expr_len,
 				  int64_t&	value,
 				  bool&	is_tls_address,
 				  dwarf_expr_eval_context &eval_ctxt)
@@ -8407,7 +8407,7 @@ eval_last_constant_dwarf_sub_expr(Dwarf_Op*	expr,
   // expression contained in the DWARF expression 'expr'.
   eval_ctxt.reset();
 
-  uint64_t index = 0, next_index = 0;
+  size_t index = 0, next_index = 0;
   do
     {
       if (op_is_arith_logic(expr, expr_len, index,
@@ -8452,7 +8452,7 @@ eval_last_constant_dwarf_sub_expr(Dwarf_Op*	expr,
 /// to evaluate, false otherwise.
 static bool
 eval_last_constant_dwarf_sub_expr(Dwarf_Op*	expr,
-				  uint64_t	expr_len,
+				  size_t	expr_len,
 				  int64_t&	value,
 				  bool&	is_tls_address)
 {
@@ -8775,7 +8775,7 @@ die_member_offset(const read_context& ctxt,
 		  int64_t& offset)
 {
   Dwarf_Op* expr = NULL;
-  uint64_t expr_len = 0;
+  size_t expr_len = 0;
   uint64_t bit_offset = 0;
 
   // First let's see if the DW_AT_data_bit_offset attribute is
@@ -8852,7 +8852,7 @@ die_location_address(Dwarf_Die*	die,
 		     bool&		is_tls_address)
 {
   Dwarf_Op* expr = NULL;
-  uint64_t expr_len = 0;
+  size_t expr_len = 0;
 
   is_tls_address = false;
 
@@ -8898,7 +8898,7 @@ die_virtual_function_index(Dwarf_Die* die,
     return false;
 
   Dwarf_Op* expr = NULL;
-  uint64_t expr_len = 0;
+  size_t expr_len = 0;
   if (!die_location_expr(die, DW_AT_vtable_elem_location,
 			 &expr, &expr_len))
     return false;
-- 
2.34.1.703.g22d0c6ccf7-goog

Re: [PATCH] DWARF reader: use size_t for DWARF expression length

[Mark Wielaard]

[-- Attachment #1: Type: text/plain, Size: 1089 bytes --]

Hi Giuliano,

On Mon, Jan 17, 2022 at 02:51:15PM +0000, Giuliano Procida wrote:
> A recent change broke 32-bit builds due to an implicit assumption that
> size_t == uint64_t. This appears in the elfutils dwarf_getlocation*
> functions' types.
> 
> This commit updates callers and other functions to use size_t
> consistently for such expression lengths and indexes.
> 
> 	* src/abg-dwarf-reader.cc (die_location_expr): Change expr_len
> 	argument type to size_t*.
> 	(op_manipulates_stack): Change expr_len and index argument
> 	types to size_t; change next_index argument type to size_t&.
> 	(eval_last_constant_dwarf_sub_expr): Change expr_len argument
> 	and local variables index and next_index types to size_t.
> 	(die_member_offset): Change local variable expr_len type to
> 	size_t.
> 	(die_location_address): Likewise.
> 	(die_virtual_function_index): Likewise.

I also needed to change the len and index arguments of
eval_last_constant_dwarf_sub_expr, op_pushes_constant_value,
op_pushes_non_constant_value, op_is_arith_logic and
op_is_control_flow.

See attached.

Cheers,

Mark

[-- Attachment #2: p --]
[-- Type: text/plain, Size: 4135 bytes --]

diff --git a/src/abg-dwarf-reader.cc b/src/abg-dwarf-reader.cc
index f125196d..d8545b4c 100644
--- a/src/abg-dwarf-reader.cc
+++ b/src/abg-dwarf-reader.cc
@@ -363,7 +363,7 @@ die_is_at_class_scope(const read_context& ctxt,
 		      Dwarf_Die& class_scope_die);
 static bool
 eval_last_constant_dwarf_sub_expr(Dwarf_Op*	expr,
-				  uint64_t	expr_len,
+				  size_t	expr_len,
 				  int64_t&	value,
 				  bool&	is_tls_address);
 
@@ -7686,7 +7686,7 @@ static bool
 die_location_expr(const Dwarf_Die* die,
 		  unsigned attr_name,
 		  Dwarf_Op** expr,
-		  uint64_t* expr_len)
+		  size_t* expr_len)
 {
   if (!die)
     return false;
@@ -7732,9 +7732,9 @@ die_location_expr(const Dwarf_Die* die,
 /// value onto the DEVM stack, false otherwise.
 static bool
 op_pushes_constant_value(Dwarf_Op*			ops,
-			 uint64_t			ops_len,
-			 uint64_t			index,
-			 uint64_t&			next_index,
+			 size_t				ops_len,
+			 size_t				index,
+			 size_t&			next_index,
 			 dwarf_expr_eval_context&	ctxt)
 {
   ABG_ASSERT(index < ops_len);
@@ -7896,9 +7896,9 @@ op_pushes_constant_value(Dwarf_Op*			ops,
 /// non-constant value onto the DEVM stack, false otherwise.
 static bool
 op_pushes_non_constant_value(Dwarf_Op* ops,
-			     uint64_t ops_len,
-			     uint64_t index,
-			     uint64_t& next_index,
+			     size_t ops_len,
+			     size_t index,
+			     size_t& next_index,
 			     dwarf_expr_eval_context& ctxt)
 {
   ABG_ASSERT(index < ops_len);
@@ -8022,9 +8022,9 @@ op_pushes_non_constant_value(Dwarf_Op* ops,
 /// DEVM stack, false otherwise.
 static bool
 op_manipulates_stack(Dwarf_Op* expr,
-		     uint64_t expr_len,
-		     uint64_t index,
-		     uint64_t& next_index,
+		     size_t expr_len,
+		     size_t index,
+		     size_t& next_index,
 		     dwarf_expr_eval_context& ctxt)
 {
   Dwarf_Op& op = expr[index];
@@ -8146,9 +8146,9 @@ op_manipulates_stack(Dwarf_Op* expr,
 /// arithmetic or logic operation.
 static bool
 op_is_arith_logic(Dwarf_Op* expr,
-		  uint64_t expr_len,
-		  uint64_t index,
-		  uint64_t& next_index,
+		  size_t expr_len,
+		  size_t index,
+		  size_t& next_index,
 		  dwarf_expr_eval_context& ctxt)
 {
   ABG_ASSERT(index < expr_len);
@@ -8279,9 +8279,9 @@ op_is_arith_logic(Dwarf_Op* expr,
 /// control flow operation, false otherwise.
 static bool
 op_is_control_flow(Dwarf_Op* expr,
-		   uint64_t expr_len,
-		   uint64_t index,
-		   uint64_t& next_index,
+		   size_t expr_len,
+		   size_t index,
+		   size_t& next_index,
 		   dwarf_expr_eval_context& ctxt)
 {
   ABG_ASSERT(index < expr_len);
@@ -8398,7 +8398,7 @@ eval_quickly(Dwarf_Op*	expr,
 /// to evaluate, false otherwise.
 static bool
 eval_last_constant_dwarf_sub_expr(Dwarf_Op*	expr,
-				  uint64_t	expr_len,
+				  size_t	expr_len,
 				  int64_t&	value,
 				  bool&	is_tls_address,
 				  dwarf_expr_eval_context &eval_ctxt)
@@ -8407,7 +8407,7 @@ eval_last_constant_dwarf_sub_expr(Dwarf_Op*	expr,
   // expression contained in the DWARF expression 'expr'.
   eval_ctxt.reset();
 
-  uint64_t index = 0, next_index = 0;
+  size_t index = 0, next_index = 0;
   do
     {
       if (op_is_arith_logic(expr, expr_len, index,
@@ -8452,7 +8452,7 @@ eval_last_constant_dwarf_sub_expr(Dwarf_Op*	expr,
 /// to evaluate, false otherwise.
 static bool
 eval_last_constant_dwarf_sub_expr(Dwarf_Op*	expr,
-				  uint64_t	expr_len,
+				  size_t	expr_len,
 				  int64_t&	value,
 				  bool&	is_tls_address)
 {
@@ -8775,7 +8775,7 @@ die_member_offset(const read_context& ctxt,
 		  int64_t& offset)
 {
   Dwarf_Op* expr = NULL;
-  uint64_t expr_len = 0;
+  size_t expr_len = 0;
   uint64_t bit_offset = 0;
 
   // First let's see if the DW_AT_data_bit_offset attribute is
@@ -8852,7 +8852,7 @@ die_location_address(Dwarf_Die*	die,
 		     bool&		is_tls_address)
 {
   Dwarf_Op* expr = NULL;
-  uint64_t expr_len = 0;
+  size_t expr_len = 0;
 
   is_tls_address = false;
 
@@ -8898,7 +8898,7 @@ die_virtual_function_index(Dwarf_Die* die,
     return false;
 
   Dwarf_Op* expr = NULL;
-  uint64_t expr_len = 0;
+  size_t expr_len = 0;
   if (!die_location_expr(die, DW_AT_vtable_elem_location,
 			 &expr, &expr_len))
     return false;

Re: [PATCH] DWARF reader: use size_t for DWARF expression length

[Giuliano Procida]

The latest merged commit doesn't have the extra fixes you mentioned.

I'm happy to replicate your work, but I risk leaving something out again.

Let me know,
Giuliano.

On Tue, 18 Jan 2022 at 09:52, Mark Wielaard <mark@klomp.org> wrote:
>
> Hi Giuliano,
>
> On Mon, Jan 17, 2022 at 02:51:15PM +0000, Giuliano Procida wrote:
> > A recent change broke 32-bit builds due to an implicit assumption that
> > size_t == uint64_t. This appears in the elfutils dwarf_getlocation*
> > functions' types.
> >
> > This commit updates callers and other functions to use size_t
> > consistently for such expression lengths and indexes.
> >
> >       * src/abg-dwarf-reader.cc (die_location_expr): Change expr_len
> >       argument type to size_t*.
> >       (op_manipulates_stack): Change expr_len and index argument
> >       types to size_t; change next_index argument type to size_t&.
> >       (eval_last_constant_dwarf_sub_expr): Change expr_len argument
> >       and local variables index and next_index types to size_t.
> >       (die_member_offset): Change local variable expr_len type to
> >       size_t.
> >       (die_location_address): Likewise.
> >       (die_virtual_function_index): Likewise.
>
> I also needed to change the len and index arguments of
> eval_last_constant_dwarf_sub_expr, op_pushes_constant_value,
> op_pushes_non_constant_value, op_is_arith_logic and
> op_is_control_flow.
>
> See attached.
>
> Cheers,
>
> Mark

Re: [PATCH] DWARF reader: use size_t for DWARF expression length

[Dodji Seketeli]

Giuliano Procida <gprocida@google.com> a écrit:

> A recent change broke 32-bit builds due to an implicit assumption that
> size_t == uint64_t. This appears in the elfutils dwarf_getlocation*
> functions' types.
>
> This commit updates callers and other functions to use size_t
> consistently for such expression lengths and indexes.
>
> 	* src/abg-dwarf-reader.cc (die_location_expr): Change expr_len
> 	argument type to size_t*.
> 	(op_manipulates_stack): Change expr_len and index argument
> 	types to size_t; change next_index argument type to size_t&.
> 	(eval_last_constant_dwarf_sub_expr): Change expr_len argument
> 	and local variables index and next_index types to size_t.
> 	(die_member_offset): Change local variable expr_len type to
> 	size_t.
> 	(die_location_address): Likewise.
> 	(die_virtual_function_index): Likewise.
>
> Fixes: 16207c4af7bc ("Bug 28191 - Interpret DWARF 5 addrx locations")
> Signed-off-by: Giuliano Procida <gprocida@google.com>

Applied to master, thanks!

[...]

Cheers,

-- 
		Dodji