PR5516: assignment to $pointers

2008-03-03  Frank Ch. Eigler  <fche@elastic.org>

	PR5516
	* elaborate.cxx (symbol_fetcher, dead_assignment_remover):
	Support unresolved $target lvalues.  Propagate pretty error
	messages.
	* staptree.cxx (varuse_collecting_visitor target_symbol): Ditto.
	* staptree.h: Corresponding decl.

	* loc2c.c: c_translate_pointer_store: New function.
	* loc2c.h: Corresponding decl.
	* tapsets.cxx (dwflpp::translate_final_fetch_or_store): Call it
	for $target pointer assignments.

2008-03-03  Frank Ch. Eigler  <fche@elastic.org>

	PR5516
	* buildok/twentynine.stp: New test.

1 files changed, 29 insertions, 20 deletions

diff --git a/tapsets.cxx b/tapsets.cxx
index 52c14024..147ea3f0 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -1601,7 +1601,7 @@ struct dwflpp
 	    if (components[i].first == target_symbol::comp_literal_array_index)
               throw semantic_error ("cannot index pointer");
             // XXX: of course, we should support this the same way C does,
-            // by explicit pointer arithmetic etc.
+            // by explicit pointer arithmetic etc.  PR4166.
 
 	    c_translate_pointer (pool, 1, module_bias, die, tail);
 	    break;
@@ -1773,10 +1773,7 @@ struct dwflpp
       case DW_TAG_array_type:
       case DW_TAG_pointer_type:
 
-	if (lvalue)
-	  throw semantic_error ("cannot store into target pointer value");
-
-	{
+          {
 	  Dwarf_Die pointee_typedie_mem;
 	  Dwarf_Die *pointee_typedie;
 	  Dwarf_Word pointee_encoding;
@@ -1790,21 +1787,33 @@ struct dwflpp
 	  dwarf_formudata (dwarf_attr_integrate (pointee_typedie, DW_AT_encoding, attr_mem),
 			   &pointee_encoding);
 
-	  // We have the pointer: cast it to an integral type via &(*(...))
-
-	  // NB: per bug #1187, at one point char*-like types were
-	  // automagically converted here to systemtap string values.
-	  // For several reasons, this was taken back out, leaving
-	  // pointer-to-string "conversion" (copying) to tapset functions.
-
-	  ty = pe_long;
-	  if (typetag == DW_TAG_array_type)
-	    c_translate_array (pool, 1, module_bias, typedie, tail, NULL, 0);
-	  else
-	    c_translate_pointer (pool, 1, module_bias, typedie, tail);
-	  c_translate_addressof (pool, 1, module_bias, NULL, pointee_typedie, tail,
-				 "THIS->__retvalue");
-	}
+          if (lvalue)
+            {
+              ty = pe_long;
+              if (typetag == DW_TAG_array_type)
+                throw semantic_error ("cannot write to array address");
+              assert (typetag == DW_TAG_pointer_type);
+              c_translate_pointer_store (pool, 1, module_bias, typedie, tail,
+                                         "THIS->value");
+            }
+          else
+            {
+              // We have the pointer: cast it to an integral type via &(*(...))
+              
+              // NB: per bug #1187, at one point char*-like types were
+              // automagically converted here to systemtap string values.
+              // For several reasons, this was taken back out, leaving
+              // pointer-to-string "conversion" (copying) to tapset functions.
+              
+              ty = pe_long;
+              if (typetag == DW_TAG_array_type)
+                c_translate_array (pool, 1, module_bias, typedie, tail, NULL, 0);
+              else
+                c_translate_pointer (pool, 1, module_bias, typedie, tail);
+              c_translate_addressof (pool, 1, module_bias, NULL, pointee_typedie, tail,
+                                     "THIS->__retvalue");
+            }
+          }
 	break;
       }
   }