[patch 10/12] entryval#3: "@entry" in input expressions

Jan Kratochvil jan.kratochvil@redhat.com
Thu Sep 29 19:55:00 GMT 2011


Hi,

[patch 10/12] entryval#2: "@entry" in input expressions
http://sourceware.org/ml/gdb-patches/2011-09/msg00232.html

doc update by Eli.


Thanks,
Jan


gdb/
2011-07-18  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Support @entry in input expressions.
	* c-exp.y (ENTRY, unknown_cpp_name): New.
	(exp: UNKNOWN_CPP_NAME): Change to `exp: unknown_cpp_name'.
	(unknown_cpp_name: UNKNOWN_CPP_NAME, unknown_cpp_name: ENTRY)
	(variable: name_not_typename '@' ENTRY, name: ENTRY)
	(name_not_typename: ENTRY): New.
	(yylex): Recognize ENTRY.
	* eval.c (evaluate_subexp_standard): Support also OP_VAR_ENTRY_VALUE.
	* expprint.c (print_subexp_standard, dump_subexp_body_standard):
	Likewise.
	* parse.c (operator_length_standard): Likewise.
	* std-operator.def: New operator OP_VAR_ENTRY_VALUE.

gdb/doc/
2011-09-29  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Support @entry in input expressions.
	* gdb.texinfo (Variables): Describe @entry names suffix.
	(Print Settings): Add anchor for `set print entry-values'.

gdb/testsuite/
2011-09-13  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Support @entry in input expressions.
	* gdb.arch/amd64-entry-value.exp (entry: p i@entry, entry: p j@entry)
	(entry_stack: p s1@entry, entry_stack: p s2@entry)
	(entry_stack: p d9@entry, entry_stack: p da@entry, tailcall: p i@entry)
	(tailcall: p j@entry): New tests.
	* gdb.cp/koenig.cc (A::entry): New function.
	(main): Call it.
	* gdb.cp/koenig.exp (p entry (c)): New test.

--- a/gdb/c-exp.y
+++ b/gdb/c-exp.y
@@ -186,6 +186,7 @@ static struct stoken operator_stoken (const char *);
 %token <tsval> STRING
 %token <tsval> CHAR
 %token <ssym> NAME /* BLOCKNAME defined below to give it higher precedence. */
+%token <ssym> ENTRY
 %token <ssym> UNKNOWN_CPP_NAME
 %token <voidval> COMPLETE
 %token <tsym> TYPENAME
@@ -194,6 +195,9 @@ static struct stoken operator_stoken (const char *);
 %type <ssym> name_not_typename
 %type <tsym> typename
 
+/* It is UNKNOWN_CPP_NAME or ENTRY, depending on the context.  */
+%type <ssym> unknown_cpp_name
+
 /* A NAME_OR_INT is a symbol which is not known in the symbol table,
    but which would parse as a valid number in the current input radix.
    E.g. "c" when input_radix==16.  Depending on the parse, it will be
@@ -392,7 +396,7 @@ exp	:	exp '('
 			  write_exp_elt_opcode (OP_FUNCALL); }
 	;
 
-exp	:	UNKNOWN_CPP_NAME '('
+exp	:	unknown_cpp_name '('
 			{
 			  /* This could potentially be a an argument defined
 			     lookup function (Koenig).  */
@@ -415,6 +419,10 @@ exp	:	UNKNOWN_CPP_NAME '('
 			}
 	;
 
+unknown_cpp_name	: UNKNOWN_CPP_NAME
+			| ENTRY
+			;
+
 lcurly	:	'{'
 			{ start_arglist (); }
 	;
@@ -756,6 +764,21 @@ block	:	block COLONCOLON name
 			  $$ = SYMBOL_BLOCK_VALUE (tem); }
 	;
 
+variable:	name_not_typename '@' ENTRY
+			{ struct symbol *sym = $1.sym;
+
+			  if (sym == NULL || !SYMBOL_IS_ARGUMENT (sym)
+			      || !symbol_read_needs_frame (sym))
+			    error (_("@entry can be used only for function "
+				     "parameters, not for \"%s\""),
+				   copy_name ($1.stoken));
+
+			  write_exp_elt_opcode (OP_VAR_ENTRY_VALUE);
+			  write_exp_elt_sym (sym);
+			  write_exp_elt_opcode (OP_VAR_ENTRY_VALUE);
+			}
+	;
+
 variable:	block COLONCOLON name
 			{ struct symbol *sym;
 			  sym = lookup_symbol (copy_name ($3), $1,
@@ -1317,11 +1340,13 @@ name	:	NAME { $$ = $1.stoken; }
 	|	TYPENAME { $$ = $1.stoken; }
 	|	NAME_OR_INT  { $$ = $1.stoken; }
 	|	UNKNOWN_CPP_NAME  { $$ = $1.stoken; }
+	|	ENTRY { $$ = $1.stoken; }
 	|	operator { $$ = $1; }
 	;
 
 name_not_typename :	NAME
 	|	BLOCKNAME
+	|	ENTRY
 /* These would be useful if name_not_typename was useful, but it is just
    a fake for "variable", so these cause reduce/reduce conflicts because
    the parser can't tell whether NAME_OR_INT is a name_not_typename (=variable,
@@ -2525,6 +2550,11 @@ yylex (void)
   current.token = lex_one_token ();
   if (current.token == NAME)
     current.token = classify_name (expression_context_block);
+  if ((current.token == NAME || current.token == UNKNOWN_CPP_NAME)
+      && yylval.sval.length == strlen ("entry")
+      && strncmp (yylval.sval.ptr, "entry", strlen ("entry")) == 0)
+    current.token = ENTRY;
+
   if (parse_language->la_language != language_cplus
       || (current.token != TYPENAME && current.token != COLONCOLON))
     return current.token;
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -7277,6 +7277,23 @@ If you ask to print an object whose contents are unknown to
 by the debug information, @value{GDBN} will say @samp{<incomplete
 type>}.  @xref{Symbols, incomplete type}, for more about this.
 
+If you append @kbd{@@entry} string to a function parameter name you get its
+value at the time the function got called.  If the value is not available an
+error message is printed.  Entry values are available only with some compilers.
+Entry values are normally also printed at the function parameter list according
+to @ref{set print entry-values}.
+
+@smallexample
+Breakpoint 1, d (i=30) at gdb.base/entry-value.c:29
+29	  i++;
+(gdb) next
+30	  e (i);
+(gdb) print i
+$1 = 31
+(gdb) print i@@entry
+$2 = 30
+@end smallexample
+
 Strings are identified as arrays of @code{char} values without specified
 signedness.  Arrays of either @code{signed char} or @code{unsigned char} get
 printed as arrays of 1 byte sized integers.  @code{-fsigned-char} or
@@ -7941,6 +7958,7 @@ thus speeding up the display of each Ada frame.
 @item show print frame-arguments
 Show how the value of arguments should be displayed when printing a frame.
 
+@anchor{set print entry-values}
 @item set print entry-values @var{value}
 @kindex set print entry-values
 Set printing of frame argument values at function entry.  In some cases
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -860,6 +860,27 @@ evaluate_subexp_standard (struct type *expect_type,
 	return ret;
       }
 
+    case OP_VAR_ENTRY_VALUE:
+      (*pos) += 2;
+      if (noside == EVAL_SKIP)
+	goto nosideret;
+
+      {
+	struct symbol *sym = exp->elts[pc + 1].symbol;
+	struct frame_info *frame;
+
+	if (noside == EVAL_AVOID_SIDE_EFFECTS)
+	  return value_zero (SYMBOL_TYPE (sym), not_lval);
+
+	if (SYMBOL_CLASS (sym) != LOC_COMPUTED
+	    || SYMBOL_COMPUTED_OPS (sym)->read_variable_at_entry == NULL)
+	  error (_("Symbol \"%s\" does not have any specific entry value"),
+		 SYMBOL_PRINT_NAME (sym));
+
+	frame = get_selected_frame (NULL);
+	return SYMBOL_COMPUTED_OPS (sym)->read_variable_at_entry (sym, frame);
+      }
+
     case OP_LAST:
       (*pos) += 2;
       return
--- a/gdb/expprint.c
+++ b/gdb/expprint.c
@@ -135,6 +135,16 @@ print_subexp_standard (struct expression *exp, int *pos,
       }
       return;
 
+    case OP_VAR_ENTRY_VALUE:
+      {
+	struct block *b;
+
+	(*pos) += 2;
+	fprintf_filtered (stream, "%s@entry",
+			  SYMBOL_PRINT_NAME (exp->elts[pc + 1].symbol));
+      }
+      return;
+
     case OP_LAST:
       (*pos) += 2;
       fprintf_filtered (stream, "$%d",
@@ -853,6 +863,13 @@ dump_subexp_body_standard (struct expression *exp,
 			SYMBOL_PRINT_NAME (exp->elts[elt + 1].symbol));
       elt += 3;
       break;
+    case OP_VAR_ENTRY_VALUE:
+      fprintf_filtered (stream, "Entry value of symbol @");
+      gdb_print_host_address (exp->elts[elt].symbol, stream);
+      fprintf_filtered (stream, " (%s)",
+			SYMBOL_PRINT_NAME (exp->elts[elt].symbol));
+      elt += 2;
+      break;
     case OP_LAST:
       fprintf_filtered (stream, "History element %ld",
 			(long) exp->elts[elt].longconst);
--- a/gdb/parse.c
+++ b/gdb/parse.c
@@ -853,6 +853,7 @@ operator_length_standard (const struct expression *expr, int endpos,
     case OP_BOOL:
     case OP_LAST:
     case OP_INTERNALVAR:
+    case OP_VAR_ENTRY_VALUE:
       oplen = 3;
       break;
 
--- a/gdb/std-operator.def
+++ b/gdb/std-operator.def
@@ -139,6 +139,12 @@ OP (OP_DOUBLE)
    use the selected frame.  */
 OP (OP_VAR_VALUE)
 
+/* OP_VAR_ENTRY_VALUE takes one struct symbol * in the following element,
+   followed by another OP_VAR_ENTRY_VALUE, making three exp_elements.
+   somename@entry may mean parameter value as present at the entry of the
+   current function.  Implemented via DW_OP_GNU_entry_value.  */
+OP (OP_VAR_ENTRY_VALUE)
+
 /* OP_LAST is followed by an integer in the next exp_element.
    The integer is zero for the last value printed,
    or it is the absolute number of a history element.
--- a/gdb/testsuite/gdb.arch/amd64-entry-value.exp
+++ b/gdb/testsuite/gdb.arch/amd64-entry-value.exp
@@ -51,7 +51,9 @@ gdb_continue_to_breakpoint "entry: breakhere"
 gdb_test "bt" "^bt\r\n#0 +d *\\(i=31, i@entry=30, j=31\\.5, j@entry=30\\.5\\) \[^\r\n\]*\r\n#1 +0x\[0-9a-f\]+ in main .*" \
 	 "entry: bt"
 gdb_test "p i" " = 31" "entry: p i"
+gdb_test "p i@entry" " = 30" "entry: p i@entry"
 gdb_test "p j" { = 31\.5} "entry: p j"
+gdb_test "p j@entry" { = 30\.5} "entry: p j@entry"
 
 
 # Test @entry values when parameter in function is locexpr (and not loclist).
@@ -76,9 +78,13 @@ gdb_test "bt" "^bt\r\n#0 +stacktest *\\(r1=r1@entry=1, r2=r2@entry=2, \[^\r\n\]+
 	 "entry_stack: bt"
 
 gdb_test "p s1" " = 3" "entry_stack: p s1"
+gdb_test "p s1@entry" " = 11" "entry_stack: p s1@entry"
 gdb_test "p s2" " = 4" "entry_stack: p s2"
+gdb_test "p s2@entry" " = 12" "entry_stack: p s2@entry"
 gdb_test "p d9" " = 3\\.5" "entry_stack: p d9"
+gdb_test "p d9@entry" " = 11\\.5" "entry_stack: p d9@entry"
 gdb_test "p da" " = 4\\.5" "entry_stack: p da"
+gdb_test "p da@entry" " = 12\\.5" "entry_stack: p da@entry"
 
 
 # Test various kinds of `set print entry-values'.
@@ -159,7 +165,9 @@ gdb_continue_to_breakpoint "tailcall: breakhere"
 gdb_test "bt" "^bt\r\n#0 +d *\\(i=71, i@entry=70, j=73\\.5, j@entry=72\\.5\\) \[^\r\n\]*\r\n#1 +0x\[0-9a-f\]+ in c \\(i=i@entry=7, j=j@entry=7\\.25\\) \[^\r\n\]*\r\n#2 +0x\[0-9a-f\]+ in b \\(i=i@entry=5, j=j@entry=5\\.25\\) \[^\r\n\]*\r\n#3 +0x\[0-9a-f\]+ in main \[^\r\n\]*" \
 	 "tailcall: bt"
 gdb_test "p i" " = 71" "tailcall: p i"
+gdb_test "p i@entry" " = 70" "tailcall: p i@entry"
 gdb_test "p j" " = 73\\.5" "tailcall: p j"
+gdb_test "p j@entry" " = 72\\.5" "tailcall: p j@entry"
 
 # Test $sp simulation for tail call frames.
 #gdb_test {p/x $sp} " = 0x.*"
--- a/gdb/testsuite/gdb.cp/koenig.cc
+++ b/gdb/testsuite/gdb.cp/koenig.cc
@@ -24,6 +24,11 @@ namespace A
     return 33;
   }
 
+  int
+  entry (C c)
+  {
+    return 44;
+  }
 }
 
 struct B
@@ -245,6 +250,7 @@ main ()
   A::first (c);
   first (0, c);
   second (0, 0, c, 0, 0);
+  entry (c);
   A::first (b.c);
 
   E::O eo;
--- a/gdb/testsuite/gdb.cp/koenig.exp
+++ b/gdb/testsuite/gdb.cp/koenig.exp
@@ -33,6 +33,9 @@ gdb_test "p first(c)" "= 11"
 # the qualifying parameter
 gdb_test "p second(0,0,c,0,0)" "= 33"
 
+# Test the name "entry" being used for `variablename@entry' entry values.
+gdb_test "p entry (c)" " = 44"
+
 # Test that koenig lookup finds correct function
 # even if it is overloaded
 gdb_test "p first(0,c)" "= 22"



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