[PATCH 3/6] Emit macro expansion related diagnostics

[Dodji Seketeli <dodji@redhat.com>]

In this third instalment the diagnostic machinery -- when faced with
the virtual location of a token resulting from macro expansion -- uses
the new linemap APIs to unwind the stack of macro expansions that led
to that token and emits a [hopefully] more useful message than what we
have today.

diagnostic_report_current_module has been slightly changed to use the
location given by client code instead of the global input_location
variable. This results in more precise diagnostic locations in general
but then the patch adjusts some C++ tests which output changed as a
result of this.

Three new regression tests have been added.

The mandatory screenshot goes like this:

[dodji@adjoa gcc]$ cat -n test.c
     1    #define OPERATE(OPRD1, OPRT, OPRD2) \
     2      OPRD1 OPRT OPRD2;
     3
     4    #define SHIFTL(A,B) \
     5      OPERATE (A,<<,B)
     6
     7    #define MULT(A) \
     8      SHIFTL (A,1)
     9
    10    void
    11    g ()
    12    {
    13      MULT (1.0);/* 1.0 << 1; <-- so this is an error.  */
    14    }

[dodji@adjoa gcc]$ ./cc1 -quiet -ftrack-macro-expansion test.c
test.c: In function ‘g’:
test.c:5:14: error: invalid operands to binary << (have ‘double’ and ‘int’)
In macro 'OPERATE' at test.c:2:9
    Expanded at test.c:5:3
In macro 'SHIFTL' at test.c:5:14
    Expanded at test.c:8:3
In macro 'MULT' at test.c:8:3
    Expanded at test.c:13:3

The combination of this patch and the previous ones boostrapped with
--enable-languages=all,ada and passed regression tests on
x86_64-unknown-linux-gnu.

gcc/

	* gcc/diagnostic.h (diagnostic_report_current_module): Add a
	location parameter.
	* diagnostic.c (struct loc_t): new struct.
	(diagnostic_report_current_module): Add a location parameter to
	the function definition. Use it here instead of input_location.
	Fully expand the location rather than just looking up its map and
	risking to touch a resulting macro map.
	(default_diagnostic_starter): Pass the relevant diagnostic
	location to diagnostic_report_current_module.
	(unwind_expanded_macro_location): New function.
	(default_diagnostic_finalizer): Use it.
	* tree-diagnostic.c (diagnostic_report_current_function): Pass the
	relevant location to diagnostic_report_current_module.

gcc/cp/

	* error.c (cp_diagnostic_starter): Pass the relevant location to
	diagnostic_report_current_module.

gcc/testsuite/

	* gcc.dg/cpp/macro-exp-tracking-1.c: New test.
	* gcc.dg/cpp/macro-exp-tracking-2.c: Likewise.
	* gcc.dg/cpp/macro-exp-tracking-3.c: Likewise.
	* g++.dg/cpp0x/initlist15.C: Discard errors pointing at multiple
	levels of included files.
	* g++.old-deja/g++.robertl/eb43.C: Likewise.
	* g++.old-deja/g++.robertl/eb79.C: Likewise.
	* gcc.target/i386/sse-vect-types.c: Likewise.
---
 gcc/Makefile.in                                 |    2 +-
 gcc/cp/error.c                                  |    2 +-
 gcc/diagnostic.c                                |  154 ++++++++++++++++++++++-
 gcc/diagnostic.h                                |    2 +-
 gcc/testsuite/g++.dg/cpp0x/initlist15.C         |    1 +
 gcc/testsuite/g++.old-deja/g++.robertl/eb43.C   |    4 +
 gcc/testsuite/g++.old-deja/g++.robertl/eb79.C   |    4 +
 gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-1.c |   30 +++++
 gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-2.c |   31 +++++
 gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-3.c |   18 +++
 gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-4.c |   19 +++
 gcc/testsuite/gcc.target/i386/sse-vect-types.c  |    6 +
 gcc/tree-diagnostic.c                           |    2 +-
 13 files changed, 266 insertions(+), 9 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-1.c
 create mode 100644 gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-2.c
 create mode 100644 gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-3.c
 create mode 100644 gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-4.c

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 717326c..604f626 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -2825,7 +2825,7 @@ fold-const.o : fold-const.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
    $(GGC_H) $(TM_P_H) langhooks.h $(MD5_H) intl.h $(TARGET_H) \
    $(GIMPLE_H) realmpfr.h $(TREE_FLOW_H)
 diagnostic.o : diagnostic.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
-   version.h $(INPUT_H) intl.h $(DIAGNOSTIC_H) diagnostic.def
+   version.h $(INPUT_H) intl.h $(DIAGNOSTIC_H) diagnostic.def $(VEC_H)
 opts.o : opts.c $(OPTS_H) $(OPTIONS_H) $(DIAGNOSTIC_CORE_H) $(CONFIG_H) $(SYSTEM_H) \
    coretypes.h $(TM_H) $(RTL_H) \
    $(DIAGNOSTIC_H) $(INSN_ATTR_H) intl.h $(TARGET_H) \
diff --git a/gcc/cp/error.c b/gcc/cp/error.c
index ed168c4..db35c61 100644
--- a/gcc/cp/error.c
+++ b/gcc/cp/error.c
@@ -2663,7 +2663,7 @@ static void
 cp_diagnostic_starter (diagnostic_context *context,
 		       diagnostic_info *diagnostic)
 {
-  diagnostic_report_current_module (context);
+  diagnostic_report_current_module (context, diagnostic->location);
   cp_print_error_function (context, diagnostic);
   maybe_print_instantiation_context (context);
   maybe_print_constexpr_context (context);
diff --git a/gcc/diagnostic.c b/gcc/diagnostic.c
index 9df540b..671b6ea 100644
--- a/gcc/diagnostic.c
+++ b/gcc/diagnostic.c
@@ -30,6 +30,15 @@ along with GCC; see the file COPYING3.  If not see
 #include "input.h"
 #include "intl.h"
 #include "diagnostic.h"
+#include "vec.h"
+
+typedef struct 
+{
+  const struct line_map *map;
+  source_location where;
+} loc_t;
+DEF_VEC_O(loc_t);
+DEF_VEC_ALLOC_O (loc_t,heap);
 
 #define pedantic_warning_kind(DC)			\
   ((DC)->pedantic_errors ? DK_ERROR : DK_WARNING)
@@ -45,6 +54,9 @@ static void diagnostic_action_after_output (diagnostic_context *,
 					    diagnostic_info *);
 static void real_abort (void) ATTRIBUTE_NORETURN;
 
+static void unwind_expanded_macro_location (diagnostic_context *, source_location,
+					    const struct line_map **);
+
 /* Name of program invoked, sans directories.  */
 
 const char *progname;
@@ -254,10 +266,138 @@ diagnostic_action_after_output (diagnostic_context *context,
     }
 }
 
+/* Unwind the different macro expansions that lead to the token which
+   location is WHERE and emit diagnostics showing the resulting
+   unwound macro expansion stack. If TOPMOST_EXP_POINT_MAP is
+   non-null, *TOPMOST_EXP_POINT_MAP is set to the map of the
+   expansion point of the top most macro of the stack. This must be
+   an ordinary map.  */
+
+static void
+unwind_expanded_macro_location (diagnostic_context *context,
+				source_location where,
+				const struct line_map **topmost_exp_point_map)
+{
+  const struct line_map *map, *resolved_map;
+  bool unwind = true;
+  source_location resolved_location;
+  VEC(loc_t, heap) *loc_vec;
+  unsigned ix, len;
+  loc_t loc, *iter;
+
+  map = linemap_lookup (line_table, where);
+  if (!linemap_macro_expansion_map_p (map))
+    return;
+
+  loc_vec = VEC_alloc (loc_t, heap, 4);
+
+  /* Let's unwind the stack of macros that got expanded and that led
+     to the token which location is WHERE. We are going to store the
+     stack into MAP_VEC, so that we can later walk MAP_VEC backward to
+     display a somewhat meaningful trace of the macro expansion
+     history to the user.  Note that the deepest macro expansion is
+     going to be store at the beginning of MAP_VEC.  */
+  while (unwind)
+    {
+      loc.where = where;
+      loc.map = map;
+      VEC_safe_push (loc_t, heap, loc_vec, &loc);
+
+      /* WHERE is the location of a token inside the expansion of a
+	 macro. MAP is the map holding the locations of that macro
+	 expansion. Let's get the location of the token inside the
+	 *definition* of the macro of MAP, that got expanded at
+	 WHERE. This is basically how we go "up" in the stack of
+	 macro expansions that led to WHERE.  */
+      resolved_location =
+	linemap_macro_map_loc_to_def_point (map, where, false);
+      resolved_map = linemap_lookup (line_table, resolved_location);
+
+      /* If the token at RESOLVED_LOCATION [at macro definition point]
+	 is itself inside an expanded macro then we keep unwinding the
+	 expansion stack by tracing the "parent macro" that got expanded
+	 inside the definition of the macro of MAP...  */
+      if (linemap_macro_expansion_map_p (resolved_map))
+	{
+	  where = resolved_location;
+	  map = resolved_map;
+	}
+      else
+	{
+	  /* Otherwise, let's consider the location of the expansion
+	     point of the macro of MAP. Keep in mind that MAP is a
+	     macro expansion map. To get a "normal map" (i.e a non
+	     macro expansion map) and be done with the unwinding, we
+	     must either consider the location of the location
+	     expansion point of the macro or the location of the token
+	     inside the macro definition that got expanded to
+	     WHERE.  */
+	  where =
+	    linemap_macro_map_loc_to_exp_point (map, where);
+	  map = linemap_lookup (line_table, where);
+	}
+      if (!linemap_macro_expansion_map_p (map))
+	unwind = false;
+    }
+
+  if (topmost_exp_point_map)
+    *topmost_exp_point_map = map;
+
+  /* Walk the map_vec and print the macro expansion stack.  */
+    len = VEC_length (loc_t, loc_vec);
+  for (ix = 0;
+       len && ix < len;
+       ++ix)
+    {
+      expanded_location def_loc, exp_loc;
+      const struct line_map *def_point_map = NULL,
+	*exp_point_map = NULL;
+
+      iter = VEC_index (loc_t, loc_vec, ix);
+
+      /* Okay, now here is what we want. For each token resulting
+	 from macro expansion we want to show:
+         1/ where in the definition of the macro the token comes from.
+
+         2/ where the macro got expanded.  */
+
+      /* Expand the location iter->where into the locus 1/ of the
+	 comment above.  */
+      def_loc =
+	linemap_expand_location_full (line_table, iter->where,
+				      LRK_MACRO_PARM_REPLACEMENT_POINT,
+				      &def_point_map);
+
+      /* Expand the location of the expansion point of the macro
+	 which expansion gave the token at represented by
+	 def_loc. This is the locus 2/ of the earlier comment.  */
+      exp_loc =
+	linemap_expand_location_full (line_table,
+				      MACRO_MAP_EXPANSION_POINT_LOCATION
+				      (iter->map),
+				      LRK_MACRO_PARM_REPLACEMENT_POINT,
+				      &exp_point_map);
+
+      if (!LINEMAP_SYSP (resolved_map))
+	{
+	  pp_verbatim (context->printer,
+		       "\nIn macro '%s' at %s:%d:%d",
+		       linemap_map_get_macro_name (iter->map),
+		       LINEMAP_FILE (def_point_map),
+		       def_loc.line, def_loc.column);
+	  pp_verbatim (context->printer,
+		       "\n    Expanded at %s:%d:%d",
+		       LINEMAP_FILE (exp_point_map),
+		       exp_loc.line, exp_loc.column);
+	}
+    }
+  VEC_free (loc_t, heap, loc_vec);
+}
+
 void
-diagnostic_report_current_module (diagnostic_context *context)
+diagnostic_report_current_module (diagnostic_context *context, location_t where)
 {
-  const struct line_map *map;
+  const struct line_map *map = NULL;
 
   if (pp_needs_newline (context->printer))
     {
@@ -265,10 +405,13 @@ diagnostic_report_current_module (diagnostic_context *context)
       pp_needs_newline (context->printer) = false;
     }
 
-  if (input_location <= BUILTINS_LOCATION)
+  if (where <= BUILTINS_LOCATION)
     return;
 
-  map = linemap_lookup (line_table, input_location);
+  linemap_expand_location_full (line_table, where,
+				LRK_MACRO_PARM_REPLACEMENT_POINT,
+				&map);
+
   if (map && diagnostic_last_module_changed (context, map))
     {
       diagnostic_set_last_module (context, map);
@@ -301,7 +444,7 @@ void
 default_diagnostic_starter (diagnostic_context *context,
 			    diagnostic_info *diagnostic)
 {
-  diagnostic_report_current_module (context);
+  diagnostic_report_current_module (context, diagnostic->location);
   pp_set_prefix (context->printer, diagnostic_build_prefix (context,
 							    diagnostic));
 }
@@ -310,6 +453,7 @@ void
 default_diagnostic_finalizer (diagnostic_context *context,
 			      diagnostic_info *diagnostic ATTRIBUTE_UNUSED)
 {
+  unwind_expanded_macro_location (context, diagnostic->location, NULL);
   pp_destroy_prefix (context->printer);
 }
 
diff --git a/gcc/diagnostic.h b/gcc/diagnostic.h
index 8074354..4b1265b 100644
--- a/gcc/diagnostic.h
+++ b/gcc/diagnostic.h
@@ -253,7 +253,7 @@ extern diagnostic_context *global_dc;
 /* Diagnostic related functions.  */
 extern void diagnostic_initialize (diagnostic_context *, int);
 extern void diagnostic_finish (diagnostic_context *);
-extern void diagnostic_report_current_module (diagnostic_context *);
+extern void diagnostic_report_current_module (diagnostic_context *, location_t);
 
 /* Force diagnostics controlled by OPTIDX to be kind KIND.  */
 extern diagnostic_t diagnostic_classify_diagnostic (diagnostic_context *,
diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist15.C b/gcc/testsuite/g++.dg/cpp0x/initlist15.C
index b75cc81..cca56b1 100644
--- a/gcc/testsuite/g++.dg/cpp0x/initlist15.C
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist15.C
@@ -2,6 +2,7 @@
 
 // Just discard errors pointing at header files
 // { dg-prune-output "include" }
+// { dg-prune-output "        from" }
 
 #include <vector>
 #include <typeinfo>
diff --git a/gcc/testsuite/g++.old-deja/g++.robertl/eb43.C b/gcc/testsuite/g++.old-deja/g++.robertl/eb43.C
index 1dc4328..bd784b1 100644
--- a/gcc/testsuite/g++.old-deja/g++.robertl/eb43.C
+++ b/gcc/testsuite/g++.old-deja/g++.robertl/eb43.C
@@ -6,6 +6,10 @@
 
 // { dg-prune-output "note" }
 
+// Discard errors pointing at header files
+// { dg-prune-output "In file included from" }
+// { dg-prune-output "        from" }
+
 #include <vector>
 #include <algorithm>
 #include <functional>
diff --git a/gcc/testsuite/g++.old-deja/g++.robertl/eb79.C b/gcc/testsuite/g++.old-deja/g++.robertl/eb79.C
index 1c1ad3e..60cc713 100644
--- a/gcc/testsuite/g++.old-deja/g++.robertl/eb79.C
+++ b/gcc/testsuite/g++.old-deja/g++.robertl/eb79.C
@@ -1,5 +1,9 @@
 // { dg-do assemble  }
 // { dg-prune-output "note" }
+
+// Discard errors pointing at header files
+// { dg-prune-output "In file included from" }
+// { dg-prune-output "        from" }
 // Makes bogus x86 assembly code.
 #include <iostream>
 
diff --git a/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-1.c b/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-1.c
new file mode 100644
index 0000000..a087050
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-1.c
@@ -0,0 +1,30 @@
+/*
+   { dg-options "-ftrack-macro-expansion=1" }
+   { dg-do compile }
+*/
+
+#define OPERATE(OPRD1, OPRT, OPRD2) \
+do \
+{ \
+ OPRD1 OPRT OPRD2; \
+} while (0)
+
+#define SHIFTL(A,B) \
+  OPERATE (A,<<,B) /* { dg-error "invalid operands to binary <<" } */
+
+void
+foo ()
+{
+  SHIFTL (0.1,0.2);
+}
+
+/*
+ { dg-message "macro 'OPERATE'\[^\n\r\]*:9:8" "In macro OPERATE" { target *-*-* } 0 }
+{ dg-message "Expanded at\[^\n\r\]*:13:3" "OPERATE expansion point" { target *-*-* } 0 }
+
+ { dg-message "macro 'SHIFTL'\[^\n\r\]*:13:14" "In macro SHIFTL" { target *-*-* } 0 }
+
+{ dg-message "Expanded at\[^\n\r\]*:18:3" "SHIFTL expansion point" { target *-*-* } 0 }
+
+
+*/
diff --git a/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-2.c b/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-2.c
new file mode 100644
index 0000000..0f15875
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-2.c
@@ -0,0 +1,31 @@
+/* 
+   { dg-options "-ftrack-macro-expansion=1" }
+   { dg-do compile }
+*/
+
+#define OPERATE(OPRD1, OPRT, OPRD2) \
+ OPRD1 OPRT OPRD2;
+
+#define SHIFTL(A,B) \
+  OPERATE (A,<<,B) /* { dg-error "invalid operands to binary <<" } */
+
+#define MULT(A) \
+  SHIFTL (A,1)
+
+void
+foo ()
+{
+  MULT (1.0);/* 1.0 << 1;*/
+}
+
+/*
+  { dg-message "macro 'OPERATE'\[^\n\r\]*:7:8*" "In macro OPERATE" { target *-*-* } 0 }
+  { dg-message "Expanded at\[^\n\r\]*:10:3" "OPERATE expansion point" { target *-*-* } 0 }
+
+  { dg-message "macro 'SHIFTL'\[^\n\r\]*:10:14" "In macro SHIFTL" { target *-*-* } 0 }
+{ dg-message "Expanded at\[^\n\r\]*:13:3" "SHIFTL expansion point" { target *-*-* } 0 }
+
+  { dg-message "macro 'MULT'\[^\n\r\]*:13:3" "In macro MULT" { target *-*-* } 0 }
+{ dg-message "Expanded at\[^\n\r\]*:18:3" "MULT expansion point" { target *-*-* } 0 }
+
+ */
diff --git a/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-3.c b/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-3.c
new file mode 100644
index 0000000..0b5c662
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-3.c
@@ -0,0 +1,18 @@
+/*
+  { dg-options "-fshow-column -ftrack-macro-expansion=1" }
+  { dg-do compile }
+ */
+
+#define SQUARE(A) A * A
+
+void
+foo()
+{
+  SQUARE (1 << 0.1); /* { dg-error "16:invalid operands to binary <<" } */
+}
+
+/*
+{ dg-message "macro 'SQUARE'\[^\n\r\]*:6:19" "In macro SQUARE" { target *-*-* } 0 }
+{ dg-message "Expanded at\[^\n\r\]*:11:3" "SQUARE expansion point" { target *-*-* } 0 }
+
+*/
diff --git a/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-4.c b/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-4.c
new file mode 100644
index 0000000..f9e4c2d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cpp/macro-exp-tracking-4.c
@@ -0,0 +1,19 @@
+/*
+  { dg-options "-fshow-column -ftrack-macro-expansion=2" }
+  { dg-do compile }
+ */
+
+#define SQUARE(A) A * A
+
+void
+foo()
+{
+  SQUARE (1 << 0.1); /* { dg-error "13:invalid operands to binary <<" } */
+}
+
+/*
+
+{ dg-message "macro 'SQUARE'\[^\n\r\]*:6:19" "In macro SQUARE" { target *-*-* } 0 }
+{ dg-message "Expanded at\[^\n\r\]*:11:3" "SQUARE expansion point" { target *-*-* } 0 }
+
+*/
diff --git a/gcc/testsuite/gcc.target/i386/sse-vect-types.c b/gcc/testsuite/gcc.target/i386/sse-vect-types.c
index 9cb6f3e..ce70125 100644
--- a/gcc/testsuite/gcc.target/i386/sse-vect-types.c
+++ b/gcc/testsuite/gcc.target/i386/sse-vect-types.c
@@ -1,6 +1,12 @@
 /* { dg-do compile } */
 /* { dg-options "-O0 -msse2" } */
 
+
+/*
+   Just discard diagnostic prolog about errors in include files
+   { dg-prune-output "In file included from" }
+*/
+
 #include <xmmintrin.h>
 
 __m128d foo1(__m128d z, __m128d  a, int N) { 
diff --git a/gcc/tree-diagnostic.c b/gcc/tree-diagnostic.c
index b456a2a..cbfd81c 100644
--- a/gcc/tree-diagnostic.c
+++ b/gcc/tree-diagnostic.c
@@ -35,7 +35,7 @@ void
 diagnostic_report_current_function (diagnostic_context *context,
 				    diagnostic_info *diagnostic)
 {
-  diagnostic_report_current_module (context);
+  diagnostic_report_current_module (context, diagnostic->location);
   lang_hooks.print_error_function (context, input_filename, diagnostic);
 }
 
-- 
        Dodji