The following proposed change adds a new mode of operation where
the discriminator field in DWARF debugging information is set from
information provided by a language front-end to discriminate
between distinct code instances coming from instances of a given
template. (Currently the discriminator is set by assigning
arbitrary distinct identifiers to each basic block associated with
a single source location).
This is intended primarily for the Ada language front-end (further
changes, to be submitted shortly, will enable the new mode of
operation under control of appropriate switches), in order to
allow per-instance source coverage analysis of generics. However
this might also be useful for other language front-ends, e.g. with
C++ templates.
Change tested on x86_64-linux. OK to commit?
2012-08-08 Thomas Quinot <qui...@adacore.com>
gcc/
* common.opt (flag_debug_instances): Define new internal flag.
* final.c (notice_source_line): If flag_debug_instances is set,
set discriminator to current instance id.
* tree-cfg.c (assign_discriminator): If flag_debug_instances is set,
nothing to do here.
* input.h (LOCATION_INSTANCE): New macro to retrieve instance id.
* emit-rtl.c (insn_instance): New function to retrieve instance id.
* rtl.h (insn_instance): Declare.
libcpp/
* include/line_map.h (struct line_map_ordinary): Add instance field.
(expanded_location): Ditto.
(ORDINARY_MAP_INSTANCE): Define.
* line-map.c (linemap_expand_location): Set instance field in expanded
location from same in set.
Index: gcc/final.c
===================================================================
--- gcc/final.c (révision 193884)
+++ gcc/final.c (copie de travail)
@@ -2894,6 +2894,10 @@
{
filename = insn_file (insn);
linenum = insn_line (insn);
+ if (flag_debug_instances)
+ {
+ discriminator = insn_instance (insn);
+ }
}
if (filename == NULL)
Index: gcc/input.h
===================================================================
--- gcc/input.h (révision 193884)
+++ gcc/input.h (copie de travail)
@@ -51,6 +51,7 @@
#define LOCATION_FILE(LOC) ((expand_location (LOC)).file)
#define LOCATION_LINE(LOC) ((expand_location (LOC)).line)
#define LOCATION_COLUMN(LOC)((expand_location (LOC)).column)
+#define LOCATION_INSTANCE(LOC) ((expand_location (LOC)).instance)
#define LOCATION_LOCUS(LOC) \
((IS_ADHOC_LOC(LOC)) ? get_location_from_adhoc_loc (line_table, LOC) : (LOC))
#define LOCATION_BLOCK(LOC) \
Index: gcc/emit-rtl.c
===================================================================
--- gcc/emit-rtl.c (révision 193884)
+++ gcc/emit-rtl.c (copie de travail)
@@ -6007,6 +6007,14 @@
return LOCATION_FILE (INSN_LOCATION (insn));
}
+/* Return source instance of the statement that produced this insn. */
+
+int
+insn_instance (const_rtx insn)
+{
+ return LOCATION_INSTANCE (INSN_LOCATION (insn));
+}
+
/* Return true if memory model MODEL requires a pre-operation (release-style)
barrier or a post-operation (acquire-style) barrier. While not universal,
this function matches behavior of several targets. */
Index: gcc/common.opt
===================================================================
--- gcc/common.opt (révision 193884)
+++ gcc/common.opt (copie de travail)
@@ -158,6 +158,11 @@
Variable
int flag_debug_asm
+; For generic instances, include complete instantiation chain in debugging
+; information (ELF discriminators).
+Variable
+int flag_debug_instances = 0
+
; -dP causes the rtl to be emitted as a comment in assembly.
Variable
int flag_dump_rtl_in_asm
Index: gcc/rtl.h
===================================================================
--- gcc/rtl.h (révision 193884)
+++ gcc/rtl.h (copie de travail)
@@ -1917,6 +1917,7 @@
/* In emit-rtl.c */
extern int insn_line (const_rtx);
extern const char * insn_file (const_rtx);
+extern int insn_instance (const_rtx);
extern tree insn_scope (const_rtx);
extern location_t prologue_location, epilogue_location;
Index: gcc/tree-cfg.c
===================================================================
--- gcc/tree-cfg.c (révision 193884)
+++ gcc/tree-cfg.c (copie de travail)
@@ -768,7 +768,7 @@
{
gimple first_in_to_bb, last_in_to_bb;
- if (locus == 0 || bb->discriminator != 0)
+ if (locus == 0 || bb->discriminator != 0 || flag_debug_instances)
return;
first_in_to_bb = first_non_label_stmt (bb);
Index: libcpp/include/line-map.h
===================================================================
--- libcpp/include/line-map.h (révision 193884)
+++ libcpp/include/line-map.h (copie de travail)
@@ -85,6 +85,12 @@
/* Number of the low-order source_location bits used for a column number. */
unsigned int column_bits : 8;
+
+ /* For languages that have the notion of instantiating a given template
+ multiple times, different line_maps can be allocated for each instance,
+ in which case this index identifies the specific instance. Set to 0
+ otherwise. */
+ int instance;
};
/* This is the highest possible source location encoded within an
@@ -230,6 +236,9 @@
#define ORDINARY_MAP_NUMBER_OF_COLUMN_BITS(MAP) \
linemap_check_ordinary (MAP)->d.ordinary.column_bits
+#define ORDINARY_MAP_INSTANCE(MAP) \
+ linemap_check_ordinary (MAP)->d.ordinary.instance
+
#define MACRO_MAP_MACRO(MAP) (MAP)->d.macro.macro
#define MACRO_MAP_NUM_MACRO_TOKENS(MAP) (MAP)->d.macro.n_tokens
@@ -638,6 +647,9 @@
/* In a system header?. */
bool sysp;
+
+ /* Instance id */
+ int instance;
} expanded_location;
/* This is enum is used by the function linemap_resolve_location
Index: libcpp/line-map.c
===================================================================
--- libcpp/line-map.c (révision 193884)
+++ libcpp/line-map.c (copie de travail)
@@ -1395,6 +1395,7 @@
xloc.line = SOURCE_LINE (map, loc);
xloc.column = SOURCE_COLUMN (map, loc);
xloc.sysp = LINEMAP_SYSP (map) != 0;
+ xloc.instance = ORDINARY_MAP_INSTANCE(map);
}
return xloc;
--
Thomas Quinot, Ph.D. ** qui...@adacore.com ** Senior Software Engineer
AdaCore -- Paris, France -- New York, USA
