If a function is contained in two sections, for instance if it is
partially cold, it gets a DW_AT_ranges attribute in its DIE rather than
the normal DW_AT_low_pc and DW_AT_high_pc.
There's no way to express this in CodeView, so rather than skipping the
function entirely, use the labels in the first entry in the range list.
gcc/
* dwarf2codeview.cc (write_function): If no DW_AT_low_pc or
DW_AT_high_pc in DIE, handle DW_AT_ranges instead.
* dwarf2out.cc (struct dw_ranges): Move to dwarf2out.h.
(get_AT_range_list): New function.
(get_range_list_labels): New function.
* dwarf2out.h (struct dw_ranges): Move from dwarf2out.cc.
(get_AT_range_list, get_range_list_labels): Add declarations.
---
gcc/dwarf2codeview.cc | 41 +++++++++++++++++++++++-------------
gcc/dwarf2out.cc | 49 ++++++++++++++++++++++++++-----------------
gcc/dwarf2out.h | 21 +++++++++++++++++++
3 files changed, 77 insertions(+), 34 deletions(-)
diff --git a/gcc/dwarf2codeview.cc b/gcc/dwarf2codeview.cc
index 5e8a4ab39e7..e12b65bc67b 100644
--- a/gcc/dwarf2codeview.cc
+++ b/gcc/dwarf2codeview.cc
@@ -3209,29 +3209,40 @@ write_function (codeview_symbol *s)
*/
loc_low = get_AT (s->function.die, DW_AT_low_pc);
- if (!loc_low)
- goto end;
+ loc_high = get_AT (s->function.die, DW_AT_high_pc);
- if (loc_low->dw_attr_val.val_class != dw_val_class_lbl_id)
- goto end;
+ if (loc_low && loc_high)
+ {
+ if (loc_low->dw_attr_val.val_class != dw_val_class_lbl_id)
+ goto end;
- label_low = loc_low->dw_attr_val.v.val_lbl_id;
- if (!label_low)
- goto end;
+ label_low = loc_low->dw_attr_val.v.val_lbl_id;
- rtx_low = gen_rtx_SYMBOL_REF (Pmode, label_low);
+ if (loc_high->dw_attr_val.val_class != dw_val_class_high_pc)
+ goto end;
- loc_high = get_AT (s->function.die, DW_AT_high_pc);
- if (!loc_high)
- goto end;
+ label_high = loc_high->dw_attr_val.v.val_lbl_id;
+ }
+ else
+ {
+ /* If a function is split over multiple sections, such as if it is
+ partially cold, its DIE gets a DW_AT_ranges rather than a
+ DW_AT_low_pc and DW_AT_high_pc.
+ There's no easy way to represent this in CodeView, so just choose the
+ first pair of labels rather than skipping the function entirely. */
- if (loc_high->dw_attr_val.val_class != dw_val_class_high_pc)
- goto end;
+ dw_ranges *ranges = get_AT_range_list (s->function.die, DW_AT_ranges);
- label_high = loc_high->dw_attr_val.v.val_lbl_id;
- if (!label_high)
+ if (!ranges)
+ goto end;
+
+ get_range_list_labels (ranges, &label_low, &label_high);
+ }
+
+ if (!label_low || !label_high)
goto end;
+ rtx_low = gen_rtx_SYMBOL_REF (Pmode, label_low);
rtx_high = gen_rtx_SYMBOL_REF (Pmode, label_high);
/* Output the S_GPROC32_ID / S_LPROC32_ID record. */
diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index a2621ec7c76..97911d6f264 100644
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -3206,25 +3206,6 @@ typedef struct GTY(()) pubname_struct {
}
pubname_entry;
-
-struct GTY(()) dw_ranges {
- const char *label;
- /* If this is positive, it's a block number, otherwise it's a
- bitwise-negated index into dw_ranges_by_label. */
- int num;
- /* If idx is equal to DW_RANGES_IDX_SKELETON, it should be emitted
- into .debug_rnglists section rather than .debug_rnglists.dwo
- for -gsplit-dwarf and DWARF >= 5. */
-#define DW_RANGES_IDX_SKELETON ((1U << 31) - 1)
- /* Index for the range list for DW_FORM_rnglistx. */
- unsigned int idx : 31;
- /* True if this range might be possibly in a different section
- from previous entry. */
- unsigned int maybe_new_sec : 1;
- addr_table_entry *begin_entry;
- addr_table_entry *end_entry;
-};
-
/* A structure to hold a macinfo entry. */
typedef struct GTY(()) macinfo_struct {
@@ -5532,6 +5513,36 @@ get_AT_file (dw_die_ref die, enum dwarf_attribute
attr_kind)
return a ? AT_file (a) : NULL;
}
+dw_ranges *
+get_AT_range_list (dw_die_ref die, enum dwarf_attribute attr_kind)
+{
+ dw_attr_node *a = get_AT (die, attr_kind);
+
+ if (!a)
+ return NULL;
+
+ return &(*ranges_table)[a->dw_attr_val.v.val_offset];
+}
+
+void
+get_range_list_labels (dw_ranges *r, const char **begin, const char **end)
+{
+ int lab_idx = - r->num - 1;
+
+ /* Positive r->num values are block nums, negative values are indexes
+ into ranges_by_label. */
+
+ if (r->num > 0)
+ {
+ *begin = NULL;
+ *end = NULL;
+ return;
+ }
+
+ *begin = (*ranges_by_label)[lab_idx].begin;
+ *end = (*ranges_by_label)[lab_idx].end;
+}
+
/* Return TRUE if the language is C. */
static inline bool
diff --git a/gcc/dwarf2out.h b/gcc/dwarf2out.h
index 27919594bef..60623eee96b 100644
--- a/gcc/dwarf2out.h
+++ b/gcc/dwarf2out.h
@@ -532,4 +532,25 @@ struct GTY((for_user)) dwarf_file_data {
extern struct dwarf_file_data *get_AT_file (dw_die_ref,
enum dwarf_attribute);
+struct GTY(()) dw_ranges {
+ const char *label;
+ /* If this is positive, it's a block number, otherwise it's a
+ bitwise-negated index into dw_ranges_by_label. */
+ int num;
+ /* If idx is equal to DW_RANGES_IDX_SKELETON, it should be emitted
+ into .debug_rnglists section rather than .debug_rnglists.dwo
+ for -gsplit-dwarf and DWARF >= 5. */
+#define DW_RANGES_IDX_SKELETON ((1U << 31) - 1)
+ /* Index for the range list for DW_FORM_rnglistx. */
+ unsigned int idx : 31;
+ /* True if this range might be possibly in a different section
+ from previous entry. */
+ unsigned int maybe_new_sec : 1;
+ addr_table_entry *begin_entry;
+ addr_table_entry *end_entry;
+};
+
+extern dw_ranges *get_AT_range_list (dw_die_ref, enum dwarf_attribute);
+extern void get_range_list_labels (dw_ranges *, const char **, const char **);
+
#endif /* GCC_DWARF2OUT_H */
--
2.45.2
