This patch adds line_info debug information support to .BTF.ext
sections.
Line info information is used by the BPF verifier to improve error
reporting and give more precise source core referenced errors.
gcc/Changelog:
* config/bpf/bpf-protos.h (bpf_output_call): Change prototype.
* config/bpf/bpf.cc (bpf_output_call): Change to adapt operands
and return
the instruction template instead of emmidiatelly emit asm and
not allow proper final expected execution flow.
(bpf_output_line_info): Add function to introduce line info
entries in respective structures
(bpf_asm_out_unwind_emit): Add function as hook to
TARGET_ASM_UNWIND_EMIT. This hook is called before any
instruction is emitted.
* config/bpf/bpf.md: Change calls to bpf_output_call.
* config/bpf/btfext-out.cc (struct btf_ext_lineinfo): Add fields
to struct.
(bpf_create_lineinfo, btf_add_line_info_for): Add support
function to insert line_info data in respective structures.
(output_btfext_line_info): Function to emit line_info data in
.BTF.ext section.
(btf_ext_output): Call output_btfext_line_info.
* config/bpf/btfext-out.h: Add prototype for
btf_add_line_info_for.
---
gcc/config/bpf/bpf-protos.h | 2 +-
gcc/config/bpf/bpf.cc | 103 ++++++++++++++---
gcc/config/bpf/bpf.md | 4 +-
gcc/config/bpf/btfext-out.cc | 108 +++++++++++++++++-
gcc/config/bpf/btfext-out.h | 4 +
.../gcc.target/bpf/btfext-funcinfo.c | 3 +-
6 files changed, 203 insertions(+), 21 deletions(-)
diff --git a/gcc/config/bpf/bpf-protos.h b/gcc/config/bpf/bpf-protos.h
index b4866d34209..ddaca50af69 100644
--- a/gcc/config/bpf/bpf-protos.h
+++ b/gcc/config/bpf/bpf-protos.h
@@ -23,7 +23,7 @@ along with GCC; see the file COPYING3. If not see
/* Routines implemented in bpf.cc. */
extern HOST_WIDE_INT bpf_initial_elimination_offset (int, int);
-extern const char *bpf_output_call (rtx);
+extern const char *bpf_output_call (const char *templ, rtx *, int
target_index);
extern void bpf_target_macros (cpp_reader *);
extern void bpf_print_operand (FILE *, rtx, int);
extern void bpf_print_operand_address (FILE *, rtx);
diff --git a/gcc/config/bpf/bpf.cc b/gcc/config/bpf/bpf.cc
index d9141dd625a..f1a8eb8d62c 100644
--- a/gcc/config/bpf/bpf.cc
+++ b/gcc/config/bpf/bpf.cc
@@ -754,14 +754,12 @@ bpf_output_destructor (rtx symbol, int priority
ATTRIBUTE_UNUSED)
bpf.md. */
const char *
-bpf_output_call (rtx target)
+bpf_output_call (const char *templ, rtx *operands, int target_index)
{
- rtx xops[1];
-
+ rtx target = operands[target_index];
switch (GET_CODE (target))
{
case CONST_INT:
- output_asm_insn ("call\t%0", &target);
break;
case SYMBOL_REF:
{
@@ -774,26 +772,20 @@ bpf_output_call (rtx target)
{
tree attr_args = TREE_VALUE (attr);
- xops[0] = GEN_INT (TREE_INT_CST_LOW (TREE_VALUE (attr_args)));
- output_asm_insn ("call\t%0", xops);
- }
- else
- output_asm_insn ("call\t%0", &target);
+ operands[target_index] = GEN_INT (TREE_INT_CST_LOW (TREE_VALUE
(attr_args)));
+ }
break;
}
default:
- if (TARGET_XBPF)
- output_asm_insn ("call\t%0", &target);
- else
+ if (!TARGET_XBPF)
{
error ("indirect call in function, which are not supported by eBPF");
- output_asm_insn ("call 0", NULL);
+ operands[target_index] = GEN_INT (0);
}
break;
}
-
- return "";
+ return templ;
}
const char *
@@ -1144,6 +1136,87 @@ bpf_debug_unwind_info ()
#undef TARGET_DEBUG_UNWIND_INFO
#define TARGET_DEBUG_UNWIND_INFO bpf_debug_unwind_info
+/* Create a BTF.ext line_info entry. */
+
+static void
+bpf_output_line_info (FILE *asm_out_file, rtx_insn *insn)
+{
+ static unsigned int line_info_label = 1;
+ static tree cfun_decl = NULL_TREE;
+ static bool func_start_added = false;
+ const char *label = NULL;
+ unsigned int loc = 0;
+ const char *filename = NULL;
+ unsigned int line = 0;
+ unsigned int column = 0;
+
+ if(!btf_debuginfo_p ())
+ return;
+
+ gcc_assert (insn != NULL_RTX);
+
+ if (current_function_decl != cfun_decl
+ && GET_CODE (insn) == NOTE)
+ {
+ label = current_function_func_begin_label;
+ loc = DECL_SOURCE_LOCATION (current_function_decl);
+ filename = LOCATION_FILE (loc);
+ line = LOCATION_LINE (loc);
+ column = LOCATION_COLUMN (loc);
+ func_start_added = true;
+ }
+ else
+ {
+ if (GET_CODE (insn) == NOTE)
+ return;
+
+ /* Already added a label for this location. This might not be fully
+ acurate but it is better then adding 2 entries on the same location,
+ which is imcompatible with the verifier expectations. */
+ if (func_start_added == true)
+ {
+ func_start_added = false;
+ return;
+ }
+
+ loc = INSN_LOCATION (insn);
+ filename = LOCATION_FILE (loc);
+ line = LOCATION_LINE (loc);
+ column = LOCATION_COLUMN (loc);
+
+ if (filename == NULL || line == 0)
+ return;
+
+ char tmp_label[25];
+ sprintf(tmp_label, "LI%u", line_info_label);
+ ASM_OUTPUT_LABEL (asm_out_file, tmp_label);
+ line_info_label += 1;
+ label = CONST_CAST (char *, ggc_strdup (tmp_label));
+ }
+
+ cfun_decl = current_function_decl;
+
+ if (filename != NULL && line != 0)
+ btf_add_line_info_for (label, filename, line, column);
+}
+
+
+/* This hook is defined as a way for BPF target to create a label before each
+ * emitted instruction and emit line_info information. This data is later
output
+ * in .BTF.ext section.
+ * This approach expects TARGET_EMIT_BEFORE_INSN to be returing TRUE as
+ * this function needs to be called before the instruction is emitted. Current
+ * default behaviour returns TRUE and the hook is left undefined. */
+
+static void
+bpf_asm_out_unwind_emit (FILE *asm_out_file, rtx_insn *insn)
+{
+ bpf_output_line_info (asm_out_file, insn);
+}
+
+#undef TARGET_ASM_UNWIND_EMIT
+#define TARGET_ASM_UNWIND_EMIT bpf_asm_out_unwind_emit
+
/* Output assembly directives to assemble data of various sized and
alignments. */
diff --git a/gcc/config/bpf/bpf.md b/gcc/config/bpf/bpf.md
index 95859328d25..3fdf81b86a6 100644
--- a/gcc/config/bpf/bpf.md
+++ b/gcc/config/bpf/bpf.md
@@ -546,7 +546,7 @@
;; operands[2] is next_arg_register
;; operands[3] is struct_value_size_rtx.
""
- { return bpf_output_call (operands[0]); }
+ { return bpf_output_call ("call\t%0", operands, 0); }
[(set_attr "type" "jmp")])
(define_expand "call_value"
@@ -569,7 +569,7 @@
;; operands[3] is next_arg_register
;; operands[4] is struct_value_size_rtx.
""
- { return bpf_output_call (operands[1]); }
+ { return bpf_output_call ("call\t%1", operands, 1); }
[(set_attr "type" "jmp")])
(define_insn "sibcall"
diff --git a/gcc/config/bpf/btfext-out.cc b/gcc/config/bpf/btfext-out.cc
index ff1fd0739f1..42ec48e394e 100644
--- a/gcc/config/bpf/btfext-out.cc
+++ b/gcc/config/bpf/btfext-out.cc
@@ -32,6 +32,7 @@
#include "rtl.h"
#include "tree-pretty-print.h"
#include "cgraph.h"
+#include "toplev.h" /* get_src_pwd */
#include "btfext-out.h"
@@ -124,7 +125,8 @@ struct GTY ((chain_next ("%h.next"))) btf_ext_funcinfo
/* A lineinfo record, in the .BTF.ext lineinfo section. */
struct GTY ((chain_next ("%h.next"))) btf_ext_lineinfo
{
- uint32_t insn_off; /* Offset of the instruction. */
+ const char *insn_label; /* Instruction label. */
+ const char *file_name; /* Source-code file name. */
uint32_t file_name_off; /* Offset of file name in BTF string table. */
uint32_t line_off; /* Offset of source line in BTF string table. */
uint32_t line_col; /* Line number (bits 31-11) and column (11-0). */
@@ -235,6 +237,26 @@ bpf_create_or_find_funcinfo (const char *fnname, const
char *sec_name,
return *head;
}
+/* Function to create a lineinfo node in info. */
+
+static struct btf_ext_lineinfo *
+bpf_create_lineinfo (const char *sec_name, btf_ext_info_sec **in_sec = NULL)
+{
+ struct btf_ext_info_sec *sec_elem =
+ btfext_info_sec_find_or_add (sec_name, true);
+
+ if (in_sec != NULL)
+ *in_sec = sec_elem;
+
+ struct btf_ext_lineinfo **head =
+ SEARCH_NODE_AND_RETURN(struct btf_ext_lineinfo,
+ sec_elem->line_info.head,
+ false);
+ *head = ggc_cleared_alloc<struct btf_ext_lineinfo> ();
+
+ return *head;
+}
+
/* Function to create a core_reloc node in info. */
static struct btf_ext_core_reloc *
@@ -429,6 +451,47 @@ btf_validate_funcinfo (btf_ext_info_sec *sec)
}
}
+struct btf_ext_lineinfo *
+btf_add_line_info_for (const char *label, const char *filename,
+ unsigned int line, unsigned int column)
+{
+ const char *sec_name = decl_section_name (current_function_decl);
+
+ if (sec_name == NULL)
+ sec_name = ".text";
+
+ struct btf_ext_info_sec *sec = NULL;
+ struct btf_ext_lineinfo *info =
+ bpf_create_lineinfo (sec_name, &sec);
+
+ unsigned int line_column = ((0x000fffff & line) << 12)
+ | (0x00000fff & column);
+
+ info->insn_label = label;
+
+ if (!IS_DIR_SEPARATOR (filename[0]))
+ {
+ char full_filename[256];
+
+ /* Filename is a relative path. */
+ const char * cu_pwd = get_src_pwd ();
+ gcc_assert (strlen (cu_pwd) + strlen (filename) + 2 < 256);
+
+ sprintf(full_filename, "%s%c%s", cu_pwd, DIR_SEPARATOR, filename);
+ info->file_name = ggc_strdup (full_filename);
+ }
+ else
+ /* Filename is an absolute path. */
+ info->file_name = ggc_strdup (filename);
+
+ info->file_name_off = btf_ext_add_string (info->file_name);
+ info->line_off = 0;
+ info->line_col = line_column;
+
+ sec->line_info.num_info += 1;
+ return info;
+}
+
/* Compute the section size in section for func_info, line_info and core_info
regions of .BTF.ext. */
@@ -537,6 +600,48 @@ output_btfext_func_info (struct btf_ext_info_sec *sec)
}
}
+/* Outputs line_info region on .BTF.ext. */
+
+static void
+output_btfext_line_info (struct btf_ext_info_sec *sec)
+{
+ unsigned int str_aux_off = ctfc_get_strtab_len (ctf_get_tu_ctfc (),
+ CTF_STRTAB);
+ bool executed = false;
+ while (sec != NULL)
+ {
+ uint32_t count = 0;
+ if (sec->line_info.num_info > 0)
+ {
+ if (executed == false && (executed = true))
+ dw2_asm_output_data (4, 16, "LineInfo entry size");
+ dw2_asm_output_data (4, sec->sec_name_off + str_aux_off,
+ "LineInfo section string for %s",
+ sec->sec_name);
+ dw2_asm_output_data (4, sec->line_info.num_info, "Number of entries");
+
+ struct btf_ext_lineinfo *elem = sec->line_info.head;
+ while (elem != NULL)
+ {
+ count += 1;
+ dw2_asm_output_offset (4, elem->insn_label, NULL, "insn_label");
+
+ unsigned int file_name_off = btf_ext_add_string (elem->file_name);
+ dw2_asm_output_data (4, file_name_off + str_aux_off,
+ "file_name_off");
+ dw2_asm_output_data (4, elem->line_off, "line_off");
+ dw2_asm_output_data (4, elem->line_col, "(line, col) (%u, %u)",
+ elem->line_col >> 12,
+ elem->line_col & 0x00000fff);
+ elem = elem->next;
+ }
+ }
+
+ gcc_assert (count == sec->line_info.num_info);
+ sec = sec->next;
+ }
+}
+
/* Output all CO-RE relocation sections. */
static void
@@ -609,6 +714,7 @@ btf_ext_output (void)
{
output_btfext_header ();
output_btfext_func_info (btf_ext);
+ output_btfext_line_info (btf_ext);
if (TARGET_BPF_CORE)
output_btfext_core_sections ();
diff --git a/gcc/config/bpf/btfext-out.h b/gcc/config/bpf/btfext-out.h
index b36309475c9..9c6848324e7 100644
--- a/gcc/config/bpf/btfext-out.h
+++ b/gcc/config/bpf/btfext-out.h
@@ -99,6 +99,10 @@ extern int bpf_core_get_sou_member_index (ctf_container_ref,
const tree);
struct btf_ext_funcinfo *btf_add_func_info_for (tree decl,
const char *label);
+struct btf_ext_lineinfo *
+btf_add_line_info_for (const char *label, const char *filename,
+ unsigned int line, unsigned int column);
+
unsigned int btf_ext_add_string (const char *str);
#ifdef __cplusplus
diff --git a/gcc/testsuite/gcc.target/bpf/btfext-funcinfo.c
b/gcc/testsuite/gcc.target/bpf/btfext-funcinfo.c
index 6fdd14574ec..0f1e0ad1e89 100644
--- a/gcc/testsuite/gcc.target/bpf/btfext-funcinfo.c
+++ b/gcc/testsuite/gcc.target/bpf/btfext-funcinfo.c
@@ -39,6 +39,5 @@ int bar_func (struct T *t)
/* { dg-final { scan-assembler-times "ascii \"bar_sec.0\"\[\t
\]+\[^\n\]*btf_aux_string" 1 } } */
/* { dg-final { scan-assembler-times "FuncInfo entry size" 1 } } */
-/* { dg-final { scan-assembler-times ".4byte\t0x1\t# Number of entries" 3 } }
*/
-/* { dg-final { scan-assembler-times ".4byte\t0x2\t# Number of entries" 1 } }
*/
+/* { dg-final { scan-assembler-times "FuncInfo section\[^\n\]*\n\[^0\]*0x1\t#
Number of entries" 2 } } */
/* { dg-final { scan-assembler-times "Required padding" 1 } } */
--
2.30.2
