[PATCH] perf jit: Fix inaccurate DWARF line table

From: Nick Gasson
Date: Thu May 28 2020 - 01:19:32 EST


Fix an issue where addresses in the DWARF line table are offset by
-0x40 (GEN_ELF_TEXT_OFFSET). This can be seen with `objdump -S` on the
ELF files after perf inject.

Signed-off-by: Nick Gasson <nick.gasson@xxxxxxx>
---
tools/perf/util/genelf_debug.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/genelf_debug.c b/tools/perf/util/genelf_debug.c
index 30e9f618f6cd..dd40683bd4c0 100644
--- a/tools/perf/util/genelf_debug.c
+++ b/tools/perf/util/genelf_debug.c
@@ -342,7 +342,7 @@ static void emit_lineno_info(struct buffer_ext *be,
*/

/* start state of the state machine we take care of */
- unsigned long last_vma = code_addr;
+ unsigned long last_vma = 0;
char const *cur_filename = NULL;
unsigned long cur_file_idx = 0;
int last_line = 1;
@@ -473,7 +473,7 @@ jit_process_debug_info(uint64_t code_addr,
ent = debug_entry_next(ent);
}
add_compilation_unit(di, buffer_ext_size(dl));
- add_debug_line(dl, debug, nr_debug_entries, 0);
+ add_debug_line(dl, debug, nr_debug_entries, GEN_ELF_TEXT_OFFSET);
add_debug_abbrev(da);
if (0) buffer_ext_dump(da, "abbrev");

--
2.26.2