On Mon, 2018-03-26 at 21:11 +0200, Torsten Polle wrote:
> > Am 26.03.2018 um 18:45 schrieb Sasha Da Rocha Pinheiro <darochapinh
> > e...@wisc.edu>:
> >
> > I have noticed that when we compile out-of-source, the paths
> > returned from libdw are gonna be relative. Otherwise, they show up
> > as full path.
> > Have you noticed it?
> >
> this is the issue that was discussed in [1] and [2].
>
> [1] https://sourceware.org/ml/elfutils-devel/2017-q1/msg00117.html
> [2] https://sourceware.org/ml/elfutils-devel/2017-q2/msg00148.html
It does indeed come up more often, and it is a little confusing.
So I am proposing the following documentation update to hopefully
explain better how to get the absolute path for a file (decl).
Hopefully this helps.
Cheers,
Mark
From e87cfeb2290bff320c7f0a45f93ba571ffe3c58d Mon Sep 17 00:00:00 2001
From: Mark Wielaard <m...@klomp.org>
Date: Thu, 29 Mar 2018 14:09:12 +0200
Subject: [PATCH] libdw: Extend documentation to explain relative file paths
and comp_dir.
Signed-off-by: Mark Wielaard <m...@klomp.org>
---
libdw/ChangeLog | 6 ++++++
libdw/libdw.h | 17 ++++++++++++++---
2 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index f552644..025b24a 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,9 @@
+2018-03-29 Mark Wielaard <m...@klomp.org>
+
+ * libdw.h (dwarf_decl_file): Extend documentation.
+ (dwarf_linesrc): Likewise.
+ (dwarf_filesrc): Likewise.
+
2018-03-06 Mark Wielaard <m...@klomp.org>
* dwarf.h: Add DW_OP_implicit_pointer, DW_OP_addrx, DW_OP_constx,
diff --git a/libdw/libdw.h b/libdw/libdw.h
index ac43ad9..0ca8878 100644
--- a/libdw/libdw.h
+++ b/libdw/libdw.h
@@ -679,11 +679,15 @@ extern int dwarf_linediscriminator (Dwarf_Line *line, unsigned int *discp)
__nonnull_attribute__ (2);
-/* Find line information for address. */
+/* Find line information for address. The returned string is NULL when
+ an error occured, or the file path. The file path is either absolute
+ or relative to the compilation directory. See dwarf_decl_file. */
extern const char *dwarf_linesrc (Dwarf_Line *line,
Dwarf_Word *mtime, Dwarf_Word *length);
-/* Return file information. */
+/* Return file information. The returned string is NULL when
+ an error occured, or the file path. The file path is either absolute
+ or relative to the compilation directory. See dwarf_decl_file. */
extern const char *dwarf_filesrc (Dwarf_Files *file, size_t idx,
Dwarf_Word *mtime, Dwarf_Word *length);
@@ -855,7 +859,14 @@ extern ptrdiff_t dwarf_getfuncs (Dwarf_Die *cudie,
void *arg, ptrdiff_t offset);
-/* Return file name containing definition of the given declaration. */
+/* Return file name containing definition of the given declaration.
+ Of the DECL has an (indirect, see dwarf_attr_integrate) decl_file
+ attribute. The returned file path is either absolute, or relative
+ to the compilation directory. Given the decl DIE, the compilation
+ directory can be retrieved through:
+ dwarf_formstring (dwarf_attr (dwarf_diecu (decl, &cudie, NULL, NULL),
+ DW_AT_comp_dir, &attr));
+ Returns NULL if no decl_file could be found or an error occured. */
extern const char *dwarf_decl_file (Dwarf_Die *decl);
/* Get line number of beginning of given declaration. */
--
1.8.3.1
