Commit graph

6 commits

Author SHA1 Message Date
Austin Clements
8dba66dfeb cmd/link: fix isStmt DWARF info
When CL 147160 introduced function ABIs encoded as symbol versions in
the linker, it became slightly more complicated to look up derived
DWARF symbols. It fixed this by introducing a dwarfFuncSym function to
hide this logic, but missed one derived lookup that was done in the
object reader itself. As a result, we lost the isStmt tables from the
compiler, so every PC was marked as a statement in the DWARF info.

Fix this by moving this derived lookup out of the object reader and
into the DWARF code and calling dwarfFuncSym to get the correctly
versioned symbol.

Should fix the linux-amd64-longtest builder.

Updates #27539.

Change-Id: If40d5ba28bab1918ac4ad18fbb5103666b6d978b
Reviewed-on: https://go-review.googlesource.com/c/149605
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2018-11-14 22:01:38 +00:00
Austin Clements
c5718b6b26 cmd/internal/obj, cmd/link: record ABIs and aliases in Go obj files
This repurposes the "version" field of a symbol reference in the Go
object file format to be an ABI field. Currently, this is just 0 or 1
depending on whether the symbol is static (the linker turns it into a
different internal version number), so it's already only tenuously a
symbol version. We change this to be -1 for static symbols and
otherwise by the ABI number.

This also adds a separate list of ABI alias symbols to be recorded in
the object file. The ABI aliases must be a separate list and not just
part of the symbol definitions because it's possible to have a symbol
defined in one package and the alias "defined" in a different package.
For example, this can happen if a symbol is defined in assembly in one
package and stubbed in a different package. The stub triggers the
generation of the ABI alias, but in a different package from the
definition.

For #27539.

Change-Id: I015c9fe54690c027de6ef77e22b5585976a01587
Reviewed-on: https://go-review.googlesource.com/c/147157
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2018-11-12 20:46:48 +00:00
Alessandro Arzilli
1c8943bd59 cmd/link: move DIE of global variables to their compile unit
The DIEs for global variables were all assigned to the first emitted
compile unit in debug_info, regardless of what it was. Move them
instead to their respective compile units.

Change-Id: If794fa0ba4702f5b959c6e8c16119b16e7ecf6d8
Reviewed-on: https://go-review.googlesource.com/137235
Reviewed-by: Than McIntosh <thanm@google.com>
2018-09-27 11:58:35 +00:00
Alessandro Arzilli
9c833831b2 cmd/link: move dwarf part of DWARF generation before type name mangling
Splits part of dwarfgeneratedebugsyms into a new function,
dwarfGenerateDebugInfo which is called between deadcode elimination
and type name mangling.
This function takes care of collecting and processing the DIEs for
all functions and package-level variables and also generates DIEs
for all types used in the program.

Fixes #23733

Change-Id: I75ef0608fbed2dffc3be7a477f1b03e7e740ec61
Reviewed-on: https://go-review.googlesource.com/111237
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
2018-09-04 17:44:41 +00:00
Austin Clements
d4dda76b5f cmd/link: one DWARF compilation unit per package
Currently, the linker generates one huge DWARF compilation unit for
the entire Go binary. This commit creates a separate compilation unit
and line table per Go package.

We temporarily lose compilation unit PC range information, since it's
now discontiguous, so harder to emit. We'll bring it back in the next
commit.

Beyond being "more traditional", this has various technical
advantages:

* It should speed up line table lookup, since that requires a
  sequential scan of the line table. With this change, a debugger can
  first locate the per-package line table and then scan only that line
  table.

* Once we emit compilation unit PC ranges again, this should also
  speed up various other debugger reverse PC lookups.

* It puts us in a good position to move more DWARF generation into the
  compiler, which could produce at least the CU header, per-function
  line table fragments, and per-function frame unwinding info that the
  linker could simply paste together.

* It will let us record a per-package compiler command-line flags
  (#22168).

Change-Id: Ibac642890984636b3ef1d4b37fe97f4453c2cc84
Reviewed-on: https://go-review.googlesource.com/69973
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-10-12 18:56:23 +00:00
David Crawshaw
9f9bb97420 cmd/link: give the object reader its own package
For #22095

Change-Id: Ie9ae84c758af99ac7daed26d0b3e3b0a47599edd
Reviewed-on: https://go-review.googlesource.com/67315
Run-TryBot: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-10-06 13:33:15 +00:00
Renamed from src/cmd/link/internal/ld/objfile.go (Browse further)