tree 1952be0eabd0b29a707ceb022f9a3c1caf3ce6dd
parent c9581de3804f94c5a74ce14befce5c57368722b9
author Ian Lance Taylor <iant@golang.org> 1550279252 -0800
committer Ian Lance Taylor <iant@golang.org> 1551306840 +0000

internal/cpu, runtime, runtime/pprof: handle function descriptors

When using PPC64 ELF ABI v1 a function address is not a PC, but is the
address of a function descriptor.  The first field in the function
descriptor is the actual PC (see
http://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#FUNC-DES).
The libbacktrace library knows about this, and libgo uses actual PC
values consistently except for the helper function funcPC that appears
in both runtime and runtime/pprof.

This patch fixes funcPC by recording, in the internal/cpu package,
whether function descriptors are being used.  We have to check for
function descriptors using a C compiler check, because GCC can be
configured using --with-abi to select the ELF ABI to use.

Fixes https://gcc.gnu.org/PR89172

Change-Id: I97d7bfbfaf35b3909c5f68f183ab6b1fbcac7f13
Reviewed-on: https://go-review.googlesource.com/c/162978
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>