Document the --enable-afdo_tools configure option, and note that
autoprofiledbootstrap can use either the in-tree tools or the
out-of-tree autofdo toolkit.
gcc/ChangeLog:
* doc/install.texi: Document --enable-afdo_tools, and update the
AutoFDO tool requirement for autoprofiledbootstrap.
Signed-off-by: Kugan Vivekanandarajah <[email protected]>
---
gcc/doc/install.texi | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index a21b9eb5651..fd7bbc8ed27 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -1270,6 +1270,21 @@ viewing @uref{https://sarifweb.azurewebsites.net/,,SARIF
files}.
attempts to replay any diagnostics within them to stderr (via
@code{libgdiagnostics}) in the style of GCC's diagnostics.
+@item --enable-afdo_tools
+Build the @file{afdo_tools} directory, which provides the host tools
+@command{afdo_create}, @command{afdo_dump} and @command{afdo_merge}.
+@command{afdo_create} turns Linux @command{perf} samples into an AutoFDO
+profile for use with @option{-fauto-profile}, @command{afdo_merge}
+combines such profiles and @command{afdo_dump} prints one in readable
+form. They are also used by @samp{make autoprofiledbootstrap} and by the
+AutoFDO tests in the testsuite.
+
+These tools read Linux @command{perf} data, so they are only built on
+GNU/Linux hosts and @samp{configure} disables them elsewhere. They
+require @code{libelf}, @code{libdw} and @code{zlib}. They run on the
+host and do not depend on the target that GCC is configured for.
+@option{--disable-afdo_tools} is the default.
+
@item --disable-gcov
Specify that the run-time library used for coverage analysis
and associated host tools should not be built.
@@ -3500,8 +3515,11 @@ On Linux/x86_64 hosts with some restrictions (no
virtualization) it is
also possible to do autofdo build with @samp{make
autoprofiledbootstrap}. This uses Linux perf to sample branches in the
binary and then rebuild it with feedback derived from the profile.
-Linux perf and the @code{autofdo} toolkit needs to be installed for
-this.
+Linux perf needs to be installed for this, together with the AutoFDO
+profile tools: either the in-tree ones enabled by
+@option{--enable-afdo_tools}, or the out-of-tree @code{autofdo}
+toolkit, selected with the @code{CREATE_GCOV} and @code{PROFILE_MERGER}
+make variables and @code{AFDO_GCOV_VERSION=3}.
Only the profile from the current build is used, so when an error
occurs it is recommended to clean before restarting. Otherwise
--
2.34.1
