build: add support for section ordering

Adds support for using a section ordering file with the gold linker.
This makes it possible to reorder functions in a build to optimize for
a specific workload.

`hfsort` is a tool that can be used to generate such a file from perf-
recorded last branch record (LBR) data by running Node.js as
`node --perf-basic-prof`.

Refs: https://github.com/facebook/hhvm/tree/9966d482c19c6120c621c6f3896525fb19fb3842/hphp/tools/hfsort
Refs: https://software.intel.com/content/www/us/en/develop/articles/runtime-optimization-blueprint-IA-optimization-with-last-branch-record.html
Refs: https://github.com/nodejs/node/pull/16891/
Signed-off-by: Gabriel Schulhof <gabriel.schulhof@intel.com>
PR-URL: https://github.com/nodejs/node/pull/35272
Reviewed-By: Christian Clauss <cclauss@me.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/common.gypi b/common.gypi
index 46b4633f5d..33b1325eb5 100644
--- a/common.gypi
+++ b/common.gypi
@@ -111,6 +111,9 @@
       ['target_arch in "ppc64 s390x"', {
         'v8_enable_backtrace': 1,
       }],
+      ['OS=="linux"', {
+        'node_section_ordering_info%': ''
+      }]
     ],
   },
 
@@ -172,6 +175,20 @@
         },
         'cflags': [ '-O3' ],
         'conditions': [
+          ['OS=="linux"', {
+            'conditions': [
+              ['node_section_ordering_info!=""', {
+                'cflags': [
+                  '-fuse-ld=gold',
+                  '-ffunction-sections',
+                ],
+                'ldflags': [
+                  '-fuse-ld=gold',
+                  '-Wl,--section-ordering-file=<(node_section_ordering_info)',
+                ],
+              }],
+            ],
+          }],
           ['OS=="solaris"', {
             # pull in V8's postmortem metadata
             'ldflags': [ '-Wl,-z,allextract' ]