From ee5298a9854774a92dd59e653d30936aa298e0b6 Mon Sep 17 00:00:00 2001
From: David Major <dmajor@mozilla.com>
Date: Mon, 8 Mar 2021 14:47:56 +0000
Subject: [PATCH] Bug 1693288 - Move linux64-ccov builds to clang 12 rc2
 r=marco

Switching linux64-ccov builds to clang from gcc in bug 1499663 uncovered some performance problems that lead to test timeouts. These are addressed in clang 12. In order to ease the starring burden on sheriffs, let's give those builds a sneak preview of clang 12 even though general builds are not yet switching over.

Differential Revision: https://phabricator.services.mozilla.com/D107104
---
 .../config/mozconfigs/linux64/code-coverage-debug  |  5 +++++
 .../config/mozconfigs/linux64/code-coverage-opt    |  5 +++++
 taskcluster/ci/build/linux.yml                     | 14 ++++++++++----
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/browser/config/mozconfigs/linux64/code-coverage-debug b/browser/config/mozconfigs/linux64/code-coverage-debug
index 23b06e8a189a..3c511dc104d4 100644
--- a/browser/config/mozconfigs/linux64/code-coverage-debug
+++ b/browser/config/mozconfigs/linux64/code-coverage-debug
@@ -2,3 +2,8 @@
 
 ac_add_options --enable-debug=-g1
 ac_add_options --enable-rust-tests
+
+# https://bugs.llvm.org/show_bug.cgi?id=49226
+# LLD 12.0.0 had a behavior change that breaks coverage builds.
+# Passing --no-fortran-common restores the old behavior.
+export LDFLAGS="$LDFLAGS -Wl,--no-fortran-common"
diff --git a/browser/config/mozconfigs/linux64/code-coverage-opt b/browser/config/mozconfigs/linux64/code-coverage-opt
index 151219de0d6a..364c8a23a98b 100644
--- a/browser/config/mozconfigs/linux64/code-coverage-opt
+++ b/browser/config/mozconfigs/linux64/code-coverage-opt
@@ -2,3 +2,8 @@
 
 ac_add_options --enable-debug-symbols=-g1
 ac_add_options --enable-rust-tests
+
+# https://bugs.llvm.org/show_bug.cgi?id=49226
+# LLD 12.0.0 had a behavior change that breaks coverage builds.
+# Passing --no-fortran-common restores the old behavior.
+export LDFLAGS="$LDFLAGS -Wl,--no-fortran-common"
diff --git a/taskcluster/ci/build/linux.yml b/taskcluster/ci/build/linux.yml
index 148afcfe7cb4..b363154d4738 100644
--- a/taskcluster/ci/build/linux.yml
+++ b/taskcluster/ci/build/linux.yml
@@ -1287,7 +1287,10 @@ linux64-ccov/opt:
     fetches:
         toolchain:
             - linux64-binutils
-            - linux64-clang
+            # For linux64-ccov only, start using the clang-12 toolchains ahead
+            # of general builds, due to bug 1692817. This can be reverted once
+            # clang-12 becomes the default (bug 1696917).
+            - linux64-clang-12
             - linux64-rust
             - linux64-cbindgen
             - linux64-dump-syms
@@ -1297,7 +1300,7 @@ linux64-ccov/opt:
             - linux64-grcov
             - linux64-lucetc
             - linux64-sysroot
-            - wasi-sysroot
+            - wasi-sysroot-12
 
 linux64-ccov/debug:
     description: "Linux64-CCov Debug"
@@ -1330,7 +1333,10 @@ linux64-ccov/debug:
     fetches:
         toolchain:
             - linux64-binutils
-            - linux64-clang
+            # For linux64-ccov only, start using the clang-12 toolchains ahead
+            # of general builds, due to bug 1692817. This can be reverted once
+            # clang-12 becomes the default (bug 1696917).
+            - linux64-clang-12
             - linux64-rust
             - linux64-cbindgen
             - linux64-dump-syms
@@ -1340,7 +1346,7 @@ linux64-ccov/debug:
             - linux64-grcov
             - linux64-lucetc
             - linux64-sysroot
-            - wasi-sysroot
+            - wasi-sysroot-12
 
 linux64-add-on-devel/opt:
     description: "Linux64 add-on-devel"