Bug 1915571 - Move mac and windows clang stage 2 build to cross-compiles. r=firefox-build-system-reviewers,sergesanspaille

By doing so, we don't really need a stage 1 clang for mac and windows
(with the downside that the final PGOed clang becomes the
clang-toolchain artifact on those platforms), and cross-compiling stage
2 is much faster as a cross-compile, leaving only stage 3 to be native.

While here, for the one build type that still does stage 2 and 3 in one
task, we actually prefer taking the llvm-profdata from stage 1, as it
doesn't contain profile instrumentation (it should actually have been
this way since the beginning).

Differential Revision: https://phabricator.services.mozilla.com/D220654

build/build-clang/build-clang.py

@@ -799,12 +799,16 @@ def main():
             assertions,
             target,
             targets,
-            is_final_stage=(stages == 2),
+            is_final_stage=(stages == 2 and not pgo),
             profile="gen" if pgo else None,
         )
 
     if stages >= 3 and skip_stages < 3:
         stage3_dir = build_dir + "/stage3"
+        if pgo:
+            profiles_dir = build_dir + "/profiles"
+            mkdir_p(profiles_dir)
+            os.environ["LLVM_PROFILE_FILE"] = profiles_dir + "/%m.profraw"
         stage3_inst_dir = stage3_dir + "/" + package_name
         final_stage_dir = stage3_dir
         if skip_stages < 2:
@@ -826,14 +830,16 @@ def main():
             assertions,
             target,
             targets,
-            (stages == 3),
+            is_final_stage=(stages == 3 and not pgo),
         )
         if pgo:
-            llvm_profdata = stage2_inst_dir + "/bin/llvm-profdata%s" % exe_ext
+            del os.environ["LLVM_PROFILE_FILE"]
+            if skip_stages < 1:
+                llvm_profdata = stage1_inst_dir + "/bin/llvm-profdata%s" % exe_ext
+            else:
+                llvm_profdata = get_tool(config, "llvm-profdata")
             merge_cmd = [llvm_profdata, "merge", "-o", "merged.profdata"]
-            profraw_files = glob.glob(
+            profraw_files = glob.glob(os.path.join(profiles_dir, "*.profraw"))
-                os.path.join(stage2_dir, "build", "profiles", "*.profraw")
-            )
             run_in(stage3_dir, merge_cmd + profraw_files)
             if stages == 3:
                 mkdir_p(upload_dir)
@@ -869,7 +875,7 @@ def main():
             assertions,
             target,
             targets,
-            (stages == 4),
+            is_final_stage=(stages == 4),
             profile=profile,
         )
 

build/build-clang/clang-18.json

@@ -10,6 +10,7 @@
         "revert-llvmorg-16-init-11301-g163bb6d64e5f_clang_18.patch",
         "revert-llvmorg-15-init-13446-g7524fe962e47.patch",
         "llvmorg-19-init-7654-gc23135c5488f.patch",
+        "llvmorg-20-init-4204-g5013cf682cf0.patch",
         "llvmorg-20-init-7208-g631bcbe9de13.patch",
         "win64-ret-null-on-commitment-limit_clang_14.patch",
         "arm64e-hack.patch",

build/build-clang/llvmorg-20-init-4204-g5013cf682cf0.patch

@@ -0,0 +1,70 @@
+From fea05619dccb54174b6cc3d4f3cef8c2d4edfe9d Mon Sep 17 00:00:00 2001
+From: Mike Hommey <mh@glandium.org>
+Date: Sat, 31 Aug 2024 08:10:22 +0900
+Subject: [PATCH] [cmake] Add symbolic links for MSVC libraries (#106710)
+
+When cross-compiling a Windows clang with `-DLLVM_BUILD_INSTRUMENTED`,
+the profiling compiler-rt is linked to binaries, as one would expect,
+but the profiling compiler-rt contains objects with `/DEFAULTLIB:LIBCMT`
+and `/DEFAULTLIB:OLDNAMES` directives, which makes the build expect
+`LIBCMT.lib` and `OLDNAMES.lib`, but they are nowhere to be found
+because they are in lowercase. While the WinMsvc.cmake helper recreates
+symbolic links to work around such case sensitivity issues for the
+Windows SDK libs, it doesn't do so for the MSVC libs, which we add here.
+---
+ llvm/cmake/platforms/WinMsvc.cmake | 25 +++++++++++++++++++++++++
+ 1 file changed, 25 insertions(+)
+
+diff --git a/llvm/cmake/platforms/WinMsvc.cmake b/llvm/cmake/platforms/WinMsvc.cmake
+index 77c3ab3d8fc1..fc07498498bf 100644
+--- a/llvm/cmake/platforms/WinMsvc.cmake
++++ b/llvm/cmake/platforms/WinMsvc.cmake
+@@ -95,6 +95,7 @@ list(APPEND CMAKE_TRY_COMPILE_PLATFORM_VARIABLES
+   LLVM_WINSYSROOT
+   MSVC_VER
+   WINSDK_VER
++  msvc_lib_symlinks_dir
+   winsdk_lib_symlinks_dir
+   winsdk_vfs_overlay_path
+   )
+@@ -156,6 +157,24 @@ function(generate_winsdk_lib_symlinks winsdk_um_lib_dir output_dir)
+   endforeach()
+ endfunction()
+ 
++function(generate_msvc_lib_symlinks msvc_lib_dir output_dir)
++  execute_process(COMMAND "${CMAKE_COMMAND}" -E make_directory "${output_dir}")
++  file(GLOB libraries RELATIVE "${msvc_lib_dir}" "${msvc_lib_dir}/*.lib")
++  foreach(library ${libraries})
++    get_filename_component(name_wle "${library}" NAME_WLE)
++    get_filename_component(ext "${library}" LAST_EXT)
++    string(TOLOWER "${ext}" lowercase_ext)
++    string(TOUPPER "${name_wle}" all_uppercase_symlink_name_wle)
++    set(uppercase_symlink_name "${all_uppercase_symlink_name_wle}${lowercase_ext}")
++    if(NOT library STREQUAL uppercase_symlink_name)
++      execute_process(COMMAND "${CMAKE_COMMAND}"
++                              -E create_symlink
++                              "${msvc_lib_dir}/${library}"
++                              "${output_dir}/${uppercase_symlink_name}")
++    endif()
++  endforeach()
++endfunction()
++
+ function(get_highest_version the_dir the_ver)
+   file(GLOB entries LIST_DIRECTORIES true RELATIVE "${the_dir}" "${the_dir}/[0-9.]*")
+   foreach(entry ${entries})
+@@ -293,6 +312,12 @@ if(case_sensitive_filesystem)
+   endif()
+   list(APPEND LINK_FLAGS
+        -libpath:"${winsdk_lib_symlinks_dir}")
++  if(NOT msvc_lib_symlinks_dir)
++    set(msvc_lib_symlinks_dir "${CMAKE_BINARY_DIR}/msvc_lib_symlinks")
++    generate_msvc_lib_symlinks("${MSVC_LIB}/${WINSDK_ARCH}" "${msvc_lib_symlinks_dir}")
++  endif()
++  list(APPEND LINK_FLAGS
++       -libpath:"${msvc_lib_symlinks_dir}")
+ endif()
+ 
+ string(REPLACE ";" " " LINK_FLAGS "${LINK_FLAGS}")
+-- 
+2.45.2.2.g32a9d489d5
+

build/build-clang/stage-2-3-pgo.json

@@ -0,0 +1,6 @@
+{
+    "skip_stages": "1",
+    "stages": "3",
+    "pgo": true,
+    "llvm-profdata": "{MOZ_FETCHES_DIR}/clang/bin/llvm-profdata"
+}

build/build-clang/stage-2-pgo.json

@@ -1,5 +1,5 @@
 {
     "skip_stages": "1",
-    "stages": "3",
+    "stages": "2",
     "pgo": true
 }

build/build-clang/stage-3-pgo.json

@@ -0,0 +1,6 @@
+{
+    "skip_stages": "2",
+    "stages": "3",
+    "pgo": true,
+    "llvm-profdata": "{MOZ_FETCHES_DIR}/clang/bin/llvm-profdata"
+}

taskcluster/kinds/toolchain/clang.yml

@@ -200,11 +200,11 @@ linux64-clang-18-profile:
         arguments:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-2-3-pgo.json'
         resources:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-2-3-pgo.json'
         toolchain-artifact: public/build/merged.profdata
     fetches:
         fetch:
@@ -275,10 +275,10 @@ linux64-clang-18:
             - win64-compiler-rt-18
             - win64-aarch64-compiler-rt-18
 
-macosx64-clang-18-stage1:
+macosx64-clang-18-stage2:
     description: "Clang 18 toolchain build"
     treeherder:
-        symbol: TM(clang-18-stage1)
+        symbol: TM(clang-18-stage2)
     run:
         using: toolchain-script
         script: build-clang.sh
@@ -286,18 +286,19 @@ macosx64-clang-18-stage1:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
         resources:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
         toolchain-artifact: public/build/clang.tar.zst
     fetches:
         fetch:
             - clang-18
         toolchain:
             - linux64-clang-18-stage1
+            - macosx64-x64-compiler-rt-18
             - macosx64-sdk-toolchain
 
 macosx64-clang-18-profile:
@@ -314,12 +315,12 @@ macosx64-clang-18-profile:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         resources:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         toolchain-artifact: public/build/merged.profdata
     fetches:
         fetch:
@@ -327,8 +328,7 @@ macosx64-clang-18-profile:
             - macosx64-cmake
             - macosx64-ninja
         toolchain:
-            - macosx64-clang-18-stage1
+            - macosx64-clang-18-stage2
-            - macosx64-x64-compiler-rt-18
             - macosx64-sdk-toolchain
 
 macosx64-clang-18-raw:
@@ -399,10 +399,10 @@ macosx64-clang-18:
             - win64-compiler-rt-18
             - win64-aarch64-compiler-rt-18
 
-macosx64-aarch64-clang-18-stage1:
+macosx64-aarch64-clang-18-stage2:
     description: "Clang 18 toolchain build"
     treeherder:
-        symbol: TMA64(clang-18-stage1)
+        symbol: TMA64(clang-18-stage2)
     run:
         using: toolchain-script
         script: build-clang.sh
@@ -410,18 +410,19 @@ macosx64-aarch64-clang-18-stage1:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64-aarch64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
         resources:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64-aarch64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
         toolchain-artifact: public/build/clang.tar.zst
     fetches:
         fetch:
             - clang-18
         toolchain:
             - linux64-clang-18-stage1
+            - macosx64-aarch64-compiler-rt-18
             - macosx64-sdk-toolchain
 
 macosx64-aarch64-clang-18-profile:
@@ -438,12 +439,12 @@ macosx64-aarch64-clang-18-profile:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64-aarch64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         resources:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64-aarch64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         toolchain-artifact: public/build/merged.profdata
     fetches:
         fetch:
@@ -451,8 +452,7 @@ macosx64-aarch64-clang-18-profile:
             - macosx64-cmake
             - macosx64-ninja
         toolchain:
-            - macosx64-aarch64-clang-18-stage1
+            - macosx64-aarch64-clang-18-stage2
-            - macosx64-aarch64-compiler-rt-18
             - macosx64-sdk-toolchain
 
 macosx64-aarch64-clang-18-raw:
@@ -521,26 +521,22 @@ macosx64-aarch64-clang-18:
             - win64-compiler-rt-18
             - win64-aarch64-compiler-rt-18
 
-win64-clang-18-stage1:
+win64-clang-18-stage2:
-    description: "Clang-cl 18 toolchain build stage 1"
+    description: "Clang-cl 18 toolchain build"
     treeherder:
-        symbol: TW64(clang-18-stage1)
+        symbol: TW64(clang-18-stage2)
     run:
         script: build-clang.sh
         arguments:
             - 'build/build-clang/use-clang-cl-artifact.json'
             - 'build/build-clang/win64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
         resources:
             - 'build/build-clang/use-clang-cl-artifact.json'
             - 'build/build-clang/win64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
-        toolchain-alias:
-            by-project:
-                toolchains: null
-                default: win64-clang-toolchain
         toolchain-artifact: public/build/clang.tar.zst
     fetches:
         fetch:
@@ -548,6 +544,7 @@ win64-clang-18-stage1:
         toolchain:
             - linux64-clang-18-stage1
             - vs-toolchain
+            - win64-compiler-rt-18
             - win64-libxml2
 
 win64-clang-18-profile:
@@ -563,21 +560,20 @@ win64-clang-18-profile:
             - 'build/build-clang/use-clang-cl-artifact.json'
             - 'build/build-clang/win64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         resources:
             - 'build/build-clang/use-clang-cl-artifact.json'
             - 'build/build-clang/win64.json'
             - 'build/build-clang/clang-18.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         toolchain-artifact: public/build/merged.profdata
     fetches:
         fetch:
             - clang-18
             - win64-ninja
         toolchain:
-            - win64-clang-18-stage1
+            - win64-clang-18-stage2
             - win64-cmake
-            - win64-compiler-rt-18
             - vs-toolchain
             - win64-libxml2
 
@@ -624,7 +620,9 @@ win64-clang-18:
         toolchain-alias:
             by-project:
                 toolchains: null
-                default: win64-clang
+                default:
+                    - win64-clang
+                    - win64-clang-toolchain
         toolchain-artifact: public/build/clang.tar.zst
     fetches:
         toolchain:
@@ -810,11 +808,11 @@ linux64-clang-trunk-profile:
         arguments:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-2-3-pgo.json'
         resources:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-2-3-pgo.json'
         toolchain-artifact: public/build/merged.profdata
     fetches:
         fetch:
@@ -887,12 +885,12 @@ linux64-clang-trunk:
             - win64-compiler-rt-trunk
             - win64-aarch64-compiler-rt-trunk
 
-macosx64-clang-trunk-stage1:
+macosx64-clang-trunk-stage2:
     description: "Clang trunk toolchain build"
     attributes:
         cached_task: false
     treeherder:
-        symbol: TM(clang-trunk-stage1)
+        symbol: TM(clang-trunk-stage2)
     run:
         using: toolchain-script
         script: build-clang.sh
@@ -900,18 +898,19 @@ macosx64-clang-trunk-stage1:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
         resources:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
         toolchain-artifact: public/build/clang.tar.zst
     fetches:
         fetch:
             - clang-trunk
         toolchain:
             - linux64-clang-trunk-stage1
+            - macosx64-x64-compiler-rt-trunk
             - macosx64-sdk-toolchain
 
 macosx64-clang-trunk-profile:
@@ -930,12 +929,12 @@ macosx64-clang-trunk-profile:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         resources:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         toolchain-artifact: public/build/merged.profdata
     fetches:
         fetch:
@@ -943,8 +942,7 @@ macosx64-clang-trunk-profile:
             - macosx64-cmake
             - macosx64-ninja
         toolchain:
-            - macosx64-clang-trunk-stage1
+            - macosx64-clang-trunk-stage2
-            - macosx64-x64-compiler-rt-trunk
             - macosx64-sdk-toolchain
 
 macosx64-clang-trunk-raw:
@@ -1017,12 +1015,12 @@ macosx64-clang-trunk:
             - win64-compiler-rt-trunk
             - win64-aarch64-compiler-rt-trunk
 
-macosx64-aarch64-clang-trunk-stage1:
+macosx64-aarch64-clang-trunk-stage2:
     description: "Clang trunk toolchain build"
     attributes:
         cached_task: false
     treeherder:
-        symbol: TMA64(clang-trunk-stage1)
+        symbol: TMA64(clang-trunk-stage2)
     run:
         using: toolchain-script
         script: build-clang.sh
@@ -1030,18 +1028,19 @@ macosx64-aarch64-clang-trunk-stage1:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64-aarch64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
         resources:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64-aarch64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
         toolchain-artifact: public/build/clang.tar.zst
     fetches:
         fetch:
             - clang-trunk
         toolchain:
             - linux64-clang-trunk-stage1
+            - macosx64-aarch64-compiler-rt-trunk
             - macosx64-sdk-toolchain
 
 macosx64-aarch64-clang-trunk-profile:
@@ -1060,12 +1059,12 @@ macosx64-aarch64-clang-trunk-profile:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64-aarch64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         resources:
             - 'build/build-clang/use-clang-artifact.json'
             - 'build/build-clang/macosx64-aarch64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         toolchain-artifact: public/build/merged.profdata
     fetches:
         fetch:
@@ -1073,8 +1072,7 @@ macosx64-aarch64-clang-trunk-profile:
             - macosx64-cmake
             - macosx64-ninja
         toolchain:
-            - macosx64-aarch64-clang-trunk-stage1
+            - macosx64-aarch64-clang-trunk-stage2
-            - macosx64-aarch64-compiler-rt-trunk
             - macosx64-sdk-toolchain
 
 macosx64-aarch64-clang-trunk-raw:
@@ -1145,28 +1143,24 @@ macosx64-aarch64-clang-trunk:
             - win64-compiler-rt-trunk
             - win64-aarch64-compiler-rt-trunk
 
-win64-clang-trunk-stage1:
+win64-clang-trunk-stage2:
-    description: "Clang-cl trunk toolchain build stage 1"
+    description: "Clang-cl trunk toolchain build"
     attributes:
         cached_task: false
     treeherder:
-        symbol: TW64(clang-trunk-stage1)
+        symbol: TW64(clang-trunk-stage2)
     run:
         script: build-clang.sh
         arguments:
             - 'build/build-clang/use-clang-cl-artifact.json'
             - 'build/build-clang/win64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
         resources:
             - 'build/build-clang/use-clang-cl-artifact.json'
             - 'build/build-clang/win64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/stage-1.json'
+            - 'build/build-clang/stage-2-pgo.json'
-        toolchain-alias:
-            by-project:
-                toolchains: win64-clang-toolchain
-                default: null
         toolchain-artifact: public/build/clang.tar.zst
     fetches:
         fetch:
@@ -1174,6 +1168,7 @@ win64-clang-trunk-stage1:
         toolchain:
             - linux64-clang-trunk-stage1
             - vs-toolchain
+            - win64-compiler-rt-trunk
             - win64-libxml2
 
 win64-clang-trunk-profile:
@@ -1191,21 +1186,20 @@ win64-clang-trunk-profile:
             - 'build/build-clang/use-clang-cl-artifact.json'
             - 'build/build-clang/win64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         resources:
             - 'build/build-clang/use-clang-cl-artifact.json'
             - 'build/build-clang/win64.json'
             - 'build/build-clang/clang-trunk.json'
-            - 'build/build-clang/profile.json'
+            - 'build/build-clang/stage-3-pgo.json'
         toolchain-artifact: public/build/merged.profdata
     fetches:
         fetch:
             - clang-trunk
             - win64-ninja
         toolchain:
-            - win64-clang-trunk-stage1
+            - win64-clang-trunk-stage2
             - win64-cmake
-            - win64-compiler-rt-trunk
             - vs-toolchain
             - win64-libxml2
 
@@ -1251,7 +1245,9 @@ win64-clang-trunk:
         script: repack-clang.sh
         toolchain-alias:
             by-project:
-                toolchains: win64-clang
+                toolchains:
+                    - win64-clang
+                    - win64-clang-toolchain
                 default: null
         toolchain-artifact: public/build/clang.tar.zst
     fetches: