Merge pull request #50208 from giordano/mg/external-llvm-patches

[build] Allow automatically applying Julia's patches to LLVM source

deps/llvm.mk

@@ -239,6 +239,21 @@ endif
 # declare that all patches must be applied before running ./configure
 $(LLVM_BUILDDIR_withtype)/build-configured: | $(LLVM_PATCH_PREV)
 
+# Apply Julia's specific patches if requested, e.g. if not using Julia's fork of LLVM.
+ifeq ($(LLVM_APPLY_JULIA_PATCHES), 1)
+# Download Julia's patchset.
+$(BUILDDIR)/julia-patches.patch:
+	$(JLDOWNLOAD) $@ $(LLVM_JULIA_DIFF_GITHUB_REPO)/compare/$(LLVM_BASE_REF)...$(LLVM_JULIA_REF).diff
+
+# Apply the patch.
+$(SRCCACHE)/$(LLVM_SRC_DIR)/julia-patches.patch-applied: $(BUILDDIR)/julia-patches.patch $(SRCCACHE)/$(LLVM_SRC_DIR)/source-extracted
+	cd $(SRCCACHE)/$(LLVM_SRC_DIR) && patch -p1 < $(realpath $<)
+	echo 1 > $@
+
+# Require application of Julia's patchset before configuring LLVM.
+$(LLVM_BUILDDIR_withtype)/build-configured: | $(SRCCACHE)/$(LLVM_SRC_DIR)/julia-patches.patch-applied
+endif
+
 $(LLVM_BUILDDIR_withtype)/build-configured: $(SRCCACHE)/$(LLVM_SRC_DIR)/source-extracted
 	mkdir -p $(dir $@)
 	cd $(dir $@) && \

deps/llvm.version

@@ -1,7 +1,23 @@
+# -*- makefile -*-
+
 ## jll artifact
 LLVM_JLL_NAME := libLLVM
 LLVM_ASSERT_JLL_VER := 15.0.7+5
 ## source build
+# Version number of LLVM
 LLVM_VER := 15.0.7
+# Git branch name in `LLVM_GIT_URL` repository
 LLVM_BRANCH=julia-15.0.7-5
+# Git ref in `LLVM_GIT_URL` repository
 LLVM_SHA1=julia-15.0.7-5
+
+## Following options are used to automatically fetch patchset from Julia's fork.  This is
+## useful if you want to build an external LLVM while still applying Julia's patches.
+# Set to 1 if you want to automatically apply Julia's patches to a different fork of LLVM.
+LLVM_APPLY_JULIA_PATCHES := 0
+# GitHub repository to use for fetching the Julia patches to apply to LLVM source code.
+LLVM_JULIA_DIFF_GITHUB_REPO := https://github.com/llvm/llvm-project
+# Base GitHub ref for generating the diff.
+LLVM_BASE_REF := llvm:llvmorg-15.0.7
+# Julia fork's GitHub ref for generating the diff.
+LLVM_JULIA_REF := JuliaLang:julia-15.0.7-5