From 397fdf56b7c409ea2d3dfd687a3ebdf319baa95d Mon Sep 17 00:00:00 2001
From: Rene Rivera <grafikrobot@gmail.com>
Date: Wed, 27 Apr 2022 23:50:50 -0500
Subject: [PATCH] Add Linux arm & x86 clang cross compile defs.

---
 .ci/azp-linux-extra.yml | 20 +++++++++++++++++++
 azure-pipelines.yml     | 16 +++++++++++++++
 src/tools/clang.jam     | 43 +++++++++++++++++++++++++----------------
 3 files changed, 62 insertions(+), 17 deletions(-)
 create mode 100644 .ci/azp-linux-extra.yml

diff --git a/.ci/azp-linux-extra.yml b/.ci/azp-linux-extra.yml
new file mode 100644
index 000000000..256da8df3
--- /dev/null
+++ b/.ci/azp-linux-extra.yml
@@ -0,0 +1,20 @@
+steps:
+  - bash: |
+      set -e
+      uname -a
+      ./.ci/linux-cxx-install.sh
+    displayName: Install
+  - bash: |
+      set -e
+      ./bootstrap.sh ${TOOLSET}
+      ./b2 --prefix=$HOME/temp/.b2 install toolset=${TOOLSET}
+      rm ./b2
+      export PATH=$HOME/temp/.b2/bin:$PATH
+      cd $HOME
+      touch build.jam
+      b2 -v
+      b2 -n --debug-configuration toolset=${TOOLSET}
+    displayName: Bootstrap
+  - { bash: "./.ci/b2_example.sh example/hello", displayName: "example/hello" }
+  - { bash: "./.ci/b2_example.sh example/libraries", displayName: "example/libraries" }
+  - { bash: "./.ci/b2_example.sh example/make", displayName: "example/make" }
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 9213599a1..fc9a99c74 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -142,6 +142,22 @@ stages:
     steps:
     - template: .ci/azp-macos-extra.yml
 
+  - job: 'Linux'
+    strategy:
+      matrix:
+        Clang ${{variables.clang_latest}} x86/64: {
+          B2_ARGS: "architecture=x86 address-model=64",
+          TOOLSET: "clang-${{variables.clang_latest}}", PACKAGES: "clang-${{variables.clang_latest}}",
+          LLVM_OS: "${{variables.linux_latest_os}}", LLVM_VER: "${{variables.clang_latest}}", VM_IMAGE: "${{variables.linux_latest_vm}}"}
+        Clang ${{variables.clang_latest}} x86/32: {
+          B2_ARGS: "architecture=x86 address-model=32",
+          TOOLSET: "clang-${{variables.clang_latest}}", PACKAGES: "clang-${{variables.clang_latest}}",
+          LLVM_OS: "${{variables.linux_latest_os}}", LLVM_VER: "${{variables.clang_latest}}", VM_IMAGE: "${{variables.linux_latest_vm}}"}
+    pool:
+      vmImage: $(VM_IMAGE)
+    steps:
+    - template: .ci/azp-linux-extra.yml
+
 - stage: Website_Update
   dependsOn: [Core, Extra]
   displayName: 'Website Update'
diff --git a/src/tools/clang.jam b/src/tools/clang.jam
index b982bcff2..269bd19bf 100644
--- a/src/tools/clang.jam
+++ b/src/tools/clang.jam
@@ -67,34 +67,43 @@ rule init-cxxstd-flags ( toolset : condition * : version )
     cxxstd-flags $(toolset) : $(condition)/<cxxstd>latest/<cxxstd-dialect>$(dialects) : -std=c++$(std) ;
 }
 
-local rule init-flags-cross ( toolset : condition * : architecture address-model target-os )
+local rule init-flags-cross ( toolset : condition * : architecture + : address-model + : target-os )
 {
-    local arch ;
-    local vendor ;
-    local sys ;
-    switch $(architecture)-$(address-model)
-    {
-        case arm-64 : arch = arm64 ;
-        case arm-32 : arch = arm ;
-        case x86-64 : arch = x86_64 ;
-        case x86-32 : arch = i386 ;
-    }
+    local vendor = unknown ;
+    local sys = unknown ;
     switch $(target-os)
     {
         case darwin : vendor = apple ; sys = darwin ;
+        case linux : vendor = pc ; sys = linux ;
+    }
+    local vendor-sys = $(vendor)-$(sys) ;
+    for local _architecture_ in $(architecture)
+    {
+        for local _address-model_ in $(address-model)
+        {
+            local arch = unknown ;
+            switch $(_architecture_)-$(_address-model_)
+            {
+                case arm-64 : arch = arm64 ;
+                case arm-32 : arch = arm ;
+                case x86-64 : arch = x86_64 ;
+                case x86-32 : arch = i386 ;
+            }
+
+            toolset.flags $(toolset)
+                OPTIONS $(condition)/<target-os>$(target-os)/<architecture>$(_architecture_)/<address-model>$(_address-model_)
+                : "--target=$(arch)-$(vendor-sys)"
+                : unchecked ;
+        }
     }
-    toolset.flags $(toolset)
-        OPTIONS $(condition)/<target-os>$(target-os)/<architecture>$(architecture)/<address-model>$(address-model)
-        : "--target=$(arch)-$(vendor)-$(sys)"
-        : unchecked ;
 }
 
 rule init-flags ( toolset : condition * : version )
 {
     init-cxxstd-flags $(toolset) : $(condition) : $(version) ;
 
-    init-flags-cross $(toolset) : $(condition) : arm 64 darwin ;
-    init-flags-cross $(toolset) : $(condition) : x86 64 darwin ;
+    init-flags-cross $(toolset) : $(condition) : arm x86 : 64 : darwin ;
+    init-flags-cross $(toolset) : $(condition) : arm x86 : 64 32 : linux ;
 
     # This is a remporary solution for doing combined architecture builds on macOS.
     toolset.flags $(toolset)