[llvm] 98c6d31 - [gn build] allow setting clang_base_path to a source-absolute path

[Nico Weber via llvm-commits]

Author: Nico Weber
Date: 2021-03-05T12:13:51-05:00
New Revision: 98c6d3194ed90217ca6ce7e451d31ea246d2afff

URL: https://github.com/llvm/llvm-project/commit/98c6d3194ed90217ca6ce7e451d31ea246d2afff
DIFF: https://github.com/llvm/llvm-project/commit/98c6d3194ed90217ca6ce7e451d31ea246d2afff.diff

LOG: [gn build] allow setting clang_base_path to a source-absolute path

With this, you can set `clang_base_path = "//out/gn1"` in `out/gn2/args.gn` and
the build in out/gn2 will use clang and lld from out/gn1.

Setting `clang_base_path` to an absolute path (with e.g.
`clang_base_path = getenv("HOME") + "/src/..."`) should behave as before.

Differential Revision: https://reviews.llvm.org/D97989

Added: 
    

Modified: 
    llvm/utils/gn/build/toolchain/BUILD.gn

Removed: 
    


################################################################################
diff  --git a/llvm/utils/gn/build/toolchain/BUILD.gn b/llvm/utils/gn/build/toolchain/BUILD.gn
index 0042df8578f7..e1aaae2c35e2 100644
--- a/llvm/utils/gn/build/toolchain/BUILD.gn
+++ b/llvm/utils/gn/build/toolchain/BUILD.gn
@@ -25,8 +25,8 @@ template("unix_toolchain") {
     cxx = "c++"
 
     if (clang_base_path != "") {
-      cc = "$clang_base_path/bin/clang"
-      cxx = "$clang_base_path/bin/clang++"
+      cc = rebase_path(clang_base_path, root_build_dir) + "/bin/clang"
+      cxx = rebase_path(clang_base_path, root_build_dir) + "/bin/clang++"
     }
 
     ld = cxx  # Don't use goma wrapper for linking.
@@ -185,7 +185,7 @@ template("stage2_unix_toolchain") {
     toolchain_args = {
       forward_variables_from(invoker.toolchain_args, "*")
 
-      clang_base_path = "."
+      clang_base_path = root_build_dir
       use_goma = false
     }
 
@@ -244,9 +244,9 @@ toolchain("win") {
   link = "link"
 
   if (clang_base_path != "") {
-    cl = "$clang_base_path/bin/clang-cl"
+    cl = rebase_path(clang_base_path, root_build_dir) + "/bin/clang-cl"
     if (use_lld) {
-      link = "$clang_base_path/bin/lld-link"
+      link = rebase_path(clang_base_path, root_build_dir) + "/bin/lld-link"
     }
   }