Use git worktree in the LLVM helper scripts

This commit adds a new script, llvm-env, which sets up the environment for
working with LLVM. It looks for an environment variable LLVM_ROOT and tries to
create the following hierarchy:

$LLVM_ROOT
  `- repos
  |    `- llvm
  |    `- clang
  |    `- compiler-rt
  |     [...]
  `- <branch1>
  |    `- llvm
  |    `- build
  |    `- debug
  `- <branch2>
  |    `- llvm
  |    `- build
  |    `- debug
  [...]

The $LLVM_ROOT/repos directory contains all the repositories, as checked out by
llvm-prepare, and will always track master. For other branches,
llvm-env <branch_name> will create a new directory, $LLVM_ROOT/<branch_name>,
and will add an llvm worktree directory there. If -d is passed, it will also
create a debug directory there, otherwise it will create a build directory.
Notice that these 2 can live in parallel, and we can switch between them at any
time by invoking llvm-env. It will set LLVM_SRC and LLVM_BLD accordingly, and
also modify the path to point to the binaries in LLVM_BLD.

The other scripts will now work with the LLVM_SRC and LLVM_BLD set by llvm-env
in the current shell. Because llvm-env controls whether or not we're doing a
debug build, llvm-build will no longer take a -d flag (it will instead look
after a LLVM_DEBUG environment variable, also set by llvm-env). There are
changes in llvm-projs, too, because now it no longer creates links - instead it
creates worktree directories in the corresponding $LLVM_ROOT/<branch>/llvm.
Other scripts have also been updated accordingly.

To make things easier, here are some of the changes that I had to make that are
not particularly important for the review (pretty mechanical stuff):
* Moved function has() from llvm-branch to llvm-common, so I could reuse it
* Because of this, I had to rename the has() function in llvm-projs to
has_link(), which is actually a better name for it anyway
* Disable the checks for LLVM_SRC and LLVM_BLD in llvm-common

Change-Id: I9e02f6d8e0c803e79838845013b81331dffba99c

1 files changed, 14 insertions, 14 deletions

diff --git a/helpers/llvm-prepare b/helpers/llvm-prepare
index 46a1780..d9f8a2a 100755
--- a/helpers/llvm-prepare
+++ b/helpers/llvm-prepare
@@ -34,43 +34,43 @@ else
   svnroot=https://$LLVM_SVNUSER@llvm.org/svn/llvm-project
 fi
 
+llvm_repos=$LLVM_ROOT/repos
+
 echo " + Setting up LLVM"
-prepare $LLVM_SRC $gitroot/llvm $svnroot/llvm/trunk
+prepare $llvm_repos/llvm $gitroot/llvm $svnroot/llvm/trunk
 
 echo " + Setting up Clang"
-prepare $LLVM_SRC/../clang $gitroot/clang $svnroot/cfe/trunk
+prepare $llvm_repos/clang $gitroot/clang $svnroot/cfe/trunk
 
 echo " + Setting up Clang Tools Extra"
-prepare $LLVM_SRC/../clang-tools-extra \
+prepare $llvm_repos/clang-tools-extra \
         $gitroot/clang-tools-extra $svnroot/clang-tools-extra/trunk
 
 echo " + Setting up Compiler-RT"
-prepare $LLVM_SRC/../compiler-rt $gitroot/compiler-rt $svnroot/compiler-rt/trunk
+prepare $llvm_repos/compiler-rt $gitroot/compiler-rt $svnroot/compiler-rt/trunk
 
 echo " + Setting up LLD Linker"
-prepare $LLVM_SRC/../lld $gitroot/lld $svnroot/lld/trunk
+prepare $llvm_repos/lld $gitroot/lld $svnroot/lld/trunk
 
 echo " + Setting up LibC++"
-prepare $LLVM_SRC/../libcxx $gitroot/libcxx $svnroot/libcxx/trunk
+prepare $llvm_repos/libcxx $gitroot/libcxx $svnroot/libcxx/trunk
 
 echo " + Setting up LibC++ABI"
-prepare $LLVM_SRC/../libcxxabi $gitroot/libcxxabi $svnroot/libcxxabi/trunk
+prepare $llvm_repos/libcxxabi $gitroot/libcxxabi $svnroot/libcxxabi/trunk
 
 echo " + Setting up LibUnwind"
-prepare $LLVM_SRC/../libunwind $gitroot/libunwind $svnroot/libunwind/trunk
+prepare $llvm_repos/libunwind $gitroot/libunwind $svnroot/libunwind/trunk
 
 echo " + Setting up LLDB Debugger"
-prepare $LLVM_SRC/../lldb $gitroot/lldb $svnroot/lldb/trunk
+prepare $llvm_repos/lldb $gitroot/lldb $svnroot/lldb/trunk
 
 echo " + Setting up Test Suite"
-prepare $LLVM_SRC/../test-suite $gitroot/test-suite $svnroot/test-suite/trunk
+prepare $llvm_repos/test-suite $gitroot/test-suite $svnroot/test-suite/trunk
 
 echo " + Setting up LNT Test harness"
-prepare $LLVM_SRC/../lnt $gitroot/lnt $svnroot/lnt/trunk
+prepare $llvm_repos/lnt $gitroot/lnt $svnroot/lnt/trunk
 
 echo " + Setting up Zorg Buildbot Config"
-prepare $LLVM_SRC/../zorg $gitroot/zorg $svnroot/zorg/trunk
-
-mkdir -p $LLVM_BLD
+prepare $llvm_repos/zorg $gitroot/zorg $svnroot/zorg/trunk
 
 echo " + Done"