[sledge] Move llvm build and install dirs out of llvm source tree

Summary:
Since version 2, none of the `opam pin` modes work reasonably well for
the standard llvm build procedure. As a workaround to prevent opam
from making several copies of the build directory when pinning, adjust
to move the llvm build and install directories out of the llvm source
tree.

Reviewed By: bennostein

Differential Revision: D17665242

fbshipit-source-id: ac84a4b0b

sledge/.gitignore

@@ -1,3 +1,5 @@
+.llvm_build
+.llvm_install
 .merlin
 /llvm/
 /model/dune

sledge/model/Makefile

@@ -10,7 +10,7 @@ CLANG_ARGS?=-g $(OPT_ARGS)
 # select llvm and clang
 SWITCH?=$(shell opam switch show)
 ROOT?=..
-LLVM=$(ROOT)/llvm/_install/$(SWITCH)
+LLVM=$(ROOT)/.llvm_install/$(SWITCH)
 
 LIBCXXABI=$(ROOT)/llvm/projects/libcxxabi
 

sledge/test/Makefile

@@ -21,7 +21,7 @@ SLEDGE=./wrap.sh $(TIMEOUT) $(MEMOUT) $(SLEDGE_EXE)
 DIFF?=diff
 
 # configure the non-host llvm and clang
-export PATH := $(CURDIR)/../llvm/_install/sledge/bin:$(PATH)
+export PATH := $(CURDIR)/../.llvm_install/sledge/bin:$(PATH)
 
 default: test