[gcmole] Modernize gcmole bootstrap script.

This updates the existing bootstrap.sh script for gcmole to work against
LLVM and Clang version 8.0 releases. This is a follow-up to a previous
change which adapted the gcmole plugin to compile against those same
versions.

R=mslekova@chromium.org
BUG=v8:8813

Change-Id: Id6052fb9a7ec8a63d205eab2d4e233e2121c733d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1511275Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60116}

tools/gcmole/Makefile

@@ -27,11 +27,14 @@
 
 # This is Makefile for clang plugin part of gcmole tool. See README.
 
-LLVM_INCLUDE:=$(LLVM_SRC_ROOT)/include
-CLANG_INCLUDE:=$(LLVM_SRC_ROOT)/tools/clang/include
+LLVM_SRC_INCLUDE:=$(LLVM_SRC_ROOT)/include
+LLVM_BUILD_INCLUDE:=$(BUILD_ROOT)/include
+CLANG_SRC_INCLUDE:=$(CLANG_SRC_ROOT)/include
+CLANG_BUILD_INCLUDE:=$(BUILD_ROOT)/tools/clang/include
 
 libgcmole.so: gcmole.cc
-	$(CXX) -I$(LLVM_INCLUDE) -I$(CLANG_INCLUDE) -I. -D_DEBUG              \
+	$(CXX) -I$(LLVM_BUILD_INCLUDE) -I$(LLVM_SRC_INCLUDE)                  \
+	-I$(CLANG_BUILD_INCLUDE) -I$(CLANG_SRC_INCLUDE) -I. -D_DEBUG          \
 	-D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS         \
 	-D__STDC_LIMIT_MACROS -O3 -fomit-frame-pointer -fno-exceptions        \
 	-fno-rtti -fPIC -Woverloaded-virtual -Wcast-qual -fno-strict-aliasing \

tools/gcmole/README

@@ -5,12 +5,12 @@ dependent GC-unsafe places in the V8 codebase.
 
 For example the following code is GC-unsafe:
 
-Handle<Object> Foo();  // Assume Foo can trigger a GC.
-void Bar(Object*, Object*);
+    Handle<Object> Foo();  // Assume Foo can trigger a GC.
+    void Bar(Object*, Object*);
 
-Handle<Object> baz;
-baz->Qux(*Foo());  // (a)  
-Bar(*Foo(), *baz);  // (b)
+    Handle<Object> baz;
+    baz->Qux(*Foo());  // (a)
+    Bar(*Foo(), *baz);  // (b)
 
 Both in cases (a) and (b) compiler is free to evaluate call arguments (that 
 includes receiver) in any order. That means it can dereference baz before 
@@ -19,20 +19,30 @@ on the stack.
 
 PREREQUISITES -----------------------------------------------------------------
 
-1) Install Lua 5.1
+(1) Install Lua 5.1
 
-2) Get LLVM 8.0 and Clang 8.0 sources and build them.
+    $ sudo apt-get install lua5.1
 
-Follow the instructions on http://clang.llvm.org/get_started.html.
+(2) Get LLVM 8.0 and Clang 8.0 sources and build them.
 
-Make sure to pass --enable-optimized to configure to get Release build 
-instead of a Debug one.
+    Follow the instructions on http://clang.llvm.org/get_started.html.
 
-3) Build gcmole Clang plugin (libgcmole.so)
+    Make sure to pass -DCMAKE_BUILD_TYPE=Release to cmake to get Release build 
+    instead of a Debug one.
 
-In the tools/gcmole execute the following command:
+(3) Build gcmole Clang plugin (libgcmole.so)
 
-LLVM_SRC_ROOT=<path-to-llvm-source-root> make
+    In the tools/gcmole directory execute the following command:
+
+    $ BUILD_ROOT=<path> LLVM_SRC_ROOT=<path> CLANG_SRC_ROOT=<path> make
+
+(*) Note that steps (2) and (3) can also be achieved by just using the included
+    bootstrapping script in this directory:
+
+    $ ./tools/gcmole/bootstrap.sh
+
+    This will use "third_party/llvm+clang-build" as a build directory and checkout
+    required sources in the "third_party" directory.
 
 USING GCMOLE ------------------------------------------------------------------
 

tools/gcmole/bootstrap.sh

@@ -28,15 +28,16 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 # This script will build libgcmole.so. Building a recent clang needs a
-# recent GCC, so if you explicitly want to use GCC 4.8, use:
+# recent GCC, so if you explicitly want to use e.g. GCC 4.8, use:
 #
 #    CC=gcc-4.8 CPP=cpp-4.8 CXX=g++-4.8 CXXFLAGS=-static-libstdc++ CXXCPP=cpp-4.8 ./bootstrap.sh
 
-CLANG_RELEASE=3.5
+CLANG_RELEASE=8.0
 
-THIS_DIR="$(dirname "${0}")"
+THIS_DIR="$(readlink -f "$(dirname "${0}")")"
 LLVM_DIR="${THIS_DIR}/../../third_party/llvm"
-CLANG_DIR="${LLVM_DIR}/tools/clang"
+CLANG_DIR="${THIS_DIR}/../../third_party/clang"
+BUILD_DIR="${THIS_DIR}/../../third_party/llvm+clang-build"
 
 LLVM_REPO_URL=${LLVM_URL:-https://llvm.org/svn/llvm-project}
 
@@ -70,7 +71,7 @@ if [[ "${OS}" = "Darwin" ]] && xcodebuild -version | grep -q 'Xcode 3.2' ; then
   fi
 fi
 
-echo Getting LLVM r"${CLANG_RELEASE}" in "${LLVM_DIR}"
+echo Getting LLVM release "${CLANG_RELEASE}" in "${LLVM_DIR}"
 if ! svn co --force \
     "${LLVM_REPO_URL}/llvm/branches/release_${CLANG_RELEASE/./}" \
     "${LLVM_DIR}"; then
@@ -81,7 +82,7 @@ if ! svn co --force \
       "${LLVM_DIR}"
 fi
 
-echo Getting clang r"${CLANG_RELEASE}" in "${CLANG_DIR}"
+echo Getting clang release "${CLANG_RELEASE}" in "${CLANG_DIR}"
 svn co --force \
     "${LLVM_REPO_URL}/cfe/branches/release_${CLANG_RELEASE/./}" \
     "${CLANG_DIR}"
@@ -97,33 +98,31 @@ elif [ "${OS}" = "Darwin" ]; then
 fi
 
 # Build clang.
-cd "${LLVM_DIR}"
-if [[ ! -f ./config.status ]]; then
-  ../llvm/configure \
-      --enable-optimized \
-      --disable-threads \
-      --disable-pthreads \
-      --without-llvmgcc \
-      --without-llvmgxx
+if [ ! -e "${BUILD_DIR}" ]; then
+  mkdir "${BUILD_DIR}"
 fi
-
+cd "${BUILD_DIR}"
+cmake -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS=clang "${LLVM_DIR}"
 MACOSX_DEPLOYMENT_TARGET=10.5 make -j"${NUM_JOBS}"
+
+# Strip the clang binary.
 STRIP_FLAGS=
 if [ "${OS}" = "Darwin" ]; then
   # See http://crbug.com/256342
   STRIP_FLAGS=-x
 fi
-strip ${STRIP_FLAGS} Release+Asserts/bin/clang
+strip ${STRIP_FLAGS} bin/clang
 cd -
 
 # Build libgcmole.so
 make -C "${THIS_DIR}" clean
-make -C "${THIS_DIR}" LLVM_SRC_ROOT="${LLVM_DIR}" libgcmole.so
+make -C "${THIS_DIR}" LLVM_SRC_ROOT="${LLVM_DIR}" \
+    CLANG_SRC_ROOT="${CLANG_DIR}" BUILD_ROOT="${BUILD_DIR}" libgcmole.so
 
 set +x
 
 echo
 echo You can now run gcmole using this command:
 echo
-echo CLANG_BIN=\"third_party/llvm/Release+Asserts/bin\" lua tools/gcmole/gcmole.lua
+echo CLANG_BIN=\"third_party/llvm+clang-build/bin\" lua tools/gcmole/gcmole.lua
 echo