From 7839e5e8a3c48b0dc2e1dc366ba45af09f857a4e Mon Sep 17 00:00:00 2001
From: Patrick Damme <pdamme@know-center.at>
Date: Wed, 17 Feb 2021 16:42:54 +0100
Subject: [PATCH] Using MLIR/LLVM as a submodule.

- It is important to stick to a certain version of MLIR/LLVM (see issue #1).
- Please see README.md for new instructions on cloning and pulling.
- This commit fixes #1.
---
 .gitignore              |  3 ++-
 .gitmodules             |  3 +++
 README.md               | 41 ++++++++++++++++++++++++-----
 build.sh                | 57 ++++++++++++++++++++++++++---------------
 pull.sh                 |  6 +++++
 thirdparty/llvm-project |  1 +
 6 files changed, 82 insertions(+), 29 deletions(-)
 create mode 100644 .gitmodules
 create mode 100755 pull.sh
 create mode 160000 thirdparty/llvm-project

diff --git a/.gitignore b/.gitignore
index 500e9d1fe..8d492b3d7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 build/
-thirdparty/
+thirdparty/*
+!thirdparty/llvm-project/
\ No newline at end of file
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 000000000..f5f664cdc
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "thirdparty/llvm-project"]
+	path = thirdparty/llvm-project
+	url = https://github.com/llvm/llvm-project.git
diff --git a/README.md b/README.md
index 7df799d96..ca0407490 100644
--- a/README.md
+++ b/README.md
@@ -19,15 +19,42 @@ Please ensure that your system meets the following requirements before trying to
 - hardware
   - about 3.5 GB disk space (only for LLVM/MLIR)
 
-## 1. Build
+## 1. Obtain the source code
 
-Simply build the prototype using `./build.sh`.
-When you do this the *first* time, it will also download and build antlr4 as well as clone and build LLVM/MLIR.
-The latter takes very long (can be about 30 minutes).
-All *following* build should take only a few seconds.
-To clean, simply delete the `build`-directory.
+The prototype is based on MLIR, which is a part of the LLVM monorepo.
+The LLVM monorepo is included in this repository as a submodule.
+Thus, clone this repository as follows to also clone the submodule:
 
-## 2. Run
+```bash
+git clone --recursive https://gitlab.know-center.tugraz.at/daphne/prototype.git
+```
+
+Upstream changes to this repository might contain changes to the submodule (we might have upgraded to a newer version of MLIR/LLVM).
+Thus, please pull as follows:
+
+```bash
+# in git >= 2.14
+git pull --recurse-submodules
+
+# in git < 2.14
+git pull && git submodule update --init --recursive
+
+# or use this little convenience script
+./pull.sh
+```
+
+## 2. Build
+
+Simply build the prototype using the build-script without any arguments:
+
+```bash
+./build.sh
+```
+
+When you do this the first time, or when there were updates to the LLVM submodule, this will also download and build the third-party material, which might increase the build time significantly.
+Subsequent builds, e.g., when you changed something in this repository, will be much faster.
+
+## 3. Run
 
 Write a little DaphneDSL script or use `example.daphne`...
 
diff --git a/build.sh b/build.sh
index acb5ce058..9b63e8f5e 100755
--- a/build.sh
+++ b/build.sh
@@ -1,16 +1,27 @@
 #!/bin/bash
 
+# This script builds the DAPHNE prototype.
+#
+# It also downloads and builds all required third-party material. Simply invoke
+# it without any arguments.
+
+
+# Stop immediately if any command fails.
 set -e
 
+
 #******************************************************************************
-# Download thirdparty material
+# Handle third-party material
 #******************************************************************************
 
 thirdpartyPath=thirdparty
-mkdir --parents $thirdpartyPath
 oldPwd=$(pwd)
 cd $thirdpartyPath
 
+#------------------------------------------------------------------------------
+# Download third-party material if necessary
+#------------------------------------------------------------------------------
+
 # Download antlr4 jar if it does not exist yet.
 antlrName=antlr-4.9.1-complete.jar
 if [ ! -f $antlrName ]
@@ -18,29 +29,32 @@ then
     wget https://www.antlr.org/download/$antlrName
 fi
 
-# Clone and build LLVM/MLIR if it does not exist yet.
+#------------------------------------------------------------------------------
+# Build MLIR
+#------------------------------------------------------------------------------
+# TODO Do this only when it is necessary, since cmake takes some time even if
+# there is nothing to do.
+
 llvmName=llvm-project
-if [ ! -d $llvmName ]
-then
-    git clone https://github.com/llvm/$llvmName.git
-    cd $llvmName
-    # We do not use the latest version of the MLIR/LLVM source code.
-    # See issue #1.
-    git checkout f1ff6d210a5fb45dc90d063d04b12b9da0ae4110
-    mkdir build
-    cd build
-    cmake -G Ninja ../llvm \
-       -DLLVM_ENABLE_PROJECTS=mlir \
-       -DLLVM_BUILD_EXAMPLES=ON \
-       -DLLVM_TARGETS_TO_BUILD="X86;NVPTX;AMDGPU" \
-       -DCMAKE_BUILD_TYPE=Release \
-       -DLLVM_ENABLE_ASSERTIONS=ON \
-       -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DLLVM_ENABLE_LLD=ON
-    cmake --build . --target check-mlir
-fi
+cd $llvmName
+mkdir --parents build
+cd build
+cmake -G Ninja ../llvm \
+   -DLLVM_ENABLE_PROJECTS=mlir \
+   -DLLVM_BUILD_EXAMPLES=ON \
+   -DLLVM_TARGETS_TO_BUILD="X86;NVPTX;AMDGPU" \
+   -DCMAKE_BUILD_TYPE=Release \
+   -DLLVM_ENABLE_ASSERTIONS=ON \
+   -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DLLVM_ENABLE_LLD=ON
+cmake --build . --target check-mlir
+
+#------------------------------------------------------------------------------
+# Go back
+#------------------------------------------------------------------------------
 
 cd $oldPwd
 
+
 # *****************************************************************************
 # Build the DAPHNE prototype.
 # *****************************************************************************
@@ -50,4 +64,5 @@ cd build
 cmake -G Ninja .. -DMLIR_DIR=$thirdpartyPath/$llvmName/build/lib/cmake/mlir/
 cmake --build . --target daphnec
 
+
 set +e
\ No newline at end of file
diff --git a/pull.sh b/pull.sh
new file mode 100755
index 000000000..0fc401b40
--- /dev/null
+++ b/pull.sh
@@ -0,0 +1,6 @@
+#!/bin/bash
+
+# This script pulls upstream changes to this repository and handles all updates
+# to the submodule(s).
+
+git pull && git submodule update --init --recursive
\ No newline at end of file
diff --git a/thirdparty/llvm-project b/thirdparty/llvm-project
new file mode 160000
index 000000000..f1ff6d210
--- /dev/null
+++ b/thirdparty/llvm-project
@@ -0,0 +1 @@
+Subproject commit f1ff6d210a5fb45dc90d063d04b12b9da0ae4110