diff --git a/aarch64-linux-deb9/Dockerfile b/aarch64-linux-deb9/Dockerfile
index 3906420363018df143bc85bc51ad5dd009747e51..0a56e4a2f9ebd627ec77f210cc471608e62d4774 100644
--- a/aarch64-linux-deb9/Dockerfile
+++ b/aarch64-linux-deb9/Dockerfile
@@ -16,31 +16,33 @@ RUN apt-get update \
     && rm -rf /var/lib/apt/lists/*
 
 # Boot LLVM
+ENV BOOT_LLVM_DIR /opt/llvm-bootstrap
+ENV BOOT_LLVM_VERSION 7.0.0
 ENV PATH /usr/local/bin:$PATH
-ENV LLVM_TARBALL http://releases.llvm.org/6.0.0/clang+llvm-6.0.0-aarch64-linux-gnu.tar.xz
-RUN curl $LLVM_TARBALL | tar -xJC . && \
-    mkdir /opt/llvm6 && \
-    cp -R clang+llvm*/* /opt/llvm6 && \
+RUN curl http://releases.llvm.org/$BOOT_LLVM_VERSION/clang+llvm-$BOOT_LLVM_VERSION-aarch64-linux-gnu.tar.xz | tar -xJC . && \
+    mkdir $BOOT_LLVM_DIR && \
+    cp -R clang+llvm*/* $BOOT_LLVM_DIR && \
     rm -R clang+llvm* && \
-    /opt/llvm6/bin/llc --version
+    $BOOT_LLVM_DIR/bin/llc --version
 
 # GHC
 # Use 8.8.1 to bootstrap, since earlier releases are especially buggy on AArch64
 ENV GHC_VERSION 8.8.1
 RUN curl http://downloads.haskell.org/~ghc/$GHC_VERSION/ghc-$GHC_VERSION-aarch64-deb9-linux.tar.xz | tar -xJ
 WORKDIR /ghc-$GHC_VERSION
-RUN ./configure --prefix=/usr/local LLC=/opt/llvm6/bin/llc OPT=/opt/llvm6/bin/opt && \
+RUN ./configure --prefix=/usr/local LLC=$BOOT_LLVM_DIR/bin/llc OPT=$BOOT_LLVM_DIR/bin/opt && \
     make install
 WORKDIR /
 RUN rm -Rf ghc-*
 RUN ghc --version
 
 # LLVM
-ENV LLVM_TARBALL http://releases.llvm.org/7.0.0/clang+llvm-7.0.0-aarch64-linux-gnu.tar.xz
-ENV PATH /opt/llvm7/bin:$PATH
-RUN curl $LLVM_TARBALL | tar -xJC . && \
-    mkdir /opt/llvm7 && \
-    cp -R clang+llvm*/* /opt/llvm7 && \
+ENV LLVM_DIR /opt/llvm
+ENV LLVM_VERSION 7.0.0
+ENV PATH $LLVM_DIR/bin:$PATH
+RUN curl http://releases.llvm.org/$LLVM_VERSION/clang+llvm-$LLVM_VERSION-aarch64-linux-gnu.tar.xz | tar -xJC . && \
+    mkdir $LLVM_DIR && \
+    cp -R clang+llvm*/* $LLVM_DIR && \
     rm -R clang+llvm* && \
     llc --version
 
diff --git a/armv7-linux-deb9/Dockerfile b/armv7-linux-deb9/Dockerfile
index 4870682f9d89f6456d9c5e18ec76473b5faaf0bf..ad0f0a136005adb7b100b5b65ff85d63fb9c878c 100644
--- a/armv7-linux-deb9/Dockerfile
+++ b/armv7-linux-deb9/Dockerfile
@@ -17,31 +17,33 @@ RUN apt-get update \
     && rm -rf /var/lib/apt/lists/*
 
 # Boot LLVM
+ENV BOOT_LLVM_DIR /opt/llvm-bootstrap
+ENV BOOT_LLVM_VERSION 7.0.0
 ENV PATH /usr/local/bin:$PATH
-ENV LLVM_TARBALL http://releases.llvm.org/5.0.1/clang+llvm-5.0.1-armv7a-linux-gnueabihf.tar.xz
-RUN curl $LLVM_TARBALL | tar -xJC . && \
-    mkdir /opt/llvm5 && \
-    cp -R clang+llvm*/* /opt/llvm5 && \
+RUN curl http://releases.llvm.org/$BOOT_LLVM_VERSION/clang+llvm-$BOOT_LLVM_VERSION-armv7a-linux-gnueabihf.tar.xz | tar -xJC . && \
+    mkdir $BOOT_LLVM_DIR && \
+    cp -R clang+llvm*/* $BOOT_LLVM_DIR && \
     rm -R clang+llvm* && \
-    /opt/llvm5/bin/llc --version
+    $BOOT_LLVM_DIR/bin/llc --version
 
 # GHC
 # Use 8.8.1 to bootstrap, since earlier releases are especially buggy on AArch64
 ENV GHC_VERSION 8.8.1
 RUN curl http://home.smart-cactus.org/~ben/ghc/ghc-$GHC_VERSION-arm-unknown-linux.tar.xz | tar -xJ
 WORKDIR /ghc-$GHC_VERSION
-RUN ./configure --prefix=/usr/local LLC=/opt/llvm5/bin/llc OPT=/opt/llvm5/bin/opt && \
+RUN ./configure --prefix=/usr/local LLC=$BOOT_LLVM_DIR/bin/llc OPT=$BOOT_LLVM_DIR/bin/opt && \
     make install
 WORKDIR /
 RUN rm -Rf ghc-*
 RUN ghc --version
 
 # LLVM
-ENV LLVM_TARBALL http://releases.llvm.org/7.0.0/clang+llvm-7.0.0-armv7a-linux-gnueabihf.tar.xz
-ENV PATH /opt/llvm7/bin:$PATH
-RUN curl $LLVM_TARBALL | tar -xJC . && \
-    mkdir /opt/llvm7 && \
-    cp -R clang+llvm*/* /opt/llvm7 && \
+ENV LLVM_DIR /opt/llvm
+ENV LLVM_VERSION 7.0.0
+ENV PATH $LLVM_DIR/bin:$PATH
+RUN curl http://releases.llvm.org/$LLVM_VERSION/clang+llvm-$LLVM_VERSION-armv7a-linux-gnueabihf.tar.xz | tar -xJC . && \
+    mkdir $LLVM_DIR && \
+    cp -R clang+llvm*/* $LLVM_DIR && \
     rm -R clang+llvm* && \
     llc --version
 
diff --git a/x86_64-linux-deb9/Dockerfile b/x86_64-linux-deb9/Dockerfile
index 9d5127bb5d184da781982c83df612d9e04af2290..9aed8114f3153c3de823d4dd93e8c0881a282130 100644
--- a/x86_64-linux-deb9/Dockerfile
+++ b/x86_64-linux-deb9/Dockerfile
@@ -48,12 +48,13 @@ RUN curl https://downloads.haskell.org/cabal/cabal-install-$CABAL_VERSION/cabal-
     mv cabal /usr/local/bin/cabal
 
 # LLVM
-ENV LLVM_TARBALL http://releases.llvm.org/7.0.0/clang+llvm-7.0.0-x86_64-linux-gnu-ubuntu-16.04.tar.xz
-ENV PATH /opt/llvm/bin:$PATH
-RUN curl $LLVM_TARBALL | tar -xJC .; \
-    mkdir /opt/llvm; \
-    cp -R clang+llvm*/* /opt/llvm; \
-    rm -R clang+llvm*; \
+ENV LLVM_DIR /opt/llvm
+ENV LLVM_VERSION 7.0.0
+ENV PATH $LLVM_DIR/bin:$PATH
+RUN curl http://releases.llvm.org/$LLVM_VERSION/clang+llvm-$LLVM_VERSION-x86_64-linux-gnu-ubuntu-16.04.tar.xz | tar -xJC .; \
+    mkdir $LLVM_DIR && \
+    cp -R clang+llvm*/* $LLVM_DIR && \
+    rm -R clang+llvm* && \
     llc --version
 
 # Create a normal user.