Avoid using 'which' for verifying prereqs (#6994)

* Use hash instead of which in build.sh

* Use hash instead of which in init-tools.sh.

* Use hash instead of which in gen-buildsys-clang.sh.

1 files changed, 47 insertions, 45 deletions

diff --git a/src/pal/tools/gen-buildsys-clang.sh b/src/pal/tools/gen-buildsys-clang.sh
index b7945f3091..9871d7c033 100755
--- a/src/pal/tools/gen-buildsys-clang.sh
+++ b/src/pal/tools/gen-buildsys-clang.sh
@@ -3,35 +3,31 @@
 # This file invokes cmake and generates the build system for Clang.
 #
 
-if [ $# -lt 4 -o $# -gt 8 ]
-then
-  echo "Usage..."
-  echo "gen-buildsys-clang.sh <path to top level CMakeLists.txt> <ClangMajorVersion> <ClangMinorVersion> <Architecture> [build flavor] [coverage] [ninja] [cmakeargs]"
-  echo "Specify the path to the top level CMake file - <ProjectK>/src/NDP"
-  echo "Specify the clang version to use, split into major and minor version"
-  echo "Specify the target architecture." 
-  echo "Optionally specify the build configuration (flavor.) Defaults to DEBUG." 
-  echo "Optionally specify 'coverage' to enable code coverage build."
-  echo "Target ninja instead of make. ninja must be on the PATH."
-  echo "Pass additional arguments to CMake call."
-  exit 1
+if [ $# -lt 4 -o $# -gt 8 ]; then
+    echo "Usage..."
+    echo "gen-buildsys-clang.sh <path to top level CMakeLists.txt> <ClangMajorVersion> <ClangMinorVersion> <Architecture> [build flavor] [coverage] [ninja] [cmakeargs]"
+    echo "Specify the path to the top level CMake file - <ProjectK>/src/NDP"
+    echo "Specify the clang version to use, split into major and minor version"
+    echo "Specify the target architecture." 
+    echo "Optionally specify the build configuration (flavor.) Defaults to DEBUG." 
+    echo "Optionally specify 'coverage' to enable code coverage build."
+    echo "Target ninja instead of make. ninja must be on the PATH."
+    echo "Pass additional arguments to CMake call."
+    exit 1
 fi
 
 # Set up the environment to be used for building with clang.
-if which "clang-$2.$3" > /dev/null 2>&1
-    then
-        export CC="$(which clang-$2.$3)"
-        export CXX="$(which clang++-$2.$3)"
-elif which "clang$2$3" > /dev/null 2>&1
-    then
-        export CC="$(which clang$2$3)"
-        export CXX="$(which clang++$2$3)"
-elif which clang > /dev/null 2>&1
-    then
-        export CC="$(which clang)"
-        export CXX="$(which clang++)"
+if hash "clang-$2.$3" 2>/dev/null; then
+    export CC="clang-$2.$3"
+    export CXX="clang++-$2.$3"
+elif hash "clang$2$3" 2>/dev/null; then
+    export CC="clang$2$3"
+    export CXX="clang++$2$3"
+elif hash clang 2>/dev/null; then
+    export CC="clang"
+    export CXX="clang++"
 else
-    echo "Unable to find Clang Compiler"
+    echo "Unable to find Clang compiler"
     exit 1
 fi
 
@@ -68,19 +64,22 @@ done
 OS=`uname`
 
 # Locate llvm
-# This can be a little complicated, because the common use-case of Ubuntu with
+#
+# This can be a little complicated, because the common use case of Ubuntu with
 # llvm-3.5 installed uses a rather unusual llvm installation with the version
-# number postfixed (i.e. llvm-ar-3.5), so we check for that first.
-# On FreeBSD the version number is appended without point and dash (i.e.
-# llvm-ar35).
-# Additionally, OSX doesn't use the llvm- prefix.
+# number postfixed (e.g. llvm-ar-3.5), so we check for that first.
+#
+# On FreeBSD, the version number is appended to the name without the dot and
+# the dash (e.g. llvm-ar35).
+#
+# OS X doesn't use the llvm- prefix.
 if [ $OS = "Linux" -o $OS = "FreeBSD" -o $OS = "OpenBSD" -o $OS = "NetBSD" -o $OS = "SunOS" ]; then
-  llvm_prefix="llvm-"
+    llvm_prefix="llvm-"
 elif [ $OS = "Darwin" ]; then
-  llvm_prefix=""
+    llvm_prefix=""
 else
-  echo "Unable to determine build platform"
-  exit 1
+    echo "Unable to determine build platform"
+    exit 1
 fi
 
 desired_llvm_major_version=$2
@@ -94,26 +93,29 @@ elif [ $OS = "NetBSD" ]; then
 elif [ $OS = "SunOS" ]; then
     desired_llvm_version=""
 else
-  desired_llvm_version="-$desired_llvm_major_version.$desired_llvm_minor_version"
+    desired_llvm_version="-$desired_llvm_major_version.$desired_llvm_minor_version"
 fi
-locate_llvm_exec() {
-  if which "$llvm_prefix$1$desired_llvm_version" > /dev/null 2>&1
-  then
-    echo "$(which $llvm_prefix$1$desired_llvm_version)"
-  elif which "$llvm_prefix$1" > /dev/null 2>&1
-  then
-    echo "$(which $llvm_prefix$1)"
-  else
-    exit 1
-  fi
+
+locate_llvm_exec() 
+{
+    if hash "$llvm_prefix$1$desired_llvm_version" 2>/dev/null; then
+        echo "$(command -v $llvm_prefix$1$desired_llvm_version)"
+    elif hash "$llvm_prefix$1" 2>/dev/null; then
+        echo "$(command -v $llvm_prefix$1)"
+    else
+        exit 1
+    fi
 }
 
 llvm_ar="$(locate_llvm_exec ar)"
 [[ $? -eq 0 ]] || { echo "Unable to locate llvm-ar"; exit 1; }
+
 llvm_link="$(locate_llvm_exec link)"
 [[ $? -eq 0 ]] || { echo "Unable to locate llvm-link"; exit 1; }
+
 llvm_nm="$(locate_llvm_exec nm)"
 [[ $? -eq 0 ]] || { echo "Unable to locate llvm-nm"; exit 1; }
+
 if [ $OS = "Linux" -o $OS = "FreeBSD" -o $OS = "OpenBSD" -o $OS = "NetBSD" -o $OS = "SunOS" ]; then
   llvm_objdump="$(locate_llvm_exec objdump)"
   [[ $? -eq 0 ]] || { echo "Unable to locate llvm-objdump"; exit 1; }