Clang: Check for required mininum LLVM/Clang version

...otherwise, if the compilation fails, the user is left without any
hint.

Change-Id: I753aefac0c9fbd24b148235e792fe3b3a2aea21b
Reviewed-by: Marco Bubke <marco.bubke@theqtcompany.com>
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>

qbs/imports/QtcClangInstallation/functions.js

@@ -1,6 +1,17 @@
 var File = loadExtension("qbs.File")
+var MinimumLLVMVersion = "3.6.0"
 
-function llvmConfig(qbs)
+function isSuitableLLVMConfig(llvmConfigCandidate, qtcFunctions, processOutputReader)
+{
+    if (File.exists(llvmConfigCandidate)) {
+        var candidateVersion = version(llvmConfigCandidate, processOutputReader);
+        if (candidateVersion && candidateVersion.length)
+            return qtcFunctions.versionIsAtLeast(candidateVersion, MinimumLLVMVersion)
+    }
+    return false;
+}
+
+function llvmConfig(qbs, qtcFunctions, processOutputReader)
 {
     var llvmInstallDirFromEnv = qbs.getEnv("LLVM_INSTALL_DIR")
     var llvmConfigVariants = [
@@ -12,7 +23,7 @@ function llvmConfig(qbs)
     if (llvmInstallDirFromEnv) {
         for (var i = 0; i < llvmConfigVariants.length; ++i) {
             var variant = llvmInstallDirFromEnv + "/bin/" + llvmConfigVariants[i];
-            if (File.exists(variant))
+            if (isSuitableLLVMConfig(variant, qtcFunctions, processOutputReader))
                 return variant;
         }
     }
@@ -24,7 +35,7 @@ function llvmConfig(qbs)
     for (var i = 0; i < llvmConfigVariants.length; ++i) {
         for (var j = 0; j < pathList.length; ++j) {
             var variant = pathList[j] + "/" + llvmConfigVariants[i];
-            if (File.exists(variant))
+            if (isSuitableLLVMConfig(variant, qtcFunctions, processOutputReader))
                 return variant;
         }
     }

src/plugins/clangcodemodel/clangcodemodel.qbs

@@ -1,6 +1,7 @@
 import qbs
 import qbs.File
 import QtcClangInstallation as Clang
+import QtcFunctions
 import QtcProcessOutputReader
 
 QtcPlugin {
@@ -23,7 +24,7 @@ QtcPlugin {
     property bool clangHighlighting: true
     property bool clangIndexing: false
 
-    property string llvmConfig: Clang.llvmConfig(qbs)
+    property string llvmConfig: Clang.llvmConfig(qbs, QtcFunctions, QtcProcessOutputReader)
     property string llvmIncludeDir: Clang.includeDir(llvmConfig, QtcProcessOutputReader)
     property string llvmLibDir: Clang.libDir(llvmConfig, QtcProcessOutputReader)
     property string llvmLibs: Clang.libraries(qbs.targetOS)

src/shared/clang/clang_installation.pri

@@ -3,6 +3,25 @@ LLVM_INSTALL_DIR = $$clean_path($$LLVM_INSTALL_DIR)
 isEmpty(LLVM_INSTALL_DIR): error("No LLVM_INSTALL_DIR provided")
 !exists($$LLVM_INSTALL_DIR): error("LLVM_INSTALL_DIR does not exist: $$LLVM_INSTALL_DIR")
 
+defineReplace(extractVersion)      { return($$replace(1, ^(\\d+\\.\\d+\\.\\d+)$, \\1)) }
+defineReplace(extractMajorVersion) { return($$replace(1, ^(\\d+)\\.\\d+\\.\\d+$, \\1)) }
+defineReplace(extractMinorVersion) { return($$replace(1, ^\\d+\\.(\\d+)\\.\\d+$, \\1)) }
+
+defineTest(versionIsAtLeast) {
+    actual_major_version = $$extractMajorVersion($$1)
+    actual_minor_version = $$extractMinorVersion($$1)
+    required_min_major_version = $$2
+    required_min_minor_version = $$3
+
+    isEqual(actual_major_version, $$required_min_major_version) {
+        isEqual(actual_minor_version, $$required_min_minor_version): return(true)
+        greaterThan(actual_minor_version, $$required_min_minor_version): return(true)
+    }
+    greaterThan(actual_major_version, $$required_min_major_version): return(true)
+
+    return(false)
+}
+
 defineReplace(findLLVMVersionFromLibDir) {
     libdir = $$1
     version_dirs = $$files($$libdir/clang/*)
@@ -60,7 +79,7 @@ unix {
         LLVM_LIBDIR = $$system($$llvm_config --libdir 2>/dev/null)
         LLVM_INCLUDEPATH = $$system($$llvm_config --includedir 2>/dev/null)
         output = $$system($$llvm_config --version 2>/dev/null)
-        LLVM_VERSION = $$replace(output, ^(\\d+\\.\\d+\\.\\d+)$, \\1)
+        LLVM_VERSION = $$extractVersion($$output)
     } else {
         #message("llvm-config not found, concluding paths and version from LLVM_INSTALL_DIR")
         LLVM_INCLUDEPATH = $$LLVM_INSTALL_DIR/include
@@ -70,9 +89,13 @@ unix {
 
     !exists($$LLVM_INCLUDEPATH): error("Cannot detect include dir for clang, candidate: $$LLVM_INCLUDEPATH")
     !exists($$LLVM_LIBDIR): error("Cannot detect lib dir for clang, candidate: $$LLVM_LIBDIR")
-    isEmpty(LLVM_VERSION): error("Cannot determine clang version at $$LLVM_INSTALL_DIR")
     clang_lib = $$findClangLibInLibDir($$LLVM_LIBDIR)
     isEmpty(clang_lib): error("Cannot find Clang shared library in $$LLVM_LIBDIR")
 
     LLVM_LIBS = -L$${LLVM_LIBDIR} -l$${clang_lib}
 }
+
+isEmpty(LLVM_VERSION): error("Cannot determine clang version at $$LLVM_INSTALL_DIR")
+!versionIsAtLeast($$LLVM_VERSION, 3, 6): {
+    error("LLVM/Clang version >= 3.6.0 required, version provided: $$LLVM_VERSION")
+}

src/tools/clangbackend/clangbackend.qbs

@@ -1,5 +1,6 @@
 import qbs 1.0
 import QtcClangInstallation as Clang
+import QtcFunctions
 import QtcProcessOutputReader
 
 QtcTool {
@@ -17,7 +18,7 @@ QtcTool {
 
     files: [ "clangbackendmain.cpp" ]
 
-    property string llvmConfig: Clang.llvmConfig(qbs)
+    property string llvmConfig: Clang.llvmConfig(qbs, QtcFunctions, QtcProcessOutputReader)
     property string llvmIncludeDir: Clang.includeDir(llvmConfig, QtcProcessOutputReader)
     property string llvmLibDir: Clang.libDir(llvmConfig, QtcProcessOutputReader)
     property string llvmLibs: Clang.libraries(qbs.targetOS)