Fix for #431: memory leak due to multiple TargetMachine creation

ispc.cpp

@@ -145,6 +145,7 @@ static const char *supportedCPUs[] = {
 
 Target::Target(const char *arch, const char *cpu, const char *isa, bool pic) :
     m_target(NULL),
+    m_targetMachine(NULL),
     m_valid(false),
     m_isa(SSE2),
     m_arch(""),
@@ -424,13 +425,31 @@ Target::Target(const char *arch, const char *cpu, const char *isa, bool pic) :
     }
 
     if (!error) {
-        llvm::TargetMachine *targetMachine = this->GetTargetMachine();
+        // Create TargetMachine
+        std::string triple = GetTripleString();
+
+        llvm::Reloc::Model relocModel = m_generatePIC ? llvm::Reloc::PIC_ :
+            llvm::Reloc::Default;
+        std::string featuresString = m_attributes;
+        llvm::TargetOptions options;
+#if !defined(LLVM_3_1)
+        if (g->opt.disableFMA == false)
+            options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
+#endif // !LLVM_3_1
+        m_targetMachine =
+            m_target->createTargetMachine(triple, m_cpu, featuresString, options,
+                    relocModel);
+        Assert(m_targetMachine != NULL);
+
+        m_targetMachine->setAsmVerbosityDefault(true);
+
+        // Set is32Bit
 #if defined(LLVM_3_1)
-        const llvm::TargetData *targetData = targetMachine->getTargetData();
+        const llvm::TargetData *targetData = m_targetMachine->getTargetData();
         this->m_is32Bit = (targetData->getPointerSize() == 4);
 #else
         int addressSpace = 0;
-        const llvm::DataLayout *dataLayout = targetMachine->getDataLayout();
+        const llvm::DataLayout *dataLayout = m_targetMachine->getDataLayout();
         this->m_is32Bit = (dataLayout->getPointerSize(addressSpace) == 4);
 #endif
 
@@ -507,28 +526,6 @@ Target::GetTripleString() const {
 }
 
 
-llvm::TargetMachine *
-Target::GetTargetMachine() const {
-    std::string triple = GetTripleString();
-
-    llvm::Reloc::Model relocModel = m_generatePIC ? llvm::Reloc::PIC_ :
-                                                  llvm::Reloc::Default;
-    std::string featuresString = m_attributes;
-    llvm::TargetOptions options;
-#if !defined(LLVM_3_1)
-    if (g->opt.disableFMA == false)
-        options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
-#endif // !LLVM_3_1
-    llvm::TargetMachine *targetMachine =
-        m_target->createTargetMachine(triple, m_cpu, featuresString, options,
-                                    relocModel);
-    Assert(targetMachine != NULL);
-
-    targetMachine->setAsmVerbosityDefault(true);
-    return targetMachine;
-}
-
-
 const char *
 Target::GetISAString() const {
     switch (m_isa) {

ispc.h

@@ -187,7 +187,7 @@ public:
 
     /** Returns the LLVM TargetMachine object corresponding to this
         target. */
-    llvm::TargetMachine *GetTargetMachine() const;
+    llvm::TargetMachine *GetTargetMachine() const {return m_targetMachine;}
 
     /** Returns a string like "avx" encoding the target. */
     const char *GetISAString() const;
@@ -251,6 +251,16 @@ private:
     /** llvm Target object representing this target. */
     const llvm::Target *m_target;
 
+    /** llvm TargetMachine.
+        Note that it's not destroyed during Target destruction, as
+        Module::CompileAndOutput() uses TargetMachines after Target is destroyed.
+        This needs to be changed.
+        It's also worth noticing, that DataLayout of TargetMachine cannot be
+        modified and for generic targets it's not what we really need, so it
+        must not be used.
+        */
+    llvm::TargetMachine *m_targetMachine;
+
     /** flag to report invalid state after construction
         (due to bad parameters passed to constructor). */
     bool m_valid;