Factor a loop out of LateLowerGCFrame::runOnFunction and into GCLower…

…ingRefs

src/llvm-late-gc-helpers.cpp

@@ -21,8 +21,10 @@ void GCLoweringRefs::initFunctions(Module &M) {
 }
 
 void GCLoweringRefs::initAll(Module &M) {
+    // First initialize the functions.
     initFunctions(M);
 
+    // Then initialize types and metadata nodes.
     auto &ctx = M.getContext();
     T_size = M.getDataLayout().getIntPtrType(ctx);
     T_int8 = Type::getInt8Ty(ctx);
@@ -56,3 +58,15 @@ void GCLoweringRefs::initAll(Module &M) {
         T_ppjlvalue_der = nullptr;
     }
 }
+
+llvm::CallInst *GCLoweringRefs::getPtls(llvm::Function &F) {
+    for (auto I = F.getEntryBlock().begin(), E = F.getEntryBlock().end();
+         ptls_getter && I != E; ++I) {
+        if (CallInst *callInst = dyn_cast<CallInst>(&*I)) {
+            if (callInst->getCalledValue() == ptls_getter) {
+                return callInst;
+            }
+        }
+    }
+    return nullptr;
+}

src/llvm-late-gc-helpers.h

@@ -4,12 +4,13 @@
 #define LLVM_LATE_GC_HELPERS_H
 
 #include <llvm/IR/Function.h>
+#include <llvm/IR/Instructions.h>
 #include <llvm/IR/Metadata.h>
 #include <llvm/IR/Module.h>
 #include <llvm/IR/Type.h>
 
 // A data structure that contains references to platform-agnostic GC lowering
-// types, metadata and functions.
+// types and functions.
 struct GCLoweringRefs {
     llvm::Type *T_prjlvalue;
     llvm::Type *T_ppjlvalue;
@@ -20,8 +21,6 @@ struct GCLoweringRefs {
     llvm::Type *T_pjlvalue;
     llvm::Type *T_pjlvalue_der;
     llvm::Type *T_ppjlvalue_der;
-    llvm::MDNode *tbaa_gcframe;
-    llvm::MDNode *tbaa_tag;
     llvm::Function *ptls_getter;
     llvm::Function *gc_flush_func;
     llvm::Function *gc_preserve_begin_func;
@@ -36,6 +35,11 @@ struct GCLoweringRefs {
 
     // Initializes a GC lowering refs structure's functions only.
     void initFunctions(llvm::Module &M);
+
+    // Gets a call to the `julia.ptls_states` intrinisc in the entry
+    // point of the given function, if there exists such as call.
+    // Otherwise, `nullptr` is returned.
+    llvm::CallInst *getPtls(llvm::Function &F);
 };
 
 #endif

src/llvm-late-gc-lowering.cpp

@@ -320,6 +320,8 @@ struct LateLowerGCFrame: public FunctionPass, private GCLoweringRefs {
     }
 
 private:
+    llvm::MDNode *tbaa_gcframe;
+    llvm::MDNode *tbaa_tag;
     Function *queueroot_func;
     Function *pool_alloc_func;
     Function *big_alloc_func;
@@ -2100,16 +2102,8 @@ bool LateLowerGCFrame::runOnFunction(Function &F) {
     initFunctions(*F.getParent());
     if (!ptls_getter)
         return CleanupIR(F);
-    ptlsStates = nullptr;
-    for (auto I = F.getEntryBlock().begin(), E = F.getEntryBlock().end();
-         ptls_getter && I != E; ++I) {
-        if (CallInst *callInst = dyn_cast<CallInst>(&*I)) {
-            if (callInst->getCalledValue() == ptls_getter) {
-                ptlsStates = callInst;
-                break;
-            }
-        }
-    }
+
+    ptlsStates = getPtls(F);
     if (!ptlsStates)
         return CleanupIR(F);
     State S = LocalScan(F);