rewrite

Author: wsmoses

src/llvm-alloc-helpers.cpp

@@ -89,7 +89,7 @@ bool AllocUseInfo::addMemOp(Instruction *inst, unsigned opno, uint32_t offset,
     memop.isobjref = hasObjref(elty);
     auto &field = getField(offset, size, elty);
 
-    field.second.hasbits |= !hasObjref(elty) || (hasObjref(elty) && !isa<PointerType>(elty));
+    field.second.hasunboxed |= !hasObjref(elty) || (hasObjref(elty) && !isa<PointerType>(elty));
 
     if (field.second.hasobjref != memop.isobjref)
         field.second.multiloc = true; // can't split this field, since it contains a mix of references and bits
@@ -201,7 +201,7 @@ void jl_alloc::runEscapeAnalysis(llvm::CallInst *I, EscapeAnalysisRequiredArgs r
                 auto elty = inst->getType();
                 required.use_info.has_unknown_objref |= hasObjref(elty);
                 required.use_info.has_unknown_objrefaggr |= hasObjref(elty) && !isa<PointerType>(elty);
-                required.use_info.has_unknown_bits |= !hasObjref(elty) || (hasObjref(elty) && !isa<PointerType>(elty));
+                required.use_info.has_unknown_unboxed |= !hasObjref(elty) || (hasObjref(elty) && !isa<PointerType>(elty));
                 required.use_info.hasunknownmem = true;
             } else if (!required.use_info.addMemOp(inst, 0, cur.offset,
                                                                inst->getType(),
@@ -293,7 +293,7 @@ void jl_alloc::runEscapeAnalysis(llvm::CallInst *I, EscapeAnalysisRequiredArgs r
                 auto elty = storev->getType();
                 required.use_info.has_unknown_objref |= hasObjref(elty);
                 required.use_info.has_unknown_objrefaggr |= hasObjref(elty) && !isa<PointerType>(elty);
-                required.use_info.has_unknown_bits |= !hasObjref(elty) || (hasObjref(elty) && !isa<PointerType>(elty));
+                required.use_info.has_unknown_unboxed |= !hasObjref(elty) || (hasObjref(elty) && !isa<PointerType>(elty));
                 required.use_info.hasunknownmem = true;
             } else if (!required.use_info.addMemOp(inst, use->getOperandNo(),
                                                                cur.offset, storev->getType(),
@@ -322,7 +322,7 @@ void jl_alloc::runEscapeAnalysis(llvm::CallInst *I, EscapeAnalysisRequiredArgs r
                 LLVM_DEBUG(dbgs() << "Atomic inst has unknown offset\n");
                 required.use_info.has_unknown_objref |= hasObjref(elty);
                 required.use_info.has_unknown_objrefaggr |= hasObjref(elty) && !isa<PointerType>(elty);
-                required.use_info.has_unknown_bits |= !hasObjref(elty) || (hasObjref(elty) && !isa<PointerType>(elty));
+                required.use_info.has_unknown_unboxed |= !hasObjref(elty) || (hasObjref(elty) && !isa<PointerType>(elty));
                 required.use_info.hasunknownmem = true;
             }
             required.use_info.refload = true;

src/llvm-alloc-helpers.h

@@ -47,7 +47,7 @@ namespace jl_alloc {
         bool multiloc:1;
         bool hasload:1;
         // The alloc has a non-julia object at this offset.
-        bool hasbits:1;
+        bool hasunboxed:1;
         llvm::Type *elty;
         llvm::SmallVector<MemOp,4> accesses;
         Field(uint32_t size, llvm::Type *elty)
@@ -56,7 +56,7 @@ namespace jl_alloc {
               hasaggr(false),
               multiloc(false),
               hasload(false),
-              hasbits(false),
+              hasunboxed(false),
               elty(elty)
         {
         }
@@ -99,7 +99,7 @@ namespace jl_alloc {
         bool has_unknown_objrefaggr:1;
 
         // The alloc has a non-julia object at an unknown offset.
-        bool has_unknown_bits:1;
+        bool has_unknown_unboxed:1;
 
         void reset()
         {
@@ -116,7 +116,7 @@ namespace jl_alloc {
             allockind = llvm::AllocFnKind::Unknown;
             has_unknown_objref = false;
             has_unknown_objrefaggr = false;
-            has_unknown_bits = false;
+            has_unknown_unboxed = false;
             uses.clear();
             preserves.clear();
             memops.clear();

src/llvm-alloc-opt.cpp

@@ -252,12 +252,12 @@ void Optimizer::optimizeAll()
             removeAlloc(orig);
             continue;
         }
-        bool has_bits = use_info.has_unknown_bits;
+        bool has_unboxed = use_info.has_unknown_bits;
         bool has_ref = use_info.has_unknown_objref;
         bool has_refaggr = use_info.has_unknown_objrefaggr;
         for (auto memop: use_info.memops) {
             auto &field = memop.second;
-            has_bits |= field.hasbits;
+            has_unboxed |= field.hasbits;
             if (field.hasobjref) {
                 has_ref = true;
                 // This can be relaxed a little based on hasload
@@ -286,7 +286,11 @@ void Optimizer::optimizeAll()
             splitOnStack(orig);
             continue;
         }
-        if (has_bits && has_ref) {
+        // The move to stack code below, if has_ref is set, changes the allocation to an array of jlvalue_t's. This is fine
+        // if all objects are jlvalue_t's. However, if part of the allocation is not a julia object (e.g. it is a { float, jlvaluet }),
+        // then the moveToStackCAll will create a [2 x jlvaluet] bitcast to { float, jlvaluet }. The float clearly is not a GC
+        // value and will result in segfaults and other problems.
+        if (has_unboxed && has_ref) {
             REMARK([&]() {
                 return OptimizationRemarkMissed(DEBUG_TYPE, "Escaped", orig)
                     << "GC allocation could not be split and contained both julia object and non-julia-object data, unable to move to stack " << ore::NV("GC Allocation", orig);