drop typed GEP calls (JuliaLang#55708)

Now that we use LLVM 18, and almost have LLVM 19 support, do cleanup to remove LLVM 15/16 type pointer support. LLVM now slightly prefers that we rewrite our complex GEP to use a simple emit_ptrgep call instead, which is also much simpler for julia to emit also.
achuchmala · Sep 10, 2024 · 3653b38 · 3653b38
1 parent d280792
commit 3653b38
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Showing 12 changed files with 187 additions and 350 deletions.
diff --git a/src/ccall.cpp b/src/ccall.cpp
@@ -1854,8 +1854,8 @@ static jl_cgval_t emit_ccall(jl_codectx_t &ctx, jl_value_t **args, size_t nargs)
         ctx.builder.SetInsertPoint(checkBB);
         auto signal_page_load = ctx.builder.CreateLoad(
                 ctx.types().T_size,
-                ctx.builder.CreateConstInBoundsGEP1_32(ctx.types().T_size,
-                    get_current_signal_page_from_ptls(ctx.builder, ctx.types().T_size, get_current_ptls(ctx), ctx.tbaa().tbaa_const), -1),
+                emit_ptrgep(ctx, get_current_signal_page_from_ptls(ctx.builder, get_current_ptls(ctx), ctx.tbaa().tbaa_const),
+                    -sizeof(size_t)),
                 true);
         setName(ctx.emission_context, signal_page_load, "signal_page_load");
         ctx.builder.CreateBr(contBB);
@@ -1870,8 +1870,7 @@ static jl_cgval_t emit_ccall(jl_codectx_t &ctx, jl_value_t **args, size_t nargs)
         auto obj = emit_pointer_from_objref(ctx, boxed(ctx, argv[0])); // T_pprjlvalue
         // The inbounds gep makes it more clear to LLVM that the resulting value is not
         // a null pointer.
-        auto strp = ctx.builder.CreateConstInBoundsGEP1_32(ctx.types().T_prjlvalue, obj, 1);
-        setName(ctx.emission_context, strp, "string_ptr");
+        auto strp = emit_ptrgep(ctx, obj, ctx.types().sizeof_ptr, "string_ptr");
         JL_GC_POP();
         return mark_or_box_ccall_result(ctx, strp, retboxed, rt, unionall, static_rt);
     }
@@ -1882,9 +1881,7 @@ static jl_cgval_t emit_ccall(jl_codectx_t &ctx, jl_value_t **args, size_t nargs)
         auto obj = emit_pointer_from_objref(ctx, boxed(ctx, argv[0])); // T_pprjlvalue
         // The inbounds gep makes it more clear to LLVM that the resulting value is not
         // a null pointer.
-        auto strp = ctx.builder.CreateConstInBoundsGEP1_32(
-            ctx.types().T_prjlvalue, obj, (sizeof(jl_sym_t) + sizeof(void*) - 1) / sizeof(void*));
-        setName(ctx.emission_context, strp, "symbol_name");
+        auto strp = emit_ptrgep(ctx, obj, sizeof(jl_sym_t), "symbol_name");
         JL_GC_POP();
         return mark_or_box_ccall_result(ctx, strp, retboxed, rt, unionall, static_rt);
     }

diff --git a/src/cgutils.cpp b/src/cgutils.cpp
diff --git a/src/codegen.cpp b/src/codegen.cpp
diff --git a/src/intrinsics.cpp b/src/intrinsics.cpp
@@ -767,7 +767,7 @@ static jl_cgval_t emit_pointerref(jl_codectx_t &ctx, ArrayRef<jl_cgval_t> argv)
                     LLT_ALIGN(size, jl_datatype_align(ety))));
         setName(ctx.emission_context, im1, "pointerref_offset");
         Value *thePtr = emit_unbox(ctx, getPointerTy(ctx.builder.getContext()), e, e.typ);
-        thePtr = ctx.builder.CreateInBoundsGEP(getInt8Ty(ctx.builder.getContext()), thePtr, im1);
+        thePtr = emit_ptrgep(ctx, thePtr, im1);
         setName(ctx.emission_context, thePtr, "pointerref_src");
         MDNode *tbaa = best_tbaa(ctx.tbaa(), ety);
         emit_memcpy(ctx, strct, jl_aliasinfo_t::fromTBAA(ctx, tbaa), thePtr, jl_aliasinfo_t::fromTBAA(ctx, nullptr), size, Align(sizeof(jl_value_t*)), Align(align_nb));
@@ -848,7 +848,7 @@ static jl_cgval_t emit_pointerset(jl_codectx_t &ctx, ArrayRef<jl_cgval_t> argv)
         im1 = ctx.builder.CreateMul(im1, ConstantInt::get(ctx.types().T_size,
                     LLT_ALIGN(size, jl_datatype_align(ety))));
         setName(ctx.emission_context, im1, "pointerset_offset");
-        auto gep = ctx.builder.CreateInBoundsGEP(getInt8Ty(ctx.builder.getContext()), thePtr, im1);
+        auto gep = emit_ptrgep(ctx, thePtr, im1);
         setName(ctx.emission_context, gep, "pointerset_ptr");
         emit_memcpy(ctx, gep, jl_aliasinfo_t::fromTBAA(ctx, nullptr), x, size, Align(align_nb), Align(julia_alignment(ety)));
     }

diff --git a/src/llvm-alloc-opt.cpp b/src/llvm-alloc-opt.cpp
@@ -770,26 +770,7 @@ void Optimizer::moveToStack(CallInst *orig_inst, size_t sz, bool has_ref, AllocF
             user->replaceUsesOfWith(orig_i, replace);
         }
         else if (isa<AddrSpaceCastInst>(user) || isa<BitCastInst>(user)) {
-            #if JL_LLVM_VERSION >= 170000
-            #ifndef JL_NDEBUG
-            auto cast_t = PointerType::get(user->getType(), new_i->getType()->getPointerAddressSpace());
-            Type *new_t = new_i->getType();
-            assert(cast_t == new_t);
-            #endif
-            auto replace_i = new_i;
-            #else
-            auto cast_t = PointerType::getWithSamePointeeType(cast<PointerType>(user->getType()), new_i->getType()->getPointerAddressSpace());
-            auto replace_i = new_i;
-            Type *new_t = new_i->getType();
-            if (cast_t != new_t) {
-                // Shouldn't get here when using opaque pointers, so the new BitCastInst is fine
-                assert(cast_t->getContext().supportsTypedPointers());
-                replace_i = new BitCastInst(replace_i, cast_t, "", user);
-                replace_i->setDebugLoc(user->getDebugLoc());
-                replace_i->takeName(user);
-            }
-            #endif
-            push_frame(user, replace_i);
+            push_frame(user, new_i);
         }
         else if (auto gep = dyn_cast<GetElementPtrInst>(user)) {
             SmallVector<Value *, 4> IdxOperands(gep->idx_begin(), gep->idx_end());

diff --git a/src/llvm-codegen-shared.h b/src/llvm-codegen-shared.h
@@ -125,7 +125,7 @@ struct CountTrackedPointers {
     CountTrackedPointers(llvm::Type *T, bool ignore_loaded=false);
 };
 
-unsigned TrackWithShadow(llvm::Value *Src, llvm::Type *T, bool isptr, llvm::Value *Dst, llvm::Type *DTy, llvm::IRBuilder<> &irbuilder);
+unsigned TrackWithShadow(llvm::Value *Src, llvm::Type *T, bool isptr, llvm::Value *Dst, llvm::IRBuilder<> &irbuilder);
 llvm::SmallVector<llvm::Value*, 0> ExtractTrackedValues(llvm::Value *Src, llvm::Type *STy, bool isptr, llvm::IRBuilder<> &irbuilder, llvm::ArrayRef<unsigned> perm_offsets={});
 
 static inline void llvm_dump(llvm::Value *v)
@@ -187,45 +187,39 @@ static inline llvm::Instruction *tbaa_decorate(llvm::MDNode *md, llvm::Instructi
 }
 
 // Get PTLS through current task.
-static inline llvm::Value *get_current_task_from_pgcstack(llvm::IRBuilder<> &builder, llvm::Type *T_size, llvm::Value *pgcstack)
+static inline llvm::Value *get_current_task_from_pgcstack(llvm::IRBuilder<> &builder, llvm::Value *pgcstack)
 {
     using namespace llvm;
-    auto T_pjlvalue = JuliaType::get_pjlvalue_ty(builder.getContext());
+    auto i8 = builder.getInt8Ty();
     const int pgcstack_offset = offsetof(jl_task_t, gcstack);
-    return builder.CreateInBoundsGEP(
-            T_pjlvalue, pgcstack,
-            ConstantInt::get(T_size, -(pgcstack_offset / sizeof(void *))),
-            "current_task");
+    return builder.CreateConstInBoundsGEP1_32(i8, pgcstack, -pgcstack_offset, "current_task");
 }
 
 // Get PTLS through current task.
-static inline llvm::Value *get_current_ptls_from_task(llvm::IRBuilder<> &builder, llvm::Type *T_size, llvm::Value *current_task, llvm::MDNode *tbaa)
+static inline llvm::Value *get_current_ptls_from_task(llvm::IRBuilder<> &builder, llvm::Value *current_task, llvm::MDNode *tbaa)
 {
     using namespace llvm;
-    auto T_pjlvalue = JuliaType::get_pjlvalue_ty(builder.getContext());
+    auto i8 = builder.getInt8Ty();
+    auto T_ptr = builder.getPtrTy();
     const int ptls_offset = offsetof(jl_task_t, ptls);
-    llvm::Value *pptls = builder.CreateInBoundsGEP(
-            T_pjlvalue, current_task,
-            ConstantInt::get(T_size, ptls_offset / sizeof(void *)),
-            "ptls_field");
-    LoadInst *ptls_load = builder.CreateAlignedLoad(T_pjlvalue,
-            pptls, Align(sizeof(void *)), "ptls_load");
+    llvm::Value *pptls = builder.CreateConstInBoundsGEP1_32(i8, current_task, ptls_offset, "ptls_field");
+    LoadInst *ptls_load = builder.CreateAlignedLoad(T_ptr, pptls, Align(sizeof(void *)), "ptls_load");
     // Note: Corresponding store (`t->ptls = ptls`) happens in `ctx_switch` of tasks.c.
     tbaa_decorate(tbaa, ptls_load);
     return ptls_load;
 }
 
 // Get signal page through current task.
-static inline llvm::Value *get_current_signal_page_from_ptls(llvm::IRBuilder<> &builder, llvm::Type *T_size, llvm::Value *ptls, llvm::MDNode *tbaa)
+static inline llvm::Value *get_current_signal_page_from_ptls(llvm::IRBuilder<> &builder, llvm::Value *ptls, llvm::MDNode *tbaa)
 {
     using namespace llvm;
     // return builder.CreateCall(prepare_call(reuse_signal_page_func));
-    auto T_psize = T_size->getPointerTo();
-    int nthfield = offsetof(jl_tls_states_t, safepoint) / sizeof(void *);
-    llvm::Value *psafepoint = builder.CreateInBoundsGEP(
-            T_psize, ptls, ConstantInt::get(T_size, nthfield));
+    auto T_ptr = builder.getPtrTy();
+    auto i8 = builder.getInt8Ty();
+    int nthfield = offsetof(jl_tls_states_t, safepoint);
+    llvm::Value *psafepoint = builder.CreateConstInBoundsGEP1_32(i8, ptls, nthfield);
     LoadInst *ptls_load = builder.CreateAlignedLoad(
-            T_psize, psafepoint, Align(sizeof(void *)), "safepoint");
+            T_ptr, psafepoint, Align(sizeof(void *)), "safepoint");
     tbaa_decorate(tbaa, ptls_load);
     return ptls_load;
 }
@@ -239,7 +233,7 @@ static inline void emit_signal_fence(llvm::IRBuilder<> &builder)
 static inline void emit_gc_safepoint(llvm::IRBuilder<> &builder, llvm::Type *T_size, llvm::Value *ptls, llvm::MDNode *tbaa, bool final = false)
 {
     using namespace llvm;
-    llvm::Value *signal_page = get_current_signal_page_from_ptls(builder, T_size, ptls, tbaa);
+    llvm::Value *signal_page = get_current_signal_page_from_ptls(builder, ptls, tbaa);
     emit_signal_fence(builder);
     Module *M = builder.GetInsertBlock()->getModule();
     LLVMContext &C = builder.getContext();
@@ -250,8 +244,7 @@ static inline void emit_gc_safepoint(llvm::IRBuilder<> &builder, llvm::Type *T_s
     else {
         Function *F = M->getFunction("julia.safepoint");
         if (!F) {
-            auto T_psize = T_size->getPointerTo();
-            FunctionType *FT = FunctionType::get(Type::getVoidTy(C), {T_psize}, false);
+            FunctionType *FT = FunctionType::get(Type::getVoidTy(C), {T_size->getPointerTo()}, false);
             F = Function::Create(FT, Function::ExternalLinkage, "julia.safepoint", M);
 #if JL_LLVM_VERSION >= 160000
             F->setMemoryEffects(MemoryEffects::inaccessibleOrArgMemOnly());
@@ -268,8 +261,8 @@ static inline llvm::Value *emit_gc_state_set(llvm::IRBuilder<> &builder, llvm::T
 {
     using namespace llvm;
     Type *T_int8 = state->getType();
-    Constant *offset = ConstantInt::getSigned(builder.getInt32Ty(), offsetof(jl_tls_states_t, gc_state));
-    Value *gc_state = builder.CreateInBoundsGEP(T_int8, ptls, ArrayRef<Value*>(offset), "gc_state");
+    unsigned offset = offsetof(jl_tls_states_t, gc_state);
+    Value *gc_state = builder.CreateConstInBoundsGEP1_32(T_int8, ptls, offset, "gc_state");
     if (old_state == nullptr) {
         old_state = builder.CreateLoad(T_int8, gc_state);
         cast<LoadInst>(old_state)->setOrdering(AtomicOrdering::Monotonic);

diff --git a/src/llvm-late-gc-lowering.cpp b/src/llvm-late-gc-lowering.cpp
@@ -350,15 +350,7 @@ void LateLowerGCFrame::LiftSelect(State &S, SelectInst *SI) {
                     ConstantInt::get(Type::getInt32Ty(Cond->getContext()), i),
                     "", SI);
         }
-        #if JL_LLVM_VERSION >= 170000
         assert(FalseElem->getType() == TrueElem->getType());
-        #else
-        if (FalseElem->getType() != TrueElem->getType()) {
-            // Shouldn't get here when using opaque pointers, so the new BitCastInst is fine
-            assert(FalseElem->getContext().supportsTypedPointers());
-            FalseElem = new BitCastInst(FalseElem, TrueElem->getType(), "", SI);
-        }
-        #endif
         SelectInst *SelectBase = SelectInst::Create(Cond, TrueElem, FalseElem, "gclift", SI);
         int Number = ++S.MaxPtrNumber;
         S.AllPtrNumbering[SelectBase] = Number;
@@ -427,33 +419,7 @@ void LateLowerGCFrame::LiftPhi(State &S, PHINode *Phi) {
                 BaseElem = Base;
             else
                 BaseElem = IncomingBases[i];
-            #if JL_LLVM_VERSION >= 170000
             assert(BaseElem->getType() == T_prjlvalue);
-            #else
-            if (BaseElem->getType() != T_prjlvalue) {
-                // Shouldn't get here when using opaque pointers, so the new BitCastInst is fine
-                assert(BaseElem->getContext().supportsTypedPointers());
-                auto &remap = CastedRoots[i][BaseElem];
-                if (!remap) {
-                    if (auto constant = dyn_cast<Constant>(BaseElem)) {
-                        remap = ConstantExpr::getBitCast(constant, T_prjlvalue, "");
-                    } else {
-                        Instruction *InsertBefore;
-                        if (auto arg = dyn_cast<Argument>(BaseElem)) {
-                            InsertBefore = &*arg->getParent()->getEntryBlock().getFirstInsertionPt();
-                        } else {
-                            assert(isa<Instruction>(BaseElem) && "Unknown value type detected!");
-                            InsertBefore = cast<Instruction>(BaseElem)->getNextNonDebugInstruction();
-                        }
-                        while (isa<PHINode>(InsertBefore)) {
-                            InsertBefore = InsertBefore->getNextNonDebugInstruction();
-                        }
-                        remap = new BitCastInst(BaseElem, T_prjlvalue, "", InsertBefore);
-                    }
-                }
-                BaseElem = remap;
-            }
-            #endif
             lift->addIncoming(BaseElem, IncomingBB);
         }
     }
@@ -1528,14 +1494,11 @@ SmallVector<Value*, 0> ExtractTrackedValues(Value *Src, Type *STy, bool isptr, I
     return Ptrs;
 }
 
-unsigned TrackWithShadow(Value *Src, Type *STy, bool isptr, Value *Dst, Type *DTy, IRBuilder<> &irbuilder) {
+unsigned TrackWithShadow(Value *Src, Type *STy, bool isptr, Value *Dst, IRBuilder<> &irbuilder) {
     auto Ptrs = ExtractTrackedValues(Src, STy, isptr, irbuilder);
     for (unsigned i = 0; i < Ptrs.size(); ++i) {
-        Value *Elem = Ptrs[i];// Dst has type `[n x {}*]*`
-        Value *Slot = irbuilder.CreateConstInBoundsGEP2_32(DTy, Dst, 0, i);
-        #if JL_LLVM_VERSION < 170000
-        assert(cast<PointerType>(Dst->getType())->isOpaqueOrPointeeTypeMatches(DTy));
-        #endif
+        Value *Elem = Ptrs[i];
+        Value *Slot = irbuilder.CreateConstInBoundsGEP1_32(irbuilder.getInt8Ty(), Dst, i * sizeof(void*));
         StoreInst *shadowStore = irbuilder.CreateAlignedStore(Elem, Slot, Align(sizeof(void*)));
         shadowStore->setOrdering(AtomicOrdering::NotAtomic);
         // TODO: shadowStore->setMetadata(LLVMContext::MD_tbaa, tbaa_gcframe);
@@ -2133,7 +2096,7 @@ bool LateLowerGCFrame::CleanupIR(Function &F, State *S, bool *CFGModified) {
                 // the type tag. (Note that if the size is not a constant, it will call
                 // gc_alloc_obj, and will redundantly set the tag.)
                 auto allocBytesIntrinsic = getOrDeclare(jl_intrinsics::GCAllocBytes);
-                auto ptls = get_current_ptls_from_task(builder, T_size, CI->getArgOperand(0), tbaa_gcframe);
+                auto ptls = get_current_ptls_from_task(builder, CI->getArgOperand(0), tbaa_gcframe);
                 auto newI = builder.CreateCall(
                     allocBytesIntrinsic,
                     {
@@ -2319,15 +2282,7 @@ void LateLowerGCFrame::PlaceGCFrameStore(State &S, unsigned R, unsigned MinColor
     // Pointee types don't have semantics, so the optimizer is
     // free to rewrite them if convenient. We need to change
     // it back here for the store.
-    #if JL_LLVM_VERSION >= 170000
     assert(Val->getType() == T_prjlvalue);
-    #else
-    if (Val->getType() != T_prjlvalue) {
-        // Shouldn't get here when using opaque pointers, so the new BitCastInst is fine
-        assert(Val->getContext().supportsTypedPointers());
-        Val = new BitCastInst(Val, T_prjlvalue, "", InsertBefore);
-    }
-    #endif
     new StoreInst(Val, slotAddress, InsertBefore);
 }
 
@@ -2407,18 +2362,7 @@ void LateLowerGCFrame::PlaceRootsAndUpdateCalls(SmallVectorImpl<int> &Colors, St
             for (CallInst *II : ToDelete) {
                 II->eraseFromParent();
             }
-            #if JL_LLVM_VERSION >= 170000
             assert(slotAddress->getType() == AI->getType());
-            #else
-            if (slotAddress->getType() != AI->getType()) {
-                // If we're replacing an ArrayAlloca, the pointer element type may need to be fixed up
-                // Shouldn't get here when using opaque pointers, so the new BitCastInst is fine
-                assert(slotAddress->getContext().supportsTypedPointers());
-                auto BCI  = new BitCastInst(slotAddress, AI->getType());
-                BCI->insertAfter(slotAddress);
-                slotAddress = BCI;
-            }
-            #endif
             AI->replaceAllUsesWith(slotAddress);
             AI->eraseFromParent();
             AI = NULL;
@@ -2443,15 +2387,7 @@ void LateLowerGCFrame::PlaceRootsAndUpdateCalls(SmallVectorImpl<int> &Colors, St
                 slotAddress->insertAfter(gcframe);
                 auto ValExpr = std::make_pair(Base, isa<PointerType>(Base->getType()) ? -1 : i);
                 auto Elem = MaybeExtractScalar(S, ValExpr, SI);
-                #if JL_LLVM_VERSION >= 170000
                 assert(Elem->getType() == T_prjlvalue);
-                #else
-                if (Elem->getType() != T_prjlvalue) {
-                    // Shouldn't get here when using opaque pointers, so the new BitCastInst is fine
-                    assert(Elem->getContext().supportsTypedPointers());
-                    Elem = new BitCastInst(Elem, T_prjlvalue, "", SI);
-                }
-                #endif
                 //auto Idxs = ArrayRef<unsigned>(Tracked[i]);
                 //Value *Elem = ExtractScalar(Base, true, Idxs, SI);
                 Value *shadowStore = new StoreInst(Elem, slotAddress, SI);

diff --git a/src/llvm-ptls.cpp b/src/llvm-ptls.cpp
@@ -191,7 +191,7 @@ void LowerPTLS::fix_pgcstack_use(CallInst *pgcstack, Function *pgcstack_getter,
         builder.SetInsertPoint(fastTerm->getParent());
         fastTerm->removeFromParent();
         MDNode *tbaa = tbaa_gcframe;
-        Value *prior = emit_gc_unsafe_enter(builder, T_size, get_current_ptls_from_task(builder, T_size, get_current_task_from_pgcstack(builder, T_size, pgcstack), tbaa), true);
+        Value *prior = emit_gc_unsafe_enter(builder, T_size, get_current_ptls_from_task(builder, get_current_task_from_pgcstack(builder, pgcstack), tbaa), true);
         builder.Insert(fastTerm);
         phi->addIncoming(pgcstack, fastTerm->getParent());
         // emit pre-return cleanup
@@ -203,7 +203,7 @@ void LowerPTLS::fix_pgcstack_use(CallInst *pgcstack, Function *pgcstack_getter,
             for (auto &BB : *pgcstack->getParent()->getParent()) {
                 if (isa<ReturnInst>(BB.getTerminator())) {
                     builder.SetInsertPoint(BB.getTerminator());
-                    emit_gc_unsafe_leave(builder, T_size, get_current_ptls_from_task(builder, T_size, get_current_task_from_pgcstack(builder, T_size, phi), tbaa), last_gc_state, true);
+                    emit_gc_unsafe_leave(builder, T_size, get_current_ptls_from_task(builder, get_current_task_from_pgcstack(builder, phi), tbaa), last_gc_state, true);
                 }
             }
         }

diff --git a/test/llvmpasses/alloc-opt-gcframe.ll b/test/llvmpasses/alloc-opt-gcframe.ll
@@ -10,7 +10,7 @@ target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 ; CHECK-NOT: @julia.gc_alloc_obj
 
 ; OPAQUE: %current_task = getelementptr inbounds ptr, ptr %gcstack, i64 -12
-; OPAQUE: [[ptls_field:%.*]] = getelementptr inbounds ptr, ptr %current_task, i64 16
+; OPAQUE: [[ptls_field:%.*]] = getelementptr inbounds i8, ptr %current_task,
 ; OPAQUE-NEXT: [[ptls_load:%.*]] = load ptr, ptr [[ptls_field]], align 8, !tbaa !0
 ; OPAQUE-NEXT: %v = call noalias nonnull align {{[0-9]+}} dereferenceable({{[0-9]+}}) ptr addrspace(10) @ijl_gc_small_alloc(ptr [[ptls_load]], i32 [[SIZE_T:[0-9]+]], i32 16, i64 {{.*}} @tag {{.*}})
 ; OPAQUE: store atomic ptr addrspace(10) @tag, ptr addrspace(10) {{.*}} unordered, align 8, !tbaa !4