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Merge pull request #23883 from JuliaLang/jn/fix-static-align
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codegen-opt: fix stack alignment
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@yuyichao
yuyichao authored Sep 27, 2017
2 parents d7e7d31 + 9eb9a10 commit b3dc531
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Showing 4 changed files with 20 additions and 35 deletions.
23 changes: 12 additions & 11 deletions src/cgutils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1168,10 +1168,7 @@ static Value *emit_bounds_check(jl_codectx_t &ctx, const jl_cgval_t &ainfo, jl_v
// If given alignment is 0 and LLVM's assumed alignment for a load/store via ptr
// might be stricter than the Julia alignment for jltype, return the alignment of jltype.
// Otherwise return the given alignment.
//
// Parameter ptr should be the pointer argument for the LoadInst or StoreInst.
// It is currently unused, but might be used in the future for a more precise answer.
static unsigned julia_alignment(Value* /*ptr*/, jl_value_t *jltype, unsigned alignment)
static unsigned julia_alignment(jl_value_t *jltype, unsigned alignment)
{
if (!alignment) {
alignment = jl_datatype_align(jltype);
Expand Down Expand Up @@ -1207,7 +1204,7 @@ static jl_cgval_t typed_load(jl_codectx_t &ctx, Value *ptr, Value *idx_0based, j
//}
//else {
Instruction *load = ctx.builder.CreateAlignedLoad(data, isboxed ?
alignment : julia_alignment(data, jltype, alignment), false);
alignment : julia_alignment(jltype, alignment), false);
if (isboxed)
load = maybe_mark_load_dereferenceable(load, true, jltype);
if (tbaa) {
Expand Down Expand Up @@ -1254,7 +1251,7 @@ static void typed_store(jl_codectx_t &ctx,
data = ptr;
}
Instruction *store = ctx.builder.CreateAlignedStore(r, ctx.builder.CreateGEP(data,
idx_0based), isboxed ? alignment : julia_alignment(r, jltype, alignment));
idx_0based), isboxed ? alignment : julia_alignment(jltype, alignment));
if (tbaa)
tbaa_decorate(tbaa, store);
}
Expand Down Expand Up @@ -1290,6 +1287,9 @@ static Value *data_pointer(jl_codectx_t &ctx, const jl_cgval_t &x, Type *astype
static void emit_memcpy_llvm(jl_codectx_t &ctx, Value *dst, Value *src,
uint64_t sz, unsigned align, bool is_volatile, MDNode *tbaa)
{
if (sz == 0)
return;
assert(align && "align must be specified");
// If the types are small and simple, use load and store directly.
// Going through memcpy can cause LLVM (e.g. SROA) to create bitcasts between float and int
// that interferes with other optimizations.
Expand Down Expand Up @@ -1466,7 +1466,7 @@ static jl_cgval_t emit_getfield_knownidx(jl_codectx_t &ctx, const jl_cgval_t &st
addr = ctx.builder.CreateStructGEP(lt, ptr, idx);
}
}
int align = jl_field_align(jt, idx);
unsigned align = jl_field_align(jt, idx);
if (jl_field_isptr(jt, idx)) {
bool maybe_null = idx >= (unsigned)jt->ninitialized;
Instruction *Load = maybe_mark_load_dereferenceable(
Expand Down Expand Up @@ -1733,7 +1733,7 @@ static Value *emit_array_nd_index(
#endif
Value **idxs = (Value**)alloca(sizeof(Value*) * nidxs);
for (size_t k = 0; k < nidxs; k++) {
idxs[k] = emit_unbox(ctx, T_size, argv[k], NULL);
idxs[k] = emit_unbox(ctx, T_size, argv[k], (jl_value_t*)jl_long_type); // type asserted by caller
}
Value *ii;
for (size_t k = 0; k < nidxs; k++) {
Expand Down Expand Up @@ -2154,7 +2154,8 @@ static void emit_unionmove(jl_codectx_t &ctx, Value *dest, const jl_cgval_t &src
dest = emit_bitcast(ctx, dest, T_pint8);
if (skip) // copy dest -> dest to simulate an undef value / conditional copy
src_ptr = ctx.builder.CreateSelect(skip, dest, src_ptr);
emit_memcpy(ctx, dest, src_ptr, jl_datatype_size(typ), 0, isVolatile, tbaa);
unsigned alignment = julia_alignment(typ, 0);
emit_memcpy(ctx, dest, src_ptr, jl_datatype_size(typ), alignment, isVolatile, tbaa);
}
}
}
Expand All @@ -2172,7 +2173,7 @@ static void emit_unionmove(jl_codectx_t &ctx, Value *dest, const jl_cgval_t &src
bool allunboxed = for_each_uniontype_small(
[&](unsigned idx, jl_datatype_t *jt) {
unsigned nb = jl_datatype_size(jt);
unsigned alignment = 0;
unsigned alignment = julia_alignment((jl_value_t*)jt, 0);
BasicBlock *tempBB = BasicBlock::Create(jl_LLVMContext, "union_move", ctx.f);
ctx.builder.SetInsertPoint(tempBB);
switchInst->addCase(ConstantInt::get(T_int8, idx), tempBB);
Expand Down Expand Up @@ -2310,7 +2311,7 @@ static void emit_setfield(jl_codectx_t &ctx,
}
}
else {
int align = jl_field_align(sty, idx0);
unsigned align = jl_field_align(sty, idx0);
typed_store(ctx, addr, ConstantInt::get(T_size, 0), rhs, jfty,
strct.tbaa, data_pointer(ctx, strct, T_pjlvalue), align);
}
Expand Down
10 changes: 5 additions & 5 deletions src/codegen.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4050,7 +4050,7 @@ static void emit_cfunc_invalidate(
}
else {
gf_ret = emit_bitcast(ctx, gf_ret, gfrt->getPointerTo());
ctx.builder.CreateRet(ctx.builder.CreateLoad(gf_ret));
ctx.builder.CreateRet(ctx.builder.CreateAlignedLoad(gf_ret, julia_alignment(astrt, 0)));
}
break;
}
Expand Down Expand Up @@ -4598,7 +4598,7 @@ static Function *gen_jlcall_wrapper(jl_method_instance_t *lam, const jl_returnin
if (lty != NULL && !isboxed) {
theArg = decay_derived(emit_bitcast(ctx, theArg, PointerType::get(lty, 0)));
if (!lty->isAggregateType()) // keep "aggregate" type values in place as pointers
theArg = ctx.builder.CreateAlignedLoad(theArg, julia_alignment(theArg, ty, 0));
theArg = ctx.builder.CreateAlignedLoad(theArg, julia_alignment(ty, 0));
}
assert(dyn_cast<UndefValue>(theArg) == NULL);
args[idx] = theArg;
Expand Down Expand Up @@ -4684,7 +4684,7 @@ static jl_returninfo_t get_specsig_function(Module *M, const std::string &name,
jl_returninfo_t props = {};
SmallVector<Type*, 8> fsig;
Type *rt;
if (jlrettype == (jl_value_t*)jl_void_type) {
if (jl_is_structtype(jlrettype) && jl_is_datatype_singleton((jl_datatype_t*)jlrettype)) {
rt = T_void;
props.cc = jl_returninfo_t::Register;
}
Expand Down Expand Up @@ -5695,9 +5695,9 @@ static std::unique_ptr<Module> emit_function(
if (returninfo.cc == jl_returninfo_t::SRet) {
assert(jl_is_leaf_type(jlrettype));
emit_memcpy(ctx, sret, retvalinfo, jl_datatype_size(jlrettype),
returninfo.union_minalign);
julia_alignment(jlrettype, 0));
}
else {
else { // must be jl_returninfo_t::Union
emit_unionmove(ctx, sret, retvalinfo, isboxed_union, false, NULL);
}
}
Expand Down
17 changes: 2 additions & 15 deletions src/intrinsics.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -341,17 +341,8 @@ static Value *emit_unbox(jl_codectx_t &ctx, Type *to, const jl_cgval_t &x, jl_va
return NULL;
}

int alignment;
if (jt) {
alignment = julia_alignment(p, jt, 0);
}
else {
// stack has default alignment
alignment = 0;
}
unsigned alignment = julia_alignment(jt, 0);
if (dest) {
// callers using the dest argument only use it for a stack slot for now
alignment = 0;
MDNode *tbaa = x.tbaa;
// the memcpy intrinsic does not allow to specify different alias tags
// for the load part (x.tbaa) and the store part (tbaa_stack).
Expand All @@ -363,11 +354,7 @@ static Value *emit_unbox(jl_codectx_t &ctx, Type *to, const jl_cgval_t &x, jl_va
return NULL;
}
else {
Instruction *load;
if (alignment)
load = ctx.builder.CreateAlignedLoad(p, alignment);
else
load = ctx.builder.CreateLoad(p);
Instruction *load = ctx.builder.CreateAlignedLoad(p, alignment);
return tbaa_decorate(x.tbaa, load);
}
}
Expand Down
5 changes: 1 addition & 4 deletions src/llvm-alloc-opt.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -715,10 +715,7 @@ bool AllocOpt::runOnFunction(Function &F)
sz += align;
}
else if (sz > 1) {
align = JL_SMALL_BYTE_ALIGNMENT;
while (sz < align) {
align = align / 2;
}
align = llvm::MinAlign(JL_SMALL_BYTE_ALIGNMENT, llvm::NextPowerOf2(sz));
}
// No debug info for prolog instructions
IRBuilder<> prolog_builder(&entry.front());
Expand Down

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