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Mark array/string/svec size range (JuliaLang#37051)
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We require the length and size to both be signed integer so mark them as such for LLVM.
This helps removing some unnecessary sign checks when calling C functions that expect a `size_t`
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@yuyichao
yuyichao committed Aug 19, 2020
1 parent c15560e commit 72ffbf1
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Showing 3 changed files with 65 additions and 33 deletions.
2 changes: 1 addition & 1 deletion src/ccall.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1683,7 +1683,7 @@ static jl_cgval_t emit_ccall(jl_codectx_t &ctx, jl_value_t **args, size_t nargs)
LoadInst *load = ctx.builder.CreateAlignedLoad(T_prjlvalue, slot_addr, sizeof(void*));
load->setAtomic(AtomicOrdering::Unordered);
tbaa_decorate(tbaa_ptrarraybuf, load);
Value *res = ctx.builder.CreateZExt(ctx.builder.CreateICmpNE(load, Constant::getNullValue(T_prjlvalue)), T_int32);
Value *res = ctx.builder.CreateZExt(ctx.builder.CreateICmpNE(load, V_rnull), T_int32);
JL_GC_POP();
return mark_or_box_ccall_result(ctx, res, retboxed, rt, unionall, static_rt);
}
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60 changes: 48 additions & 12 deletions src/cgutils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -819,18 +819,18 @@ static Value *emit_nthptr_addr(jl_codectx_t &ctx, Value *v, Value *idx)
idx);
}

static Value *emit_nthptr_recast(jl_codectx_t &ctx, Value *v, Value *idx, MDNode *tbaa, Type *ptype)
static LoadInst *emit_nthptr_recast(jl_codectx_t &ctx, Value *v, Value *idx, MDNode *tbaa, Type *ptype)
{
// p = (jl_value_t**)v; *(ptype)&p[n]
Value *vptr = emit_nthptr_addr(ctx, v, idx);
return tbaa_decorate(tbaa, ctx.builder.CreateLoad(emit_bitcast(ctx, vptr, ptype)));
return cast<LoadInst>(tbaa_decorate(tbaa, ctx.builder.CreateLoad(emit_bitcast(ctx, vptr, ptype))));
}

static Value *emit_nthptr_recast(jl_codectx_t &ctx, Value *v, ssize_t n, MDNode *tbaa, Type *ptype)
static LoadInst *emit_nthptr_recast(jl_codectx_t &ctx, Value *v, ssize_t n, MDNode *tbaa, Type *ptype)
{
// p = (jl_value_t**)v; *(ptype)&p[n]
Value *vptr = emit_nthptr_addr(ctx, v, n);
return tbaa_decorate(tbaa, ctx.builder.CreateLoad(emit_bitcast(ctx, vptr, ptype)));
return cast<LoadInst>(tbaa_decorate(tbaa, ctx.builder.CreateLoad(emit_bitcast(ctx, vptr, ptype))));
}

static Value *boxed(jl_codectx_t &ctx, const jl_cgval_t &v);
Expand Down Expand Up @@ -864,8 +864,7 @@ static jl_cgval_t emit_typeof(jl_codectx_t &ctx, const jl_cgval_t &p)
[&](unsigned idx, jl_datatype_t *jt) { },
p.typ,
counter);
Value *datatype_or_p = (imaging_mode ? Constant::getNullValue(T_ppjlvalue) :
Constant::getNullValue(T_prjlvalue));
Value *datatype_or_p = imaging_mode ? Constant::getNullValue(T_ppjlvalue) : V_rnull;
counter = 0;
for_each_uniontype_small(
[&](unsigned idx, jl_datatype_t *jt) {
Expand Down Expand Up @@ -1017,7 +1016,7 @@ static Value *emit_datatype_abstract(jl_codectx_t &ctx, Value *dt)
static Value *emit_datatype_isprimitivetype(jl_codectx_t &ctx, Value *dt)
{
Value *immut = ctx.builder.CreateNot(emit_datatype_mutabl(ctx, dt));
Value *nofields = ctx.builder.CreateICmpEQ(emit_datatype_nfields(ctx, dt), ConstantInt::get(T_size, 0));
Value *nofields = ctx.builder.CreateICmpEQ(emit_datatype_nfields(ctx, dt), V_size0);
Value *sized = ctx.builder.CreateICmpSGT(emit_datatype_size(ctx, dt), ConstantInt::get(T_int32, 0));
return ctx.builder.CreateAnd(immut, ctx.builder.CreateAnd(nofields, sized));
}
Expand Down Expand Up @@ -1830,15 +1829,51 @@ static bool arraytype_constshape(jl_value_t *ty)
jl_is_long(jl_tparam1(ty)) && jl_unbox_long(jl_tparam1(ty)) != 1);
}

static bool arraytype_constelsize(jl_datatype_t *ty, size_t *elsz)
{
assert(jl_is_array_type(ty));
jl_value_t *ety = jl_tparam0(ty);
if (jl_has_free_typevars(ety))
return false;
// `jl_islayout_inline` requires `*elsz` and `al` to be initialized.
size_t al = 0;
*elsz = 0;
int union_max = jl_islayout_inline(ety, elsz, &al);
bool isboxed = (union_max == 0);
if (isboxed) {
*elsz = sizeof(void*);
}
else if (jl_is_primitivetype(ety)) {
// Primitive types should use the array element size, but
// this can be different from the type's size
*elsz = LLT_ALIGN(*elsz, al);
}
return true;
}

static intptr_t arraytype_maxsize(jl_value_t *ty)
{
if (!jl_is_array_type(ty))
return INTPTR_MAX;
size_t elsz;
if (arraytype_constelsize((jl_datatype_t*)ty, &elsz) || elsz == 0)
return INTPTR_MAX;
return INTPTR_MAX / elsz;
}

static Value *emit_arraysize(jl_codectx_t &ctx, const jl_cgval_t &tinfo, Value *dim)
{
Value *t = boxed(ctx, tinfo);
int o = offsetof(jl_array_t, nrows) / sizeof(void*) - 1;
MDNode *tbaa = arraytype_constshape(tinfo.typ) ? tbaa_const : tbaa_arraysize;
return emit_nthptr_recast(ctx,
auto load = emit_nthptr_recast(ctx,
t,
ctx.builder.CreateAdd(dim, ConstantInt::get(dim->getType(), o)),
tbaa, T_psize);
MDBuilder MDB(jl_LLVMContext);
auto rng = MDB.createRange(V_size0, ConstantInt::get(T_size, arraytype_maxsize(tinfo.typ)));
load->setMetadata(LLVMContext::MD_range, rng);
return load;
}

static Value *emit_arraysize(jl_codectx_t &ctx, const jl_cgval_t &tinfo, int dim)
Expand All @@ -1862,6 +1897,9 @@ static Value *emit_arraylen_prim(jl_codectx_t &ctx, const jl_cgval_t &tinfo)
MDNode *tbaa = arraytype_constshape(ty) ? tbaa_const : tbaa_arraylen;
LoadInst *len = ctx.builder.CreateAlignedLoad(addr, sizeof(size_t));
len->setOrdering(AtomicOrdering::NotAtomic);
MDBuilder MDB(jl_LLVMContext);
auto rng = MDB.createRange(V_size0, ConstantInt::get(T_size, arraytype_maxsize(tinfo.typ)));
len->setMetadata(LLVMContext::MD_range, rng);
return tbaa_decorate(tbaa, len);
#else
jl_value_t *p1 = jl_tparam1(ty); // FIXME: check that ty is an array type
Expand Down Expand Up @@ -2007,7 +2045,7 @@ static Value *emit_array_nd_index(
const jl_cgval_t *argv, size_t nidxs, jl_value_t *inbounds)
{
Value *a = boxed(ctx, ainfo);
Value *i = ConstantInt::get(T_size, 0);
Value *i = V_size0;
Value *stride = ConstantInt::get(T_size, 1);
#if CHECK_BOUNDS==1
bool bc = bounds_check_enabled(ctx, inbounds);
Expand Down Expand Up @@ -2493,9 +2531,7 @@ static void emit_unionmove(jl_codectx_t &ctx, Value *dest, MDNode *tbaa_dst, con
// TODO: this Select is very bad for performance, but is necessary to work around LLVM bugs with the undef option that we want to use:
// select copy dest -> dest to simulate an undef value / conditional copy
// src_ptr = ctx.builder.CreateSelect(skip, dest, src_ptr);
nbytes = ctx.builder.CreateSelect(skip,
ConstantInt::get(T_size, 0),
nbytes);
nbytes = ctx.builder.CreateSelect(skip, V_size0, nbytes);
}
emit_memcpy(ctx, dest, tbaa_dst, src_ptr, src.tbaa, nbytes, alignment, isVolatile);
}
Expand Down
36 changes: 16 additions & 20 deletions src/codegen.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -235,6 +235,7 @@ static DISubroutineType *jl_di_func_null_sig;
// constants
static Constant *V_null;
static Constant *V_rnull;
static Constant *V_size0;
static bool type_is_ghost(Type *ty)
{
return (ty == T_void || ty->isEmptyTy());
Expand Down Expand Up @@ -2690,7 +2691,7 @@ static bool emit_builtin_call(jl_codectx_t &ctx, jl_cgval_t *ret, jl_value_t *f,
}
else {
Value *idx_dyn = emit_unbox(ctx, T_size, idx, (jl_value_t*)jl_long_type);
error_unless(ctx, ctx.builder.CreateICmpSGT(idx_dyn, ConstantInt::get(T_size, 0)),
error_unless(ctx, ctx.builder.CreateICmpSGT(idx_dyn, V_size0),
"arraysize: dimension out of range");
BasicBlock *outBB = BasicBlock::Create(jl_LLVMContext, "outofrange", ctx.f);
BasicBlock *inBB = BasicBlock::Create(jl_LLVMContext, "inrange");
Expand Down Expand Up @@ -3058,32 +3059,27 @@ static bool emit_builtin_call(jl_codectx_t &ctx, jl_cgval_t *ret, jl_value_t *f,
// String and SimpleVector's length fields have the same layout
auto ptr = emit_bitcast(ctx, boxed(ctx, obj), T_psize);
Value *len = tbaa_decorate(tbaa_mutab, ctx.builder.CreateAlignedLoad(T_size, ptr, sizeof(size_t)));
MDBuilder MDB(jl_LLVMContext);
if (sty == jl_simplevector_type) {
auto rng = MDB.createRange(
V_size0, ConstantInt::get(T_size, INTPTR_MAX / sizeof(void*) - 1));
cast<LoadInst>(len)->setMetadata(LLVMContext::MD_range, rng);
len = ctx.builder.CreateMul(len, ConstantInt::get(T_size, sizeof(void*)));
len = ctx.builder.CreateAdd(len, ConstantInt::get(T_size, sizeof(void*)));
}
else {
auto rng = MDB.createRange(V_size0, ConstantInt::get(T_size, INTPTR_MAX));
cast<LoadInst>(len)->setMetadata(LLVMContext::MD_range, rng);
}
*ret = mark_julia_type(ctx, len, false, jl_long_type);
return true;
}
else if (jl_is_array_type(sty)) {
auto len = emit_arraylen(ctx, obj);
jl_value_t *ety = jl_tparam0(sty);
Value *elsize;
size_t elsz = 0, al = 0;
int union_max = jl_islayout_inline(ety, &elsz, &al);
bool isboxed = (union_max == 0);
if (!jl_has_free_typevars(ety)) {
if (isboxed) {
elsize = ConstantInt::get(T_size, sizeof(void*));
}
else if (jl_is_primitivetype(ety)) {
// Primitive types should use the array element size, but
// this can be different from the type's size
elsize = ConstantInt::get(T_size, LLT_ALIGN(elsz, al));
}
else {
elsize = ConstantInt::get(T_size, elsz);
}
size_t elsz;
if (arraytype_constelsize(sty, &elsz)) {
elsize = ConstantInt::get(T_size, elsz);
}
else {
elsize = ctx.builder.CreateZExt(emit_arrayelsize(ctx, obj), T_size);
Expand Down Expand Up @@ -5267,10 +5263,9 @@ static jl_cgval_t emit_cfunction(jl_codectx_t &ctx, jl_value_t *output_type, con
tbaa_decorate(tbaa, ctx.builder.CreateStore(
ctx.builder.CreatePtrToInt(literal_pointer_val(ctx, fexpr_rt.constant), T_size),
ctx.builder.CreateConstInBoundsGEP1_32(T_size, derived_strct, 1)));
Value *zero = ConstantInt::get(T_size, 0);
tbaa_decorate(tbaa, ctx.builder.CreateStore(zero,
tbaa_decorate(tbaa, ctx.builder.CreateStore(V_size0,
ctx.builder.CreateConstInBoundsGEP1_32(T_size, derived_strct, 2)));
tbaa_decorate(tbaa, ctx.builder.CreateStore(zero,
tbaa_decorate(tbaa, ctx.builder.CreateStore(V_size0,
ctx.builder.CreateConstInBoundsGEP1_32(T_size, derived_strct, 3)));
F = strct;
}
Expand Down Expand Up @@ -7374,6 +7369,7 @@ static void init_julia_llvm_env(Module *m)
T_pprjlvalue = PointerType::get(T_prjlvalue, 0);
V_null = Constant::getNullValue(T_pjlvalue);
V_rnull = Constant::getNullValue(T_prjlvalue);
V_size0 = Constant::getNullValue(T_size);

std::vector<Type*> ftargs(0);
ftargs.push_back(T_prjlvalue); // function
Expand Down

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