roc/compiler/gen/src/llvm/build_list.rs

1388 lines
48 KiB
Rust

use crate::llvm::build::{load_symbol, load_symbol_and_layout, Env, InPlace, Scope};
use crate::llvm::convert::{basic_type_from_layout, collection, get_ptr_type, ptr_int};
use inkwell::builder::Builder;
use inkwell::context::Context;
use inkwell::types::{BasicTypeEnum, PointerType};
use inkwell::values::{BasicValueEnum, FunctionValue, IntValue, PointerValue, StructValue};
use inkwell::{AddressSpace, IntPredicate};
use roc_module::symbol::Symbol;
use roc_mono::layout::{Builtin, Layout, MemoryMode};
/// List.single : a -> List a
pub fn list_single<'a, 'ctx, 'env>(
env: &Env<'a, 'ctx, 'env>,
elem: BasicValueEnum<'ctx>,
elem_layout: &Layout<'a>,
) -> BasicValueEnum<'ctx> {
let builder = env.builder;
let ctx = env.context;
// allocate a list of size 1 on the heap
let size = ctx.i64_type().const_int(1, false);
let ptr = allocate_list(env, elem_layout, size);
// Put the element into the list
let elem_ptr = unsafe {
builder.build_in_bounds_gep(
ptr,
&[ctx.i64_type().const_int(
// 0 as in 0 index of our new list
0 as u64, false,
)],
"index",
)
};
builder.build_store(elem_ptr, elem);
let ptr_bytes = env.ptr_bytes;
let int_type = ptr_int(ctx, ptr_bytes);
let ptr_as_int = builder.build_ptr_to_int(ptr, int_type, "list_cast_ptr");
let struct_type = collection(ctx, ptr_bytes);
let len = BasicValueEnum::IntValue(env.ptr_int().const_int(1, false));
let mut struct_val;
// Store the pointer
struct_val = builder
.build_insert_value(
struct_type.get_undef(),
ptr_as_int,
Builtin::WRAPPER_PTR,
"insert_ptr",
)
.unwrap();
// Store the length
struct_val = builder
.build_insert_value(struct_val, len, Builtin::WRAPPER_LEN, "insert_len")
.unwrap();
//
builder.build_bitcast(
struct_val.into_struct_value(),
collection(ctx, ptr_bytes),
"cast_collection",
)
}
/// List.repeat : Int, elem -> List elem
pub fn list_repeat<'a, 'ctx, 'env>(
env: &Env<'a, 'ctx, 'env>,
parent: FunctionValue<'ctx>,
list_len: IntValue<'ctx>,
elem: BasicValueEnum<'ctx>,
elem_layout: &Layout<'a>,
) -> BasicValueEnum<'ctx> {
let builder = env.builder;
let ctx = env.context;
// list_len > 0
// We have to do a loop below, continuously adding the `elem`
// to the output list `List elem` until we have reached the
// number of repeats. This `comparison` is used to check
// if we need to do any looping; because if we dont, then we
// dont need to allocate memory for the index or the check
// if index != 0
let comparison = builder.build_int_compare(
IntPredicate::UGT,
list_len,
ctx.i64_type().const_int(0, false),
"atleastzero",
);
let build_then = || {
// Allocate space for the new array that we'll copy into.
let list_ptr = allocate_list(env, elem_layout, list_len);
// TODO check if malloc returned null; if so, runtime error for OOM!
let index_name = "#index";
let start_alloca = builder.build_alloca(ctx.i64_type(), index_name);
// Start at the last element in the list.
let last_elem_index = builder.build_int_sub(
list_len,
ctx.i64_type().const_int(1, false),
"lastelemindex",
);
builder.build_store(start_alloca, last_elem_index);
let loop_bb = ctx.append_basic_block(parent, "loop");
builder.build_unconditional_branch(loop_bb);
builder.position_at_end(loop_bb);
// #index = #index - 1
let curr_index = builder
.build_load(start_alloca, index_name)
.into_int_value();
let next_index =
builder.build_int_sub(curr_index, ctx.i64_type().const_int(1, false), "nextindex");
builder.build_store(start_alloca, next_index);
let elem_ptr =
unsafe { builder.build_in_bounds_gep(list_ptr, &[curr_index], "load_index") };
// Mutate the new array in-place to change the element.
builder.build_store(elem_ptr, elem);
// #index != 0
let end_cond = builder.build_int_compare(
IntPredicate::NE,
ctx.i64_type().const_int(0, false),
curr_index,
"loopcond",
);
let after_bb = ctx.append_basic_block(parent, "afterloop");
builder.build_conditional_branch(end_cond, loop_bb, after_bb);
builder.position_at_end(after_bb);
let ptr_bytes = env.ptr_bytes;
let int_type = ptr_int(ctx, ptr_bytes);
let ptr_as_int = builder.build_ptr_to_int(list_ptr, int_type, "list_cast_ptr");
let struct_type = collection(ctx, ptr_bytes);
let mut struct_val;
// Store the pointer
struct_val = builder
.build_insert_value(
struct_type.get_undef(),
ptr_as_int,
Builtin::WRAPPER_PTR,
"insert_ptr",
)
.unwrap();
// Store the length
struct_val = builder
.build_insert_value(struct_val, list_len, Builtin::WRAPPER_LEN, "insert_len")
.unwrap();
builder.build_bitcast(
struct_val.into_struct_value(),
collection(ctx, ptr_bytes),
"cast_collection",
)
};
let build_else = || empty_polymorphic_list(env);
let struct_type = collection(ctx, env.ptr_bytes);
build_basic_phi2(
env,
parent,
comparison,
build_then,
build_else,
BasicTypeEnum::StructType(struct_type),
)
}
/// List.prepend List elem, elem -> List elem
pub fn list_prepend<'a, 'ctx, 'env>(
env: &Env<'a, 'ctx, 'env>,
original_wrapper: StructValue<'ctx>,
elem: BasicValueEnum<'ctx>,
elem_layout: &Layout<'a>,
) -> BasicValueEnum<'ctx> {
let builder = env.builder;
let ctx = env.context;
// Load the usize length from the wrapper.
let len = list_len(builder, original_wrapper);
let elem_type = basic_type_from_layout(env.arena, ctx, elem_layout, env.ptr_bytes);
let ptr_type = get_ptr_type(&elem_type, AddressSpace::Generic);
let list_ptr = load_list_ptr(builder, original_wrapper, ptr_type);
// The output list length, which is the old list length + 1
let new_list_len = env.builder.build_int_add(
ctx.i64_type().const_int(1 as u64, false),
len,
"new_list_length",
);
let ptr_bytes = env.ptr_bytes;
// Allocate space for the new array that we'll copy into.
let elem_type = basic_type_from_layout(env.arena, ctx, elem_layout, env.ptr_bytes);
let clone_ptr = builder
.build_array_malloc(elem_type, new_list_len, "list_ptr")
.unwrap();
let int_type = ptr_int(ctx, ptr_bytes);
let ptr_as_int = builder.build_ptr_to_int(clone_ptr, int_type, "list_cast_ptr");
builder.build_store(clone_ptr, elem);
let index_1_ptr = unsafe {
builder.build_in_bounds_gep(
clone_ptr,
&[ctx.i64_type().const_int(1 as u64, false)],
"load_index",
)
};
// Calculate the number of bytes we'll need to allocate.
let elem_bytes = env
.ptr_int()
.const_int(elem_layout.stack_size(env.ptr_bytes) as u64, false);
// This is the size of the list coming in, before we have added an element
// to the beginning.
let list_size = env
.builder
.build_int_mul(elem_bytes, len, "mul_old_len_by_elem_bytes");
if elem_layout.safe_to_memcpy() {
// Copy the bytes from the original array into the new
// one we just malloc'd.
//
// TODO how do we decide when to do the small memcpy vs the normal one?
builder.build_memcpy(index_1_ptr, ptr_bytes, list_ptr, ptr_bytes, list_size);
} else {
panic!("TODO Cranelift currently only knows how to clone list elements that are Copy.");
}
// Create a fresh wrapper struct for the newly populated array
let struct_type = collection(ctx, env.ptr_bytes);
let mut struct_val;
// Store the pointer
struct_val = builder
.build_insert_value(
struct_type.get_undef(),
ptr_as_int,
Builtin::WRAPPER_PTR,
"insert_ptr",
)
.unwrap();
// Store the length
struct_val = builder
.build_insert_value(struct_val, new_list_len, Builtin::WRAPPER_LEN, "insert_len")
.unwrap();
builder.build_bitcast(
struct_val.into_struct_value(),
collection(ctx, ptr_bytes),
"cast_collection",
)
}
/// List.join : List (List elem) -> List elem
pub fn list_join<'a, 'ctx, 'env>(
env: &Env<'a, 'ctx, 'env>,
parent: FunctionValue<'ctx>,
outer_list_wrapper: StructValue<'ctx>,
outer_list_layout: &Layout<'a>,
) -> BasicValueEnum<'ctx> {
// List.join is implemented as follows:
// 1. loop over every list to sum the list lengths
// 2. using the sum of all the list lengths, allocate an output list of
// that size.
// 3. loop over every list, for every list, loop over every element
// putting it into the output list
match outer_list_layout {
// If the input list is empty, or if it is a list of empty lists
// then simply return an empty list
Layout::Builtin(Builtin::EmptyList)
| Layout::Builtin(Builtin::List(_, Layout::Builtin(Builtin::EmptyList))) => empty_list(env),
Layout::Builtin(Builtin::List(_, Layout::Builtin(Builtin::List(_, elem_layout)))) => {
let inner_list_layout =
Layout::Builtin(Builtin::List(MemoryMode::Refcounted, elem_layout));
let builder = env.builder;
let ctx = env.context;
let elem_type = basic_type_from_layout(env.arena, ctx, elem_layout, env.ptr_bytes);
let elem_ptr_type = get_ptr_type(&elem_type, AddressSpace::Generic);
let inner_list_type =
basic_type_from_layout(env.arena, ctx, &inner_list_layout, env.ptr_bytes);
let outer_list_len = list_len(builder, outer_list_wrapper);
let outer_list_ptr = {
let elem_ptr_type = get_ptr_type(&inner_list_type, AddressSpace::Generic);
load_list_ptr(builder, outer_list_wrapper, elem_ptr_type)
};
// outer_list_len > 0
// We do this check to avoid allocating memory. If the input
// list is empty, then we can just return an empty list.
let comparison = list_is_not_empty(builder, ctx, outer_list_len);
let build_then = || {
let list_len_sum_name = "#listslengthsum";
let list_len_sum_alloca = builder.build_alloca(ctx.i64_type(), list_len_sum_name);
builder.build_store(list_len_sum_alloca, ctx.i64_type().const_int(0, false));
// List Sum Loop
let sum_loop = |sum_index| {
let inner_list_wrapper_ptr = unsafe {
builder.build_in_bounds_gep(outer_list_ptr, &[sum_index], "load_index")
};
let inner_list = builder.build_load(inner_list_wrapper_ptr, "inner_list");
let inner_list_len = list_len(builder, inner_list.into_struct_value());
let next_list_sum = builder.build_int_add(
builder
.build_load(list_len_sum_alloca, list_len_sum_name)
.into_int_value(),
inner_list_len,
"nextlistsum",
);
builder.build_store(list_len_sum_alloca, next_list_sum);
};
incrementing_index_loop(
builder,
parent,
ctx,
outer_list_len,
"#sum_index",
None,
sum_loop,
);
let final_list_sum = builder
.build_load(list_len_sum_alloca, list_len_sum_name)
.into_int_value();
let final_list_ptr = builder
.build_array_malloc(elem_type, final_list_sum, "final_list_sum")
.unwrap();
let dest_elem_ptr_alloca = builder.build_alloca(elem_ptr_type, "dest_elem");
builder.build_store(dest_elem_ptr_alloca, final_list_ptr);
// Inner List Loop
let inner_list_loop = |index| {
let inner_list_wrapper = {
let wrapper_ptr = unsafe {
builder.build_in_bounds_gep(outer_list_ptr, &[index], "load_index")
};
builder
.build_load(wrapper_ptr, "inner_list_wrapper")
.into_struct_value()
};
let inner_list_len = list_len(builder, inner_list_wrapper);
// inner_list_len > 0
let inner_list_comparison = list_is_not_empty(builder, ctx, inner_list_len);
let inner_list_non_empty_block =
ctx.append_basic_block(parent, "inner_list_non_empty");
let after_inner_list_non_empty_block =
ctx.append_basic_block(parent, "branchcont");
builder.build_conditional_branch(
inner_list_comparison,
inner_list_non_empty_block,
after_inner_list_non_empty_block,
);
builder.position_at_end(inner_list_non_empty_block);
// Element Inserting Loop
let inner_elem_loop = |inner_index| {
let src_elem_ptr = unsafe {
let inner_list_ptr =
load_list_ptr(builder, inner_list_wrapper, elem_ptr_type);
builder.build_in_bounds_gep(
inner_list_ptr,
&[inner_index],
"load_index",
)
};
let src_elem = builder.build_load(src_elem_ptr, "get_elem");
// TODO clone src_elem
let curr_dest_elem_ptr = builder
.build_load(dest_elem_ptr_alloca, "load_dest_elem_ptr")
.into_pointer_value();
builder.build_store(curr_dest_elem_ptr, src_elem);
let inc_dest_elem_ptr = BasicValueEnum::PointerValue(unsafe {
builder.build_in_bounds_gep(
curr_dest_elem_ptr,
&[env.ptr_int().const_int(1 as u64, false)],
"increment_dest_elem",
)
});
builder.build_store(dest_elem_ptr_alloca, inc_dest_elem_ptr);
};
incrementing_index_loop(
builder,
parent,
ctx,
inner_list_len,
"#inner_index",
None,
inner_elem_loop,
);
builder.build_unconditional_branch(after_inner_list_non_empty_block);
builder.position_at_end(after_inner_list_non_empty_block);
};
incrementing_index_loop(
builder,
parent,
ctx,
outer_list_len,
"#inner_list_index",
None,
inner_list_loop,
);
let ptr_bytes = env.ptr_bytes;
let int_type = ptr_int(ctx, ptr_bytes);
let ptr_as_int =
builder.build_ptr_to_int(final_list_ptr, int_type, "list_cast_ptr");
let struct_type = collection(ctx, ptr_bytes);
let mut struct_val;
// Store the pointer
struct_val = builder
.build_insert_value(
struct_type.get_undef(),
ptr_as_int,
Builtin::WRAPPER_PTR,
"insert_ptr",
)
.unwrap();
// Store the length
struct_val = builder
.build_insert_value(
struct_val,
final_list_sum,
Builtin::WRAPPER_LEN,
"insert_len",
)
.unwrap();
builder.build_bitcast(
struct_val.into_struct_value(),
collection(ctx, ptr_bytes),
"cast_collection",
)
};
let build_else = || empty_list(env);
let struct_type = collection(ctx, env.ptr_bytes);
build_basic_phi2(
env,
parent,
comparison,
build_then,
build_else,
BasicTypeEnum::StructType(struct_type),
)
}
_ => {
unreachable!("Invalid List layout for List.join {:?}", outer_list_layout);
}
}
}
/// List.reverse : List elem -> List elem
pub fn list_reverse<'a, 'ctx, 'env>(
env: &Env<'a, 'ctx, 'env>,
parent: FunctionValue<'ctx>,
scope: &Scope<'a, 'ctx>,
list: &Symbol,
) -> BasicValueEnum<'ctx> {
let (_, list_layout) = load_symbol_and_layout(env, scope, list);
match list_layout {
Layout::Builtin(Builtin::EmptyList) => empty_list(env),
Layout::Builtin(Builtin::List(_, elem_layout)) => {
let wrapper_struct = load_symbol(env, scope, list).into_struct_value();
let builder = env.builder;
let ctx = env.context;
let len = list_len(builder, wrapper_struct);
// list_len > 0
// We do this check to avoid allocating memory. If the input
// list is empty, then we can just return an empty list.
let comparison = builder.build_int_compare(
IntPredicate::UGT,
len,
ctx.i64_type().const_int(0, false),
"greaterthanzero",
);
let build_then = || {
// Allocate space for the new array that we'll copy into.
let elem_type = basic_type_from_layout(env.arena, ctx, elem_layout, env.ptr_bytes);
let ptr_type = get_ptr_type(&elem_type, AddressSpace::Generic);
let reversed_list_ptr = allocate_list(env, elem_layout, len);
// TODO check if malloc returned null; if so, runtime error for OOM!
let index_name = "#index";
let start_alloca = builder.build_alloca(ctx.i64_type(), index_name);
// Start at the last element in the list.
let last_elem_index =
builder.build_int_sub(len, ctx.i64_type().const_int(1, false), "lastelemindex");
builder.build_store(start_alloca, last_elem_index);
let loop_bb = ctx.append_basic_block(parent, "loop");
builder.build_unconditional_branch(loop_bb);
builder.position_at_end(loop_bb);
// #index = #index - 1
let curr_index = builder
.build_load(start_alloca, index_name)
.into_int_value();
let next_index = builder.build_int_sub(
curr_index,
ctx.i64_type().const_int(1, false),
"nextindex",
);
builder.build_store(start_alloca, next_index);
let list_ptr = load_list_ptr(builder, wrapper_struct, ptr_type);
// The pointer to the element in the input list
let elem_ptr =
unsafe { builder.build_in_bounds_gep(list_ptr, &[curr_index], "load_index") };
// The pointer to the element in the reversed list
let reverse_elem_ptr = unsafe {
builder.build_in_bounds_gep(
reversed_list_ptr,
&[builder.build_int_sub(
len,
builder.build_int_add(
curr_index,
ctx.i64_type().const_int(1, false),
"curr_index_plus_one",
),
"next_index",
)],
"load_index_reversed_list",
)
};
let elem = builder.build_load(elem_ptr, "get_elem");
// Mutate the new array in-place to change the element.
builder.build_store(reverse_elem_ptr, elem);
// #index != 0
let end_cond = builder.build_int_compare(
IntPredicate::NE,
ctx.i64_type().const_int(0, false),
curr_index,
"loopcond",
);
let after_bb = ctx.append_basic_block(parent, "afterloop");
builder.build_conditional_branch(end_cond, loop_bb, after_bb);
builder.position_at_end(after_bb);
let ptr_bytes = env.ptr_bytes;
let int_type = ptr_int(ctx, ptr_bytes);
let ptr_as_int =
builder.build_ptr_to_int(reversed_list_ptr, int_type, "list_cast_ptr");
let struct_type = collection(ctx, ptr_bytes);
let mut struct_val;
// Store the pointer
struct_val = builder
.build_insert_value(
struct_type.get_undef(),
ptr_as_int,
Builtin::WRAPPER_PTR,
"insert_ptr",
)
.unwrap();
// Store the length
struct_val = builder
.build_insert_value(struct_val, len, Builtin::WRAPPER_LEN, "insert_len")
.unwrap();
builder.build_bitcast(
struct_val.into_struct_value(),
collection(ctx, ptr_bytes),
"cast_collection",
)
};
let build_else = || empty_list(env);
let struct_type = collection(ctx, env.ptr_bytes);
build_basic_phi2(
env,
parent,
comparison,
build_then,
build_else,
BasicTypeEnum::StructType(struct_type),
)
}
_ => {
unreachable!("Invalid List layout for List.reverse {:?}", list_layout);
}
}
}
pub fn list_get_unsafe<'a, 'ctx, 'env>(
env: &Env<'a, 'ctx, 'env>,
list_layout: &Layout<'a>,
elem_index: IntValue<'ctx>,
wrapper_struct: StructValue<'ctx>,
) -> BasicValueEnum<'ctx> {
let builder = env.builder;
match list_layout {
Layout::Builtin(Builtin::List(_, elem_layout)) => {
let ctx = env.context;
let elem_type = basic_type_from_layout(env.arena, ctx, elem_layout, env.ptr_bytes);
let ptr_type = get_ptr_type(&elem_type, AddressSpace::Generic);
// Load the pointer to the array data
let array_data_ptr = load_list_ptr(builder, wrapper_struct, ptr_type);
// Assume the bounds have already been checked earlier
// (e.g. by List.get or List.first, which wrap List.#getUnsafe)
let elem_ptr =
unsafe { builder.build_in_bounds_gep(array_data_ptr, &[elem_index], "elem") };
builder.build_load(elem_ptr, "List.get")
}
_ => {
unreachable!(
"Invalid List layout for ListGetUnsafe operation: {:?}",
list_layout
);
}
}
}
/// List.push List elem, elem -> List elem
pub fn list_append<'a, 'ctx, 'env>(
env: &Env<'a, 'ctx, 'env>,
original_wrapper: StructValue<'ctx>,
elem: BasicValueEnum<'ctx>,
elem_layout: &Layout<'a>,
) -> BasicValueEnum<'ctx> {
let builder = env.builder;
let ctx = env.context;
// Load the usize length from the wrapper.
let list_len = list_len(builder, original_wrapper);
let elem_type = basic_type_from_layout(env.arena, ctx, elem_layout, env.ptr_bytes);
let ptr_type = get_ptr_type(&elem_type, AddressSpace::Generic);
let list_ptr = load_list_ptr(builder, original_wrapper, ptr_type);
// The output list length, which is the old list length + 1
let new_list_len = env.builder.build_int_add(
ctx.i64_type().const_int(1 as u64, false),
list_len,
"new_list_length",
);
let ptr_bytes = env.ptr_bytes;
// Calculate the number of bytes we'll need to allocate.
let elem_bytes = env
.ptr_int()
.const_int(elem_layout.stack_size(env.ptr_bytes) as u64, false);
// This is the size of the list coming in, before we have added an element
// to the end.
let list_size = env
.builder
.build_int_mul(elem_bytes, list_len, "mul_old_len_by_elem_bytes");
// Allocate space for the new array that we'll copy into.
let clone_ptr = allocate_list(env, elem_layout, new_list_len);
let int_type = ptr_int(ctx, ptr_bytes);
let ptr_as_int = builder.build_ptr_to_int(clone_ptr, int_type, "list_cast_ptr");
// TODO check if malloc returned null; if so, runtime error for OOM!
if elem_layout.safe_to_memcpy() {
// Copy the bytes from the original array into the new
// one we just malloc'd.
//
// TODO how do we decide when to do the small memcpy vs the normal one?
builder.build_memcpy(clone_ptr, ptr_bytes, list_ptr, ptr_bytes, list_size);
} else {
panic!("TODO Cranelift currently only knows how to clone list elements that are Copy.");
}
// Create a fresh wrapper struct for the newly populated array
let struct_type = collection(ctx, env.ptr_bytes);
let mut struct_val;
// Store the pointer
struct_val = builder
.build_insert_value(
struct_type.get_undef(),
ptr_as_int,
Builtin::WRAPPER_PTR,
"insert_ptr",
)
.unwrap();
// Store the length
struct_val = builder
.build_insert_value(struct_val, new_list_len, Builtin::WRAPPER_LEN, "insert_len")
.unwrap();
let elem_ptr = unsafe { builder.build_in_bounds_gep(clone_ptr, &[list_len], "load_index") };
builder.build_store(elem_ptr, elem);
builder.build_bitcast(
struct_val.into_struct_value(),
collection(ctx, ptr_bytes),
"cast_collection",
)
}
/// List.set : List elem, Int, elem -> List elem
pub fn list_set<'a, 'ctx, 'env>(
parent: FunctionValue<'ctx>,
args: &[(BasicValueEnum<'ctx>, &'a Layout<'a>)],
env: &Env<'a, 'ctx, 'env>,
in_place: InPlace,
) -> BasicValueEnum<'ctx> {
let builder = env.builder;
debug_assert_eq!(args.len(), 3);
let original_wrapper = args[0].0.into_struct_value();
let elem_index = args[1].0.into_int_value();
// Load the usize length from the wrapper. We need it for bounds checking.
let list_len = list_len(builder, original_wrapper);
// Bounds check: only proceed if index < length.
// Otherwise, return the list unaltered.
let comparison = bounds_check_comparison(builder, elem_index, list_len);
// If the index is in bounds, clone and mutate in place.
let build_then = || {
let (elem, elem_layout) = args[2];
let ctx = env.context;
let elem_type = basic_type_from_layout(env.arena, ctx, elem_layout, env.ptr_bytes);
let ptr_type = get_ptr_type(&elem_type, AddressSpace::Generic);
let (new_wrapper, array_data_ptr) = match in_place {
InPlace::InPlace => (
original_wrapper,
load_list_ptr(builder, original_wrapper, ptr_type),
),
InPlace::Clone => clone_nonempty_list(
env,
list_len,
load_list_ptr(builder, original_wrapper, ptr_type),
elem_layout,
),
};
// If we got here, we passed the bounds check, so this is an in-bounds GEP
let elem_ptr =
unsafe { builder.build_in_bounds_gep(array_data_ptr, &[elem_index], "load_index") };
// Mutate the new array in-place to change the element.
builder.build_store(elem_ptr, elem);
BasicValueEnum::StructValue(new_wrapper)
};
// If the index was out of bounds, return the original list unaltered.
let build_else = || BasicValueEnum::StructValue(original_wrapper);
let ret_type = original_wrapper.get_type();
build_basic_phi2(
env,
parent,
comparison,
build_then,
build_else,
ret_type.into(),
)
}
fn bounds_check_comparison<'ctx>(
builder: &Builder<'ctx>,
elem_index: IntValue<'ctx>,
len: IntValue<'ctx>,
) -> IntValue<'ctx> {
// Note: Check for index < length as the "true" condition,
// to avoid misprediction. (In practice this should usually pass,
// and CPUs generally default to predicting that a forward jump
// shouldn't be taken; that is, they predict "else" won't be taken.)
builder.build_int_compare(IntPredicate::ULT, elem_index, len, "bounds_check")
}
/// List.len : List elem -> Int
pub fn list_len<'ctx>(
builder: &Builder<'ctx>,
wrapper_struct: StructValue<'ctx>,
) -> IntValue<'ctx> {
builder
.build_extract_value(wrapper_struct, Builtin::WRAPPER_LEN, "list_len")
.unwrap()
.into_int_value()
}
/// List.concat : List elem, List elem -> List elem
pub fn list_concat<'a, 'ctx, 'env>(
env: &Env<'a, 'ctx, 'env>,
scope: &Scope<'a, 'ctx>,
parent: FunctionValue<'ctx>,
args: &[Symbol],
) -> BasicValueEnum<'ctx> {
debug_assert_eq!(args.len(), 2);
let builder = env.builder;
let ctx = env.context;
let (first_list, list_layout) = load_symbol_and_layout(env, scope, &args[0]);
let second_list = load_symbol(env, scope, &args[1]);
let second_list_wrapper = second_list.into_struct_value();
let second_list_len = list_len(builder, second_list_wrapper);
// We only match on the first lists layout
// because the first and second input lists
// necessarily have the same layout
match list_layout {
Layout::Builtin(Builtin::EmptyList) => empty_list(env),
Layout::Builtin(Builtin::List(_, elem_layout)) => {
let first_list_wrapper = first_list.into_struct_value();
let first_list_len = list_len(builder, first_list_wrapper);
// first_list_len > 0
// We do this check to avoid allocating memory. If the first input
// list is empty, then we can just return the second list cloned
let first_list_length_comparison = list_is_not_empty(builder, ctx, first_list_len);
let if_first_list_is_empty = || {
// second_list_len > 0
// We do this check to avoid allocating memory. If the second input
// list is empty, then we can just return the first list cloned
let second_list_length_comparison =
list_is_not_empty(builder, ctx, second_list_len);
let build_second_list_then = || {
let elem_type =
basic_type_from_layout(env.arena, ctx, elem_layout, env.ptr_bytes);
let ptr_type = get_ptr_type(&elem_type, AddressSpace::Generic);
let (new_wrapper, _) = clone_nonempty_list(
env,
second_list_len,
load_list_ptr(builder, second_list_wrapper, ptr_type),
elem_layout,
);
BasicValueEnum::StructValue(new_wrapper)
};
let build_second_list_else = || empty_list(env);
build_basic_phi2(
env,
parent,
second_list_length_comparison,
build_second_list_then,
build_second_list_else,
BasicTypeEnum::StructType(collection(ctx, env.ptr_bytes)),
)
};
let if_first_list_is_not_empty = || {
let elem_type = basic_type_from_layout(env.arena, ctx, elem_layout, env.ptr_bytes);
let ptr_type = get_ptr_type(&elem_type, AddressSpace::Generic);
let if_second_list_is_empty = || {
let (new_wrapper, _) = clone_nonempty_list(
env,
first_list_len,
load_list_ptr(builder, first_list_wrapper, ptr_type),
elem_layout,
);
BasicValueEnum::StructValue(new_wrapper)
};
// second_list_len > 0
// We do this check to avoid allocating memory. If the second input
// list is empty, then we can just return the first list cloned
let second_list_length_comparison =
list_is_not_empty(builder, ctx, second_list_len);
let if_second_list_is_not_empty = || {
let combined_list_len =
builder.build_int_add(first_list_len, second_list_len, "add_list_lengths");
let combined_list_ptr = allocate_list(env, elem_layout, combined_list_len);
// FIRST LOOP
let first_loop = |first_index| {
let first_list_ptr = load_list_ptr(builder, first_list_wrapper, ptr_type);
// The pointer to the element in the first list
let first_list_elem_ptr = unsafe {
builder.build_in_bounds_gep(
first_list_ptr,
&[first_index],
"load_index",
)
};
// The pointer to the element in the combined list
let combined_list_elem_ptr = unsafe {
builder.build_in_bounds_gep(
combined_list_ptr,
&[first_index],
"load_index_combined_list",
)
};
let first_list_elem = builder.build_load(first_list_elem_ptr, "get_elem");
// Mutate the new array in-place to change the element.
builder.build_store(combined_list_elem_ptr, first_list_elem);
};
let index_name = "#index";
let index_alloca = incrementing_index_loop(
builder,
parent,
ctx,
first_list_len,
index_name,
None,
first_loop,
);
// Reset the index variable to 0
builder.build_store(index_alloca, ctx.i64_type().const_int(0, false));
// SECOND LOOP
let second_loop = |second_index| {
let second_list_ptr = load_list_ptr(builder, second_list_wrapper, ptr_type);
// The pointer to the element in the second list
let second_list_elem_ptr = unsafe {
builder.build_in_bounds_gep(
second_list_ptr,
&[second_index],
"load_index",
)
};
// The pointer to the element in the combined list.
// Note that the pointer does not start at the index
// 0, it starts at the index of first_list_len. In that
// sense it is "offset".
let offset_combined_list_elem_ptr = unsafe {
builder.build_in_bounds_gep(
combined_list_ptr,
&[first_list_len],
"elem",
)
};
// The pointer to the element from the second list
// in the combined list
let combined_list_elem_ptr = unsafe {
builder.build_in_bounds_gep(
offset_combined_list_elem_ptr,
&[second_index],
"load_index_combined_list",
)
};
let second_list_elem = builder.build_load(second_list_elem_ptr, "get_elem");
// Mutate the new array in-place to change the element.
builder.build_store(combined_list_elem_ptr, second_list_elem);
};
incrementing_index_loop(
builder,
parent,
ctx,
second_list_len,
index_name,
Some(index_alloca),
second_loop,
);
let ptr_bytes = env.ptr_bytes;
let int_type = ptr_int(ctx, ptr_bytes);
let ptr_as_int =
builder.build_ptr_to_int(combined_list_ptr, int_type, "list_cast_ptr");
let struct_type = collection(ctx, ptr_bytes);
let mut struct_val;
// Store the pointer
struct_val = builder
.build_insert_value(
struct_type.get_undef(),
ptr_as_int,
Builtin::WRAPPER_PTR,
"insert_ptr",
)
.unwrap();
// Store the length
struct_val = builder
.build_insert_value(
struct_val,
combined_list_len,
Builtin::WRAPPER_LEN,
"insert_len",
)
.unwrap();
builder.build_bitcast(
struct_val.into_struct_value(),
collection(ctx, ptr_bytes),
"cast_collection",
)
};
build_basic_phi2(
env,
parent,
second_list_length_comparison,
if_second_list_is_not_empty,
if_second_list_is_empty,
BasicTypeEnum::StructType(collection(ctx, env.ptr_bytes)),
)
};
build_basic_phi2(
env,
parent,
first_list_length_comparison,
if_first_list_is_not_empty,
if_first_list_is_empty,
BasicTypeEnum::StructType(collection(ctx, env.ptr_bytes)),
)
}
_ => {
unreachable!(
"Invalid List layout for first list in List.concat : {:?}",
list_layout
);
}
}
}
// This helper simulates a basic for loop, where
// and index increments up from 0 to some end value
fn incrementing_index_loop<'ctx, LoopFn>(
builder: &Builder<'ctx>,
parent: FunctionValue<'ctx>,
ctx: &'ctx Context,
end: IntValue<'ctx>,
index_name: &str,
// allocating memory for an index is costly, so sometimes
// we want to reuse an index if multiple loops happen in a
// series, such as the case in List.concat. A memory
// allocation cab be passed in to be used, and the memory
// allocation that _is_ used is the return value.
maybe_alloca: Option<PointerValue<'ctx>>,
mut loop_fn: LoopFn,
) -> PointerValue<'ctx>
where
LoopFn: FnMut(IntValue<'ctx>),
{
let index_alloca = match maybe_alloca {
None => builder.build_alloca(ctx.i64_type(), index_name),
Some(alloca) => alloca,
};
builder.build_store(index_alloca, ctx.i64_type().const_int(0, false));
let loop_bb = ctx.append_basic_block(parent, "loop");
builder.build_unconditional_branch(loop_bb);
builder.position_at_end(loop_bb);
let curr_index = builder
.build_load(index_alloca, index_name)
.into_int_value();
let next_index =
builder.build_int_add(curr_index, ctx.i64_type().const_int(1, false), "nextindex");
builder.build_store(index_alloca, next_index);
// The body of the loop
loop_fn(curr_index);
// #index < end
let loop_end_cond = bounds_check_comparison(builder, next_index, end);
let after_loop_bb = ctx.append_basic_block(parent, "after_outer_loop");
builder.build_conditional_branch(loop_end_cond, loop_bb, after_loop_bb);
builder.position_at_end(after_loop_bb);
index_alloca
}
fn build_basic_phi2<'a, 'ctx, 'env, PassFn, FailFn>(
env: &Env<'a, 'ctx, 'env>,
parent: FunctionValue<'ctx>,
comparison: IntValue<'ctx>,
mut build_pass: PassFn,
mut build_fail: FailFn,
ret_type: BasicTypeEnum<'ctx>,
) -> BasicValueEnum<'ctx>
where
PassFn: FnMut() -> BasicValueEnum<'ctx>,
FailFn: FnMut() -> BasicValueEnum<'ctx>,
{
let builder = env.builder;
let context = env.context;
// build blocks
let then_block = context.append_basic_block(parent, "then");
let else_block = context.append_basic_block(parent, "else");
let cont_block = context.append_basic_block(parent, "branchcont");
builder.build_conditional_branch(comparison, then_block, else_block);
// build then block
builder.position_at_end(then_block);
let then_val = build_pass();
builder.build_unconditional_branch(cont_block);
let then_block = builder.get_insert_block().unwrap();
// build else block
builder.position_at_end(else_block);
let else_val = build_fail();
builder.build_unconditional_branch(cont_block);
let else_block = builder.get_insert_block().unwrap();
// emit merge block
builder.position_at_end(cont_block);
let phi = builder.build_phi(ret_type, "branch");
phi.add_incoming(&[(&then_val, then_block), (&else_val, else_block)]);
phi.as_basic_value()
}
pub fn empty_polymorphic_list<'a, 'ctx, 'env>(env: &Env<'a, 'ctx, 'env>) -> BasicValueEnum<'ctx> {
let ctx = env.context;
let struct_type = collection(ctx, env.ptr_bytes);
// The pointer should be null (aka zero) and the length should be zero,
// so the whole struct should be a const_zero
BasicValueEnum::StructValue(struct_type.const_zero())
}
// TODO investigate: does this cause problems when the layout is known? this value is now not refcounted!
pub fn empty_list<'a, 'ctx, 'env>(env: &Env<'a, 'ctx, 'env>) -> BasicValueEnum<'ctx> {
let ctx = env.context;
let struct_type = collection(ctx, env.ptr_bytes);
// The pointer should be null (aka zero) and the length should be zero,
// so the whole struct should be a const_zero
BasicValueEnum::StructValue(struct_type.const_zero())
}
fn list_is_not_empty<'ctx>(
builder: &Builder<'ctx>,
ctx: &'ctx Context,
list_len: IntValue<'ctx>,
) -> IntValue<'ctx> {
builder.build_int_compare(
IntPredicate::UGT,
list_len,
ctx.i64_type().const_int(0, false),
"greaterthanzero",
)
}
fn load_list_ptr<'ctx>(
builder: &Builder<'ctx>,
wrapper_struct: StructValue<'ctx>,
ptr_type: PointerType<'ctx>,
) -> PointerValue<'ctx> {
let ptr_as_int = builder
.build_extract_value(wrapper_struct, Builtin::WRAPPER_PTR, "read_list_ptr")
.unwrap()
.into_int_value();
builder.build_int_to_ptr(ptr_as_int, ptr_type, "list_cast_ptr")
}
fn clone_nonempty_list<'a, 'ctx, 'env>(
env: &Env<'a, 'ctx, 'env>,
list_len: IntValue<'ctx>,
elems_ptr: PointerValue<'ctx>,
elem_layout: &Layout<'_>,
) -> (StructValue<'ctx>, PointerValue<'ctx>) {
let builder = env.builder;
let ctx = env.context;
let ptr_bytes = env.ptr_bytes;
// Calculate the number of bytes we'll need to allocate.
let elem_bytes = env
.ptr_int()
.const_int(elem_layout.stack_size(env.ptr_bytes) as u64, false);
let size = env
.builder
.build_int_mul(elem_bytes, list_len, "clone_mul_len_by_elem_bytes");
// Allocate space for the new array that we'll copy into.
let clone_ptr = allocate_list(env, elem_layout, list_len);
let int_type = ptr_int(ctx, ptr_bytes);
let ptr_as_int = builder.build_ptr_to_int(clone_ptr, int_type, "list_cast_ptr");
// TODO check if malloc returned null; if so, runtime error for OOM!
// Either memcpy or deep clone the array elements
if elem_layout.safe_to_memcpy() {
// Copy the bytes from the original array into the new
// one we just malloc'd.
//
// TODO how do we decide when to do the small memcpy vs the normal one?
builder.build_memcpy(clone_ptr, ptr_bytes, elems_ptr, ptr_bytes, size);
} else {
panic!("TODO Cranelift currently only knows how to clone list elements that are Copy.");
}
// Create a fresh wrapper struct for the newly populated array
let struct_type = collection(ctx, env.ptr_bytes);
let mut struct_val;
// Store the pointer
struct_val = builder
.build_insert_value(
struct_type.get_undef(),
ptr_as_int,
Builtin::WRAPPER_PTR,
"insert_ptr",
)
.unwrap();
// Store the length
struct_val = builder
.build_insert_value(struct_val, list_len, Builtin::WRAPPER_LEN, "insert_len")
.unwrap();
let answer = builder
.build_bitcast(
struct_val.into_struct_value(),
collection(ctx, ptr_bytes),
"cast_collection",
)
.into_struct_value();
(answer, clone_ptr)
}
pub fn allocate_list<'a, 'ctx, 'env>(
env: &Env<'a, 'ctx, 'env>,
elem_layout: &Layout<'a>,
length: IntValue<'ctx>,
) -> PointerValue<'ctx> {
let builder = env.builder;
let ctx = env.context;
let elem_type = basic_type_from_layout(env.arena, ctx, elem_layout, env.ptr_bytes);
let elem_bytes = elem_layout.stack_size(env.ptr_bytes) as u64;
let len_type = env.ptr_int();
// bytes per element
let bytes_len = len_type.const_int(elem_bytes, false);
let offset = (env.ptr_bytes as u64).max(elem_bytes);
let ptr = {
let len = builder.build_int_mul(bytes_len, length, "data_length");
let len =
builder.build_int_add(len, len_type.const_int(offset, false), "add_refcount_space");
env.builder
.build_array_malloc(ctx.i8_type(), len, "create_list_ptr")
.unwrap()
// TODO check if malloc returned null; if so, runtime error for OOM!
};
// We must return a pointer to the first element:
let ptr_bytes = env.ptr_bytes;
let int_type = ptr_int(ctx, ptr_bytes);
let ptr_as_int = builder.build_ptr_to_int(ptr, int_type, "list_cast_ptr");
let incremented = builder.build_int_add(
ptr_as_int,
ctx.i64_type().const_int(offset, false),
"increment_list_ptr",
);
let ptr_type = get_ptr_type(&elem_type, AddressSpace::Generic);
let list_element_ptr = builder.build_int_to_ptr(incremented, ptr_type, "list_cast_ptr");
// subtract ptr_size, to access the refcount
let refcount_ptr = builder.build_int_sub(
incremented,
ctx.i64_type().const_int(env.ptr_bytes as u64, false),
"refcount_ptr",
);
let refcount_ptr = builder.build_int_to_ptr(
refcount_ptr,
int_type.ptr_type(AddressSpace::Generic),
"make ptr",
);
// put our "refcount 0" in the first slot
let ref_count_zero = ctx.i64_type().const_int(std::usize::MAX as u64, false);
builder.build_store(refcount_ptr, ref_count_zero);
list_element_ptr
}