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Aug 11, 2022
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stage2 llvm: implement more C ABI #12395

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124 changes: 115 additions & 9 deletions src/codegen/llvm.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -917,6 +917,40 @@ pub const Object = struct {
};
try args.append(loaded);
},
.multiple_llvm_float => {
const llvm_floats = it.llvm_types_buffer[0..it.llvm_types_len];
const param_ty = fn_info.param_types[it.zig_index - 1];
const param_llvm_ty = try dg.lowerType(param_ty);
const param_alignment = param_ty.abiAlignment(target);
const arg_ptr = buildAllocaInner(builder, llvm_func, false, param_llvm_ty);
arg_ptr.setAlignment(param_alignment);
var field_types_buf: [8]*const llvm.Type = undefined;
const field_types = field_types_buf[0..llvm_floats.len];
for (llvm_floats) |float_bits, i| {
switch (float_bits) {
64 => field_types[i] = dg.context.doubleType(),
80 => field_types[i] = dg.context.x86FP80Type(),
else => {},
}
}
const ints_llvm_ty = dg.context.structType(field_types.ptr, @intCast(c_uint, field_types.len), .False);
const casted_ptr = builder.buildBitCast(arg_ptr, ints_llvm_ty.pointerType(0), "");
for (llvm_floats) |_, i_usize| {
const i = @intCast(c_uint, i_usize);
const param = llvm_func.getParam(i);
const field_ptr = builder.buildStructGEP(casted_ptr, i, "");
const store_inst = builder.buildStore(param, field_ptr);
store_inst.setAlignment(target.cpu.arch.ptrBitWidth() / 8);
}

const is_by_ref = isByRef(param_ty);
const loaded = if (is_by_ref) arg_ptr else l: {
const load_inst = builder.buildLoad(arg_ptr, "");
load_inst.setAlignment(param_alignment);
break :l load_inst;
};
try args.append(loaded);
},
.as_u16 => {
const param = llvm_func.getParam(llvm_arg_i);
llvm_arg_i += 1;
Expand Down Expand Up @@ -2331,6 +2365,14 @@ pub const DeclGen = struct {
dg.addFnAttr(llvm_fn, "noreturn");
}

var llvm_arg_i = @as(c_uint, @boolToInt(sret)) + @boolToInt(err_return_tracing);
var it = iterateParamTypes(dg, fn_info);
while (it.next()) |_| : (llvm_arg_i += 1) {
if (!it.byval_attr) continue;
const param = llvm_fn.getParam(llvm_arg_i);
llvm_fn.addByValAttr(llvm_arg_i, param.typeOf().getElementType());
}

return llvm_fn;
}

Expand Down Expand Up @@ -2886,6 +2928,18 @@ pub const DeclGen = struct {
llvm_params.appendAssumeCapacity(big_int_ty);
}
},
.multiple_llvm_float => {
const llvm_ints = it.llvm_types_buffer[0..it.llvm_types_len];
try llvm_params.ensureUnusedCapacity(it.llvm_types_len);
for (llvm_ints) |float_bits| {
const float_ty = switch (float_bits) {
64 => dg.context.doubleType(),
80 => dg.context.x86FP80Type(),
else => unreachable,
};
llvm_params.appendAssumeCapacity(float_ty);
}
},
.as_u16 => {
try llvm_params.append(dg.context.intType(16));
},
Expand Down Expand Up @@ -4394,6 +4448,39 @@ pub const FuncGen = struct {
llvm_args.appendAssumeCapacity(load_inst);
}
},
.multiple_llvm_float => {
const arg = args[it.zig_index - 1];
const param_ty = self.air.typeOf(arg);
const llvm_floats = it.llvm_types_buffer[0..it.llvm_types_len];
const llvm_arg = try self.resolveInst(arg);
const is_by_ref = isByRef(param_ty);
const arg_ptr = if (is_by_ref) llvm_arg else p: {
const p = self.buildAlloca(llvm_arg.typeOf());
const store_inst = self.builder.buildStore(llvm_arg, p);
store_inst.setAlignment(param_ty.abiAlignment(target));
break :p p;
};

var field_types_buf: [8]*const llvm.Type = undefined;
const field_types = field_types_buf[0..llvm_floats.len];
for (llvm_floats) |float_bits, i| {
switch (float_bits) {
64 => field_types[i] = self.dg.context.doubleType(),
80 => field_types[i] = self.dg.context.x86FP80Type(),
else => {},
}
}
const ints_llvm_ty = self.dg.context.structType(field_types.ptr, @intCast(c_uint, field_types.len), .False);
const casted_ptr = self.builder.buildBitCast(arg_ptr, ints_llvm_ty.pointerType(0), "");
try llvm_args.ensureUnusedCapacity(it.llvm_types_len);
for (llvm_floats) |_, i_usize| {
const i = @intCast(c_uint, i_usize);
const field_ptr = self.builder.buildStructGEP(casted_ptr, i, "");
const load_inst = self.builder.buildLoad(field_ptr, "");
load_inst.setAlignment(target.cpu.arch.ptrBitWidth() / 8);
llvm_args.appendAssumeCapacity(load_inst);
}
},
.as_u16 => {
const arg = args[it.zig_index - 1];
const llvm_arg = try self.resolveInst(arg);
Expand Down Expand Up @@ -9359,16 +9446,20 @@ fn lowerFnRetTy(dg: *DeclGen, fn_info: Type.Payload.Function.Data) !*const llvm.
llvm_types_index += 1;
},
.sse => {
@panic("TODO");
llvm_types_buffer[llvm_types_index] = dg.context.doubleType();
llvm_types_index += 1;
},
.sseup => {
@panic("TODO");
llvm_types_buffer[llvm_types_index] = dg.context.doubleType();
llvm_types_index += 1;
},
.x87 => {
@panic("TODO");
llvm_types_buffer[llvm_types_index] = dg.context.x86FP80Type();
llvm_types_index += 1;
},
.x87up => {
@panic("TODO");
llvm_types_buffer[llvm_types_index] = dg.context.x86FP80Type();
llvm_types_index += 1;
},
.complex_x87 => {
@panic("TODO");
Expand Down Expand Up @@ -9414,20 +9505,23 @@ const ParamTypeIterator = struct {
target: std.Target,
llvm_types_len: u32,
llvm_types_buffer: [8]u16,
byval_attr: bool,

const Lowering = enum {
no_bits,
byval,
byref,
abi_sized_int,
multiple_llvm_ints,
multiple_llvm_float,
slice,
as_u16,
};

pub fn next(it: *ParamTypeIterator) ?Lowering {
if (it.zig_index >= it.fn_info.param_types.len) return null;
const ty = it.fn_info.param_types[it.zig_index];
it.byval_attr = false;
return nextInner(it, ty);
}

Expand Down Expand Up @@ -9513,6 +9607,7 @@ const ParamTypeIterator = struct {
.memory => {
it.zig_index += 1;
it.llvm_index += 1;
it.byval_attr = true;
return .byref;
},
.sse => {
Expand All @@ -9532,6 +9627,7 @@ const ParamTypeIterator = struct {
if (classes[0] == .memory) {
it.zig_index += 1;
it.llvm_index += 1;
it.byval_attr = true;
return .byref;
}
var llvm_types_buffer: [8]u16 = undefined;
Expand All @@ -9543,16 +9639,20 @@ const ParamTypeIterator = struct {
llvm_types_index += 1;
},
.sse => {
@panic("TODO");
llvm_types_buffer[llvm_types_index] = 64;
llvm_types_index += 1;
},
.sseup => {
@panic("TODO");
llvm_types_buffer[llvm_types_index] = 64;
llvm_types_index += 1;
},
.x87 => {
@panic("TODO");
llvm_types_buffer[llvm_types_index] = 80;
llvm_types_index += 1;
},
.x87up => {
@panic("TODO");
llvm_types_buffer[llvm_types_index] = 80;
llvm_types_index += 1;
},
.complex_x87 => {
@panic("TODO");
Expand All @@ -9566,11 +9666,16 @@ const ParamTypeIterator = struct {
it.llvm_index += 1;
return .abi_sized_int;
}
if (classes[0] == .sse and classes[1] == .none) {
it.zig_index += 1;
it.llvm_index += 1;
return .byval;
}
it.llvm_types_buffer = llvm_types_buffer;
it.llvm_types_len = llvm_types_index;
it.llvm_index += llvm_types_index;
it.zig_index += 1;
return .multiple_llvm_ints;
return if (classes[0] == .integer) .multiple_llvm_ints else .multiple_llvm_float;
},
},
.wasm32 => {
Expand Down Expand Up @@ -9611,6 +9716,7 @@ fn iterateParamTypes(dg: *DeclGen, fn_info: Type.Payload.Function.Data) ParamTyp
.target = dg.module.getTarget(),
.llvm_types_buffer = undefined,
.llvm_types_len = 0,
.byval_attr = false,
};
}

Expand Down
3 changes: 3 additions & 0 deletions src/codegen/llvm/bindings.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -245,6 +245,9 @@ pub const Value = opaque {

pub const addFunctionAttr = ZigLLVMAddFunctionAttr;
extern fn ZigLLVMAddFunctionAttr(Fn: *const Value, attr_name: [*:0]const u8, attr_value: [*:0]const u8) void;

pub const addByValAttr = ZigLLVMAddByValAttr;
extern fn ZigLLVMAddByValAttr(Fn: *const Value, ArgNo: c_uint, type: *const Type) void;
};

pub const Type = opaque {
Expand Down
2 changes: 1 addition & 1 deletion test/standalone.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@ pub fn addCases(cases: *tests.StandaloneContext) void {
}
// C ABI compatibility issue: https://github.com/ziglang/zig/issues/1481
if (builtin.cpu.arch == .x86_64) {
if (builtin.zig_backend == .stage1) { // https://github.com/ziglang/zig/issues/12222
if (builtin.zig_backend == .stage1 or builtin.zig_backend == .stage2_llvm) { // https://github.com/ziglang/zig/issues/12222
cases.addBuildFile("test/c_abi/build.zig", .{});
}
}
Expand Down