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stage2: C backend: pointer cast decl refs if necessary

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This commit is contained in:
Andrew Kelley
2020-12-28 17:46:50 -07:00
parent 87c6341b61
commit 52056b156b
1 changed files with 32 additions and 19 deletions
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51
src/codegen/c.zig
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@@ -11,6 +11,7 @@ const Type = @import("../type.zig").Type;
const C = link.File.C;
const Decl = Module.Decl;
const mem = std.mem;
const log = std.log.scoped(.c);
const Writer = std.ArrayList(u8).Writer;
@@ -22,7 +23,6 @@ fn map(allocator: *std.mem.Allocator, name: []const u8) ![]const u8 {
fn renderType(
ctx: *Context,
header: *C.Header,
writer: Writer,
t: Type,
) error{ OutOfMemory, AnalysisFail }!void {
@@ -80,12 +80,12 @@ fn renderType(
if (t.isVolatilePtr()) {
try writer.writeAll("volatile ");
}
try renderType(ctx, header, writer, t.elemType());
try renderType(ctx, writer, t.elemType());
try writer.writeAll(" *");
}
},
.Array => {
try renderType(ctx, header, writer, t.elemType());
try renderType(ctx, writer, t.elemType());
const sentinel_bit = @boolToInt(t.sentinel() != null);
const c_len = t.arrayLen() + sentinel_bit;
try writer.print("[{d}]", .{c_len});
@@ -113,7 +113,16 @@ fn renderValue(
.one => try writer.writeAll("1"),
.decl_ref => {
const decl_ref_payload = val.cast(Value.Payload.DeclRef).?;
try writer.print("&{s}", .{decl_ref_payload.decl.name});
// Determine if we must pointer cast.
const decl_tv = decl_ref_payload.decl.typed_value.most_recent.typed_value;
if (t.eql(decl_tv.ty)) {
try writer.print("&{s}", .{decl_ref_payload.decl.name});
} else {
try writer.writeAll("(");
try renderType(ctx, writer, t);
try writer.print(")&{s}", .{decl_ref_payload.decl.name});
}
},
.function => {
const payload = val.cast(Value.Payload.Function).?;
@@ -155,12 +164,11 @@ fn renderValue(
fn renderFunctionSignature(
ctx: *Context,
header: *C.Header,
writer: Writer,
decl: *Decl,
) !void {
const tv = decl.typed_value.most_recent.typed_value;
try renderType(ctx, header, writer, tv.ty.fnReturnType());
try renderType(ctx, writer, tv.ty.fnReturnType());
// Use the child allocator directly, as we know the name can be freed before
// the rest of the arena.
const name = try map(ctx.arena.child_allocator, mem.spanZ(decl.name));
@@ -175,7 +183,7 @@ fn renderFunctionSignature(
if (index > 0) {
try writer.writeAll(", ");
}
try renderType(ctx, header, writer, tv.ty.fnParamType(index));
try renderType(ctx, writer, tv.ty.fnParamType(index));
try writer.print(" arg{}", .{index});
}
}
@@ -194,6 +202,7 @@ pub fn generate(file: *C, decl: *Decl) !void {
.arena = &arena,
.inst_map = &inst_map,
.target = file.base.options.target,
.header = &file.header,
};
defer {
file.error_msg = ctx.error_msg;
@@ -202,7 +211,7 @@ pub fn generate(file: *C, decl: *Decl) !void {
if (tv.val.cast(Value.Payload.Function)) |func_payload| {
const writer = file.main.writer();
try renderFunctionSignature(&ctx, &file.header, writer, decl);
try renderFunctionSignature(&ctx, writer, decl);
try writer.writeAll(" {");
@@ -211,9 +220,11 @@ pub fn generate(file: *C, decl: *Decl) !void {
if (instructions.len > 0) {
try writer.writeAll("\n");
for (instructions) |inst| {
const indent_size = 4;
const indent_level = 1;
try writer.writeByteNTimes(' ', indent_size * indent_level);
if (inst.tag != .dbg_stmt) {
const indent_size = 4;
const indent_level = 1;
try writer.writeByteNTimes(' ', indent_size * indent_level);
}
if (switch (inst.tag) {
.assembly => try genAsm(&ctx, file, inst.castTag(.assembly).?),
.call => try genCall(&ctx, file, inst.castTag(.call).?),
@@ -226,7 +237,7 @@ pub fn generate(file: *C, decl: *Decl) !void {
.breakpoint => try genBreak(&ctx, inst.castTag(.breakpoint).?),
.unreach => try genUnreach(file, inst.castTag(.unreach).?),
.intcast => try genIntCast(&ctx, file, inst.castTag(.intcast).?),
else => |e| return ctx.fail(decl.src(), "TODO implement C codegen for {}", .{e}),
else => |e| return ctx.fail(decl.src(), "TODO: C backend: implement codegen for {}", .{e}),
}) |name| {
try ctx.inst_map.putNoClobber(inst, name);
}
@@ -243,7 +254,7 @@ pub fn generate(file: *C, decl: *Decl) !void {
// TODO ask the Decl if it is const
// https://github.com/ziglang/zig/issues/7582
try renderType(&ctx, &file.header, writer, tv.ty);
try renderType(&ctx, writer, tv.ty);
try writer.print(" {s} = ", .{decl.name});
try renderValue(&ctx, writer, tv.ty, tv.val);
try writer.writeAll(";\n");
@@ -269,9 +280,10 @@ pub fn generateHeader(
.arena = &arena,
.inst_map = &inst_map,
.target = comp.getTarget(),
.header = header,
};
const writer = header.buf.writer();
renderFunctionSignature(&ctx, header, writer, decl) catch |err| {
renderFunctionSignature(&ctx, writer, decl) catch |err| {
if (err == error.AnalysisFail) {
try module.failed_decls.put(module.gpa, decl, ctx.error_msg);
}
@@ -291,6 +303,7 @@ const Context = struct {
unnamed_index: usize = 0,
error_msg: *Compilation.ErrorMsg = undefined,
target: std.Target,
header: *C.Header,
fn resolveInst(self: *Context, inst: *Inst) ![]u8 {
if (inst.cast(Inst.Constant)) |const_inst| {
@@ -355,9 +368,9 @@ fn genIntCast(ctx: *Context, file: *C, inst: *Inst.UnOp) !?[]u8 {
const name = try ctx.name();
const from = try ctx.resolveInst(inst.operand);
try writer.writeAll("const ");
try renderType(ctx, &file.header, writer, inst.base.ty);
try renderType(ctx, writer, inst.base.ty);
try writer.print(" {} = (", .{name});
try renderType(ctx, &file.header, writer, inst.base.ty);
try renderType(ctx, writer, inst.base.ty);
try writer.print("){};\n", .{from});
return name;
}
@@ -370,7 +383,7 @@ fn genBinOp(ctx: *Context, file: *C, inst: *Inst.BinOp, comptime operator: []con
const writer = file.main.writer();
const name = try ctx.name();
try writer.writeAll("const ");
try renderType(ctx, &file.header, writer, inst.base.ty);
try renderType(ctx, writer, inst.base.ty);
try writer.print(" {} = {} " ++ operator ++ " {};\n", .{ name, lhs, rhs });
return name;
}
@@ -394,7 +407,7 @@ fn genCall(ctx: *Context, file: *C, inst: *Inst.Call) !?[]u8 {
const fn_name = mem.spanZ(fn_decl.name);
if (file.called.get(fn_name) == null) {
try file.called.put(fn_name, void{});
try renderFunctionSignature(ctx, &file.header, header, fn_decl);
try renderFunctionSignature(ctx, header, fn_decl);
try header.writeAll(";\n");
}
try writer.print("{s}(", .{fn_name});
@@ -440,7 +453,7 @@ fn genAsm(ctx: *Context, file: *C, as: *Inst.Assembly) !?[]u8 {
const reg = i[1 .. i.len - 1];
const arg = as.args[index];
try writer.writeAll("register ");
try renderType(ctx, &file.header, writer, arg.ty);
try renderType(ctx, writer, arg.ty);
try writer.print(" {}_constant __asm__(\"{}\") = ", .{ reg, reg });
// TODO merge constant handling into inst_map as well
if (arg.castTag(.constant)) |c| {