Merge branch 'pixelherodev-cbe'

closes #6007

6 files changed, 341 insertions, 84 deletions

diff --git a/src-self-hosted/cbe.h b/src-self-hosted/cbe.h
index 66e7b8bd3e..854032227d 100644
--- a/src-self-hosted/cbe.h
+++ b/src-self-hosted/cbe.h
@@ -1,8 +1,15 @@
 #if __STDC_VERSION__ >= 201112L
-#define noreturn _Noreturn
-#elif __GNUC__ && !__STRICT_ANSI__
-#define noreturn __attribute__ ((noreturn))
+#define zig_noreturn _Noreturn
+#elif __GNUC__
+#define zig_noreturn __attribute__ ((noreturn))
+#elif _MSC_VER
+#define zig_noreturn __declspec(noreturn)
 #else
-#define noreturn
+#define zig_noreturn
 #endif
 
+#if __GNUC__
+#define zig_unreachable() __builtin_unreachable()
+#else
+#define zig_unreachable()
+#endif
diff --git a/src-self-hosted/codegen/c.zig b/src-self-hosted/codegen/c.zig
index db9d9a1030..f0d3d8367a 100644
--- a/src-self-hosted/codegen/c.zig
+++ b/src-self-hosted/codegen/c.zig
@@ -17,40 +17,58 @@ fn map(allocator: *std.mem.Allocator, name: []const u8) ![]const u8 {
     return allocator.dupe(u8, name);
 }
 
-fn renderType(file: *C, writer: std.ArrayList(u8).Writer, T: Type, src: usize) !void {
-    if (T.tag() == .usize) {
-        file.need_stddef = true;
-        try writer.writeAll("size_t");
-    } else {
-        switch (T.zigTypeTag()) {
-            .NoReturn => {
-                file.need_noreturn = true;
-                try writer.writeAll("noreturn void");
-            },
-            .Void => try writer.writeAll("void"),
-            .Int => {
-                if (T.tag() == .u8) {
-                    file.need_stdint = true;
-                    try writer.writeAll("uint8_t");
-                } else {
-                    return file.fail(src, "TODO implement int types", .{});
-                }
-            },
-            else => |e| return file.fail(src, "TODO implement type {}", .{e}),
-        }
+fn renderType(ctx: *Context, writer: std.ArrayList(u8).Writer, T: Type) !void {
+    switch (T.zigTypeTag()) {
+        .NoReturn => {
+            try writer.writeAll("zig_noreturn void");
+        },
+        .Void => try writer.writeAll("void"),
+        .Int => {
+            if (T.tag() == .u8) {
+                ctx.file.need_stdint = true;
+                try writer.writeAll("uint8_t");
+            } else if (T.tag() == .usize) {
+                ctx.file.need_stddef = true;
+                try writer.writeAll("size_t");
+            } else {
+                return ctx.file.fail(ctx.decl.src(), "TODO implement int types", .{});
+            }
+        },
+        else => |e| return ctx.file.fail(ctx.decl.src(), "TODO implement type {}", .{e}),
     }
 }
 
-fn renderFunctionSignature(file: *C, writer: std.ArrayList(u8).Writer, decl: *Decl) !void {
+fn renderValue(ctx: *Context, writer: std.ArrayList(u8).Writer, T: Type, val: Value) !void {
+    switch (T.zigTypeTag()) {
+        .Int => {
+            if (T.isSignedInt())
+                return writer.print("{}", .{val.toSignedInt()});
+            return writer.print("{}", .{val.toUnsignedInt()});
+        },
+        else => |e| return ctx.file.fail(ctx.decl.src(), "TODO implement value {}", .{e}),
+    }
+}
+
+fn renderFunctionSignature(ctx: *Context, writer: std.ArrayList(u8).Writer, decl: *Decl) !void {
     const tv = decl.typed_value.most_recent.typed_value;
-    try renderType(file, writer, tv.ty.fnReturnType(), decl.src());
-    const name = try map(file.base.allocator, mem.spanZ(decl.name));
-    defer file.base.allocator.free(name);
+    try renderType(ctx, writer, tv.ty.fnReturnType());
+    const name = try map(ctx.file.base.allocator, mem.spanZ(decl.name));
+    defer ctx.file.base.allocator.free(name);
     try writer.print(" {}(", .{name});
-    if (tv.ty.fnParamLen() == 0)
-        try writer.writeAll("void)")
-    else
-        return file.fail(decl.src(), "TODO implement parameters", .{});
+    var param_len = tv.ty.fnParamLen();
+    if (param_len == 0)
+        try writer.writeAll("void")
+    else {
+        var index: usize = 0;
+        while (index < param_len) : (index += 1) {
+            if (index > 0) {
+                try writer.writeAll(", ");
+            }
+            try renderType(ctx, writer, tv.ty.fnParamType(index));
+            try writer.print(" arg{}", .{index});
+        }
+    }
+    try writer.writeByte(')');
 }
 
 pub fn generate(file: *C, decl: *Decl) !void {
@@ -78,11 +96,40 @@ fn genArray(file: *C, decl: *Decl) !void {
         return file.fail(decl.src(), "TODO non-byte arrays", .{});
 }
 
+const Context = struct {
+    file: *C,
+    decl: *Decl,
+    inst_map: std.AutoHashMap(*Inst, []u8),
+    argdex: usize = 0,
+    unnamed_index: usize = 0,
+
+    fn name(self: *Context) ![]u8 {
+        const val = try std.fmt.allocPrint(self.file.base.allocator, "__temp_{}", .{self.unnamed_index});
+        self.unnamed_index += 1;
+        return val;
+    }
+
+    fn deinit(self: *Context) void {
+        for (self.inst_map.items()) |kv| {
+            self.file.base.allocator.free(kv.value);
+        }
+        self.inst_map.deinit();
+        self.* = undefined;
+    }
+};
+
 fn genFn(file: *C, decl: *Decl) !void {
     const writer = file.main.writer();
     const tv = decl.typed_value.most_recent.typed_value;
 
-    try renderFunctionSignature(file, writer, decl);
+    var ctx = Context{
+        .file = file,
+        .decl = decl,
+        .inst_map = std.AutoHashMap(*Inst, []u8).init(file.base.allocator),
+    };
+    defer ctx.deinit();
+
+    try renderFunctionSignature(&ctx, writer, decl);
 
     try writer.writeAll(" {");
 
@@ -91,13 +138,19 @@ fn genFn(file: *C, decl: *Decl) !void {
     if (instructions.len > 0) {
         try writer.writeAll("\n");
         for (instructions) |inst| {
-            switch (inst.tag) {
-                .assembly => try genAsm(file, inst.castTag(.assembly).?, decl),
-                .call => try genCall(file, inst.castTag(.call).?, decl),
-                .ret => try genRet(file, inst.castTag(.ret).?, decl, tv.ty.fnReturnType()),
-                .retvoid => try file.main.writer().print("    return;\n", .{}),
-                .dbg_stmt => try genDbgStmt(file, inst.castTag(.dbg_stmt).?, decl),
+            if (switch (inst.tag) {
+                .assembly => try genAsm(&ctx, inst.castTag(.assembly).?),
+                .call => try genCall(&ctx, inst.castTag(.call).?),
+                .ret => try genRet(&ctx, inst.castTag(.ret).?),
+                .retvoid => try genRetVoid(&ctx),
+                .arg => try genArg(&ctx),
+                .dbg_stmt => try genDbgStmt(&ctx, inst.castTag(.dbg_stmt).?),
+                .breakpoint => try genBreak(&ctx, inst.castTag(.breakpoint).?),
+                .unreach => try genUnreach(&ctx, inst.castTag(.unreach).?),
+                .intcast => try genIntCast(&ctx, inst.castTag(.intcast).?),
                 else => |e| return file.fail(decl.src(), "TODO implement C codegen for {}", .{e}),
+            }) |name| {
+                try ctx.inst_map.putNoClobber(inst, name);
             }
         }
     }
@@ -105,13 +158,40 @@ fn genFn(file: *C, decl: *Decl) !void {
     try writer.writeAll("}\n\n");
 }
 
-fn genRet(file: *C, inst: *Inst.UnOp, decl: *Decl, expected_return_type: Type) !void {
-    return file.fail(decl.src(), "TODO return {}", .{expected_return_type});
+fn genArg(ctx: *Context) !?[]u8 {
+    const name = try std.fmt.allocPrint(ctx.file.base.allocator, "arg{}", .{ctx.argdex});
+    ctx.argdex += 1;
+    return name;
 }
 
-fn genCall(file: *C, inst: *Inst.Call, decl: *Decl) !void {
-    const writer = file.main.writer();
-    const header = file.header.writer();
+fn genRetVoid(ctx: *Context) !?[]u8 {
+    try ctx.file.main.writer().print("    return;\n", .{});
+    return null;
+}
+
+fn genRet(ctx: *Context, inst: *Inst.UnOp) !?[]u8 {
+    return ctx.file.fail(ctx.decl.src(), "TODO return", .{});
+}
+
+fn genIntCast(ctx: *Context, inst: *Inst.UnOp) !?[]u8 {
+    if (inst.base.isUnused())
+        return null;
+    const op = inst.operand;
+    const writer = ctx.file.main.writer();
+    const name = try ctx.name();
+    const from = ctx.inst_map.get(op) orelse
+        return ctx.file.fail(ctx.decl.src(), "Internal error in C backend: intCast argument not found in inst_map", .{});
+    try writer.writeAll("    const ");
+    try renderType(ctx, writer, inst.base.ty);
+    try writer.print(" {} = (", .{name});
+    try renderType(ctx, writer, inst.base.ty);
+    try writer.print("){};\n", .{from});
+    return name;
+}
+
+fn genCall(ctx: *Context, inst: *Inst.Call) !?[]u8 {
+    const writer = ctx.file.main.writer();
+    const header = ctx.file.header.writer();
     try writer.writeAll("    ");
     if (inst.func.castTag(.constant)) |func_inst| {
         if (func_inst.val.cast(Value.Payload.Function)) |func_val| {
@@ -122,52 +202,77 @@ fn genCall(file: *C, inst: *Inst.Call, decl: *Decl) !void {
                 try writer.print("(void)", .{});
             }
             const tname = mem.spanZ(target.name);
-            if (file.called.get(tname) == null) {
-                try file.called.put(tname, void{});
-                try renderFunctionSignature(file, header, target);
+            if (ctx.file.called.get(tname) == null) {
+                try ctx.file.called.put(tname, void{});
+                try renderFunctionSignature(ctx, header, target);
                 try header.writeAll(";\n");
             }
-            try writer.print("{}();\n", .{tname});
+            try writer.print("{}(", .{tname});
+            if (inst.args.len != 0) {
+                for (inst.args) |arg, i| {
+                    if (i > 0) {
+                        try writer.writeAll(", ");
+                    }
+                    if (arg.cast(Inst.Constant)) |con| {
+                        try renderValue(ctx, writer, arg.ty, con.val);
+                    } else {
+                        return ctx.file.fail(ctx.decl.src(), "TODO call pass arg {}", .{arg});
+                    }
+                }
+            }
+            try writer.writeAll(");\n");
         } else {
-            return file.fail(decl.src(), "TODO non-function call target?", .{});
-        }
-        if (inst.args.len != 0) {
-            return file.fail(decl.src(), "TODO function arguments", .{});
+            return ctx.file.fail(ctx.decl.src(), "TODO non-function call target?", .{});
         }
     } else {
-        return file.fail(decl.src(), "TODO non-constant call inst?", .{});
+        return ctx.file.fail(ctx.decl.src(), "TODO non-constant call inst?", .{});
     }
+    return null;
 }
 
-fn genDbgStmt(file: *C, inst: *Inst.NoOp, decl: *Decl) !void {
+fn genDbgStmt(ctx: *Context, inst: *Inst.NoOp) !?[]u8 {
     // TODO emit #line directive here with line number and filename
+    return null;
 }
 
-fn genAsm(file: *C, as: *Inst.Assembly, decl: *Decl) !void {
-    const writer = file.main.writer();
+fn genBreak(ctx: *Context, inst: *Inst.NoOp) !?[]u8 {
+    // TODO ??
+    return null;
+}
+
+fn genUnreach(ctx: *Context, inst: *Inst.NoOp) !?[]u8 {
+    try ctx.file.main.writer().writeAll("    zig_unreachable();\n");
+    return null;
+}
+
+fn genAsm(ctx: *Context, as: *Inst.Assembly) !?[]u8 {
+    const writer = ctx.file.main.writer();
     try writer.writeAll("    ");
     for (as.inputs) |i, index| {
         if (i[0] == '{' and i[i.len - 1] == '}') {
             const reg = i[1 .. i.len - 1];
             const arg = as.args[index];
+            try writer.writeAll("register ");
+            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| {
-                if (c.val.tag() == .int_u64) {
-                    try writer.writeAll("register ");
-                    try renderType(file, writer, arg.ty, decl.src());
-                    try writer.print(" {}_constant __asm__(\"{}\") = {};\n    ", .{ reg, reg, c.val.toUnsignedInt() });
-                } else {
-                    return file.fail(decl.src(), "TODO inline asm {} args", .{c.val.tag()});
-                }
+                try renderValue(ctx, writer, arg.ty, c.val);
+                try writer.writeAll(";\n    ");
             } else {
-                return file.fail(decl.src(), "TODO non-constant inline asm args", .{});
+                const gop = try ctx.inst_map.getOrPut(arg);
+                if (!gop.found_existing) {
+                    return ctx.file.fail(ctx.decl.src(), "Internal error in C backend: asm argument not found in inst_map", .{});
+                }
+                try writer.print("{};\n    ", .{gop.entry.value});
             }
         } else {
-            return file.fail(decl.src(), "TODO non-explicit inline asm regs", .{});
+            return ctx.file.fail(ctx.decl.src(), "TODO non-explicit inline asm regs", .{});
         }
     }
     try writer.print("__asm {} (\"{}\"", .{ if (as.is_volatile) @as([]const u8, "volatile") else "", as.asm_source });
     if (as.output) |o| {
-        return file.fail(decl.src(), "TODO inline asm output", .{});
+        return ctx.file.fail(ctx.decl.src(), "TODO inline asm output", .{});
     }
     if (as.inputs.len > 0) {
         if (as.output == null) {
@@ -181,12 +286,7 @@ fn genAsm(file: *C, as: *Inst.Assembly, decl: *Decl) !void {
                 if (index > 0) {
                     try writer.writeAll(", ");
                 }
-                if (arg.castTag(.constant)) |c| {
-                    try writer.print("\"\"({}_constant)", .{reg});
-                } else {
-                    // This is blocked by the earlier test
-                    unreachable;
-                }
+                try writer.print("\"\"({}_constant)", .{reg});
             } else {
                 // This is blocked by the earlier test
                 unreachable;
@@ -194,4 +294,5 @@ fn genAsm(file: *C, as: *Inst.Assembly, decl: *Decl) !void {
         }
     }
     try writer.writeAll(");\n");
+    return null;
 }
diff --git a/src-self-hosted/link.zig b/src-self-hosted/link.zig
index 431d510b01..7c5e645fb5 100644
--- a/src-self-hosted/link.zig
+++ b/src-self-hosted/link.zig
@@ -202,7 +202,6 @@ pub const File = struct {
         called: std.StringHashMap(void),
         need_stddef: bool = false,
         need_stdint: bool = false,
-        need_noreturn: bool = false,
         error_msg: *Module.ErrorMsg = undefined,
 
         pub fn openPath(allocator: *Allocator, dir: fs.Dir, sub_path: []const u8, options: Options) !*File {
@@ -230,7 +229,7 @@ pub const File = struct {
             return &c_file.base;
         }
 
-        pub fn fail(self: *C, src: usize, comptime format: []const u8, args: anytype) !void {
+        pub fn fail(self: *C, src: usize, comptime format: []const u8, args: anytype) error{AnalysisFail, OutOfMemory} {
             self.error_msg = try Module.ErrorMsg.create(self.base.allocator, src, format, args);
             return error.AnalysisFail;
         }
diff --git a/src-self-hosted/test.zig b/src-self-hosted/test.zig
index 7d4cc7d563..265c26b2dc 100644
--- a/src-self-hosted/test.zig
+++ b/src-self-hosted/test.zig
@@ -478,6 +478,10 @@ pub const TestContext = struct {
                     for (all_errors.list) |err| {
                         std.debug.warn(":{}:{}: error: {}\n================\n", .{ err.line + 1, err.column + 1, err.msg });
                     }
+                    if (case.cbe) {
+                        const C = module.bin_file.cast(link.File.C).?;
+                        std.debug.warn("Generated C: \n===============\n{}\n\n===========\n\n", .{C.main.items});
+                    }
                     std.debug.warn("Test failed.\n", .{});
                     std.process.exit(1);
                 }
diff --git a/src-self-hosted/value.zig b/src-self-hosted/value.zig
index e71805dc5b..b2fad9207d 100644
--- a/src-self-hosted/value.zig
+++ b/src-self-hosted/value.zig
@@ -568,6 +568,81 @@ pub const Value = extern union {
         }
     }
 
+    /// Asserts the value is an integer and it fits in a i64
+    pub fn toSignedInt(self: Value) i64 {
+        switch (self.tag()) {
+            .ty,
+            .int_type,
+            .u8_type,
+            .i8_type,
+            .u16_type,
+            .i16_type,
+            .u32_type,
+            .i32_type,
+            .u64_type,
+            .i64_type,
+            .usize_type,
+            .isize_type,
+            .c_short_type,
+            .c_ushort_type,
+            .c_int_type,
+            .c_uint_type,
+            .c_long_type,
+            .c_ulong_type,
+            .c_longlong_type,
+            .c_ulonglong_type,
+            .c_longdouble_type,
+            .f16_type,
+            .f32_type,
+            .f64_type,
+            .f128_type,
+            .c_void_type,
+            .bool_type,
+            .void_type,
+            .type_type,
+            .anyerror_type,
+            .comptime_int_type,
+            .comptime_float_type,
+            .noreturn_type,
+            .null_type,
+            .undefined_type,
+            .fn_noreturn_no_args_type,
+            .fn_void_no_args_type,
+            .fn_naked_noreturn_no_args_type,
+            .fn_ccc_void_no_args_type,
+            .single_const_pointer_to_comptime_int_type,
+            .const_slice_u8_type,
+            .null_value,
+            .function,
+            .ref_val,
+            .decl_ref,
+            .elem_ptr,
+            .bytes,
+            .repeated,
+            .float_16,
+            .float_32,
+            .float_64,
+            .float_128,
+            .void_value,
+            .unreachable_value,
+            .empty_array,
+            => unreachable,
+
+            .undef => unreachable,
+
+            .zero,
+            .bool_false,
+            => return 0,
+
+            .bool_true => return 1,
+
+            .int_u64 => return @intCast(i64, self.cast(Payload.Int_i64).?.int),
+            .int_i64 => return self.cast(Payload.Int_i64).?.int,
+            .int_big_positive => return self.cast(Payload.IntBigPositive).?.asBigInt().to(i64) catch unreachable,
+            .int_big_negative => return self.cast(Payload.IntBigNegative).?.asBigInt().to(i64) catch unreachable,
+        }
+    }
+
     pub fn toBool(self: Value) bool {
         return switch (self.tag()) {
             .bool_true => true,
diff --git a/test/stage2/cbe.zig b/test/stage2/cbe.zig
index 2c3f0631c8..5e2d56b5ed 100644
--- a/test/stage2/cbe.zig
+++ b/test/stage2/cbe.zig
@@ -12,7 +12,7 @@ pub fn addCases(ctx: *TestContext) !void {
     ctx.c("empty start function", linux_x64,
         \\export fn _start() noreturn {}
     ,
-        \\noreturn void _start(void) {}
+        \\zig_noreturn void _start(void) {}
         \\
     );
     ctx.c("less empty start function", linux_x64,
@@ -22,19 +22,19 @@ pub fn addCases(ctx: *TestContext) !void {
         \\    main();
         \\}
     ,
-        \\noreturn void main(void);
+        \\zig_noreturn void main(void);
         \\
-        \\noreturn void _start(void) {
+        \\zig_noreturn void _start(void) {
         \\    main();
         \\}
         \\
-        \\noreturn void main(void) {}
+        \\zig_noreturn void main(void) {}
         \\
     );
     // TODO: implement return values
     // TODO: figure out a way to prevent asm constants from being generated
     ctx.c("inline asm", linux_x64,
-        \\fn exitGood() void {
+        \\fn exitGood() noreturn {
         \\    asm volatile ("syscall"
         \\        :
         \\        : [number] "{rax}" (231),
@@ -48,21 +48,92 @@ pub fn addCases(ctx: *TestContext) !void {
     ,
         \\#include <stddef.h>
         \\
-        \\void exitGood(void);
+        \\zig_noreturn void exitGood(void);
         \\
         \\const char *const exitGood__anon_0 = "{rax}";
         \\const char *const exitGood__anon_1 = "{rdi}";
         \\const char *const exitGood__anon_2 = "syscall";
         \\
-        \\noreturn void _start(void) {
+        \\zig_noreturn void _start(void) {
         \\    exitGood();
         \\}
         \\
-        \\void exitGood(void) {
+        \\zig_noreturn void exitGood(void) {
         \\    register size_t rax_constant __asm__("rax") = 231;
         \\    register size_t rdi_constant __asm__("rdi") = 0;
         \\    __asm volatile ("syscall" :: ""(rax_constant), ""(rdi_constant));
-        \\    return;
+        \\}
+        \\
+    );
+    ctx.c("exit with parameter", linux_x64,
+        \\export fn _start() noreturn {
+        \\    exit(0);
+        \\}
+        \\
+        \\fn exit(code: usize) noreturn {
+        \\    asm volatile ("syscall"
+        \\        :
+        \\        : [number] "{rax}" (231),
+        \\          [arg1] "{rdi}" (code)
+        \\    );
+        \\    unreachable;
+        \\}
+        \\
+    ,
+        \\#include <stddef.h>
+        \\
+        \\zig_noreturn void exit(size_t arg0);
+        \\
+        \\const char *const exit__anon_0 = "{rax}";
+        \\const char *const exit__anon_1 = "{rdi}";
+        \\const char *const exit__anon_2 = "syscall";
+        \\
+        \\zig_noreturn void _start(void) {
+        \\    exit(0);
+        \\}
+        \\
+        \\zig_noreturn void exit(size_t arg0) {
+        \\    register size_t rax_constant __asm__("rax") = 231;
+        \\    register size_t rdi_constant __asm__("rdi") = arg0;
+        \\    __asm volatile ("syscall" :: ""(rax_constant), ""(rdi_constant));
+        \\    zig_unreachable();
+        \\}
+        \\
+    );
+    ctx.c("exit with u8 parameter", linux_x64,
+        \\export fn _start() noreturn {
+        \\    exit(0);
+        \\}
+        \\
+        \\fn exit(code: u8) noreturn {
+        \\    asm volatile ("syscall"
+        \\        :
+        \\        : [number] "{rax}" (231),
+        \\          [arg1] "{rdi}" (code)
+        \\    );
+        \\    unreachable;
+        \\}
+        \\
+    ,
+        \\#include <stddef.h>
+        \\#include <stdint.h>
+        \\
+        \\zig_noreturn void exit(uint8_t arg0);
+        \\
+        \\const char *const exit__anon_0 = "{rax}";
+        \\const char *const exit__anon_1 = "{rdi}";
+        \\const char *const exit__anon_2 = "syscall";
+        \\
+        \\zig_noreturn void _start(void) {
+        \\    exit(0);
+        \\}
+        \\
+        \\zig_noreturn void exit(uint8_t arg0) {
+        \\    const size_t __temp_0 = (size_t)arg0;
+        \\    register size_t rax_constant __asm__("rax") = 231;
+        \\    register size_t rdi_constant __asm__("rdi") = __temp_0;
+        \\    __asm volatile ("syscall" :: ""(rax_constant), ""(rdi_constant));
+        \\    zig_unreachable();
         \\}
         \\
     );