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cbe: avoid collisions with builtins and intrinsics

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Changes:
- Add `isMangledIdent` to determine if `fmtIdent` would make any edits to the identifier
- Any function that has a mangled identifier is referred to using the mangled identifer
  within the current file, but if it is exported the first export will be with the non-mangled name.
- Add `zig_import` to import a symbol under a different name
- Add a level of indirection to float function names. Now, they are referred to as
  `zig_float_fn_<float type>_<operation>`. The definitions in zig.h are wrapped
  with `zig_import` to import the symbol under the real name.

The specific problem that sparked this change was the combination of
`zig_libc_name_f80(name) __##name##x` with the input `fma`, resulting
in `__fmax`, which is a new intrinsic in recent versions of cl.exe.

With the above changes in place, compiler_rt can output the following:

```
static zig_weak_linkage_fn zig_f80 zig_e___fmax(zig_f80, zig_f80, zig_f80);
zig_export(zig_weak_linkage_fn zig_f80 zig_e___fmax(zig_f80, zig_f80, zig_f80), __fmax, "__fmax");
```

Within compiler_rt, `zig_e___fmax` is used to refer to the function, but consumers
will import `__fmax`, which maps to their `zig_float_fn_f80_fma` definition from zig.h.
This commit is contained in:
kcbanner
2023-11-02 00:02:37 -04:00
parent 58789cb054
commit ce293c982e
2 changed files with 89 additions and 52 deletions
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71
src/codegen/c.zig
View File

@@ -258,6 +258,20 @@ pub fn fmtIdent(ident: []const u8) std.fmt.Formatter(formatIdent) {
return .{ .data = ident };
}
// Returns true if `formatIdent` would make any edits to ident.
// This must be kept in sync with `formatIdent`.
pub fn isMangledIdent(ident: []const u8, solo: bool) bool {
if (solo and isReservedIdent(ident)) return true;
for (ident, 0..) |c, i| {
switch (c) {
'a'...'z', 'A'...'Z', '_' => {},
'0'...'9' => if (i == 0) return true,
else => return true,
}
}
return false;
}
/// This data is available when outputting .c code for a `InternPool.Index`
/// that corresponds to `func`.
/// It is not available when generating .h file.
@@ -526,6 +540,7 @@ pub const DeclGen = struct {
is_naked_fn: bool,
/// This is a borrowed reference from `link.C`.
fwd_decl: std.ArrayList(u8),
error_msg: ?*Module.ErrorMsg,
ctypes: CType.Store,
/// Keeps track of anonymous decls that need to be rendered before this
@@ -1598,7 +1613,7 @@ pub const DeclGen = struct {
switch (name) {
.export_index => |export_index| try dg.renderDeclName(w, fn_decl_index, export_index),
.string => |string| try w.writeAll(string),
.string => |string| try w.print("{ }", .{fmtIdent(string)}),
}
try renderTypeSuffix(
@@ -1813,9 +1828,17 @@ pub const DeclGen = struct {
fn declIsGlobal(dg: *DeclGen, tv: TypedValue) bool {
const mod = dg.module;
return switch (mod.intern_pool.indexToKey(tv.val.ip_index)) {
.variable => |variable| mod.decl_exports.contains(variable.decl),
.variable => |variable| {
if (mod.decl_exports.get(variable.decl)) |exports| {
return !isMangledIdent(dg.module.intern_pool.stringToSlice(exports.items[0].opts.name), true);
} else return false;
},
.extern_func => true,
.func => |func| mod.decl_exports.contains(func.owner_decl),
.func => |func| {
if (mod.decl_exports.get(func.owner_decl)) |exports| {
return !isMangledIdent(dg.module.intern_pool.stringToSlice(exports.items[0].opts.name), true);
} else return false;
},
else => unreachable,
};
}
@@ -1925,9 +1948,9 @@ pub const DeclGen = struct {
try mod.markDeclAlive(decl);
if (mod.decl_exports.get(decl_index)) |exports| {
try writer.print("{}", .{exports.items[export_index].opts.name.fmt(&mod.intern_pool)});
try writer.print("{ }", .{fmtIdent(mod.intern_pool.stringToSlice(exports.items[export_index].opts.name))});
} else if (decl.getExternDecl(mod).unwrap()) |extern_decl_index| {
try writer.print("{}", .{mod.declPtr(extern_decl_index).name.fmt(&mod.intern_pool)});
try writer.print("{ }", .{fmtIdent(mod.intern_pool.stringToSlice(mod.declPtr(extern_decl_index).name))});
} else {
// MSVC has a limit of 4095 character token length limit, and fmtIdent can (worst case),
// expand to 3x the length of its input, but let's cut it off at a much shorter limit.
@@ -2564,16 +2587,19 @@ fn genExports(o: *Object) !void {
const fwd = o.dg.fwd_decl.writer();
const exports = mod.decl_exports.get(decl_index) orelse return;
if (exports.items.len < 2) return;
const is_mangled = isMangledIdent(ip.stringToSlice(exports.items[0].opts.name), true);
if (exports.items.len < 2 and !is_mangled) return;
switch (ip.indexToKey(tv.val.toIntern())) {
.func => {
for (exports.items[1..], 1..) |@"export", i| {
const start_i = 1 - @intFromBool(is_mangled);
for (exports.items[start_i..], start_i..) |@"export", i| {
try fwd.writeAll("zig_export(");
if (exports.items[i].opts.linkage == .Weak) try fwd.writeAll("zig_weak_linkage_fn ");
try o.dg.renderFunctionSignature(fwd, decl_index, .forward, .{ .export_index = @as(u32, @intCast(i)) });
try fwd.print(", {s}, {s});\n", .{
fmtStringLiteral(ip.stringToSlice(exports.items[0].opts.name), null),
try fwd.print(", { }, {s});\n", .{
fmtIdent(ip.stringToSlice(exports.items[0].opts.name)),
fmtStringLiteral(ip.stringToSlice(@"export".opts.name), null),
});
}
@@ -2583,7 +2609,8 @@ fn genExports(o: *Object) !void {
unreachable;
},
.variable => |variable| {
for (exports.items[1..], 1..) |@"export", i| {
const start_i = 1 - @intFromBool(is_mangled);
for (exports.items[start_i..], start_i..) |@"export", i| {
try fwd.writeAll("zig_export(");
if (exports.items[i].opts.linkage == .Weak) try fwd.writeAll("zig_weak_linkage ");
const alias = ip.stringToSlice(@"export".opts.name);
@@ -2595,8 +2622,8 @@ fn genExports(o: *Object) !void {
decl.alignment,
.complete,
);
try fwd.print(", {s}, {s});\n", .{
fmtStringLiteral(ip.stringToSlice(exports.items[0].opts.name), null),
try fwd.print(", { }, {s});\n", .{
fmtIdent(ip.stringToSlice(exports.items[0].opts.name)),
fmtStringLiteral(alias, null),
});
}
@@ -6861,9 +6888,9 @@ fn airReduce(f: *Function, inst: Air.Inst.Index) !CValue {
try f.writeCValue(writer, accum, .Other);
switch (op) {
.float_op => |func| {
try writer.writeAll(" = zig_libc_name_");
try writer.writeAll(" = zig_float_fn_");
try f.object.dg.renderTypeForBuiltinFnName(writer, scalar_ty);
try writer.print("({s})(", .{func.operation});
try writer.print("_{s}(", .{func.operation});
try f.writeCValue(writer, accum, .FunctionArgument);
try writer.writeAll(", ");
try f.writeCValue(writer, operand, .Other);
@@ -7195,11 +7222,9 @@ fn unFloatOp(f: *Function, inst: Air.Inst.Index, operand: CValue, ty: Type, oper
const v = try Vectorize.start(f, inst, writer, ty);
try f.writeCValue(writer, local, .Other);
try v.elem(f, writer);
try writer.writeAll(" = zig_libc_name_");
try writer.writeAll(" = zig_float_fn_");
try f.object.dg.renderTypeForBuiltinFnName(writer, scalar_ty);
try writer.writeByte('(');
try writer.writeAll(operation);
try writer.writeAll(")(");
try writer.print("_{s}(", .{operation});
try f.writeCValue(writer, operand, .FunctionArgument);
try v.elem(f, writer);
try writer.writeAll(");\n");
@@ -7234,11 +7259,9 @@ fn airBinFloatOp(f: *Function, inst: Air.Inst.Index, operation: []const u8) !CVa
const v = try Vectorize.start(f, inst, writer, inst_ty);
try f.writeCValue(writer, local, .Other);
try v.elem(f, writer);
try writer.writeAll(" = zig_libc_name_");
try writer.writeAll(" = zig_float_fn_");
try f.object.dg.renderTypeForBuiltinFnName(writer, inst_scalar_ty);
try writer.writeByte('(');
try writer.writeAll(operation);
try writer.writeAll(")(");
try writer.print("_{s}(", .{operation});
try f.writeCValue(writer, lhs, .FunctionArgument);
try v.elem(f, writer);
try writer.writeAll(", ");
@@ -7268,9 +7291,9 @@ fn airMulAdd(f: *Function, inst: Air.Inst.Index) !CValue {
const v = try Vectorize.start(f, inst, writer, inst_ty);
try f.writeCValue(writer, local, .Other);
try v.elem(f, writer);
try writer.writeAll(" = zig_libc_name_");
try writer.writeAll(" = zig_float_fn_");
try f.object.dg.renderTypeForBuiltinFnName(writer, inst_scalar_ty);
try writer.writeAll("(fma)(");
try writer.writeAll("_fma(");
try f.writeCValue(writer, mulend1, .FunctionArgument);
try v.elem(f, writer);
try writer.writeAll(", ");