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Parser: add grammar comments for inline assembly
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Also rearrange some code to make the grammar easier to specify
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@ehaas
ehaas committed Aug 31, 2023
1 parent c7d5504 commit 99b83bd
Showing 1 changed file with 63 additions and 42 deletions.
105 changes: 63 additions & 42 deletions src/Parser.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -3638,46 +3638,50 @@ fn convertInitList(p: *Parser, il: InitList, init_ty: Type) Error!NodeIndex {
}
}

fn parseMSVCAsmStmt(p: *Parser) Error!?NodeIndex {
fn msvcAsmStmt(p: *Parser) Error!?NodeIndex {
return p.todo("MSVC assembly statements");
}

fn parseAsmOperands(p: *Parser, names: *std.ArrayList(?TokenIndex), constraints: *NodeList, exprs: *NodeList) Error!void {
if (!p.tok_ids[p.tok_i].isStringLiteral() and p.tok_ids[p.tok_i] != .l_bracket) {
// Empty
return;
}
while (true) {
if (p.eatToken(.l_bracket)) |l_bracket| {
const ident = (try p.eatIdentifier()) orelse {
try p.err(.expected_identifier);
return error.ParsingFailed;
};
try names.append(ident);
try p.expectClosing(l_bracket, .r_bracket);
} else {
try names.append(null);
}
const constraint = try p.asmStr();
try constraints.append(constraint.node);

const l_paren = p.eatToken(.l_paren) orelse {
try p.errExtra(.expected_token, p.tok_i, .{ .tok_id = .{ .actual = p.tok_ids[p.tok_i], .expected = .l_paren } });
/// asmOperand : ('[' IDENTIFIER ']')? asmStr '(' expr ')'
fn asmOperand(p: *Parser, names: *std.ArrayList(?TokenIndex), constraints: *NodeList, exprs: *NodeList) Error!void {
if (p.eatToken(.l_bracket)) |l_bracket| {
const ident = (try p.eatIdentifier()) orelse {
try p.err(.expected_identifier);
return error.ParsingFailed;
};
const res = try p.expr();
try p.expectClosing(l_paren, .r_paren);
try res.expect(p);
try exprs.append(res.node);
if (p.eatToken(.comma) == null) return;
try names.append(ident);
try p.expectClosing(l_bracket, .r_bracket);
} else {
try names.append(null);
}
const constraint = try p.asmStr();
try constraints.append(constraint.node);

const l_paren = p.eatToken(.l_paren) orelse {
try p.errExtra(.expected_token, p.tok_i, .{ .tok_id = .{ .actual = p.tok_ids[p.tok_i], .expected = .l_paren } });
return error.ParsingFailed;
};
const res = try p.expr();
try p.expectClosing(l_paren, .r_paren);
try res.expect(p);
try exprs.append(res.node);
}
fn parseGNUAsmStmt(p: *Parser, asm_str_node: NodeIndex, quals: Tree.GNUAssemblyQualifiers) Error!NodeIndex {

/// gnuAsmStmt
/// : asmStr
/// | asmStr ':' asmOperand*
/// | asmStr ':' asmOperand* ':' asmOperand*
/// | asmStr ':' asmOperand* ':' asmOperand* : asmStr? (',' asmStr)*
/// | asmStr ':' asmOperand* ':' asmOperand* : asmStr? (',' asmStr)* : IDENTIFIER (',' IDENTIFIER)*
fn gnuAsmStmt(p: *Parser, quals: Tree.GNUAssemblyQualifiers, l_paren: TokenIndex) Error!NodeIndex {
const asm_str = try p.asmStr();
try p.checkAsmStr(asm_str.val, l_paren);

if (p.tok_ids[p.tok_i] == .r_paren) {
return p.addNode(.{
.tag = .gnu_asm_simple,
.ty = .{ .specifier = .void },
.data = .{ .un = asm_str_node },
.data = .{ .un = asm_str.node },
});
}

Expand All @@ -3702,7 +3706,12 @@ fn parseGNUAsmStmt(p: *Parser, asm_str_node: NodeIndex, quals: Tree.GNUAssemblyQ
if (p.eatToken(.colon) orelse p.eatToken(.colon_colon)) |tok_i| {
ate_extra_colon = p.tok_ids[tok_i] == .colon_colon;
if (!ate_extra_colon) {
try p.parseAsmOperands(&names, &constraints, &exprs);
if (p.tok_ids[p.tok_i].isStringLiteral() or p.tok_ids[p.tok_i] == .l_bracket) {
while (true) {
try p.asmOperand(&names, &constraints, &exprs);
if (p.eatToken(.comma) == null) break;
}
}
}
}

Expand All @@ -3717,7 +3726,12 @@ fn parseGNUAsmStmt(p: *Parser, asm_str_node: NodeIndex, quals: Tree.GNUAssemblyQ
p.tok_i += 1;
}
if (!ate_extra_colon) {
try p.parseAsmOperands(&names, &constraints, &exprs);
if (p.tok_ids[p.tok_i].isStringLiteral() or p.tok_ids[p.tok_i] == .l_bracket) {
while (true) {
try p.asmOperand(&names, &constraints, &exprs);
if (p.eatToken(.comma) == null) break;
}
}
}
}
std.debug.assert(names.items.len == constraints.items.len and constraints.items.len == exprs.items.len);
Expand Down Expand Up @@ -3787,7 +3801,19 @@ fn parseGNUAsmStmt(p: *Parser, asm_str_node: NodeIndex, quals: Tree.GNUAssemblyQ
return .none;
}

/// assembly : keyword_asm asmQual* '(' asmStr ')'
fn checkAsmStr(p: *Parser, asm_str: Value, tok: TokenIndex) !void {
if (!p.comp.langopts.gnu_asm) {
const str = asm_str.data.bytes;
if (str.len > 1) {
// Empty string (just a NUL byte) is ok because it does not emit any assembly
try p.errTok(.gnu_asm_disabled, tok);
}
}
}

/// assembly
/// : keyword_asm asmQual* '(' asmStr gnuAsmStmt? ')'
/// | keyword_asm msvcAsmStmt
fn assembly(p: *Parser, kind: enum { global, decl_label, stmt }) Error!?NodeIndex {
const asm_tok = p.tok_i;
switch (p.tok_ids[p.tok_i]) {
Expand All @@ -3800,7 +3826,7 @@ fn assembly(p: *Parser, kind: enum { global, decl_label, stmt }) Error!?NodeInde
}

if (!p.tok_ids[p.tok_i].canOpenGCCAsmStmt()) {
return p.parseMSVCAsmStmt();
return p.msvcAsmStmt();
}

var quals: Tree.GNUAssemblyQualifiers = .{};
Expand All @@ -3825,28 +3851,23 @@ fn assembly(p: *Parser, kind: enum { global, decl_label, stmt }) Error!?NodeInde

const l_paren = try p.expectToken(.l_paren);
var result_node: NodeIndex = .none;
const asm_str = try p.asmStr();
if (kind != .decl_label and !p.comp.langopts.gnu_asm) {
const str = asm_str.val.data.bytes;
if (str.len > 1) {
// Empty string (just a NUL byte) is ok because it does not emit any assembly
try p.errTok(.gnu_asm_disabled, l_paren);
}
}
switch (kind) {
.decl_label => {
const asm_str = try p.asmStr();
const str = asm_str.val.data.bytes;
const attr = Attribute{ .tag = .asm_label, .args = .{ .asm_label = .{ .name = str[0 .. str.len - 1] } }, .syntax = .keyword };
try p.attr_buf.append(p.gpa, .{ .attr = attr, .tok = asm_tok });
},
.global => {
const asm_str = try p.asmStr();
try p.checkAsmStr(asm_str.val, l_paren);
result_node = try p.addNode(.{
.tag = .file_scope_asm,
.ty = .{ .specifier = .void },
.data = .{ .decl = .{ .name = asm_tok, .node = asm_str.node } },
});
},
.stmt => result_node = try p.parseGNUAsmStmt(asm_str.node, quals),
.stmt => result_node = try p.gnuAsmStmt(quals, l_paren),
}
try p.expectClosing(l_paren, .r_paren);

Expand Down

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