Commit 8547c42ba5
Changed files (2)
lib
std
lib/std/dwarf/expressions.zig
@@ -33,7 +33,7 @@ pub const ExpressionOptions = struct {
endian: std.builtin.Endian = .Little,
/// Restrict the stack machine to a subset of opcodes used in call frame instructions
- call_frame_mode: bool = false,
+ call_frame_context: bool = false,
};
/// A stack machine that can decode and run DWARF expressions.
@@ -111,13 +111,15 @@ pub fn StackMachine(comptime options: ExpressionOptions) type {
// TODO: For these two prongs, look up the type and assert it's integral?
.regval_type => |regval_type| regval_type.value,
.const_type => |const_type| {
- return switch (const_type.value_bytes.len) {
+ const value: u64 = switch (const_type.value_bytes.len) {
1 => mem.readIntSliceNative(u8, const_type.value_bytes),
2 => mem.readIntSliceNative(u16, const_type.value_bytes),
4 => mem.readIntSliceNative(u32, const_type.value_bytes),
8 => mem.readIntSliceNative(u64, const_type.value_bytes),
- else => error.InvalidIntegralTypeLength,
+ else => return error.InvalidIntegralTypeSize,
};
+
+ return std.math.cast(addr_type, value) orelse error.TruncatedIntegralType;
},
};
}
@@ -278,26 +280,7 @@ pub fn StackMachine(comptime options: ExpressionOptions) type {
@compileError("Execution of non-native address sizees / endianness is not supported");
const opcode = try stream.reader().readByte();
- if (options.call_frame_mode) {
- // Certain opcodes are not allowed in a CFA context, see 6.4.2
- switch (opcode) {
- OP.addrx,
- OP.call2,
- OP.call4,
- OP.call_ref,
- OP.const_type,
- OP.constx,
- OP.convert,
- OP.deref_type,
- OP.regval_type,
- OP.reinterpret,
- OP.push_object_address,
- OP.call_frame_cfa,
- => return error.InvalidCFAExpression,
- else => {},
- }
- }
-
+ if (options.call_frame_context and !opcodeValidInCFA(opcode)) return error.InvalidCFAOpcode;
switch (opcode) {
// 2.5.1.1: Literal Encodings
@@ -420,7 +403,7 @@ pub fn StackMachine(comptime options: ExpressionOptions) type {
OP.xderef_type,
=> {
if (self.stack.items.len == 0) return error.InvalidExpression;
- var addr = try self.stack.pop().asIntegral();
+ var addr = try self.stack.items[self.stack.items.len - 1].asIntegral();
const addr_space_identifier: ?usize = switch (opcode) {
OP.xderef,
OP.xderef_size,
@@ -447,24 +430,24 @@ pub fn StackMachine(comptime options: ExpressionOptions) type {
else => unreachable,
};
- const value: u64 = switch (size) {
+ const value: addr_type = std.math.cast(addr_type, @as(u64, switch (size) {
1 => @as(*const u8, @ptrFromInt(addr)).*,
2 => @as(*const u16, @ptrFromInt(addr)).*,
4 => @as(*const u32, @ptrFromInt(addr)).*,
8 => @as(*const u64, @ptrFromInt(addr)).*,
else => return error.InvalidExpression,
- };
+ })) orelse return error.InvalidExpression;
if (opcode == OP.deref_type) {
- try self.stack.append(allocator, .{
+ self.stack.items[self.stack.items.len - 1] = .{
.regval_type = .{
.type_offset = operand.?.deref_type.type_offset,
.type_size = operand.?.deref_type.size,
.value = value,
},
- });
+ };
} else {
- try self.stack.append(allocator, .{ .generic = value });
+ self.stack.items[self.stack.items.len - 1] = .{ .generic = value };
}
},
OP.push_object_address,
@@ -738,6 +721,7 @@ pub fn Writer(options: ExpressionOptions) type {
return struct {
/// Zero-operand instructions
pub fn writeOpcode(writer: anytype, comptime opcode: u8) !void {
+ if (options.call_frame_context and !comptime opcodeValidInCFA(opcode)) return error.InvalidCFAOpcode;
switch (opcode) {
OP.dup,
OP.drop,
@@ -820,6 +804,7 @@ pub fn Writer(options: ExpressionOptions) type {
}
pub fn writeConstType(writer: anytype, die_offset: anytype, size: u8, value_bytes: []const u8) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
if (size != value_bytes.len) return error.InvalidValueSize;
try writer.writeByte(OP.const_type);
try leb.writeULEB128(writer, die_offset);
@@ -833,6 +818,7 @@ pub fn Writer(options: ExpressionOptions) type {
}
pub fn writeAddrx(writer: anytype, debug_addr_offset: anytype) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.addrx);
try leb.writeULEB128(writer, debug_addr_offset);
}
@@ -856,6 +842,7 @@ pub fn Writer(options: ExpressionOptions) type {
}
pub fn writeRegvalType(writer: anytype, register: anytype, offset: anytype) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.bregx);
try leb.writeULEB128(writer, register);
try leb.writeULEB128(writer, offset);
@@ -878,6 +865,7 @@ pub fn Writer(options: ExpressionOptions) type {
}
pub fn writeDerefType(writer: anytype, size: u8, die_offset: anytype) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.deref_type);
try writer.writeByte(size);
try leb.writeULEB128(writer, die_offset);
@@ -909,6 +897,7 @@ pub fn Writer(options: ExpressionOptions) type {
}
pub fn writeCall(writer: anytype, comptime T: type, offset: T) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
switch (T) {
u16 => try writer.writeByte(OP.call2),
u32 => try writer.writeByte(OP.call4),
@@ -919,16 +908,19 @@ pub fn Writer(options: ExpressionOptions) type {
}
pub fn writeCallRef(writer: anytype, debug_info_offset: addr_type) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.call_ref);
try writer.writeInt(addr_type, debug_info_offset, options.endian);
}
pub fn writeConvert(writer: anytype, die_offset: anytype) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.convert);
try leb.writeULEB128(writer, die_offset);
}
pub fn writeReinterpret(writer: anytype, die_offset: anytype) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.reinterpret);
try leb.writeULEB128(writer, die_offset);
}
@@ -942,12 +934,31 @@ pub fn Writer(options: ExpressionOptions) type {
}
// 2.6: Location Descriptions
-
// TODO
};
}
+// Certain opcodes are not allowed in a CFA context, see 6.4.2
+fn opcodeValidInCFA(opcode: u8) bool {
+ return switch (opcode) {
+ OP.addrx,
+ OP.call2,
+ OP.call4,
+ OP.call_ref,
+ OP.const_type,
+ OP.constx,
+ OP.convert,
+ OP.deref_type,
+ OP.regval_type,
+ OP.reinterpret,
+ OP.push_object_address,
+ OP.call_frame_cfa,
+ => false,
+ else => true,
+ };
+}
+
test "DWARF expressions" {
const allocator = std.testing.allocator;
lib/std/dwarf.zig
@@ -1783,7 +1783,7 @@ pub const UnwindContext = struct {
reg_ctx: abi.RegisterContext,
isValidMemory: *const fn (address: usize) bool,
vm: call_frame.VirtualMachine = .{},
- stack_machine: expressions.StackMachine(.{ .call_frame_mode = true }) = .{},
+ stack_machine: expressions.StackMachine(.{ .call_frame_context = true }) = .{},
pub fn init(allocator: mem.Allocator, ucontext: *const os.ucontext_t, isValidMemory: *const fn (address: usize) bool) !UnwindContext {
const pc = mem.readIntSliceNative(usize, try abi.regBytes(ucontext, abi.ipRegNum(), null));