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stage2: implement safety checks at the zir_sema level

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This commit is contained in:
Andrew Kelley
2020-08-13 10:04:46 -07:00
parent 6b2ce9d1e9
commit ec4953504a
5 changed files with 91 additions and 31 deletions
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72
src-self-hosted/Module.zig
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@@ -2219,11 +2219,6 @@ pub fn wantSafety(self: *Module, scope: *Scope) bool {
};
}
pub fn analyzeUnreach(self: *Module, scope: *Scope, src: usize) InnerError!*Inst {
const b = try self.requireRuntimeBlock(scope, src);
return self.addNoOp(b, src, Type.initTag(.noreturn), .unreach);
}
pub fn analyzeIsNull(
self: *Module,
scope: *Scope,
@@ -2902,3 +2897,70 @@ pub fn dumpInst(self: *Module, scope: *Scope, inst: *Inst) void {
});
}
}
pub const PanicId = enum {
unreach,
unwrap_null,
};
pub fn addSafetyCheck(mod: *Module, parent_block: *Scope.Block, ok: *Inst, panic_id: PanicId) !void {
const block_inst = try parent_block.arena.create(Inst.Block);
block_inst.* = .{
.base = .{
.tag = Inst.Block.base_tag,
.ty = Type.initTag(.void),
.src = ok.src,
},
.body = .{
.instructions = try parent_block.arena.alloc(*Inst, 1), // Only need space for the condbr.
},
};
const ok_body: ir.Body = .{
.instructions = try parent_block.arena.alloc(*Inst, 1), // Only need space for the brvoid.
};
const brvoid = try parent_block.arena.create(Inst.BrVoid);
brvoid.* = .{
.base = .{
.tag = .brvoid,
.ty = Type.initTag(.noreturn),
.src = ok.src,
},
.block = block_inst,
};
ok_body.instructions[0] = &brvoid.base;
var fail_block: Scope.Block = .{
.parent = parent_block,
.func = parent_block.func,
.decl = parent_block.decl,
.instructions = .{},
.arena = parent_block.arena,
};
defer fail_block.instructions.deinit(mod.gpa);
_ = try mod.safetyPanic(&fail_block, ok.src, panic_id);
const fail_body: ir.Body = .{ .instructions = try parent_block.arena.dupe(*Inst, fail_block.instructions.items) };
const condbr = try parent_block.arena.create(Inst.CondBr);
condbr.* = .{
.base = .{
.tag = .condbr,
.ty = Type.initTag(.noreturn),
.src = ok.src,
},
.condition = ok,
.then_body = ok_body,
.else_body = fail_body,
};
block_inst.body.instructions[0] = &condbr.base;
try parent_block.instructions.append(mod.gpa, &block_inst.base);
}
pub fn safetyPanic(mod: *Module, block: *Scope.Block, src: usize, panic_id: PanicId) !*Inst {
// TODO Once we have a panic function to call, call it here instead of breakpoint.
_ = try mod.addNoOp(block, src, Type.initTag(.void), .breakpoint);
return mod.addNoOp(block, src, Type.initTag(.noreturn), .unreach);
}

5
src-self-hosted/codegen.zig
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@@ -668,8 +668,7 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
.store => return self.genStore(inst.castTag(.store).?),
.sub => return self.genSub(inst.castTag(.sub).?),
.unreach => return MCValue{ .unreach = {} },
.unwrap_optional_safe => return self.genUnwrapOptional(inst.castTag(.unwrap_optional_safe).?, true),
.unwrap_optional_unsafe => return self.genUnwrapOptional(inst.castTag(.unwrap_optional_unsafe).?, false),
.unwrap_optional => return self.genUnwrapOptional(inst.castTag(.unwrap_optional).?),
}
}
@@ -819,7 +818,7 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
}
}
fn genUnwrapOptional(self: *Self, inst: *ir.Inst.UnOp, safety_check: bool) !MCValue {
fn genUnwrapOptional(self: *Self, inst: *ir.Inst.UnOp) !MCValue {
// No side effects, so if it's unreferenced, do nothing.
if (inst.base.isUnused())
return MCValue.dead;

6
src-self-hosted/ir.zig
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@@ -82,8 +82,7 @@ pub const Inst = struct {
not,
floatcast,
intcast,
unwrap_optional_safe,
unwrap_optional_unsafe,
unwrap_optional,
pub fn Type(tag: Tag) type {
return switch (tag) {
@@ -104,8 +103,7 @@ pub const Inst = struct {
.floatcast,
.intcast,
.load,
.unwrap_optional_safe,
.unwrap_optional_unsafe,
.unwrap_optional,
=> UnOp,
.add,

3
src-self-hosted/zir.zig
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@@ -1927,8 +1927,7 @@ const EmitZIR = struct {
.isnonnull => try self.emitUnOp(inst.src, new_body, inst.castTag(.isnonnull).?, .isnonnull),
.load => try self.emitUnOp(inst.src, new_body, inst.castTag(.load).?, .deref),
.ref => try self.emitUnOp(inst.src, new_body, inst.castTag(.ref).?, .ref),
.unwrap_optional_safe => try self.emitUnOp(inst.src, new_body, inst.castTag(.unwrap_optional_safe).?, .unwrap_optional_safe),
.unwrap_optional_unsafe => try self.emitUnOp(inst.src, new_body, inst.castTag(.unwrap_optional_unsafe).?, .unwrap_optional_unsafe),
.unwrap_optional => try self.emitUnOp(inst.src, new_body, inst.castTag(.unwrap_optional).?, .unwrap_optional_unsafe),
.add => try self.emitBinOp(inst.src, new_body, inst.castTag(.add).?, .add),
.sub => try self.emitBinOp(inst.src, new_body, inst.castTag(.sub).?, .sub),

36
src-self-hosted/zir_sema.zig
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@@ -68,8 +68,8 @@ pub fn analyzeInst(mod: *Module, scope: *Scope, old_inst: *zir.Inst) InnerError!
.deref => return analyzeInstDeref(mod, scope, old_inst.castTag(.deref).?),
.as => return analyzeInstAs(mod, scope, old_inst.castTag(.as).?),
.@"asm" => return analyzeInstAsm(mod, scope, old_inst.castTag(.@"asm").?),
.@"unreachable" => return analyzeInstUnreachable(mod, scope, old_inst.castTag(.@"unreachable").?),
.unreach_nocheck => return analyzeInstUnreachNoChk(mod, scope, old_inst.castTag(.unreach_nocheck).?),
.@"unreachable" => return analyzeInstUnreachable(mod, scope, old_inst.castTag(.@"unreachable").?, true),
.unreach_nocheck => return analyzeInstUnreachable(mod, scope, old_inst.castTag(.unreach_nocheck).?, false),
.@"return" => return analyzeInstRet(mod, scope, old_inst.castTag(.@"return").?),
.returnvoid => return analyzeInstRetVoid(mod, scope, old_inst.castTag(.returnvoid).?),
.@"fn" => return analyzeInstFn(mod, scope, old_inst.castTag(.@"fn").?),
@@ -313,7 +313,7 @@ fn analyzeInstRef(mod: *Module, scope: *Scope, inst: *zir.Inst.UnOp) InnerError!
if (operand.value()) |val| {
const ref_payload = try scope.arena().create(Value.Payload.RefVal);
ref_payload.* = .{ .val = val };
return mod.constInst(scope, inst.base.src, .{
.ty = ptr_type,
.val = Value.initPayload(&ref_payload.base),
@@ -677,7 +677,7 @@ fn analyzeInstUnwrapOptional(mod: *Module, scope: *Scope, unwrap: *zir.Inst.UnOp
try mod.singleMutPtrType(scope, unwrap.base.src, child_type);
if (operand.value()) |val| {
if (val.tag() == .null_value) {
if (val.isNull()) {
return mod.fail(scope, unwrap.base.src, "unable to unwrap null", .{});
}
return mod.constInst(scope, unwrap.base.src, .{
@@ -687,10 +687,11 @@ fn analyzeInstUnwrapOptional(mod: *Module, scope: *Scope, unwrap: *zir.Inst.UnOp
}
const b = try mod.requireRuntimeBlock(scope, unwrap.base.src);
return if (safety_check)
mod.addUnOp(b, unwrap.base.src, child_pointer, .unwrap_optional_safe, operand)
else
mod.addUnOp(b, unwrap.base.src, child_pointer, .unwrap_optional_unsafe, operand);
if (safety_check and mod.wantSafety(scope)) {
const is_non_null = try mod.addUnOp(b, unwrap.base.src, Type.initTag(.bool), .isnonnull, operand);
try mod.addSafetyCheck(b, is_non_null, .unwrap_null);
}
return mod.addUnOp(b, unwrap.base.src, child_pointer, .unwrap_optional, operand);
}
fn analyzeInstFnType(mod: *Module, scope: *Scope, fntype: *zir.Inst.FnType) InnerError!*Inst {
@@ -1167,18 +1168,19 @@ fn analyzeInstCondBr(mod: *Module, scope: *Scope, inst: *zir.Inst.CondBr) InnerE
return mod.addCondBr(parent_block, inst.base.src, cond, then_body, else_body);
}
fn analyzeInstUnreachNoChk(mod: *Module, scope: *Scope, unreach: *zir.Inst.NoOp) InnerError!*Inst {
return mod.analyzeUnreach(scope, unreach.base.src);
}
fn analyzeInstUnreachable(mod: *Module, scope: *Scope, unreach: *zir.Inst.NoOp) InnerError!*Inst {
fn analyzeInstUnreachable(
mod: *Module,
scope: *Scope,
unreach: *zir.Inst.NoOp,
safety_check: bool,
) InnerError!*Inst {
const b = try mod.requireRuntimeBlock(scope, unreach.base.src);
// TODO Add compile error for @optimizeFor occurring too late in a scope.
if (mod.wantSafety(scope)) {
// TODO Once we have a panic function to call, call it here instead of this.
_ = try mod.addNoOp(b, unreach.base.src, Type.initTag(.void), .breakpoint);
if (safety_check and mod.wantSafety(scope)) {
return mod.safetyPanic(b, unreach.base.src, .unreach);
} else {
return mod.addNoOp(b, unreach.base.src, Type.initTag(.noreturn), .unreach);
}
return mod.analyzeUnreach(scope, unreach.base.src);
}
fn analyzeInstRet(mod: *Module, scope: *Scope, inst: *zir.Inst.UnOp) InnerError!*Inst {