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stage2: prevent UB in the LLVM backend

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* Sema: fix `zirTypeInfo` allocating with the wrong arenas for some
   stuff.
 * LLVM: split `airDbgInline` into two functions, one for each AIR tag.
   - remove the redundant copy to type_map_arena. This is the first
     thing that lowerDebugType does so this hack was probably just
     accidentally avoiding UB (which is still present prior to this
     commit).
   - don't store an inline fn inst into the di_map for the generic
     decl.
   - use a dummy function type for the debug info to avoid whatever UB
     is happening.
   - we are now ignoring the function type passed in with the
     dbg_inline_begin and dbg_inline_end.
 * behavior tests: prepare the vector tests to be enabled one at a time.

Mitigates #11199.
This commit is contained in:
Andrew Kelley
2022-03-16 23:54:25 -07:00
parent 79d3780fbd
commit 87779cfd93
4 changed files with 55 additions and 30 deletions
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50
src/codegen/llvm.zig
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@@ -3472,8 +3472,8 @@ pub const FuncGen = struct {
.const_ty => unreachable,
.unreach => self.airUnreach(inst),
.dbg_stmt => self.airDbgStmt(inst),
.dbg_inline_begin => try self.airDbgInline(inst, true),
.dbg_inline_end => try self.airDbgInline(inst, false),
.dbg_inline_begin => try self.airDbgInlineBegin(inst),
.dbg_inline_end => try self.airDbgInlineEnd(inst),
.dbg_var_ptr => try self.airDbgVarPtr(inst),
.dbg_var_val => try self.airDbgVarVal(inst),
// zig fmt: on
@@ -4199,7 +4199,7 @@ pub const FuncGen = struct {
return null;
}
fn airDbgInline(self: *FuncGen, inst: Air.Inst.Index, start: bool) !?*const llvm.Value {
fn airDbgInlineBegin(self: *FuncGen, inst: Air.Inst.Index) !?*const llvm.Value {
const dib = self.dg.object.di_builder orelse return null;
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
@@ -4209,52 +4209,52 @@ pub const FuncGen = struct {
self.di_file = di_file;
const line_number = decl.src_line + 1;
const cur_debug_location = self.builder.getCurrentDebugLocation2();
if (start) {
try self.dbg_inlined.append(self.gpa, .{
.loc = @ptrCast(*llvm.DILocation, cur_debug_location),
.scope = self.di_scope.?,
.base_line = self.base_line,
});
} else {
const old = self.dbg_inlined.pop();
self.di_scope = old.scope;
self.base_line = old.base_line;
return null;
}
const fn_ty = try self.air.getRefType(ty_pl.ty).copy(self.dg.object.type_map_arena.allocator());
try self.dbg_inlined.append(self.gpa, .{
.loc = @ptrCast(*llvm.DILocation, cur_debug_location),
.scope = self.di_scope.?,
.base_line = self.base_line,
});
const fqn = try decl.getFullyQualifiedName(self.gpa);
defer self.gpa.free(fqn);
const fn_info = fn_ty.fnInfo();
const is_internal_linkage = !self.dg.module.decl_exports.contains(decl);
const noret_bit: c_uint = if (fn_info.return_type.isNoReturn())
llvm.DIFlags.NoReturn
else
0;
const subprogram = dib.createFunction(
di_file.toScope(),
decl.name,
fqn,
di_file,
line_number,
try self.dg.object.lowerDebugType(fn_ty, .full),
try self.dg.object.lowerDebugType(Type.initTag(.fn_void_no_args), .full),
is_internal_linkage,
true, // is definition
line_number + func.lbrace_line, // scope line
llvm.DIFlags.StaticMember | noret_bit,
llvm.DIFlags.StaticMember,
self.dg.module.comp.bin_file.options.optimize_mode != .Debug,
null, // decl_subprogram
);
try self.dg.object.di_map.put(self.gpa, decl, subprogram.toNode());
const lexical_block = dib.createLexicalBlock(subprogram.toScope(), di_file, line_number, 1);
self.di_scope = lexical_block.toScope();
self.base_line = decl.src_line;
return null;
}
fn airDbgInlineEnd(self: *FuncGen, inst: Air.Inst.Index) !?*const llvm.Value {
if (self.dg.object.di_builder == null) return null;
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const func = self.air.values[ty_pl.payload].castTag(.function).?.data;
const decl = func.owner_decl;
const di_file = try self.dg.object.getDIFile(self.gpa, decl.src_namespace.file_scope);
self.di_file = di_file;
const old = self.dbg_inlined.pop();
self.di_scope = old.scope;
self.base_line = old.base_line;
return null;
}
fn airDbgVarPtr(self: *FuncGen, inst: Air.Inst.Index) !?*const llvm.Value {
const dib = self.dg.object.di_builder orelse return null;
const pl_op = self.air.instructions.items(.data)[inst].pl_op;