Add initial AST and MIR support for unwinding from inline assembly

Author: Amanieu

compiler/rustc_ast/src/ast.rs

@@ -1981,7 +1981,7 @@ pub enum InlineAsmRegOrRegClass {
 
 bitflags::bitflags! {
     #[derive(Encodable, Decodable, HashStable_Generic)]
-    pub struct InlineAsmOptions: u8 {
+    pub struct InlineAsmOptions: u16 {
         const PURE = 1 << 0;
         const NOMEM = 1 << 1;
         const READONLY = 1 << 2;
@@ -1990,6 +1990,7 @@ bitflags::bitflags! {
         const NOSTACK = 1 << 5;
         const ATT_SYNTAX = 1 << 6;
         const RAW = 1 << 7;
+        const MAY_UNWIND = 1 << 8;
     }
 }
 

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -2338,6 +2338,9 @@ impl<'a> State<'a> {
                 if opts.contains(InlineAsmOptions::RAW) {
                     options.push("raw");
                 }
+                if opts.contains(InlineAsmOptions::MAY_UNWIND) {
+                    options.push("may_unwind");
+                }
                 s.commasep(Inconsistent, &options, |s, &opt| {
                     s.word(opt);
                 });

compiler/rustc_borrowck/src/dataflow.rs

@@ -5,7 +5,7 @@ use rustc_middle::ty::RegionVid;
 use rustc_middle::ty::TyCtxt;
 use rustc_mir_dataflow::impls::{EverInitializedPlaces, MaybeUninitializedPlaces};
 use rustc_mir_dataflow::ResultsVisitable;
-use rustc_mir_dataflow::{self, fmt::DebugWithContext, GenKill};
+use rustc_mir_dataflow::{self, fmt::DebugWithContext, CallReturnPlaces, GenKill};
 use rustc_mir_dataflow::{Analysis, Direction, Results};
 use std::fmt;
 use std::iter;
@@ -434,9 +434,7 @@ impl<'tcx> rustc_mir_dataflow::GenKillAnalysis<'tcx> for Borrows<'_, 'tcx> {
         &self,
         _trans: &mut impl GenKill<Self::Idx>,
         _block: mir::BasicBlock,
-        _func: &mir::Operand<'tcx>,
-        _args: &[mir::Operand<'tcx>],
-        _dest_place: mir::Place<'tcx>,
+        _return_places: CallReturnPlaces<'_, 'tcx>,
     ) {
     }
 }

compiler/rustc_borrowck/src/def_use.rs

@@ -17,7 +17,7 @@ pub fn categorize(context: PlaceContext) -> Option<DefUse> {
         PlaceContext::MutatingUse(MutatingUseContext::Store) |
 
         // This is potentially both a def and a use...
-        PlaceContext::MutatingUse(MutatingUseContext::AsmOutput) |
+        PlaceContext::MutatingUse(MutatingUseContext::LlvmAsmOutput) |
 
         // We let Call define the result in both the success and
         // unwind cases. This is not really correct, however it
@@ -26,6 +26,7 @@ pub fn categorize(context: PlaceContext) -> Option<DefUse> {
         // the def in call only to the input from the success
         // path and not the unwind path. -nmatsakis
         PlaceContext::MutatingUse(MutatingUseContext::Call) |
+        PlaceContext::MutatingUse(MutatingUseContext::AsmOutput) |
         PlaceContext::MutatingUse(MutatingUseContext::Yield) |
 
         // Storage live and storage dead aren't proper defines, but we can ignore

compiler/rustc_borrowck/src/invalidation.rs

@@ -199,6 +199,7 @@ impl<'cx, 'tcx> Visitor<'tcx> for InvalidationGenerator<'cx, 'tcx> {
                 options: _,
                 line_spans: _,
                 destination: _,
+                cleanup: _,
             } => {
                 for op in operands {
                     match *op {

compiler/rustc_borrowck/src/lib.rs

@@ -791,6 +791,7 @@ impl<'cx, 'tcx> rustc_mir_dataflow::ResultsVisitor<'cx, 'tcx> for MirBorrowckCtx
                 options: _,
                 line_spans: _,
                 destination: _,
+                cleanup: _,
             } => {
                 for op in operands {
                     match *op {

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1828,10 +1828,16 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                     self.assert_iscleanup(body, block_data, unwind, true);
                 }
             }
-            TerminatorKind::InlineAsm { destination, .. } => {
+            TerminatorKind::InlineAsm { destination, cleanup, .. } => {
                 if let Some(target) = destination {
                     self.assert_iscleanup(body, block_data, target, is_cleanup);
                 }
+                if let Some(cleanup) = cleanup {
+                    if is_cleanup {
+                        span_mirbug!(self, block_data, "cleanup on cleanup block")
+                    }
+                    self.assert_iscleanup(body, block_data, cleanup, true);
+                }
             }
         }
     }

compiler/rustc_builtin_macros/src/asm.rs

@@ -420,6 +420,8 @@ fn parse_options<'a>(
             try_set_option(p, args, sym::att_syntax, ast::InlineAsmOptions::ATT_SYNTAX);
         } else if p.eat_keyword(kw::Raw) {
             try_set_option(p, args, kw::Raw, ast::InlineAsmOptions::RAW);
+        } else if p.eat_keyword(sym::may_unwind) {
+            try_set_option(p, args, kw::Raw, ast::InlineAsmOptions::MAY_UNWIND);
         } else {
             return p.unexpected();
         }

compiler/rustc_codegen_ssa/src/mir/analyze.rs

@@ -211,6 +211,7 @@ impl<'mir, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> Visitor<'tcx>
 
             PlaceContext::MutatingUse(
                 MutatingUseContext::Store
+                | MutatingUseContext::LlvmAsmOutput
                 | MutatingUseContext::AsmOutput
                 | MutatingUseContext::Borrow
                 | MutatingUseContext::AddressOf

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -1041,6 +1041,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 options,
                 line_spans,
                 destination,
+                cleanup: _, // TODO
             } => {
                 self.codegen_asm_terminator(
                     helper,