std: Move pc-windows-gnu to SEH-based unwinding

mk/cfg/i686-pc-windows-gnu.mk

@@ -22,6 +22,5 @@ CFG_LDPATH_i686-pc-windows-gnu :=
 CFG_RUN_i686-pc-windows-gnu=$(2)
 CFG_RUN_TARG_i686-pc-windows-gnu=$(call CFG_RUN_i686-pc-windows-gnu,,$(2))
 CFG_GNU_TRIPLE_i686-pc-windows-gnu := i686-w64-mingw32
-CFG_THIRD_PARTY_OBJECTS_i686-pc-windows-gnu := crt2.o dllcrt2.o
-CFG_INSTALLED_OBJECTS_i686-pc-windows-gnu := crt2.o dllcrt2.o rsbegin.o rsend.o
-CFG_RUSTRT_HAS_STARTUP_OBJS_i686-pc-windows-gnu := 1
+CFG_THIRD_PARTY_OBJECTS_i686-pc-windows-gnu :=
+CFG_INSTALLED_OBJECTS_i686-pc-windows-gnu :=

mk/cfg/x86_64-pc-windows-gnu.mk

@@ -22,6 +22,5 @@ CFG_LDPATH_x86_64-pc-windows-gnu :=
 CFG_RUN_x86_64-pc-windows-gnu=$(2)
 CFG_RUN_TARG_x86_64-pc-windows-gnu=$(call CFG_RUN_x86_64-pc-windows-gnu,,$(2))
 CFG_GNU_TRIPLE_x86_64-pc-windows-gnu := x86_64-w64-mingw32
-CFG_THIRD_PARTY_OBJECTS_x86_64-pc-windows-gnu := crt2.o dllcrt2.o
-CFG_INSTALLED_OBJECTS_x86_64-pc-windows-gnu := crt2.o dllcrt2.o rsbegin.o rsend.o
-CFG_RUSTRT_HAS_STARTUP_OBJS_x86_64-pc-windows-gnu := 1
+CFG_THIRD_PARTY_OBJECTS_x86_64-pc-windows-gnu :=
+CFG_INSTALLED_OBJECTS_x86_64-pc-windows-gnu :=

mk/dist.mk

@@ -58,7 +58,6 @@ PKG_FILES := \
       libcoretest                              \
       libbacktrace                             \
       rt                                       \
-      rtstartup                                \
       rustllvm                                 \
       snapshots.txt                            \
       rust-installer                           \

mk/rt.mk

@@ -291,10 +291,8 @@ BACKTRACE_NAME_$(1) := $$(call CFG_STATIC_LIB_NAME_$(1),backtrace)
 BACKTRACE_LIB_$(1) := $$(RT_OUTPUT_DIR_$(1))/$$(BACKTRACE_NAME_$(1))
 BACKTRACE_BUILD_DIR_$(1) := $$(RT_OUTPUT_DIR_$(1))/libbacktrace
 
-# We don't use this on platforms that aren't linux-based (with the exception of
-# msys2/mingw builds on windows, which use it to read the dwarf debug
-# information) so just make the file available, the compilation of libstd won't
-# actually build it.
+# We don't use this on platforms that aren't linux-based so just make the file
+# available, the compilation of libstd won't actually build it.
 ifeq ($$(findstring darwin,$$(OSTYPE_$(1))),darwin)
 # See comment above
 $$(BACKTRACE_LIB_$(1)):
@@ -307,7 +305,7 @@ $$(BACKTRACE_LIB_$(1)):
 	touch $$@
 else
 
-ifeq ($$(findstring msvc,$(1)),msvc)
+ifeq ($$(findstring windows,$(1)),windows)
 # See comment above
 $$(BACKTRACE_LIB_$(1)):
 	touch $$@
@@ -382,10 +380,6 @@ endif # endif for darwin
 ifeq ($$(findstring musl,$(1)),musl)
 $$(RT_OUTPUT_DIR_$(1))/%: $$(CFG_MUSL_ROOT)/lib/%
 	cp $$^ $$@
-else
-# Ask gcc where it is
-$$(RT_OUTPUT_DIR_$(1))/%:
-	cp $$(shell $$(CC_$(1)) -print-file-name=$$(@F)) $$@
 endif
 
 endef

mk/target.mk

@@ -126,34 +126,6 @@ $$(TBIN$(1)_T_$(2)_H_$(3))/$(4)$$(X_$(2)): \
 
 endef
 
-# Macro for building runtime startup/shutdown object files;
-# these are Rust's equivalent of crti.o, crtn.o
-#
-# $(1) - stage
-# $(2) - target triple
-# $(3) - host triple
-# $(4) - object basename
-define TARGET_RUSTRT_STARTUP_OBJ
-
-$$(TLIB$(1)_T_$(2)_H_$(3))/$(4).o: \
-		$(S)src/rtstartup/$(4).rs \
-		$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.core \
-		$$(HSREQ$(1)_T_$(2)_H_$(3)) \
-		| $$(TBIN$(1)_T_$(2)_H_$(3))/
-	@$$(call E, rustc: $$@)
-	$$(STAGE$(1)_T_$(2)_H_$(3)) --emit=obj -o $$@ $$<
-
-ifeq ($$(CFG_RUSTRT_HAS_STARTUP_OBJS_$(2)), 1)
-# Add dependencies on Rust startup objects to all crates that depend on core.
-# This ensures that they are built after core (since they depend on it),
-# but before everything else (since they are needed for linking dylib crates).
-$$(foreach crate, $$(TARGET_CRATES), \
-	$$(if $$(findstring core,$$(DEPS_$$(crate))), \
-		$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.$$(crate))) : $$(TLIB$(1)_T_$(2)_H_$(3))/$(4).o
-endif
-
-endef
-
 # Every recipe in RUST_TARGET_STAGE_N outputs to $$(TLIB$(1)_T_$(2)_H_$(3),
 # a directory that can be cleaned out during the middle of a run of
 # the get-snapshot.py script.  Therefore, every recipe needs to have
@@ -166,7 +138,10 @@ SNAPSHOT_RUSTC_POST_CLEANUP=$(HBIN0_H_$(CFG_BUILD))/rustc$(X_$(CFG_BUILD))
 
 define TARGET_HOST_RULES
 
-$$(TLIB$(1)_T_$(2)_H_$(3))/:
+$$(TLIB$(1)_T_$(2)_H_$(3))/: | $$(SNAPSHOT_RUSTC_POST_CLEANUP)
+	mkdir -p $$@
+
+$$(TBIN$(1)_T_$(2)_H_$(3))/: | $$(SNAPSHOT_RUSTC_POST_CLEANUP)
 	mkdir -p $$@
 
 $$(TLIB$(1)_T_$(2)_H_$(3))/%: $$(RT_OUTPUT_DIR_$(2))/% \
@@ -197,8 +172,33 @@ $(foreach host,$(CFG_HOST), \
    $(foreach tool,$(TOOLS), \
     $(eval $(call TARGET_TOOL,$(stage),$(target),$(host),$(tool)))))))
 
+# FIXME(stage0) - remove everything here after a snapshot
+#
+# The stage0 compiler requires the rsend.o, rsbegin.o, crt2.o, and dllcrt2.o
+# startup objects on the pc-windows-gnu targets, but that's no longer the case.
+# Hack in support to the makefiles to ensure that these objects all exist.
+#
+# Note that the rs*.o files can just be blank object files.
+define STARTUP_OBJS_COMPAT
+ifeq ($$(findstring pc-windows-gnu,$(2)),pc-windows-gnu)
+DUMMY_DEPS_$(2)_H_$(3) := \
+	$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.core \
+	$$(HSREQ$(1)_T_$(2)_H_$(3))/stamp.core
+$$(TLIB$(1)_T_$(2)_H_$(3))/rsend.o $$(TLIB$(1)_T_$(2)_H_$(3))/rsbegin.o: \
+		$$(DUMMY_DEPS_$(2)_H_$(3) \
+		| $$(TLIB$(1)_T_$(2)_H_$(3))/ $$(SNAPSHOT_RUSTC_POST_CLEANUP)
+	$$(CC_$(2)) $$(CFG_GCCISH_CFLAGS_$(2)) -c -x c - -o $$@ < /dev/null
+$$(TLIB$(1)_T_$(2)_H_$(3))/dllcrt2.o $$(TLIB$(1)_T_$(2)_H_$(3))/crt2.o: \
+		$$(DUMMY_DEPS_$(2)_H_$(3) \
+		| $$(TLIB$(1)_T_$(2)_H_$(3))/ $$(SNAPSHOT_RUSTC_POST_CLEANUP)
+	cp $$(shell $$(CC_$(2)) -print-file-name=$$(@F)) $$@
+$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.std: \
+	$$(TLIB$(1)_T_$(2)_H_$(3))/rsend.o \
+	$$(TLIB$(1)_T_$(2)_H_$(3))/rsbegin.o \
+	$$(TLIB$(1)_T_$(2)_H_$(3))/dllcrt2.o \
+	$$(TLIB$(1)_T_$(2)_H_$(3))/crt2.o
+endif
+endef
 $(foreach host,$(CFG_HOST), \
  $(foreach target,$(CFG_TARGET), \
-  $(foreach stage,$(STAGES), \
-   $(foreach obj,rsbegin rsend, \
-    $(eval $(call TARGET_RUSTRT_STARTUP_OBJ,$(stage),$(target),$(host),$(obj)))))))
+  $(eval $(call STARTUP_OBJS_COMPAT,0,$(target),$(host)))))

src/doc/book/custom-allocators.md

@@ -138,9 +138,6 @@ pub extern fn __rust_usable_size(size: usize, _align: usize) -> usize {
 # fn main() {}
 # #[lang = "panic_fmt"] fn panic_fmt() {}
 # #[lang = "eh_personality"] fn eh_personality() {}
-# #[lang = "eh_unwind_resume"] extern fn eh_unwind_resume() {}
-# #[no_mangle] pub extern fn rust_eh_register_frames () {}
-# #[no_mangle] pub extern fn rust_eh_unregister_frames () {}
 ```
 
 After we compile this crate, it can be used as follows:

src/doc/book/lang-items.md

@@ -59,9 +59,6 @@ fn main(argc: isize, argv: *const *const u8) -> isize {
 
 #[lang = "eh_personality"] extern fn eh_personality() {}
 #[lang = "panic_fmt"] fn panic_fmt() -> ! { loop {} }
-# #[lang = "eh_unwind_resume"] extern fn rust_eh_unwind_resume() {}
-# #[no_mangle] pub extern fn rust_eh_register_frames () {}
-# #[no_mangle] pub extern fn rust_eh_unregister_frames () {}
 ```
 
 Note the use of `abort`: the `exchange_malloc` lang item is assumed to

src/doc/book/no-stdlib.md

@@ -39,9 +39,6 @@ fn start(_argc: isize, _argv: *const *const u8) -> isize {
 // provided by libstd.
 #[lang = "eh_personality"] extern fn eh_personality() {}
 #[lang = "panic_fmt"] fn panic_fmt() -> ! { loop {} }
-# #[lang = "eh_unwind_resume"] extern fn rust_eh_unwind_resume() {}
-# #[no_mangle] pub extern fn rust_eh_register_frames () {}
-# #[no_mangle] pub extern fn rust_eh_unregister_frames () {}
 # // fn main() {} tricked you, rustdoc!
 ```
 
@@ -66,9 +63,6 @@ pub extern fn main(argc: i32, argv: *const *const u8) -> i32 {
 
 #[lang = "eh_personality"] extern fn eh_personality() {}
 #[lang = "panic_fmt"] fn panic_fmt() -> ! { loop {} }
-# #[lang = "eh_unwind_resume"] extern fn rust_eh_unwind_resume() {}
-# #[no_mangle] pub extern fn rust_eh_register_frames () {}
-# #[no_mangle] pub extern fn rust_eh_unregister_frames () {}
 # // fn main() {} tricked you, rustdoc!
 ```
 

src/librustc/middle/lang_items.rs

@@ -340,7 +340,6 @@ lets_do_this! {
 
     EhPersonalityLangItem,           "eh_personality",          eh_personality;
     EhPersonalityCatchLangItem,      "eh_personality_catch",    eh_personality_catch;
-    EhUnwindResumeLangItem,          "eh_unwind_resume",        eh_unwind_resume;
     MSVCTryFilterLangItem,           "msvc_try_filter",         msvc_try_filter;
 
     OwnedBoxLangItem,                "owned_box",               owned_box;

src/librustc/middle/weak_lang_items.rs

@@ -43,10 +43,6 @@ pub fn check_crate(krate: &hir::Crate,
     if items.eh_personality().is_none() {
         items.missing.push(lang_items::EhPersonalityLangItem);
     }
-    if sess.target.target.options.custom_unwind_resume &
-       items.eh_unwind_resume().is_none() {
-        items.missing.push(lang_items::EhUnwindResumeLangItem);
-    }
 
     {
         let mut cx = Context { sess: sess, items: items };
@@ -123,5 +119,4 @@ impl<'a, 'v> Visitor<'v> for Context<'a> {
 weak_lang_items! {
     panic_fmt,          PanicFmtLangItem,           rust_begin_unwind;
     eh_personality,     EhPersonalityLangItem,      rust_eh_personality;
-    eh_unwind_resume,   EhUnwindResumeLangItem,     rust_eh_unwind_resume;
 }

src/librustc_back/target/mod.rs

@@ -191,11 +191,6 @@ pub struct TargetOptions {
     pub archive_format: String,
     /// Is asm!() allowed? Defaults to true.
     pub allow_asm: bool,
-    /// Whether the target uses a custom unwind resumption routine.
-    /// By default LLVM lowers `resume` instructions into calls to `_Unwind_Resume`
-    /// defined in libgcc.  If this option is enabled, the target must provide
-    /// `eh_unwind_resume` lang item.
-    pub custom_unwind_resume: bool,
 
     /// Default crate for allocation symbols to link against
     pub lib_allocation_crate: String,
@@ -250,7 +245,6 @@ impl Default for TargetOptions {
             post_link_objects: Vec::new(),
             late_link_args: Vec::new(),
             archive_format: String::new(),
-            custom_unwind_resume: false,
             lib_allocation_crate: "alloc_system".to_string(),
             exe_allocation_crate: "alloc_system".to_string(),
             allow_asm: true,
@@ -365,7 +359,6 @@ impl Target {
         key!(post_link_args, list);
         key!(archive_format);
         key!(allow_asm, bool);
-        key!(custom_unwind_resume, bool);
 
         base
     }

src/librustc_back/target/windows_base.rs

@@ -23,7 +23,7 @@ pub fn opts() -> TargetOptions {
         exe_suffix: ".exe".to_string(),
         staticlib_prefix: "".to_string(),
         staticlib_suffix: ".lib".to_string(),
-        no_default_libraries: true,
+        no_default_libraries: false,
         is_like_windows: true,
         archive_format: "gnu".to_string(),
         pre_link_args: vec!(
@@ -60,30 +60,7 @@ pub fn opts() -> TargetOptions {
 
             // Always enable DEP (NX bit) when it is available
             "-Wl,--nxcompat".to_string(),
-
-            // Do not use the standard system startup files or libraries when linking
-            "-nostdlib".to_string(),
-        ),
-        pre_link_objects_exe: vec!(
-            "crt2.o".to_string(),    // mingw C runtime initialization for executables
-            "rsbegin.o".to_string(), // Rust compiler runtime initialization, see rsbegin.rs
-        ),
-        pre_link_objects_dll: vec!(
-            "dllcrt2.o".to_string(), // mingw C runtime initialization for dlls
-            "rsbegin.o".to_string(),
-        ),
-        late_link_args: vec!(
-            "-lmingwex".to_string(),
-            "-lmingw32".to_string(),
-            "-lgcc".to_string(), // alas, mingw* libraries above depend on libgcc
-            "-lmsvcrt".to_string(),
-            "-luser32".to_string(),
-            "-lkernel32".to_string(),
-        ),
-        post_link_objects: vec!(
-            "rsend.o".to_string()
         ),
-        custom_unwind_resume: true,
 
         .. Default::default()
     }

src/librustc_llvm/lib.rs

@@ -2490,3 +2490,17 @@ impl Drop for OperandBundleDef {
 mod llvmdeps {
     include! { env!("CFG_LLVM_LINKAGE_FILE") }
 }
+
+// Currenty when compiling LLVM for i686-pc-windows-gnu it will think that it's
+// got "ehtable support", and these two symbols here will be referenced from
+// RTDyldMemoryManager. This class is, however, only really used from jits, so
+// we don't really need it to work. For now just define two dummy symbols, but
+// ideally we'd upstream some patch or configure LLVM in such a way that it
+// doesn't even need these symbols defined.
+#[cfg(all(windows, target_env = "gnu", target_arch = "x86"))]
+pub mod __dummy_llvm_required_symbols {
+    #[no_mangle]
+    pub extern fn __register_frame(_ptr: *mut u8) {}
+    #[no_mangle]
+    pub extern fn __deregister_frame(_ptr: *mut u8) {}
+}

src/librustc_trans/trans/base.rs

@@ -980,11 +980,9 @@ pub fn invoke<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
 
 /// Returns whether this session's target will use SEH-based unwinding.
 ///
-/// This is only true for MSVC targets, and even then the 64-bit MSVC target
-/// currently uses SEH-ish unwinding with DWARF info tables to the side (same as
-/// 64-bit MinGW) instead of "full SEH".
+/// This is currentlyt true for all Windows targets.
 pub fn wants_msvc_seh(sess: &Session) -> bool {
-    sess.target.target.options.is_like_msvc
+    sess.target.target.options.is_like_windows
 }
 
 pub fn avoid_invoke(bcx: Block) -> bool {
@@ -1220,19 +1218,6 @@ pub fn call_lifetime_end(cx: Block, ptr: ValueRef) {
     })
 }
 
-// Generates code for resumption of unwind at the end of a landing pad.
-pub fn trans_unwind_resume(bcx: Block, lpval: ValueRef) {
-    if !bcx.sess().target.target.options.custom_unwind_resume {
-        Resume(bcx, lpval);
-    } else {
-        let exc_ptr = ExtractValue(bcx, lpval, 0);
-        let llunwresume = bcx.fcx.eh_unwind_resume();
-        Call(bcx, llunwresume, &[exc_ptr], None, DebugLoc::None);
-        Unreachable(bcx);
-    }
-}
-
-
 pub fn call_memcpy(cx: Block, dst: ValueRef, src: ValueRef, n_bytes: ValueRef, align: u32) {
     let _icx = push_ctxt("call_memcpy");
     let ccx = cx.ccx();
@@ -1981,7 +1966,9 @@ pub fn trans_closure<'a, 'b, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
     record_translation_item_as_generated(ccx, fn_ast_id, param_substs);
 
     let _icx = push_ctxt("trans_closure");
-    attributes::emit_uwtable(llfndecl, true);
+    if !wants_msvc_seh(ccx.sess()) {
+        attributes::emit_uwtable(llfndecl, true);
+    }
 
     debug!("trans_closure(..., param_substs={:?})", param_substs);
 

src/librustc_trans/trans/cleanup.rs

@@ -747,7 +747,7 @@ impl<'blk, 'tcx> CleanupHelperMethods<'blk, 'tcx> for FunctionContext<'blk, 'tcx
                                                .unwrap();
                                 let lp = build::Load(bcx, addr);
                                 base::call_lifetime_end(bcx, addr);
-                                base::trans_unwind_resume(bcx, lp);
+                                build::Resume(bcx, lp);
                             }
                             UnwindKind::CleanupPad(_) => {
                                 let pad = build::CleanupPad(bcx, None, &[]);

src/librustc_trans/trans/common.rs

@@ -534,35 +534,6 @@ impl<'a, 'tcx> FunctionContext<'a, 'tcx> {
             }
         }
     }
-
-    // Returns a ValueRef of the "eh_unwind_resume" lang item if one is defined,
-    // otherwise declares it as an external funtion.
-    pub fn eh_unwind_resume(&self) -> ValueRef {
-        use trans::attributes;
-        assert!(self.ccx.sess().target.target.options.custom_unwind_resume);
-        match self.ccx.tcx().lang_items.eh_unwind_resume() {
-            Some(def_id) => {
-                callee::trans_fn_ref(self.ccx, def_id, ExprId(0),
-                                     self.param_substs).val
-            }
-            None => {
-                let mut unwresume = self.ccx.eh_unwind_resume().borrow_mut();
-                match *unwresume {
-                    Some(llfn) => llfn,
-                    None => {
-                        let fty = Type::func(&[Type::i8p(self.ccx)], &Type::void(self.ccx));
-                        let llfn = declare::declare_fn(self.ccx,
-                                                       "rust_eh_unwind_resume",
-                                                       llvm::CCallConv,
-                                                       fty, ty::FnDiverging);
-                        attributes::unwind(llfn, true);
-                        *unwresume = Some(llfn);
-                        llfn
-                    }
-                }
-            }
-        }
-    }
 }
 
 // Basic block context.  We create a block context for each basic block