Remove morestack support

mk/clean.mk

@@ -101,7 +101,6 @@ define CLEAN_TARGET_STAGE_N
 clean$(1)_T_$(2)_H_$(3): \
 	    $$(foreach crate,$$(CRATES),clean$(1)_T_$(2)_H_$(3)-lib-$$(crate)) \
 	    $$(foreach tool,$$(TOOLS) $$(DEBUGGER_BIN_SCRIPTS_ALL),clean$(1)_T_$(2)_H_$(3)-tool-$$(tool))
-	$$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/libmorestack.a
 	$$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/libcompiler-rt.a
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/librun_pass_stage* # For unix
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/run_pass_stage* # For windows

mk/crates.mk

@@ -65,7 +65,7 @@ DEPS_libc := core
 DEPS_rustc_unicode := core
 DEPS_alloc := core libc native:jemalloc
 DEPS_std := core libc rand alloc collections rustc_unicode \
-	native:rust_builtin native:backtrace native:rustrt_native \
+	native:rust_builtin native:backtrace \
 	rustc_bitflags
 DEPS_graphviz := std
 DEPS_syntax := std term serialize log fmt_macros arena libc

mk/main.mk

@@ -163,7 +163,7 @@ endif
 # that the snapshot will be generated with a statically linked rustc so we only
 # have to worry about the distribution of one file (with its native dynamic
 # dependencies)
-RUSTFLAGS_STAGE0 += -C prefer-dynamic
+RUSTFLAGS_STAGE0 += -C prefer-dynamic -C no-stack-check
 RUSTFLAGS_STAGE1 += -C prefer-dynamic
 RUST_LIB_FLAGS_ST2 += -C prefer-dynamic
 RUST_LIB_FLAGS_ST3 += -C prefer-dynamic
@@ -400,6 +400,11 @@ TSREQ$(1)_T_$(2)_H_$(3) = \
 	$$(foreach obj,$$(INSTALLED_OBJECTS_$(2)),\
 		$$(TLIB$(1)_T_$(2)_H_$(3))/$$(obj))
 
+ifeq ($(1),0)
+TSREQ$(1)_T_$(2)_H_$(3) += \
+	$$(TLIB$(1)_T_$(2)_H_$(3))/$$(call CFG_STATIC_LIB_NAME_$(2),morestack)
+endif
+
 # Prerequisites for a working stageN compiler and libraries, for a specific
 # target
 SREQ$(1)_T_$(2)_H_$(3) = \

mk/platform.mk

@@ -113,8 +113,7 @@ CFG_RLIB_GLOB=lib$(1)-*.rlib
 include $(wildcard $(CFG_SRC_DIR)mk/cfg/*.mk)
 
 define ADD_INSTALLED_OBJECTS
-  INSTALLED_OBJECTS_$(1) += $$(call CFG_STATIC_LIB_NAME_$(1),morestack) \
-                            $$(call CFG_STATIC_LIB_NAME_$(1),compiler-rt)
+  INSTALLED_OBJECTS_$(1) += $$(call CFG_STATIC_LIB_NAME_$(1),compiler-rt)
 endef
 
 $(foreach target,$(CFG_TARGET), \

mk/rt.mk

@@ -35,8 +35,8 @@
 # that's per-target so you're allowed to conditionally add files based on the
 # target.
 ################################################################################
-NATIVE_LIBS := rust_builtin hoedown morestack miniz \
-		rustrt_native rust_test_helpers
+NATIVE_LIBS := rust_builtin hoedown miniz \
+		rust_test_helpers morestack
 
 # $(1) is the target triple
 define NATIVE_LIBRARIES
@@ -53,10 +53,8 @@ NATIVE_DEPS_hoedown_$(1) := hoedown/src/autolink.c \
 NATIVE_DEPS_miniz_$(1) = miniz.c
 NATIVE_DEPS_rust_builtin_$(1) := rust_builtin.c \
 			rust_android_dummy.c
-NATIVE_DEPS_rustrt_native_$(1) := arch/$$(HOST_$(1))/record_sp.S
 NATIVE_DEPS_rust_test_helpers_$(1) := rust_test_helpers.c
-NATIVE_DEPS_morestack_$(1) := arch/$$(HOST_$(1))/morestack.S
-
+NATIVE_DEPS_morestack_$(1) := empty.c
 
 ################################################################################
 # You shouldn't find it that necessary to edit anything below this line.

mk/target.mk

@@ -56,8 +56,7 @@ $(foreach host,$(CFG_HOST), \
 #   1. The immediate dependencies are the rust source files
 #   2. Each rust crate dependency is listed (based on their stamp files),
 #      as well as all native dependencies (listed in RT_OUTPUT_DIR)
-#   3. The stage (n-1) compiler is required through the TSREQ dependency, along
-#      with the morestack library
+#   3. The stage (n-1) compiler is required through the TSREQ dependency
 #   4. When actually executing the rule, the first thing we do is to clean out
 #      old libs and rlibs via the REMOVE_ALL_OLD_GLOB_MATCHES macro
 #   5. Finally, we get around to building the actual crate. It's just one

src/doc/trpl/lang-items.md

@@ -51,7 +51,6 @@ fn main(argc: isize, argv: *const *const u8) -> isize {
     0
 }
 
-#[lang = "stack_exhausted"] extern fn stack_exhausted() {}
 #[lang = "eh_personality"] extern fn eh_personality() {}
 #[lang = "panic_fmt"] fn panic_fmt() -> ! { loop {} }
 # #[lang = "eh_unwind_resume"] extern fn rust_eh_unwind_resume() {}

src/doc/trpl/no-stdlib.md

@@ -36,7 +36,6 @@ fn start(_argc: isize, _argv: *const *const u8) -> isize {
 // These functions and traits are used by the compiler, but not
 // for a bare-bones hello world. These are normally
 // provided by libstd.
-#[lang = "stack_exhausted"] extern fn stack_exhausted() {}
 #[lang = "eh_personality"] extern fn eh_personality() {}
 #[lang = "panic_fmt"] fn panic_fmt() -> ! { loop {} }
 # #[lang = "eh_unwind_resume"] extern fn rust_eh_unwind_resume() {}
@@ -61,7 +60,6 @@ pub extern fn main(argc: i32, argv: *const *const u8) -> i32 {
     0
 }
 
-#[lang = "stack_exhausted"] extern fn stack_exhausted() {}
 #[lang = "eh_personality"] extern fn eh_personality() {}
 #[lang = "panic_fmt"] fn panic_fmt() -> ! { loop {} }
 # #[lang = "eh_unwind_resume"] extern fn rust_eh_unwind_resume() {}
@@ -73,18 +71,12 @@ The compiler currently makes a few assumptions about symbols which are available
 in the executable to call. Normally these functions are provided by the standard
 library, but without it you must define your own.
 
-The first of these three functions, `stack_exhausted`, is invoked whenever stack
-overflow is detected.  This function has a number of restrictions about how it
-can be called and what it must do, but if the stack limit register is not being
-maintained then a thread always has an "infinite stack" and this function
-shouldn't get triggered.
-
-The second of these three functions, `eh_personality`, is used by the
+The first of these two functions, `eh_personality`, is used by the
 failure mechanisms of the compiler. This is often mapped to GCC's
 personality function (see the
 [libstd implementation](../std/rt/unwind/index.html) for more
 information), but crates which do not trigger a panic can be assured
-that this function is never called. The final function, `panic_fmt`, is
+that this function is never called. The second function, `panic_fmt`, is
 also used by the failure mechanisms of the compiler.
 
 ## Using libcore
@@ -150,7 +142,6 @@ extern fn panic_fmt(args: &core::fmt::Arguments,
     loop {}
 }
 
-#[lang = "stack_exhausted"] extern fn stack_exhausted() {}
 #[lang = "eh_personality"] extern fn eh_personality() {}
 # #[lang = "eh_unwind_resume"] extern fn rust_eh_unwind_resume() {}
 # #[start] fn start(argc: isize, argv: *const *const u8) -> isize { 0 }

src/librustc/middle/lang_items.rs

@@ -347,7 +347,5 @@ lets_do_this! {
 
     NonZeroItem,                     "non_zero",                non_zero;
 
-    StackExhaustedLangItem,          "stack_exhausted",         stack_exhausted;
-
     DebugTraitLangItem,              "debug_trait",             debug_trait;
 }

src/librustc/middle/weak_lang_items.rs

@@ -39,9 +39,6 @@ pub fn check_crate(krate: &ast::Crate,
     // These are never called by user code, they're generated by the compiler.
     // They will never implicitly be added to the `missing` array unless we do
     // so here.
-    if items.stack_exhausted().is_none() {
-        items.missing.push(lang_items::StackExhaustedLangItem);
-    }
     if items.eh_personality().is_none() {
         items.missing.push(lang_items::EhPersonalityLangItem);
     }
@@ -124,7 +121,6 @@ impl<'a, 'v> Visitor<'v> for Context<'a> {
 
 weak_lang_items! {
     panic_fmt,          PanicFmtLangItem,           rust_begin_unwind;
-    stack_exhausted,    StackExhaustedLangItem,     rust_stack_exhausted;
     eh_personality,     EhPersonalityLangItem,      rust_eh_personality;
     eh_unwind_resume,   EhUnwindResumeLangItem,     rust_eh_unwind_resume;
 }

src/librustc_back/target/apple_base.rs

@@ -19,7 +19,6 @@ pub fn opts() -> TargetOptions {
         dynamic_linking: true,
         executables: true,
         is_like_osx: true,
-        morestack: true,
         has_rpath: true,
         dll_prefix: "lib".to_string(),
         dll_suffix: ".dylib".to_string(),

src/librustc_back/target/apple_ios_base.rs

@@ -87,14 +87,6 @@ pub fn opts(arch: Arch) -> TargetOptions {
         cpu: target_cpu(arch),
         dynamic_linking: false,
         executables: true,
-        // Although there is an experimental implementation of LLVM which
-        // supports SS on armv7 it wasn't approved by Apple, see:
-        // http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140505/216350.html
-        // It looks like it might be never accepted to upstream LLVM.
-        //
-        // SS might be also enabled on Arm64 as it has builtin support in LLVM
-        // but I haven't tested it through yet
-        morestack: false,
         pre_link_args: pre_link_args(arch),
         .. super::apple_base::opts()
     }

src/librustc_back/target/bitrig_base.rs

@@ -16,7 +16,6 @@ pub fn opts() -> TargetOptions {
         linker: "cc".to_string(),
         dynamic_linking: true,
         executables: true,
-        morestack: false,
         linker_is_gnu: true,
         has_rpath: true,
         position_independent_executables: true,

src/librustc_back/target/dragonfly_base.rs

@@ -16,7 +16,6 @@ pub fn opts() -> TargetOptions {
         linker: "cc".to_string(),
         dynamic_linking: true,
         executables: true,
-        morestack: true,
         linker_is_gnu: true,
         has_rpath: true,
         pre_link_args: vec!(

src/librustc_back/target/freebsd_base.rs

@@ -16,7 +16,6 @@ pub fn opts() -> TargetOptions {
         linker: "cc".to_string(),
         dynamic_linking: true,
         executables: true,
-        morestack: true,
         has_rpath: true,
         archive_format: "gnu".to_string(),
 

src/librustc_back/target/i686_unknown_freebsd.rs

@@ -14,7 +14,6 @@ pub fn target() -> Target {
     let mut base = super::freebsd_base::opts();
     base.cpu = "pentium4".to_string();
     base.pre_link_args.push("-m32".to_string());
-    base.morestack = false;
 
     Target {
         llvm_target: "i686-unknown-freebsd".to_string(),

src/librustc_back/target/linux_base.rs

@@ -15,7 +15,6 @@ pub fn opts() -> TargetOptions {
     TargetOptions {
         dynamic_linking: true,
         executables: true,
-        morestack: true,
         linker_is_gnu: true,
         has_rpath: true,
         pre_link_args: vec![

src/librustc_back/target/mod.rs

@@ -118,9 +118,6 @@ pub struct TargetOptions {
     /// Whether executables are available on this target. iOS, for example, only allows static
     /// libraries. Defaults to false.
     pub executables: bool,
-    /// Whether LLVM's segmented stack prelude is supported by whatever runtime is available.
-    /// Will emit stack checks and calls to __morestack. Defaults to false.
-    pub morestack: bool,
     /// Relocation model to use in object file. Corresponds to `llc
     /// -relocation-model=$relocation_model`. Defaults to "pic".
     pub relocation_model: String,
@@ -192,7 +189,6 @@ impl Default for TargetOptions {
             features: "".to_string(),
             dynamic_linking: false,
             executables: false,
-            morestack: false,
             relocation_model: "pic".to_string(),
             code_model: "default".to_string(),
             disable_redzone: false,
@@ -298,7 +294,6 @@ impl Target {
         key!(data_layout);
         key!(dynamic_linking, bool);
         key!(executables, bool);
-        key!(morestack, bool);
         key!(disable_redzone, bool);
         key!(eliminate_frame_pointer, bool);
         key!(function_sections, bool);

src/librustc_back/target/netbsd_base.rs

@@ -16,7 +16,6 @@ pub fn opts() -> TargetOptions {
         linker: "cc".to_string(),
         dynamic_linking: true,
         executables: true,
-        morestack: false,
         linker_is_gnu: true,
         has_rpath: true,
         pre_link_args: vec!(

src/librustc_back/target/openbsd_base.rs

@@ -16,7 +16,6 @@ pub fn opts() -> TargetOptions {
         linker: "cc".to_string(),
         dynamic_linking: true,
         executables: true,
-        morestack: false,
         linker_is_gnu: true,
         has_rpath: true,
         pre_link_args: vec!(

src/librustc_back/target/windows_base.rs

@@ -23,7 +23,6 @@ pub fn opts() -> TargetOptions {
         exe_suffix: ".exe".to_string(),
         staticlib_prefix: "".to_string(),
         staticlib_suffix: ".lib".to_string(),
-        morestack: false,
         is_like_windows: true,
         archive_format: "gnu".to_string(),
         pre_link_args: vec!(

src/librustc_back/target/windows_msvc_base.rs

@@ -53,7 +53,6 @@ pub fn opts() -> TargetOptions {
         exe_suffix: ".exe".to_string(),
         staticlib_prefix: "".to_string(),
         staticlib_suffix: ".lib".to_string(),
-        morestack: false,
         is_like_windows: true,
         is_like_msvc: true,
         pre_link_args: vec![

src/librustc_trans/back/link.rs

@@ -759,9 +759,6 @@ fn link_staticlib(sess: &Session, objects: &[PathBuf], out_filename: &Path,
     if sess.target.target.options.is_like_osx && !ab.using_llvm() {
         ab.build();
     }
-    if sess.target.target.options.morestack {
-        ab.add_native_library("morestack").unwrap();
-    }
     if !sess.target.target.options.no_compiler_rt {
         ab.add_native_library("compiler-rt").unwrap();
     }
@@ -905,26 +902,6 @@ fn link_args(cmd: &mut Linker,
     }
     cmd.output_filename(out_filename);
 
-    // Stack growth requires statically linking a __morestack function. Note
-    // that this is listed *before* all other libraries. Due to the usage of the
-    // --as-needed flag below, the standard library may only be useful for its
-    // rust_stack_exhausted function. In this case, we must ensure that the
-    // libmorestack.a file appears *before* the standard library (so we put it
-    // at the very front).
-    //
-    // Most of the time this is sufficient, except for when LLVM gets super
-    // clever. If, for example, we have a main function `fn main() {}`, LLVM
-    // will optimize out calls to `__morestack` entirely because the function
-    // doesn't need any stack at all!
-    //
-    // To get around this snag, we specially tell the linker to always include
-    // all contents of this library. This way we're guaranteed that the linker
-    // will include the __morestack symbol 100% of the time, always resolving
-    // references to it even if the object above didn't use it.
-    if t.options.morestack {
-        cmd.link_whole_staticlib("morestack", &[lib_path]);
-    }
-
     // When linking a dynamic library, we put the metadata into a section of the
     // executable. This metadata is in a separate object file from the main
     // object file, so we link that in here.

src/librustc_trans/trans/attributes.rs

@@ -23,19 +23,6 @@ use trans::context::CrateContext;
 use trans::machine;
 use trans::type_of;
 
-/// Mark LLVM function to use split stack.
-#[inline]
-pub fn split_stack(val: ValueRef, set: bool) {
-    unsafe {
-        let attr = "split-stack\0".as_ptr() as *const _;
-        if set {
-            llvm::LLVMAddFunctionAttrString(val, llvm::FunctionIndex as c_uint, attr);
-        } else {
-            llvm::LLVMRemoveFunctionAttrString(val, llvm::FunctionIndex as c_uint, attr);
-        }
-    }
-}
-
 /// Mark LLVM function to use provided inline heuristic.
 #[inline]
 pub fn inline(val: ValueRef, inline: InlineAttr) {
@@ -123,9 +110,7 @@ pub fn from_fn_attrs(ccx: &CrateContext, attrs: &[ast::Attribute], llfn: ValueRe
     }
 
     for attr in attrs {
-        if attr.check_name("no_stack_check") {
-            split_stack(llfn, false);
-        } else if attr.check_name("cold") {
+        if attr.check_name("cold") {
             unsafe {
                 llvm::LLVMAddFunctionAttribute(llfn,
                                                llvm::FunctionIndex as c_uint,

src/librustc_trans/trans/base.rs

@@ -2173,17 +2173,8 @@ fn finish_register_fn(ccx: &CrateContext, sym: String, node_id: ast::NodeId,
                       llfn: ValueRef) {
     ccx.item_symbols().borrow_mut().insert(node_id, sym);
 
-    // The stack exhaustion lang item shouldn't have a split stack because
-    // otherwise it would continue to be exhausted (bad), and both it and the
-    // eh_personality functions need to be externally linkable.
+    // The eh_personality function need to be externally linkable.
     let def = ast_util::local_def(node_id);
-    if ccx.tcx().lang_items.stack_exhausted() == Some(def) {
-        attributes::split_stack(llfn, false);
-        llvm::SetLinkage(llfn, llvm::ExternalLinkage);
-        if ccx.use_dll_storage_attrs() {
-            llvm::SetDLLStorageClass(llfn, llvm::DLLExportStorageClass);
-        }
-    }
     if ccx.tcx().lang_items.eh_personality() == Some(def) {
         llvm::SetLinkage(llfn, llvm::ExternalLinkage);
         if ccx.use_dll_storage_attrs() {
@@ -2801,13 +2792,8 @@ pub fn trans_crate(tcx: &ty::ctxt, analysis: ty::CrateAnalysis) -> CrateTranslat
     });
 
     // Make sure that some other crucial symbols are not eliminated from the
-    // module. This includes the main function, the crate map (used for debug
-    // log settings and I/O), and finally the curious rust_stack_exhausted
-    // symbol. This symbol is required for use by the libmorestack library that
-    // we link in, so we must ensure that this symbol is not internalized (if
-    // defined in the crate).
+    // module, including the main function.
     reachable.push("main".to_string());
-    reachable.push("rust_stack_exhausted".to_string());
 
     // referenced from .eh_frame section on some platforms
     reachable.push("rust_eh_personality".to_string());

src/librustc_trans/trans/context.rs

@@ -570,11 +570,6 @@ impl<'b, 'tcx> CrateContext<'b, 'tcx> {
         }
     }
 
-    pub fn is_split_stack_supported(&self) -> bool {
-        self.sess().target.target.options.morestack
-    }
-
-
     pub fn llmod(&self) -> ModuleRef {
         self.local.llmod
     }