From 3ad8c8858e93020416edef421d489c15e46a0365 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 11 Apr 2020 02:52:34 +0300
Subject: [PATCH 1/9] rustc_target: Make sure lld-link is treated as link.exe
 by default

The differences if they are discovered will need to be explicitly documented
---
 src/librustc_codegen_ssa/back/link.rs         |  6 +-
 .../spec/i686_pc_windows_msvc.rs              | 24 ++++---
 src/librustc_target/spec/mod.rs               | 35 ++++++++++-
 .../spec/thumbv7a_pc_windows_msvc.rs          |  9 ++-
 src/librustc_target/spec/uefi_base.rs         | 62 +++++++++----------
 src/librustc_target/spec/windows_msvc_base.rs | 10 +--
 .../spec/windows_uwp_msvc_base.rs             | 24 +++----
 7 files changed, 106 insertions(+), 64 deletions(-)

diff --git a/src/librustc_codegen_ssa/back/link.rs b/src/librustc_codegen_ssa/back/link.rs
index 20e64f0c48851..5f7a1938a3304 100644
--- a/src/librustc_codegen_ssa/back/link.rs
+++ b/src/librustc_codegen_ssa/back/link.rs
@@ -12,7 +12,7 @@ use rustc_session::search_paths::PathKind;
 /// need out of the shared crate context before we get rid of it.
 use rustc_session::{filesearch, Session};
 use rustc_span::symbol::Symbol;
-use rustc_target::spec::{LinkerFlavor, PanicStrategy, RelroLevel};
+use rustc_target::spec::{LinkerFlavor, LldFlavor, PanicStrategy, RelroLevel};
 
 use super::archive::ArchiveBuilder;
 use super::command::Command;
@@ -182,7 +182,9 @@ fn get_linker(sess: &Session, linker: &Path, flavor: LinkerFlavor) -> Command {
     // To comply with the Windows App Certification Kit,
     // MSVC needs to link with the Store versions of the runtime libraries (vcruntime, msvcrt, etc).
     let t = &sess.target.target;
-    if flavor == LinkerFlavor::Msvc && t.target_vendor == "uwp" {
+    if (flavor == LinkerFlavor::Msvc || flavor == LinkerFlavor::Lld(LldFlavor::Link))
+        && t.target_vendor == "uwp"
+    {
         if let Some(ref tool) = msvc_tool {
             let original_path = tool.path();
             if let Some(ref root_lib_path) = original_path.ancestors().nth(4) {
diff --git a/src/librustc_target/spec/i686_pc_windows_msvc.rs b/src/librustc_target/spec/i686_pc_windows_msvc.rs
index ffb66afc76182..9d0922b8ce5a9 100644
--- a/src/librustc_target/spec/i686_pc_windows_msvc.rs
+++ b/src/librustc_target/spec/i686_pc_windows_msvc.rs
@@ -1,18 +1,24 @@
-use crate::spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_msvc_base::opts();
     base.cpu = "pentium4".to_string();
     base.max_atomic_width = Some(64);
 
-    // Mark all dynamic libraries and executables as compatible with the larger 4GiB address
-    // space available to x86 Windows binaries on x86_64.
-    base.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().push("/LARGEADDRESSAWARE".to_string());
-
-    // Ensure the linker will only produce an image if it can also produce a table of
-    // the image's safe exception handlers.
-    // https://docs.microsoft.com/en-us/cpp/build/reference/safeseh-image-has-safe-exception-handlers
-    base.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().push("/SAFESEH".to_string());
+    let pre_link_args_msvc = vec![
+        // Mark all dynamic libraries and executables as compatible with the larger 4GiB address
+        // space available to x86 Windows binaries on x86_64.
+        "/LARGEADDRESSAWARE".to_string(),
+        // Ensure the linker will only produce an image if it can also produce a table of
+        // the image's safe exception handlers.
+        // https://docs.microsoft.com/en-us/cpp/build/reference/safeseh-image-has-safe-exception-handlers
+        "/SAFESEH".to_string(),
+    ];
+    base.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().extend(pre_link_args_msvc.clone());
+    base.pre_link_args
+        .get_mut(&LinkerFlavor::Lld(LldFlavor::Link))
+        .unwrap()
+        .extend(pre_link_args_msvc);
 
     Ok(Target {
         llvm_target: "i686-pc-windows-msvc".to_string(),
diff --git a/src/librustc_target/spec/mod.rs b/src/librustc_target/spec/mod.rs
index 1bc2bf12fad9e..a1b9974826085 100644
--- a/src/librustc_target/spec/mod.rs
+++ b/src/librustc_target/spec/mod.rs
@@ -322,6 +322,7 @@ macro_rules! supported_targets {
                     // Target on this testing platform (i.e., checking the iOS targets
                     // only on a Mac test platform).
                     let _ = $module::target().map(|original| {
+                        original.check_consistency();
                         let as_json = original.to_json();
                         let parsed = Target::from_json(as_json).unwrap();
                         assert_eq!(original, parsed);
@@ -538,7 +539,8 @@ pub struct Target {
     pub arch: String,
     /// [Data layout](http://llvm.org/docs/LangRef.html#data-layout) to pass to LLVM.
     pub data_layout: String,
-    /// Linker flavor
+    /// Default linker flavor used if `-C linker-flavor` or `-C linker` are not passed
+    /// on the command line.
     pub linker_flavor: LinkerFlavor,
     /// Optional settings with defaults.
     pub options: TargetOptions,
@@ -566,7 +568,8 @@ pub struct TargetOptions {
     /// Linker to invoke
     pub linker: Option<String>,
 
-    /// LLD flavor
+    /// LLD flavor used if `lld` (or `rust-lld`) is specified as a linker
+    /// without clarifying its flavor in any way.
     pub lld_flavor: LldFlavor,
 
     /// Linker arguments that are passed *before* any user-defined libraries.
@@ -1286,6 +1289,34 @@ impl Target {
             }
         }
     }
+
+    #[cfg(test)]
+    fn check_consistency(&self) {
+        // Check that LLD with the given flavor is treated identically to the linker it emulates.
+        // If you target really needs to deviate from the rules below, whitelist it
+        // and document the reasons.
+        assert_eq!(
+            self.linker_flavor == LinkerFlavor::Msvc
+                || self.linker_flavor == LinkerFlavor::Lld(LldFlavor::Link),
+            self.options.lld_flavor == LldFlavor::Link,
+        );
+        for args in &[
+            &self.options.pre_link_args,
+            &self.options.pre_link_args_crt,
+            &self.options.late_link_args,
+            &self.options.late_link_args_dynamic,
+            &self.options.late_link_args_static,
+            &self.options.post_link_args,
+        ] {
+            assert_eq!(
+                args.get(&LinkerFlavor::Msvc),
+                args.get(&LinkerFlavor::Lld(LldFlavor::Link)),
+            );
+            if args.contains_key(&LinkerFlavor::Msvc) {
+                assert_eq!(self.options.lld_flavor, LldFlavor::Link);
+            }
+        }
+    }
 }
 
 impl ToJson for Target {
diff --git a/src/librustc_target/spec/thumbv7a_pc_windows_msvc.rs b/src/librustc_target/spec/thumbv7a_pc_windows_msvc.rs
index ab0f7791e2cda..21d62d252e09a 100644
--- a/src/librustc_target/spec/thumbv7a_pc_windows_msvc.rs
+++ b/src/librustc_target/spec/thumbv7a_pc_windows_msvc.rs
@@ -1,4 +1,4 @@
-use crate::spec::{LinkerFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_msvc_base::opts();
@@ -10,7 +10,12 @@ pub fn target() -> TargetResult {
     // should be smart enough to insert branch islands only
     // where necessary, but this is not the observed behavior.
     // Disabling the LBR optimization works around the issue.
-    base.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().push("/OPT:NOLBR".to_string());
+    let pre_link_args_msvc = "/OPT:NOLBR".to_string();
+    base.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().push(pre_link_args_msvc.clone());
+    base.pre_link_args
+        .get_mut(&LinkerFlavor::Lld(LldFlavor::Link))
+        .unwrap()
+        .push(pre_link_args_msvc);
 
     // FIXME(jordanrh): use PanicStrategy::Unwind when SEH is
     // implemented for windows/arm in LLVM
diff --git a/src/librustc_target/spec/uefi_base.rs b/src/librustc_target/spec/uefi_base.rs
index d09da9478fb2b..030eb12eb0ec5 100644
--- a/src/librustc_target/spec/uefi_base.rs
+++ b/src/librustc_target/spec/uefi_base.rs
@@ -13,39 +13,37 @@ use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, PanicStrategy, TargetOption
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
+    let pre_link_args_msvc = vec![
+        // Suppress the verbose logo and authorship debugging output, which would needlessly
+        // clog any log files.
+        "/NOLOGO".to_string(),
+        // UEFI is fully compatible to non-executable data pages. Tell the compiler that
+        // non-code sections can be marked as non-executable, including stack pages. In fact,
+        // firmware might enforce this, so we better let the linker know about this, so it
+        // will fail if the compiler ever tries placing code on the stack (e.g., trampoline
+        // constructs and alike).
+        "/NXCOMPAT".to_string(),
+        // There is no runtime for UEFI targets, prevent them from being linked. UEFI targets
+        // must be freestanding.
+        "/nodefaultlib".to_string(),
+        // Non-standard subsystems have no default entry-point in PE+ files. We have to define
+        // one. "efi_main" seems to be a common choice amongst other implementations and the
+        // spec.
+        "/entry:efi_main".to_string(),
+        // COFF images have a "Subsystem" field in their header, which defines what kind of
+        // program it is. UEFI has 3 fields reserved, which are EFI_APPLICATION,
+        // EFI_BOOT_SERVICE_DRIVER, and EFI_RUNTIME_DRIVER. We default to EFI_APPLICATION,
+        // which is very likely the most common option. Individual projects can override this
+        // with custom linker flags.
+        // The subsystem-type only has minor effects on the application. It defines the memory
+        // regions the application is loaded into (runtime-drivers need to be put into
+        // reserved areas), as well as whether a return from the entry-point is treated as
+        // exit (default for applications).
+        "/subsystem:efi_application".to_string(),
+    ];
     let mut pre_link_args = LinkArgs::new();
-
-    pre_link_args.insert(
-        LinkerFlavor::Lld(LldFlavor::Link),
-        vec![
-            // Suppress the verbose logo and authorship debugging output, which would needlessly
-            // clog any log files.
-            "/NOLOGO".to_string(),
-            // UEFI is fully compatible to non-executable data pages. Tell the compiler that
-            // non-code sections can be marked as non-executable, including stack pages. In fact,
-            // firmware might enforce this, so we better let the linker know about this, so it
-            // will fail if the compiler ever tries placing code on the stack (e.g., trampoline
-            // constructs and alike).
-            "/NXCOMPAT".to_string(),
-            // There is no runtime for UEFI targets, prevent them from being linked. UEFI targets
-            // must be freestanding.
-            "/nodefaultlib".to_string(),
-            // Non-standard subsystems have no default entry-point in PE+ files. We have to define
-            // one. "efi_main" seems to be a common choice amongst other implementations and the
-            // spec.
-            "/entry:efi_main".to_string(),
-            // COFF images have a "Subsystem" field in their header, which defines what kind of
-            // program it is. UEFI has 3 fields reserved, which are EFI_APPLICATION,
-            // EFI_BOOT_SERVICE_DRIVER, and EFI_RUNTIME_DRIVER. We default to EFI_APPLICATION,
-            // which is very likely the most common option. Individual projects can override this
-            // with custom linker flags.
-            // The subsystem-type only has minor effects on the application. It defines the memory
-            // regions the application is loaded into (runtime-drivers need to be put into
-            // reserved areas), as well as whether a return from the entry-point is treated as
-            // exit (default for applications).
-            "/subsystem:efi_application".to_string(),
-        ],
-    );
+    pre_link_args.insert(LinkerFlavor::Msvc, pre_link_args_msvc.clone());
+    pre_link_args.insert(LinkerFlavor::Lld(LldFlavor::Link), pre_link_args_msvc);
 
     TargetOptions {
         dynamic_linking: false,
diff --git a/src/librustc_target/spec/windows_msvc_base.rs b/src/librustc_target/spec/windows_msvc_base.rs
index 52b166df93996..78567a4382bed 100644
--- a/src/librustc_target/spec/windows_msvc_base.rs
+++ b/src/librustc_target/spec/windows_msvc_base.rs
@@ -2,10 +2,10 @@ use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
-    let pre_args = vec!["/NOLOGO".to_string(), "/NXCOMPAT".to_string()];
-    let mut args = LinkArgs::new();
-    args.insert(LinkerFlavor::Msvc, pre_args.clone());
-    args.insert(LinkerFlavor::Lld(LldFlavor::Link), pre_args);
+    let pre_link_args_msvc = vec!["/NOLOGO".to_string(), "/NXCOMPAT".to_string()];
+    let mut pre_link_args = LinkArgs::new();
+    pre_link_args.insert(LinkerFlavor::Msvc, pre_link_args_msvc.clone());
+    pre_link_args.insert(LinkerFlavor::Lld(LldFlavor::Link), pre_link_args_msvc);
 
     TargetOptions {
         function_sections: true,
@@ -24,7 +24,7 @@ pub fn opts() -> TargetOptions {
         // messages if a link error occurred.
         link_env: vec![("VSLANG".to_string(), "1033".to_string())],
         lld_flavor: LldFlavor::Link,
-        pre_link_args: args,
+        pre_link_args,
         crt_static_allows_dylibs: true,
         crt_static_respected: true,
         abi_return_struct_as_int: true,
diff --git a/src/librustc_target/spec/windows_uwp_msvc_base.rs b/src/librustc_target/spec/windows_uwp_msvc_base.rs
index 3d639b6b628b3..9497e525dd97c 100644
--- a/src/librustc_target/spec/windows_uwp_msvc_base.rs
+++ b/src/librustc_target/spec/windows_uwp_msvc_base.rs
@@ -1,17 +1,16 @@
-use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
-    let mut args = LinkArgs::new();
-    args.insert(
-        LinkerFlavor::Msvc,
-        vec![
-            "/NOLOGO".to_string(),
-            "/NXCOMPAT".to_string(),
-            "/APPCONTAINER".to_string(),
-            "mincore.lib".to_string(),
-        ],
-    );
+    let pre_link_args_msvc = vec![
+        "/NOLOGO".to_string(),
+        "/NXCOMPAT".to_string(),
+        "/APPCONTAINER".to_string(),
+        "mincore.lib".to_string(),
+    ];
+    let mut pre_link_args = LinkArgs::new();
+    pre_link_args.insert(LinkerFlavor::Msvc, pre_link_args_msvc.clone());
+    pre_link_args.insert(LinkerFlavor::Lld(LldFlavor::Link), pre_link_args_msvc);
 
     TargetOptions {
         function_sections: true,
@@ -25,12 +24,13 @@ pub fn opts() -> TargetOptions {
         target_family: Some("windows".to_string()),
         is_like_windows: true,
         is_like_msvc: true,
-        pre_link_args: args,
+        pre_link_args,
         crt_static_allows_dylibs: true,
         crt_static_respected: true,
         abi_return_struct_as_int: true,
         emit_debug_gdb_scripts: false,
         requires_uwtable: true,
+        lld_flavor: LldFlavor::Link,
 
         ..Default::default()
     }

From 7a4f059add44699af6d24abdcfd39f429dd54084 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 11 Apr 2020 13:53:12 +0300
Subject: [PATCH 2/9] rustc_target: Move tests into a separate unconfigured
 file

as much as possible.
---
 src/librustc_target/spec/mod.rs              | 48 ++------------------
 src/librustc_target/spec/tests/tests_impl.rs | 43 ++++++++++++++++++
 2 files changed, 48 insertions(+), 43 deletions(-)
 create mode 100644 src/librustc_target/spec/tests/tests_impl.rs

diff --git a/src/librustc_target/spec/mod.rs b/src/librustc_target/spec/mod.rs
index a1b9974826085..91fd3f8e18ed2 100644
--- a/src/librustc_target/spec/mod.rs
+++ b/src/librustc_target/spec/mod.rs
@@ -309,24 +309,14 @@ macro_rules! supported_targets {
         }
 
         #[cfg(test)]
-        mod test_json_encode_decode {
-            use rustc_serialize::json::ToJson;
-            use super::Target;
-            $(use super::$module;)+
+        mod tests {
+            mod tests_impl;
 
+            // Cannot put this into a separate file without duplication, make an exception.
             $(
-                #[test] // `#[test]` - this is hard to put into a separate file, make an exception
+                #[test] // `#[test]`
                 fn $module() {
-                    // Grab the TargetResult struct. If we successfully retrieved
-                    // a Target, then the test JSON encoding/decoding can run for this
-                    // Target on this testing platform (i.e., checking the iOS targets
-                    // only on a Mac test platform).
-                    let _ = $module::target().map(|original| {
-                        original.check_consistency();
-                        let as_json = original.to_json();
-                        let parsed = Target::from_json(as_json).unwrap();
-                        assert_eq!(original, parsed);
-                    });
+                    tests_impl::test_target(super::$module::target());
                 }
             )+
         }
@@ -1289,34 +1279,6 @@ impl Target {
             }
         }
     }
-
-    #[cfg(test)]
-    fn check_consistency(&self) {
-        // Check that LLD with the given flavor is treated identically to the linker it emulates.
-        // If you target really needs to deviate from the rules below, whitelist it
-        // and document the reasons.
-        assert_eq!(
-            self.linker_flavor == LinkerFlavor::Msvc
-                || self.linker_flavor == LinkerFlavor::Lld(LldFlavor::Link),
-            self.options.lld_flavor == LldFlavor::Link,
-        );
-        for args in &[
-            &self.options.pre_link_args,
-            &self.options.pre_link_args_crt,
-            &self.options.late_link_args,
-            &self.options.late_link_args_dynamic,
-            &self.options.late_link_args_static,
-            &self.options.post_link_args,
-        ] {
-            assert_eq!(
-                args.get(&LinkerFlavor::Msvc),
-                args.get(&LinkerFlavor::Lld(LldFlavor::Link)),
-            );
-            if args.contains_key(&LinkerFlavor::Msvc) {
-                assert_eq!(self.options.lld_flavor, LldFlavor::Link);
-            }
-        }
-    }
 }
 
 impl ToJson for Target {
diff --git a/src/librustc_target/spec/tests/tests_impl.rs b/src/librustc_target/spec/tests/tests_impl.rs
new file mode 100644
index 0000000000000..4cf186bdd7c1a
--- /dev/null
+++ b/src/librustc_target/spec/tests/tests_impl.rs
@@ -0,0 +1,43 @@
+use super::super::*;
+
+pub(super) fn test_target(target: TargetResult) {
+    // Grab the TargetResult struct. If we successfully retrieved
+    // a Target, then the test JSON encoding/decoding can run for this
+    // Target on this testing platform (i.e., checking the iOS targets
+    // only on a Mac test platform).
+    if let Ok(original) = target {
+        original.check_consistency();
+        let as_json = original.to_json();
+        let parsed = Target::from_json(as_json).unwrap();
+        assert_eq!(original, parsed);
+    }
+}
+
+impl Target {
+    fn check_consistency(&self) {
+        // Check that LLD with the given flavor is treated identically to the linker it emulates.
+        // If you target really needs to deviate from the rules below, whitelist it
+        // and document the reasons.
+        assert_eq!(
+            self.linker_flavor == LinkerFlavor::Msvc
+                || self.linker_flavor == LinkerFlavor::Lld(LldFlavor::Link),
+            self.options.lld_flavor == LldFlavor::Link,
+        );
+        for args in &[
+            &self.options.pre_link_args,
+            &self.options.pre_link_args_crt,
+            &self.options.late_link_args,
+            &self.options.late_link_args_dynamic,
+            &self.options.late_link_args_static,
+            &self.options.post_link_args,
+        ] {
+            assert_eq!(
+                args.get(&LinkerFlavor::Msvc),
+                args.get(&LinkerFlavor::Lld(LldFlavor::Link)),
+            );
+            if args.contains_key(&LinkerFlavor::Msvc) {
+                assert_eq!(self.options.lld_flavor, LldFlavor::Link);
+            }
+        }
+    }
+}

From cfe90ebfe3599bebf301dbac3e74ed557f7ecf24 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 11 Apr 2020 14:53:39 +0300
Subject: [PATCH 3/9] linker: Pass `/NODEFAULTLIB` in a more regular way

---
 src/librustc_codegen_ssa/back/link.rs             |  9 ++-------
 src/librustc_codegen_ssa/back/linker.rs           | 10 +---------
 src/librustc_target/spec/uefi_base.rs             |  3 ---
 src/librustc_target/spec/windows_msvc_base.rs     | 10 ++++++++++
 src/librustc_target/spec/windows_uwp_msvc_base.rs | 10 ++++++++++
 5 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/src/librustc_codegen_ssa/back/link.rs b/src/librustc_codegen_ssa/back/link.rs
index 5f7a1938a3304..d58d9b91c73ac 100644
--- a/src/librustc_codegen_ssa/back/link.rs
+++ b/src/librustc_codegen_ssa/back/link.rs
@@ -1532,13 +1532,8 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
     cmd.debuginfo();
 
     // OBJECT-FILES-NO, AUDIT-ORDER
-    // We want to, by default, prevent the compiler from accidentally leaking in
-    // any system libraries, so we may explicitly ask linkers to not link to any
-    // libraries by default. Note that this does not happen for windows because
-    // windows pulls in some large number of libraries and I couldn't quite
-    // figure out which subset we wanted.
-    //
-    // This is all naturally configurable via the standard methods as well.
+    // We want to prevent the compiler from accidentally leaking in any system libraries,
+    // so by default we tell linkers not to link to any default libraries.
     if !sess.opts.cg.default_linker_libraries.unwrap_or(false)
         && sess.target.target.options.no_default_libraries
     {
diff --git a/src/librustc_codegen_ssa/back/linker.rs b/src/librustc_codegen_ssa/back/linker.rs
index 0baa37ae9f1ab..d8c5ddf586f45 100644
--- a/src/librustc_codegen_ssa/back/linker.rs
+++ b/src/librustc_codegen_ssa/back/linker.rs
@@ -631,15 +631,7 @@ impl<'a> Linker for MsvcLinker<'a> {
     }
 
     fn no_default_libraries(&mut self) {
-        // Currently we don't pass the /NODEFAULTLIB flag to the linker on MSVC
-        // as there's been trouble in the past of linking the C++ standard
-        // library required by LLVM. This likely needs to happen one day, but
-        // in general Windows is also a more controlled environment than
-        // Unix, so it's not necessarily as critical that this be implemented.
-        //
-        // Note that there are also some licensing worries about statically
-        // linking some libraries which require a specific agreement, so it may
-        // not ever be possible for us to pass this flag.
+        self.cmd.arg("/NODEFAULTLIB");
     }
 
     fn include_path(&mut self, path: &Path) {
diff --git a/src/librustc_target/spec/uefi_base.rs b/src/librustc_target/spec/uefi_base.rs
index 030eb12eb0ec5..6f5e1badfb662 100644
--- a/src/librustc_target/spec/uefi_base.rs
+++ b/src/librustc_target/spec/uefi_base.rs
@@ -23,9 +23,6 @@ pub fn opts() -> TargetOptions {
         // will fail if the compiler ever tries placing code on the stack (e.g., trampoline
         // constructs and alike).
         "/NXCOMPAT".to_string(),
-        // There is no runtime for UEFI targets, prevent them from being linked. UEFI targets
-        // must be freestanding.
-        "/nodefaultlib".to_string(),
         // Non-standard subsystems have no default entry-point in PE+ files. We have to define
         // one. "efi_main" seems to be a common choice amongst other implementations and the
         // spec.
diff --git a/src/librustc_target/spec/windows_msvc_base.rs b/src/librustc_target/spec/windows_msvc_base.rs
index 78567a4382bed..dc56dd916ff0b 100644
--- a/src/librustc_target/spec/windows_msvc_base.rs
+++ b/src/librustc_target/spec/windows_msvc_base.rs
@@ -30,6 +30,16 @@ pub fn opts() -> TargetOptions {
         abi_return_struct_as_int: true,
         emit_debug_gdb_scripts: false,
         requires_uwtable: true,
+        // Currently we don't pass the /NODEFAULTLIB flag to the linker on MSVC
+        // as there's been trouble in the past of linking the C++ standard
+        // library required by LLVM. This likely needs to happen one day, but
+        // in general Windows is also a more controlled environment than
+        // Unix, so it's not necessarily as critical that this be implemented.
+        //
+        // Note that there are also some licensing worries about statically
+        // linking some libraries which require a specific agreement, so it may
+        // not ever be possible for us to pass this flag.
+        no_default_libraries: false,
 
         ..Default::default()
     }
diff --git a/src/librustc_target/spec/windows_uwp_msvc_base.rs b/src/librustc_target/spec/windows_uwp_msvc_base.rs
index 9497e525dd97c..2c70ba7abe262 100644
--- a/src/librustc_target/spec/windows_uwp_msvc_base.rs
+++ b/src/librustc_target/spec/windows_uwp_msvc_base.rs
@@ -31,6 +31,16 @@ pub fn opts() -> TargetOptions {
         emit_debug_gdb_scripts: false,
         requires_uwtable: true,
         lld_flavor: LldFlavor::Link,
+        // Currently we don't pass the /NODEFAULTLIB flag to the linker on MSVC
+        // as there's been trouble in the past of linking the C++ standard
+        // library required by LLVM. This likely needs to happen one day, but
+        // in general Windows is also a more controlled environment than
+        // Unix, so it's not necessarily as critical that this be implemented.
+        //
+        // Note that there are also some licensing worries about statically
+        // linking some libraries which require a specific agreement, so it may
+        // not ever be possible for us to pass this flag.
+        no_default_libraries: false,
 
         ..Default::default()
     }

From 6580ceb9e1d8c0afcb0a53677c6b633c43a7068d Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 11 Apr 2020 16:04:18 +0300
Subject: [PATCH 4/9] rustc_target: `windows(_uwp)_base` ->
 `windows(_uwp)_gnu_base`

The old naming is from ancient times when there was no MSVC support.

Also `uefi_base` -> `uefi_msvc_base`.
It will inherit from `msvc_base` in a future commit, plus a GNU UEFI target is also potentially possible.
---
 src/librustc_target/spec/i686_pc_windows_gnu.rs             | 2 +-
 src/librustc_target/spec/i686_unknown_uefi.rs               | 2 +-
 src/librustc_target/spec/i686_uwp_windows_gnu.rs            | 2 +-
 src/librustc_target/spec/mod.rs                             | 6 +++---
 .../spec/{uefi_base.rs => uefi_msvc_base.rs}                | 0
 .../spec/{windows_base.rs => windows_gnu_base.rs}           | 0
 .../spec/{windows_uwp_base.rs => windows_uwp_gnu_base.rs}   | 0
 src/librustc_target/spec/x86_64_pc_windows_gnu.rs           | 2 +-
 src/librustc_target/spec/x86_64_unknown_uefi.rs             | 2 +-
 src/librustc_target/spec/x86_64_uwp_windows_gnu.rs          | 2 +-
 10 files changed, 9 insertions(+), 9 deletions(-)
 rename src/librustc_target/spec/{uefi_base.rs => uefi_msvc_base.rs} (100%)
 rename src/librustc_target/spec/{windows_base.rs => windows_gnu_base.rs} (100%)
 rename src/librustc_target/spec/{windows_uwp_base.rs => windows_uwp_gnu_base.rs} (100%)

diff --git a/src/librustc_target/spec/i686_pc_windows_gnu.rs b/src/librustc_target/spec/i686_pc_windows_gnu.rs
index 2091902d7ce21..d12afe5a40bcc 100644
--- a/src/librustc_target/spec/i686_pc_windows_gnu.rs
+++ b/src/librustc_target/spec/i686_pc_windows_gnu.rs
@@ -1,7 +1,7 @@
 use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
-    let mut base = super::windows_base::opts();
+    let mut base = super::windows_gnu_base::opts();
     base.cpu = "pentium4".to_string();
     base.max_atomic_width = Some(64);
     base.eliminate_frame_pointer = false; // Required for backtraces
diff --git a/src/librustc_target/spec/i686_unknown_uefi.rs b/src/librustc_target/spec/i686_unknown_uefi.rs
index e299f92fdeb63..bf3064f437ff1 100644
--- a/src/librustc_target/spec/i686_unknown_uefi.rs
+++ b/src/librustc_target/spec/i686_unknown_uefi.rs
@@ -8,7 +8,7 @@
 use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
-    let mut base = super::uefi_base::opts();
+    let mut base = super::uefi_msvc_base::opts();
     base.cpu = "pentium4".to_string();
     base.max_atomic_width = Some(64);
 
diff --git a/src/librustc_target/spec/i686_uwp_windows_gnu.rs b/src/librustc_target/spec/i686_uwp_windows_gnu.rs
index 93f396de0a051..4e582fb8c63ab 100644
--- a/src/librustc_target/spec/i686_uwp_windows_gnu.rs
+++ b/src/librustc_target/spec/i686_uwp_windows_gnu.rs
@@ -1,7 +1,7 @@
 use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
-    let mut base = super::windows_uwp_base::opts();
+    let mut base = super::windows_uwp_gnu_base::opts();
     base.cpu = "pentium4".to_string();
     base.max_atomic_width = Some(64);
     base.eliminate_frame_pointer = false; // Required for backtraces
diff --git a/src/librustc_target/spec/mod.rs b/src/librustc_target/spec/mod.rs
index 91fd3f8e18ed2..d29b1dcdf8a44 100644
--- a/src/librustc_target/spec/mod.rs
+++ b/src/librustc_target/spec/mod.rs
@@ -66,12 +66,12 @@ mod redox_base;
 mod riscv_base;
 mod solaris_base;
 mod thumb_base;
-mod uefi_base;
+mod uefi_msvc_base;
 mod vxworks_base;
 mod wasm32_base;
-mod windows_base;
+mod windows_gnu_base;
 mod windows_msvc_base;
-mod windows_uwp_base;
+mod windows_uwp_gnu_base;
 mod windows_uwp_msvc_base;
 
 #[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
diff --git a/src/librustc_target/spec/uefi_base.rs b/src/librustc_target/spec/uefi_msvc_base.rs
similarity index 100%
rename from src/librustc_target/spec/uefi_base.rs
rename to src/librustc_target/spec/uefi_msvc_base.rs
diff --git a/src/librustc_target/spec/windows_base.rs b/src/librustc_target/spec/windows_gnu_base.rs
similarity index 100%
rename from src/librustc_target/spec/windows_base.rs
rename to src/librustc_target/spec/windows_gnu_base.rs
diff --git a/src/librustc_target/spec/windows_uwp_base.rs b/src/librustc_target/spec/windows_uwp_gnu_base.rs
similarity index 100%
rename from src/librustc_target/spec/windows_uwp_base.rs
rename to src/librustc_target/spec/windows_uwp_gnu_base.rs
diff --git a/src/librustc_target/spec/x86_64_pc_windows_gnu.rs b/src/librustc_target/spec/x86_64_pc_windows_gnu.rs
index 3d3acc682dea4..eb97fa56814d8 100644
--- a/src/librustc_target/spec/x86_64_pc_windows_gnu.rs
+++ b/src/librustc_target/spec/x86_64_pc_windows_gnu.rs
@@ -1,7 +1,7 @@
 use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
-    let mut base = super::windows_base::opts();
+    let mut base = super::windows_gnu_base::opts();
     base.cpu = "x86-64".to_string();
     base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
     base.max_atomic_width = Some(64);
diff --git a/src/librustc_target/spec/x86_64_unknown_uefi.rs b/src/librustc_target/spec/x86_64_unknown_uefi.rs
index 7660b68aae62e..588de409d4519 100644
--- a/src/librustc_target/spec/x86_64_unknown_uefi.rs
+++ b/src/librustc_target/spec/x86_64_unknown_uefi.rs
@@ -8,7 +8,7 @@
 use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
-    let mut base = super::uefi_base::opts();
+    let mut base = super::uefi_msvc_base::opts();
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
 
diff --git a/src/librustc_target/spec/x86_64_uwp_windows_gnu.rs b/src/librustc_target/spec/x86_64_uwp_windows_gnu.rs
index 48366e24a39e4..ad6002f6b89e4 100644
--- a/src/librustc_target/spec/x86_64_uwp_windows_gnu.rs
+++ b/src/librustc_target/spec/x86_64_uwp_windows_gnu.rs
@@ -1,7 +1,7 @@
 use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
-    let mut base = super::windows_uwp_base::opts();
+    let mut base = super::windows_uwp_gnu_base::opts();
     base.cpu = "x86-64".to_string();
     base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
     base.max_atomic_width = Some(64);

From 9c9db3ab4b5fcb3349ec744c4f168dd3e753d57b Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 11 Apr 2020 16:35:25 +0300
Subject: [PATCH 5/9] rustc_target: Remove some useless imports

---
 src/librustc_target/spec/armebv7r_none_eabi.rs    | 1 -
 src/librustc_target/spec/armebv7r_none_eabihf.rs  | 1 -
 src/librustc_target/spec/armv7r_none_eabi.rs      | 1 -
 src/librustc_target/spec/armv7r_none_eabihf.rs    | 1 -
 src/librustc_target/spec/dragonfly_base.rs        | 1 -
 src/librustc_target/spec/freebsd_base.rs          | 1 -
 src/librustc_target/spec/fuchsia_base.rs          | 1 -
 src/librustc_target/spec/haiku_base.rs            | 1 -
 src/librustc_target/spec/hermit_base.rs           | 1 -
 src/librustc_target/spec/hermit_kernel_base.rs    | 1 -
 src/librustc_target/spec/l4re_base.rs             | 1 -
 src/librustc_target/spec/linux_base.rs            | 1 -
 src/librustc_target/spec/linux_kernel_base.rs     | 1 -
 src/librustc_target/spec/mod.rs                   | 1 -
 src/librustc_target/spec/netbsd_base.rs           | 1 -
 src/librustc_target/spec/openbsd_base.rs          | 1 -
 src/librustc_target/spec/redox_base.rs            | 1 -
 src/librustc_target/spec/solaris_base.rs          | 1 -
 src/librustc_target/spec/thumb_base.rs            | 1 -
 src/librustc_target/spec/uefi_msvc_base.rs        | 1 -
 src/librustc_target/spec/vxworks_base.rs          | 1 -
 src/librustc_target/spec/windows_gnu_base.rs      | 1 -
 src/librustc_target/spec/windows_msvc_base.rs     | 1 -
 src/librustc_target/spec/windows_uwp_gnu_base.rs  | 1 -
 src/librustc_target/spec/windows_uwp_msvc_base.rs | 1 -
 25 files changed, 25 deletions(-)

diff --git a/src/librustc_target/spec/armebv7r_none_eabi.rs b/src/librustc_target/spec/armebv7r_none_eabi.rs
index 3a5957892b59c..ebe901e4f274d 100644
--- a/src/librustc_target/spec/armebv7r_none_eabi.rs
+++ b/src/librustc_target/spec/armebv7r_none_eabi.rs
@@ -1,7 +1,6 @@
 // Targets the Big endian Cortex-R4/R5 processor (ARMv7-R)
 
 use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
-use std::default::Default;
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/armebv7r_none_eabihf.rs b/src/librustc_target/spec/armebv7r_none_eabihf.rs
index 9f95a1a6f44fc..8652d1051ad05 100644
--- a/src/librustc_target/spec/armebv7r_none_eabihf.rs
+++ b/src/librustc_target/spec/armebv7r_none_eabihf.rs
@@ -1,7 +1,6 @@
 // Targets the Cortex-R4F/R5F processor (ARMv7-R)
 
 use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
-use std::default::Default;
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/armv7r_none_eabi.rs b/src/librustc_target/spec/armv7r_none_eabi.rs
index 517368e6a23e9..b7fcda63db00b 100644
--- a/src/librustc_target/spec/armv7r_none_eabi.rs
+++ b/src/librustc_target/spec/armv7r_none_eabi.rs
@@ -1,7 +1,6 @@
 // Targets the Little-endian Cortex-R4/R5 processor (ARMv7-R)
 
 use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
-use std::default::Default;
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/armv7r_none_eabihf.rs b/src/librustc_target/spec/armv7r_none_eabihf.rs
index 6363469d92925..340090fd43b7c 100644
--- a/src/librustc_target/spec/armv7r_none_eabihf.rs
+++ b/src/librustc_target/spec/armv7r_none_eabihf.rs
@@ -1,7 +1,6 @@
 // Targets the Little-endian Cortex-R4F/R5F processor (ARMv7-R)
 
 use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
-use std::default::Default;
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/dragonfly_base.rs b/src/librustc_target/spec/dragonfly_base.rs
index e26d0ae50b26d..c7062e1ca5196 100644
--- a/src/librustc_target/spec/dragonfly_base.rs
+++ b/src/librustc_target/spec/dragonfly_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, RelroLevel, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut args = LinkArgs::new();
diff --git a/src/librustc_target/spec/freebsd_base.rs b/src/librustc_target/spec/freebsd_base.rs
index fc252b6d43d26..d2a087ab62f9f 100644
--- a/src/librustc_target/spec/freebsd_base.rs
+++ b/src/librustc_target/spec/freebsd_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, RelroLevel, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut args = LinkArgs::new();
diff --git a/src/librustc_target/spec/fuchsia_base.rs b/src/librustc_target/spec/fuchsia_base.rs
index 046388e9be8f4..4060b126cddb7 100644
--- a/src/librustc_target/spec/fuchsia_base.rs
+++ b/src/librustc_target/spec/fuchsia_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut pre_link_args = LinkArgs::new();
diff --git a/src/librustc_target/spec/haiku_base.rs b/src/librustc_target/spec/haiku_base.rs
index 1ddab7be180e0..3d7ae6c302d9c 100644
--- a/src/librustc_target/spec/haiku_base.rs
+++ b/src/librustc_target/spec/haiku_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{RelroLevel, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     TargetOptions {
diff --git a/src/librustc_target/spec/hermit_base.rs b/src/librustc_target/spec/hermit_base.rs
index 3f9dad689fd59..b9f94023e7a79 100644
--- a/src/librustc_target/spec/hermit_base.rs
+++ b/src/librustc_target/spec/hermit_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, PanicStrategy, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut pre_link_args = LinkArgs::new();
diff --git a/src/librustc_target/spec/hermit_kernel_base.rs b/src/librustc_target/spec/hermit_kernel_base.rs
index 650219c21ac40..1f9b195e2e698 100644
--- a/src/librustc_target/spec/hermit_kernel_base.rs
+++ b/src/librustc_target/spec/hermit_kernel_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, PanicStrategy, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut pre_link_args = LinkArgs::new();
diff --git a/src/librustc_target/spec/l4re_base.rs b/src/librustc_target/spec/l4re_base.rs
index b712dcae89970..5caad10161d8e 100644
--- a/src/librustc_target/spec/l4re_base.rs
+++ b/src/librustc_target/spec/l4re_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, PanicStrategy, TargetOptions};
-use std::default::Default;
 //use std::process::Command;
 
 // Use GCC to locate code for crt* libraries from the host, not from L4Re. Note
diff --git a/src/librustc_target/spec/linux_base.rs b/src/librustc_target/spec/linux_base.rs
index a5d7f8e07c443..52892fc35924e 100644
--- a/src/librustc_target/spec/linux_base.rs
+++ b/src/librustc_target/spec/linux_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, RelroLevel, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut args = LinkArgs::new();
diff --git a/src/librustc_target/spec/linux_kernel_base.rs b/src/librustc_target/spec/linux_kernel_base.rs
index fae44836fa821..4a900d1b02cbf 100644
--- a/src/librustc_target/spec/linux_kernel_base.rs
+++ b/src/librustc_target/spec/linux_kernel_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, PanicStrategy, RelroLevel, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut pre_link_args = LinkArgs::new();
diff --git a/src/librustc_target/spec/mod.rs b/src/librustc_target/spec/mod.rs
index d29b1dcdf8a44..d0129b2cdd37e 100644
--- a/src/librustc_target/spec/mod.rs
+++ b/src/librustc_target/spec/mod.rs
@@ -37,7 +37,6 @@
 use crate::spec::abi::{lookup as lookup_abi, Abi};
 use rustc_serialize::json::{Json, ToJson};
 use std::collections::BTreeMap;
-use std::default::Default;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::{fmt, io};
diff --git a/src/librustc_target/spec/netbsd_base.rs b/src/librustc_target/spec/netbsd_base.rs
index eb359b920463b..95c4749f9c74c 100644
--- a/src/librustc_target/spec/netbsd_base.rs
+++ b/src/librustc_target/spec/netbsd_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, RelroLevel, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut args = LinkArgs::new();
diff --git a/src/librustc_target/spec/openbsd_base.rs b/src/librustc_target/spec/openbsd_base.rs
index b66c56e1a7aea..cadd14df69352 100644
--- a/src/librustc_target/spec/openbsd_base.rs
+++ b/src/librustc_target/spec/openbsd_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, RelroLevel, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut args = LinkArgs::new();
diff --git a/src/librustc_target/spec/redox_base.rs b/src/librustc_target/spec/redox_base.rs
index 6398fa91f0253..18cafe654d17f 100644
--- a/src/librustc_target/spec/redox_base.rs
+++ b/src/librustc_target/spec/redox_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, RelroLevel, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut args = LinkArgs::new();
diff --git a/src/librustc_target/spec/solaris_base.rs b/src/librustc_target/spec/solaris_base.rs
index 98a2a0fbc9cc1..8d3a3563f4164 100644
--- a/src/librustc_target/spec/solaris_base.rs
+++ b/src/librustc_target/spec/solaris_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::TargetOptions;
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     TargetOptions {
diff --git a/src/librustc_target/spec/thumb_base.rs b/src/librustc_target/spec/thumb_base.rs
index 99ab996be959d..eca095b594289 100644
--- a/src/librustc_target/spec/thumb_base.rs
+++ b/src/librustc_target/spec/thumb_base.rs
@@ -28,7 +28,6 @@
 // build scripts / gcc flags.
 
 use crate::spec::{PanicStrategy, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     // See rust-lang/rfcs#1645 for a discussion about these defaults
diff --git a/src/librustc_target/spec/uefi_msvc_base.rs b/src/librustc_target/spec/uefi_msvc_base.rs
index 6f5e1badfb662..148658f4abb92 100644
--- a/src/librustc_target/spec/uefi_msvc_base.rs
+++ b/src/librustc_target/spec/uefi_msvc_base.rs
@@ -10,7 +10,6 @@
 // code runs in the same environment, no process separation is supported.
 
 use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, PanicStrategy, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let pre_link_args_msvc = vec![
diff --git a/src/librustc_target/spec/vxworks_base.rs b/src/librustc_target/spec/vxworks_base.rs
index 1763c9139b1bf..1b25c51278d4a 100644
--- a/src/librustc_target/spec/vxworks_base.rs
+++ b/src/librustc_target/spec/vxworks_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut args_crt = LinkArgs::new();
diff --git a/src/librustc_target/spec/windows_gnu_base.rs b/src/librustc_target/spec/windows_gnu_base.rs
index 097ee09f1ea8c..33ecb1d0d48ce 100644
--- a/src/librustc_target/spec/windows_gnu_base.rs
+++ b/src/librustc_target/spec/windows_gnu_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut pre_link_args = LinkArgs::new();
diff --git a/src/librustc_target/spec/windows_msvc_base.rs b/src/librustc_target/spec/windows_msvc_base.rs
index dc56dd916ff0b..328cdec5492ee 100644
--- a/src/librustc_target/spec/windows_msvc_base.rs
+++ b/src/librustc_target/spec/windows_msvc_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let pre_link_args_msvc = vec!["/NOLOGO".to_string(), "/NXCOMPAT".to_string()];
diff --git a/src/librustc_target/spec/windows_uwp_gnu_base.rs b/src/librustc_target/spec/windows_uwp_gnu_base.rs
index f19bd10dc0bbd..bd1e0bc5eba94 100644
--- a/src/librustc_target/spec/windows_uwp_gnu_base.rs
+++ b/src/librustc_target/spec/windows_uwp_gnu_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let mut pre_link_args = LinkArgs::new();
diff --git a/src/librustc_target/spec/windows_uwp_msvc_base.rs b/src/librustc_target/spec/windows_uwp_msvc_base.rs
index 2c70ba7abe262..3372da857feec 100644
--- a/src/librustc_target/spec/windows_uwp_msvc_base.rs
+++ b/src/librustc_target/spec/windows_uwp_msvc_base.rs
@@ -1,5 +1,4 @@
 use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
-use std::default::Default;
 
 pub fn opts() -> TargetOptions {
     let pre_link_args_msvc = vec![

From fd0e2987eda697cfa1ec754021477f54a46645aa Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 11 Apr 2020 16:38:36 +0300
Subject: [PATCH 6/9] rustc_target: Inherit `windows_uwp_msvc_base` from
 `windows_msvc_base`

---
 .../spec/windows_uwp_msvc_base.rs             | 50 ++++---------------
 1 file changed, 9 insertions(+), 41 deletions(-)

diff --git a/src/librustc_target/spec/windows_uwp_msvc_base.rs b/src/librustc_target/spec/windows_uwp_msvc_base.rs
index 3372da857feec..04ffa1a0addbe 100644
--- a/src/librustc_target/spec/windows_uwp_msvc_base.rs
+++ b/src/librustc_target/spec/windows_uwp_msvc_base.rs
@@ -1,46 +1,14 @@
-use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
+use crate::spec::{LinkerFlavor, LldFlavor, TargetOptions};
 
 pub fn opts() -> TargetOptions {
-    let pre_link_args_msvc = vec![
-        "/NOLOGO".to_string(),
-        "/NXCOMPAT".to_string(),
-        "/APPCONTAINER".to_string(),
-        "mincore.lib".to_string(),
-    ];
-    let mut pre_link_args = LinkArgs::new();
-    pre_link_args.insert(LinkerFlavor::Msvc, pre_link_args_msvc.clone());
-    pre_link_args.insert(LinkerFlavor::Lld(LldFlavor::Link), pre_link_args_msvc);
+    let mut opts = super::windows_msvc_base::opts();
 
-    TargetOptions {
-        function_sections: true,
-        dynamic_linking: true,
-        executables: true,
-        dll_prefix: String::new(),
-        dll_suffix: ".dll".to_string(),
-        exe_suffix: ".exe".to_string(),
-        staticlib_prefix: String::new(),
-        staticlib_suffix: ".lib".to_string(),
-        target_family: Some("windows".to_string()),
-        is_like_windows: true,
-        is_like_msvc: true,
-        pre_link_args,
-        crt_static_allows_dylibs: true,
-        crt_static_respected: true,
-        abi_return_struct_as_int: true,
-        emit_debug_gdb_scripts: false,
-        requires_uwtable: true,
-        lld_flavor: LldFlavor::Link,
-        // Currently we don't pass the /NODEFAULTLIB flag to the linker on MSVC
-        // as there's been trouble in the past of linking the C++ standard
-        // library required by LLVM. This likely needs to happen one day, but
-        // in general Windows is also a more controlled environment than
-        // Unix, so it's not necessarily as critical that this be implemented.
-        //
-        // Note that there are also some licensing worries about statically
-        // linking some libraries which require a specific agreement, so it may
-        // not ever be possible for us to pass this flag.
-        no_default_libraries: false,
+    let pre_link_args_msvc = vec!["/APPCONTAINER".to_string(), "mincore.lib".to_string()];
+    opts.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().extend(pre_link_args_msvc.clone());
+    opts.pre_link_args
+        .get_mut(&LinkerFlavor::Lld(LldFlavor::Link))
+        .unwrap()
+        .extend(pre_link_args_msvc);
 
-        ..Default::default()
-    }
+    opts
 }

From 88c480279b9da4487aa779c26f0445aaaf268834 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 11 Apr 2020 17:07:39 +0300
Subject: [PATCH 7/9] rustc_target: Inherit `windows_uwp_gnu_base` from
 `windows_gnu_base`

---
 .../spec/windows_uwp_gnu_base.rs              | 34 +++++++------------
 1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/src/librustc_target/spec/windows_uwp_gnu_base.rs b/src/librustc_target/spec/windows_uwp_gnu_base.rs
index bd1e0bc5eba94..aa99c3f7d95e5 100644
--- a/src/librustc_target/spec/windows_uwp_gnu_base.rs
+++ b/src/librustc_target/spec/windows_uwp_gnu_base.rs
@@ -1,6 +1,9 @@
 use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
 
 pub fn opts() -> TargetOptions {
+    let base = super::windows_gnu_base::opts();
+
+    // FIXME: Consider adding `-nostdlib` and inheriting from `windows_gnu_base`.
     let mut pre_link_args = LinkArgs::new();
     pre_link_args.insert(
         LinkerFlavor::Gcc,
@@ -13,7 +16,10 @@ pub fn opts() -> TargetOptions {
         ],
     );
 
+    // FIXME: Should UWP target be updated for the exception machinery changes from #67502?
     let mut late_link_args = LinkArgs::new();
+    let late_link_args_dynamic = LinkArgs::new();
+    let late_link_args_static = LinkArgs::new();
     late_link_args.insert(
         LinkerFlavor::Gcc,
         vec![
@@ -32,31 +38,17 @@ pub fn opts() -> TargetOptions {
     );
 
     TargetOptions {
-        // FIXME(#13846) this should be enabled for windows
-        function_sections: false,
-        linker: Some("gcc".to_string()),
-        dynamic_linking: true,
         executables: false,
-        dll_prefix: String::new(),
-        dll_suffix: ".dll".to_string(),
-        exe_suffix: ".exe".to_string(),
-        staticlib_prefix: "lib".to_string(),
-        staticlib_suffix: ".a".to_string(),
-        target_family: Some("windows".to_string()),
-        is_like_windows: true,
-        allows_weak_linkage: false,
+        limit_rdylib_exports: false,
         pre_link_args,
-        pre_link_objects_exe: vec![
-            "rsbegin.o".to_string(), // Rust compiler runtime initialization, see rsbegin.rs
-        ],
+        // FIXME: Consider adding `-nostdlib` and inheriting from `windows_gnu_base`.
+        pre_link_objects_exe: vec!["rsbegin.o".to_string()],
+        // FIXME: Consider adding `-nostdlib` and inheriting from `windows_gnu_base`.
         pre_link_objects_dll: vec!["rsbegin.o".to_string()],
         late_link_args,
-        post_link_objects: vec!["rsend.o".to_string()],
-        abi_return_struct_as_int: true,
-        emit_debug_gdb_scripts: false,
-        requires_uwtable: true,
-        limit_rdylib_exports: false,
+        late_link_args_dynamic,
+        late_link_args_static,
 
-        ..Default::default()
+        ..base
     }
 }

From 57870ea2ca2f9795e875d55d60df57d47e4a3eba Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 11 Apr 2020 17:30:09 +0300
Subject: [PATCH 8/9] rustc_target: Introduce `msvc_base`

and inherit both `windows_msvc_base` and `uefi_msvc_base` from it.
---
 src/librustc_target/spec/i686_unknown_uefi.rs |  5 ---
 src/librustc_target/spec/mod.rs               |  1 +
 src/librustc_target/spec/msvc_base.rs         | 38 +++++++++++++++++++
 src/librustc_target/spec/uefi_msvc_base.rs    | 37 +++++++++---------
 src/librustc_target/spec/windows_msvc_base.rs | 21 ++--------
 .../spec/x86_64_unknown_uefi.rs               |  5 ---
 6 files changed, 59 insertions(+), 48 deletions(-)
 create mode 100644 src/librustc_target/spec/msvc_base.rs

diff --git a/src/librustc_target/spec/i686_unknown_uefi.rs b/src/librustc_target/spec/i686_unknown_uefi.rs
index bf3064f437ff1..221d5f0785cd2 100644
--- a/src/librustc_target/spec/i686_unknown_uefi.rs
+++ b/src/librustc_target/spec/i686_unknown_uefi.rs
@@ -23,11 +23,6 @@ pub fn target() -> TargetResult {
     // arguments, thus giving you access to full MMX/SSE acceleration.
     base.features = "-mmx,-sse,+soft-float".to_string();
 
-    // UEFI mirrors the calling-conventions used on windows. In case of i686 this means small
-    // structs will be returned as int. This shouldn't matter much, since the restrictions placed
-    // by the UEFI specifications forbid any ABI to return structures.
-    base.abi_return_struct_as_int = true;
-
     // Use -GNU here, because of the reason below:
     // Background and Problem:
     //   If we use i686-unknown-windows, the LLVM IA32 MSVC generates compiler intrinsic
diff --git a/src/librustc_target/spec/mod.rs b/src/librustc_target/spec/mod.rs
index d0129b2cdd37e..6ff812754aa7d 100644
--- a/src/librustc_target/spec/mod.rs
+++ b/src/librustc_target/spec/mod.rs
@@ -59,6 +59,7 @@ mod l4re_base;
 mod linux_base;
 mod linux_kernel_base;
 mod linux_musl_base;
+mod msvc_base;
 mod netbsd_base;
 mod openbsd_base;
 mod redox_base;
diff --git a/src/librustc_target/spec/msvc_base.rs b/src/librustc_target/spec/msvc_base.rs
new file mode 100644
index 0000000000000..4d921b5d5fe10
--- /dev/null
+++ b/src/librustc_target/spec/msvc_base.rs
@@ -0,0 +1,38 @@
+use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
+
+pub fn opts() -> TargetOptions {
+    let pre_link_args_msvc = vec![
+        // Suppress the verbose logo and authorship debugging output, which would needlessly
+        // clog any log files.
+        "/NOLOGO".to_string(),
+        // Tell the compiler that non-code sections can be marked as non-executable,
+        // including stack pages.
+        // UEFI is fully compatible to non-executable data pages.
+        // In fact, firmware might enforce this, so we better let the linker know about this,
+        // so it will fail if the compiler ever tries placing code on the stack
+        // (e.g., trampoline constructs and alike).
+        "/NXCOMPAT".to_string(),
+    ];
+    let mut pre_link_args = LinkArgs::new();
+    pre_link_args.insert(LinkerFlavor::Msvc, pre_link_args_msvc.clone());
+    pre_link_args.insert(LinkerFlavor::Lld(LldFlavor::Link), pre_link_args_msvc);
+
+    TargetOptions {
+        executables: true,
+        is_like_windows: true,
+        is_like_msvc: true,
+        // set VSLANG to 1033 can prevent link.exe from using
+        // language packs, and avoid generating Non-UTF-8 error
+        // messages if a link error occurred.
+        link_env: vec![("VSLANG".to_string(), "1033".to_string())],
+        lld_flavor: LldFlavor::Link,
+        pre_link_args,
+        // UEFI mirrors the calling-conventions used on windows. In case of x86-64 and i686 this
+        // means small structs will be returned as int. This shouldn't matter much, since the
+        // restrictions placed by the UEFI specifications forbid any ABI to return structures.
+        abi_return_struct_as_int: true,
+        emit_debug_gdb_scripts: false,
+
+        ..Default::default()
+    }
+}
diff --git a/src/librustc_target/spec/uefi_msvc_base.rs b/src/librustc_target/spec/uefi_msvc_base.rs
index 148658f4abb92..3f7c78c8e7d47 100644
--- a/src/librustc_target/spec/uefi_msvc_base.rs
+++ b/src/librustc_target/spec/uefi_msvc_base.rs
@@ -9,19 +9,12 @@
 // the timer-interrupt. Device-drivers are required to use polling-based models. Furthermore, all
 // code runs in the same environment, no process separation is supported.
 
-use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, PanicStrategy, TargetOptions};
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, TargetOptions};
 
 pub fn opts() -> TargetOptions {
+    let mut base = super::msvc_base::opts();
+
     let pre_link_args_msvc = vec![
-        // Suppress the verbose logo and authorship debugging output, which would needlessly
-        // clog any log files.
-        "/NOLOGO".to_string(),
-        // UEFI is fully compatible to non-executable data pages. Tell the compiler that
-        // non-code sections can be marked as non-executable, including stack pages. In fact,
-        // firmware might enforce this, so we better let the linker know about this, so it
-        // will fail if the compiler ever tries placing code on the stack (e.g., trampoline
-        // constructs and alike).
-        "/NXCOMPAT".to_string(),
         // Non-standard subsystems have no default entry-point in PE+ files. We have to define
         // one. "efi_main" seems to be a common choice amongst other implementations and the
         // spec.
@@ -37,25 +30,29 @@ pub fn opts() -> TargetOptions {
         // exit (default for applications).
         "/subsystem:efi_application".to_string(),
     ];
-    let mut pre_link_args = LinkArgs::new();
-    pre_link_args.insert(LinkerFlavor::Msvc, pre_link_args_msvc.clone());
-    pre_link_args.insert(LinkerFlavor::Lld(LldFlavor::Link), pre_link_args_msvc);
+    base.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().extend(pre_link_args_msvc.clone());
+    base.pre_link_args
+        .get_mut(&LinkerFlavor::Lld(LldFlavor::Link))
+        .unwrap()
+        .extend(pre_link_args_msvc);
 
     TargetOptions {
-        dynamic_linking: false,
-        executables: true,
         disable_redzone: true,
         exe_suffix: ".efi".to_string(),
         allows_weak_linkage: false,
         panic_strategy: PanicStrategy::Abort,
         stack_probes: true,
         singlethread: true,
-        emit_debug_gdb_scripts: false,
-
         linker: Some("rust-lld".to_string()),
-        lld_flavor: LldFlavor::Link,
-        pre_link_args,
+        // FIXME: This should likely be `true` inherited from `msvc_base`
+        // because UEFI follows Windows ABI and uses PE/COFF.
+        // The `false` is probably causing ABI bugs right now.
+        is_like_windows: false,
+        // FIXME: This should likely be `true` inherited from `msvc_base`
+        // because UEFI follows Windows ABI and uses PE/COFF.
+        // The `false` is probably causing ABI bugs right now.
+        is_like_msvc: false,
 
-        ..Default::default()
+        ..base
     }
 }
diff --git a/src/librustc_target/spec/windows_msvc_base.rs b/src/librustc_target/spec/windows_msvc_base.rs
index 328cdec5492ee..77171f8672e8a 100644
--- a/src/librustc_target/spec/windows_msvc_base.rs
+++ b/src/librustc_target/spec/windows_msvc_base.rs
@@ -1,33 +1,18 @@
-use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
+use crate::spec::TargetOptions;
 
 pub fn opts() -> TargetOptions {
-    let pre_link_args_msvc = vec!["/NOLOGO".to_string(), "/NXCOMPAT".to_string()];
-    let mut pre_link_args = LinkArgs::new();
-    pre_link_args.insert(LinkerFlavor::Msvc, pre_link_args_msvc.clone());
-    pre_link_args.insert(LinkerFlavor::Lld(LldFlavor::Link), pre_link_args_msvc);
+    let base = super::msvc_base::opts();
 
     TargetOptions {
-        function_sections: true,
         dynamic_linking: true,
-        executables: true,
         dll_prefix: String::new(),
         dll_suffix: ".dll".to_string(),
         exe_suffix: ".exe".to_string(),
         staticlib_prefix: String::new(),
         staticlib_suffix: ".lib".to_string(),
         target_family: Some("windows".to_string()),
-        is_like_windows: true,
-        is_like_msvc: true,
-        // set VSLANG to 1033 can prevent link.exe from using
-        // language packs, and avoid generating Non-UTF-8 error
-        // messages if a link error occurred.
-        link_env: vec![("VSLANG".to_string(), "1033".to_string())],
-        lld_flavor: LldFlavor::Link,
-        pre_link_args,
         crt_static_allows_dylibs: true,
         crt_static_respected: true,
-        abi_return_struct_as_int: true,
-        emit_debug_gdb_scripts: false,
         requires_uwtable: true,
         // Currently we don't pass the /NODEFAULTLIB flag to the linker on MSVC
         // as there's been trouble in the past of linking the C++ standard
@@ -40,6 +25,6 @@ pub fn opts() -> TargetOptions {
         // not ever be possible for us to pass this flag.
         no_default_libraries: false,
 
-        ..Default::default()
+        ..base
     }
 }
diff --git a/src/librustc_target/spec/x86_64_unknown_uefi.rs b/src/librustc_target/spec/x86_64_unknown_uefi.rs
index 588de409d4519..12edc29330a49 100644
--- a/src/librustc_target/spec/x86_64_unknown_uefi.rs
+++ b/src/librustc_target/spec/x86_64_unknown_uefi.rs
@@ -28,11 +28,6 @@ pub fn target() -> TargetResult {
     // places no locality-restrictions, so it fits well here.
     base.code_model = Some("large".to_string());
 
-    // UEFI mirrors the calling-conventions used on windows. In case of x86-64 this means small
-    // structs will be returned as int. This shouldn't matter much, since the restrictions placed
-    // by the UEFI specifications forbid any ABI to return structures.
-    base.abi_return_struct_as_int = true;
-
     Ok(Target {
         llvm_target: "x86_64-unknown-windows".to_string(),
         target_endian: "little".to_string(),

From 8392e477e73c12566803411396b0ff18a0864c81 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sun, 12 Apr 2020 23:36:37 +0300
Subject: [PATCH 9/9] Address review comments

---
 src/librustc_target/spec/msvc_base.rs            | 3 ---
 src/librustc_target/spec/windows_uwp_gnu_base.rs | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/librustc_target/spec/msvc_base.rs b/src/librustc_target/spec/msvc_base.rs
index 4d921b5d5fe10..817a322a9e4da 100644
--- a/src/librustc_target/spec/msvc_base.rs
+++ b/src/librustc_target/spec/msvc_base.rs
@@ -27,9 +27,6 @@ pub fn opts() -> TargetOptions {
         link_env: vec![("VSLANG".to_string(), "1033".to_string())],
         lld_flavor: LldFlavor::Link,
         pre_link_args,
-        // UEFI mirrors the calling-conventions used on windows. In case of x86-64 and i686 this
-        // means small structs will be returned as int. This shouldn't matter much, since the
-        // restrictions placed by the UEFI specifications forbid any ABI to return structures.
         abi_return_struct_as_int: true,
         emit_debug_gdb_scripts: false,
 
diff --git a/src/librustc_target/spec/windows_uwp_gnu_base.rs b/src/librustc_target/spec/windows_uwp_gnu_base.rs
index aa99c3f7d95e5..dd3b60344be22 100644
--- a/src/librustc_target/spec/windows_uwp_gnu_base.rs
+++ b/src/librustc_target/spec/windows_uwp_gnu_base.rs
@@ -16,7 +16,7 @@ pub fn opts() -> TargetOptions {
         ],
     );
 
-    // FIXME: Should UWP target be updated for the exception machinery changes from #67502?
+    // FIXME: This should be updated for the exception machinery changes from #67502.
     let mut late_link_args = LinkArgs::new();
     let late_link_args_dynamic = LinkArgs::new();
     let late_link_args_static = LinkArgs::new();