Add new {x86_64,i686}-win7-windows-gnu targets

These are in symmetry with `{x86_64,i686}-win7-windows-msvc`.

Author: tbu-

compiler/rustc_target/src/spec/mod.rs

@@ -1782,9 +1782,11 @@ supported_targets! {
     ("aarch64-unknown-illumos", aarch64_unknown_illumos),
 
     ("x86_64-pc-windows-gnu", x86_64_pc_windows_gnu),
+    ("x86_64-uwp-windows-gnu", x86_64_uwp_windows_gnu),
+    ("x86_64-win7-windows-gnu", x86_64_win7_windows_gnu),
     ("i686-pc-windows-gnu", i686_pc_windows_gnu),
     ("i686-uwp-windows-gnu", i686_uwp_windows_gnu),
-    ("x86_64-uwp-windows-gnu", x86_64_uwp_windows_gnu),
+    ("i686-win7-windows-gnu", i686_win7_windows_gnu),
 
     ("aarch64-pc-windows-gnullvm", aarch64_pc_windows_gnullvm),
     ("i686-pc-windows-gnullvm", i686_pc_windows_gnullvm),

compiler/rustc_target/src/spec/targets/i686_win7_windows_gnu.rs

@@ -0,0 +1,35 @@
+use crate::spec::{Cc, FramePointer, LinkerFlavor, Lld, Target, base};
+
+pub(crate) fn target() -> Target {
+    let mut base = base::windows_gnu::opts();
+    base.vendor = "win7".into();
+    base.cpu = "pentium4".into();
+    base.max_atomic_width = Some(64);
+    base.frame_pointer = FramePointer::Always; // Required for backtraces
+    base.linker = Some("i686-w64-mingw32-gcc".into());
+
+    // Mark all dynamic libraries and executables as compatible with the larger 4GiB address
+    // space available to x86 Windows binaries on x86_64.
+    base.add_pre_link_args(LinkerFlavor::Gnu(Cc::No, Lld::No), &[
+        "-m",
+        "i386pe",
+        "--large-address-aware",
+    ]);
+    base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-Wl,--large-address-aware"]);
+
+    Target {
+        llvm_target: "i686-pc-windows-gnu".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: Some("32-bit MinGW (Windows 7+)".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(true),
+        },
+        pointer_width: 32,
+        data_layout: "e-m:x-p:32:32-p270:32:32-p271:32:32-p272:64:64-\
+            i64:64-i128:128-f80:32-n8:16:32-a:0:32-S32"
+            .into(),
+        arch: "x86".into(),
+        options: base,
+    }
+}

compiler/rustc_target/src/spec/targets/x86_64_win7_windows_gnu.rs

@@ -0,0 +1,33 @@
+use crate::spec::{Cc, LinkerFlavor, Lld, Target, base};
+
+pub(crate) fn target() -> Target {
+    let mut base = base::windows_gnu::opts();
+    base.vendor = "win7".into();
+    base.cpu = "x86-64".into();
+    base.features = "+cx16,+sse3,+sahf".into();
+    base.plt_by_default = false;
+    // Use high-entropy 64 bit address space for ASLR
+    base.add_pre_link_args(LinkerFlavor::Gnu(Cc::No, Lld::No), &[
+        "-m",
+        "i386pep",
+        "--high-entropy-va",
+    ]);
+    base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m64", "-Wl,--high-entropy-va"]);
+    base.max_atomic_width = Some(128);
+    base.linker = Some("x86_64-w64-mingw32-gcc".into());
+
+    Target {
+        llvm_target: "x86_64-pc-windows-gnu".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: Some("64-bit MinGW (Windows 7+)".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(true),
+        },
+        pointer_width: 64,
+        data_layout:
+            "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128".into(),
+        arch: "x86_64".into(),
+        options: base,
+    }
+}

src/doc/rustc/src/SUMMARY.md

@@ -93,6 +93,7 @@
     - [wasm32-unknown-unknown](platform-support/wasm32-unknown-unknown.md)
     - [wasm32v1-none](platform-support/wasm32v1-none.md)
     - [wasm64-unknown-unknown](platform-support/wasm64-unknown-unknown.md)
+    - [\*-win7-windows-gnu](platform-support/win7-windows-gnu.md)
     - [\*-win7-windows-msvc](platform-support/win7-windows-msvc.md)
     - [x86_64-fortanix-unknown-sgx](platform-support/x86_64-fortanix-unknown-sgx.md)
     - [x86_64-pc-solaris](platform-support/solaris.md)

src/doc/rustc/src/platform-support.md

@@ -313,6 +313,7 @@ target | std | host | notes
 [`i686-unknown-redox`](platform-support/redox.md) | ✓ |  | i686 Redox OS
 `i686-uwp-windows-gnu` | ✓ |  | [^x86_32-floats-return-ABI]
 `i686-uwp-windows-msvc` | ✓ |  | [^x86_32-floats-return-ABI]
+[`i686-win7-windows-gnu`](platform-support/win7-windows-gnu.md) | ✓ |   | 32-bit Windows 7 support [^x86_32-floats-return-ABI]
 [`i686-win7-windows-msvc`](platform-support/win7-windows-msvc.md) | ✓ |   | 32-bit Windows 7 support [^x86_32-floats-return-ABI]
 [`i686-wrs-vxworks`](platform-support/vxworks.md) | ✓ |  | [^x86_32-floats-return-ABI]
 [`loongarch64-unknown-linux-ohos`](platform-support/openharmony.md) | ✓ |   | LoongArch64 OpenHarmony
@@ -391,6 +392,7 @@ target | std | host | notes
 [`x86_64-unknown-trusty`](platform-support/trusty.md) | ? |  |
 `x86_64-uwp-windows-gnu` | ✓ |  |
 `x86_64-uwp-windows-msvc` | ✓ |  |
+[`x86_64-win7-windows-gnu`](platform-support/win7-windows-gnu.md) | ✓ |   | 64-bit Windows 7 support
 [`x86_64-win7-windows-msvc`](platform-support/win7-windows-msvc.md) | ✓ |   | 64-bit Windows 7 support
 [`x86_64-wrs-vxworks`](platform-support/vxworks.md) | ✓ |  |
 [`x86_64h-apple-darwin`](platform-support/x86_64h-apple-darwin.md) | ✓ | ✓ | macOS with late-gen Intel (at least Haswell)

src/doc/rustc/src/platform-support/win7-windows-gnu.md

@@ -0,0 +1,44 @@
+# \*-win7-windows-gnu
+
+**Tier: 3**
+
+Windows targets continuing support of Windows 7.
+
+## Target maintainers
+
+- @tbu-
+
+## Requirements
+
+This target supports all of core, alloc, std and test. Host
+tools may also work, though those are not currently tested.
+
+Those targets follow Windows calling convention for extern "C".
+
+Like any other Windows target, the created binaries are in PE format.
+
+## Building the target
+
+You can build Rust with support for the targets by adding it to the target list in config.toml:
+
+```toml
+[build]
+build-stage = 1
+target = ["x86_64-win7-windows-gnu"]
+```
+
+## Building Rust programs
+
+Rust does not ship pre-compiled artifacts for this target. To compile for this
+target, you will either need to build Rust with the target enabled (see
+"Building the target" above), or build your own copy by using `build-std` or
+similar.
+
+## Testing
+
+Created binaries work fine on Windows or Wine using native hardware. Remote
+testing is possible using the `remote-test-server` described [here](https://rustc-dev-guide.rust-lang.org/tests/running.html#running-tests-on-a-remote-machine).
+
+## Cross-compilation toolchains and C code
+
+Compatible C code can be built with gcc's `{i686,x86_64}-w64-mingw32-gcc`.

src/doc/rustc/src/platform-support/win7-windows-msvc.md

@@ -1,8 +1,8 @@
-# *-win7-windows-msvc
+# \*-win7-windows-msvc
 
 **Tier: 3**
 
-Windows targets continuing support of windows7.
+Windows targets continuing support of Windows 7.
 
 ## Target maintainers