rustdoc: Output target feature information

`#[target_feature]` attributes refer to a target-specific list of
features. Enabling certain features can imply enabling other features.
Certain features are always enabled on certain targets, since they are
required by the target's ABI. Features can also be enabled indirectly
based on other compiler flags.

Feature information is ultimately known to `rustc`. Rather than force
external tools to track it -- which may be wildly impractical due to
`-C target-cpu` -- have `rustdoc` output `rustc`'s feature data.

10 files changed, 132 insertions, 0 deletions

diff --git a/tests/rustdoc-json/targets/aarch64_apple_darwin.rs b/tests/rustdoc-json/targets/aarch64_apple_darwin.rs
new file mode 100644
index 00000000000..c6ae5517d47
--- /dev/null
+++ b/tests/rustdoc-json/targets/aarch64_apple_darwin.rs
@@ -0,0 +1,14 @@
+//@ only-aarch64-apple-darwin
+
+//@ is "$.target.triple" \"aarch64-apple-darwin\"
+//@ is "$.target.target_features[?(@.name=='vh')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='sve')].globally_enabled" false
+//@ has "$.target.target_features[?(@.name=='sve2')].implies_features" '["sve"]'
+//@ is "$.target.target_features[?(@.name=='sve2')].unstable_feature_gate" null
+
+// If this breaks due to stabilization, check rustc_target::target_features for a replacement
+//@ is "$.target.target_features[?(@.name=='cssc')].unstable_feature_gate" '"aarch64_unstable_target_feature"'
+//@ is "$.target.target_features[?(@.name=='v9a')].unstable_feature_gate" '"aarch64_ver_target_feature"'
+
+// Ensure we don't look like x86-64
+//@ !has "$.target.target_features[?(@.name=='avx2')]"
diff --git a/tests/rustdoc-json/targets/aarch64_reflects_compiler_options.rs b/tests/rustdoc-json/targets/aarch64_reflects_compiler_options.rs
new file mode 100644
index 00000000000..f91221eb23c
--- /dev/null
+++ b/tests/rustdoc-json/targets/aarch64_reflects_compiler_options.rs
@@ -0,0 +1,10 @@
+//@ only-aarch64
+
+// If we enable SVE Bit Permute, we should see that it is enabled
+//@ compile-flags: -Ctarget-feature=+sve2-bitperm
+//@ is "$.target.target_features[?(@.name=='sve2-bitperm')].globally_enabled" true
+
+// As well as its dependency chain
+//@ is "$.target.target_features[?(@.name=='sve2')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='sve')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='neon')].globally_enabled" true
diff --git a/tests/rustdoc-json/targets/aarch64_unknown_linux_gnu.rs b/tests/rustdoc-json/targets/aarch64_unknown_linux_gnu.rs
new file mode 100644
index 00000000000..9139b00a128
--- /dev/null
+++ b/tests/rustdoc-json/targets/aarch64_unknown_linux_gnu.rs
@@ -0,0 +1,14 @@
+//@ only-aarch64-unknown-linux-gnu
+
+//@ is "$.target.triple" \"aarch64-unknown-linux-gnu\"
+//@ is "$.target.target_features[?(@.name=='neon')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='sve')].globally_enabled" false
+//@ has "$.target.target_features[?(@.name=='sve2')].implies_features" '["sve"]'
+//@ is "$.target.target_features[?(@.name=='sve2')].unstable_feature_gate" null
+
+// If this breaks due to stabilization, check rustc_target::target_features for a replacement
+//@ is "$.target.target_features[?(@.name=='cssc')].unstable_feature_gate" '"aarch64_unstable_target_feature"'
+//@ is "$.target.target_features[?(@.name=='v9a')].unstable_feature_gate" '"aarch64_ver_target_feature"'
+
+// Ensure we don't look like x86-64
+//@ !has "$.target.target_features[?(@.name=='avx2')]"
diff --git a/tests/rustdoc-json/targets/i686_pc_windows_msvc.rs b/tests/rustdoc-json/targets/i686_pc_windows_msvc.rs
new file mode 100644
index 00000000000..088c741d113
--- /dev/null
+++ b/tests/rustdoc-json/targets/i686_pc_windows_msvc.rs
@@ -0,0 +1,14 @@
+//@ only-i686-pc-windows-msvc
+
+//@ is "$.target.triple" \"i686-pc-windows-msvc\"
+//@ is "$.target.target_features[?(@.name=='sse2')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='avx2')].globally_enabled" false
+//@ has "$.target.target_features[?(@.name=='avx2')].implies_features" '["avx"]'
+//@ is "$.target.target_features[?(@.name=='avx2')].unstable_feature_gate" null
+
+// If this breaks due to stabilization, check rustc_target::target_features for a replacement
+//@ is "$.target.target_features[?(@.name=='amx-tile')].unstable_feature_gate" '"x86_amx_intrinsics"'
+//@ is "$.target.target_features[?(@.name=='x87')].unstable_feature_gate" '"x87_target_feature"'
+
+// Ensure we don't look like aarch64
+//@ !has "$.target.target_features[?(@.name=='sve2')]"
diff --git a/tests/rustdoc-json/targets/i686_unknown_linux_gnu.rs b/tests/rustdoc-json/targets/i686_unknown_linux_gnu.rs
new file mode 100644
index 00000000000..03788b000f1
--- /dev/null
+++ b/tests/rustdoc-json/targets/i686_unknown_linux_gnu.rs
@@ -0,0 +1,14 @@
+//@ only-i686-unknown-linux-gnu
+
+//@ is "$.target.triple" \"i686-unknown-linux-gnu\"
+//@ is "$.target.target_features[?(@.name=='sse2')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='avx2')].globally_enabled" false
+//@ has "$.target.target_features[?(@.name=='avx2')].implies_features" '["avx"]'
+//@ is "$.target.target_features[?(@.name=='avx2')].unstable_feature_gate" null
+
+// If this breaks due to stabilization, check rustc_target::target_features for a replacement
+//@ is "$.target.target_features[?(@.name=='amx-tile')].unstable_feature_gate" '"x86_amx_intrinsics"'
+//@ is "$.target.target_features[?(@.name=='x87')].unstable_feature_gate" '"x87_target_feature"'
+
+// Ensure we don't look like aarch64
+//@ !has "$.target.target_features[?(@.name=='sve2')]"
diff --git a/tests/rustdoc-json/targets/x86_64_apple_darwin.rs b/tests/rustdoc-json/targets/x86_64_apple_darwin.rs
new file mode 100644
index 00000000000..a46f9138e86
--- /dev/null
+++ b/tests/rustdoc-json/targets/x86_64_apple_darwin.rs
@@ -0,0 +1,14 @@
+//@ only-x86_64-apple-darwin
+
+//@ is "$.target.triple" \"x86_64-apple-darwin\"
+//@ is "$.target.target_features[?(@.name=='sse2')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='avx2')].globally_enabled" false
+//@ has "$.target.target_features[?(@.name=='avx2')].implies_features" '["avx"]'
+//@ is "$.target.target_features[?(@.name=='avx2')].unstable_feature_gate" null
+
+// If this breaks due to stabilization, check rustc_target::target_features for a replacement
+//@ is "$.target.target_features[?(@.name=='amx-tile')].unstable_feature_gate" '"x86_amx_intrinsics"'
+//@ is "$.target.target_features[?(@.name=='x87')].unstable_feature_gate" '"x87_target_feature"'
+
+// Ensure we don't look like aarch64
+//@ !has "$.target.target_features[?(@.name=='sve2')]"
diff --git a/tests/rustdoc-json/targets/x86_64_pc_windows_gnu.rs b/tests/rustdoc-json/targets/x86_64_pc_windows_gnu.rs
new file mode 100644
index 00000000000..7da12eb4d58
--- /dev/null
+++ b/tests/rustdoc-json/targets/x86_64_pc_windows_gnu.rs
@@ -0,0 +1,14 @@
+//@ only-x86_64-pc-windows-gnu
+
+//@ is "$.target.triple" \"x86_64-pc-windows-gnu\"
+//@ is "$.target.target_features[?(@.name=='sse2')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='avx2')].globally_enabled" false
+//@ has "$.target.target_features[?(@.name=='avx2')].implies_features" '["avx"]'
+//@ is "$.target.target_features[?(@.name=='avx2')].unstable_feature_gate" null
+
+// If this breaks due to stabilization, check rustc_target::target_features for a replacement
+//@ is "$.target.target_features[?(@.name=='amx-tile')].unstable_feature_gate" '"x86_amx_intrinsics"'
+//@ is "$.target.target_features[?(@.name=='x87')].unstable_feature_gate" '"x87_target_feature"'
+
+// Ensure we don't look like aarch64
+//@ !has "$.target.target_features[?(@.name=='sve2')]"
diff --git a/tests/rustdoc-json/targets/x86_64_pc_windows_msvc.rs b/tests/rustdoc-json/targets/x86_64_pc_windows_msvc.rs
new file mode 100644
index 00000000000..d55f5776e85
--- /dev/null
+++ b/tests/rustdoc-json/targets/x86_64_pc_windows_msvc.rs
@@ -0,0 +1,14 @@
+//@ only-x86_64-pc-windows-msvc
+
+//@ is "$.target.triple" \"x86_64-pc-windows-msvc\"
+//@ is "$.target.target_features[?(@.name=='sse2')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='avx2')].globally_enabled" false
+//@ has "$.target.target_features[?(@.name=='avx2')].implies_features" '["avx"]'
+//@ is "$.target.target_features[?(@.name=='avx2')].unstable_feature_gate" null
+
+// If this breaks due to stabilization, check rustc_target::target_features for a replacement
+//@ is "$.target.target_features[?(@.name=='amx-tile')].unstable_feature_gate" '"x86_amx_intrinsics"'
+//@ is "$.target.target_features[?(@.name=='x87')].unstable_feature_gate" '"x87_target_feature"'
+
+// Ensure we don't look like aarch64
+//@ !has "$.target.target_features[?(@.name=='sve2')]"
diff --git a/tests/rustdoc-json/targets/x86_64_reflects_compiler_options.rs b/tests/rustdoc-json/targets/x86_64_reflects_compiler_options.rs
new file mode 100644
index 00000000000..ba029b09996
--- /dev/null
+++ b/tests/rustdoc-json/targets/x86_64_reflects_compiler_options.rs
@@ -0,0 +1,10 @@
+//@ only-x86_64
+
+// If we enable AVX2, we should see that it is enabled
+//@ compile-flags: -Ctarget-feature=+avx2
+//@ is "$.target.target_features[?(@.name=='avx2')].globally_enabled" true
+
+// As well as its dependency chain
+//@ is "$.target.target_features[?(@.name=='avx')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='sse4.2')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='sse4.1')].globally_enabled" true
diff --git a/tests/rustdoc-json/targets/x86_64_unknown_linux_gnu.rs b/tests/rustdoc-json/targets/x86_64_unknown_linux_gnu.rs
new file mode 100644
index 00000000000..3372fe7eb9d
--- /dev/null
+++ b/tests/rustdoc-json/targets/x86_64_unknown_linux_gnu.rs
@@ -0,0 +1,14 @@
+//@ only-x86_64-unknown-linux-gnu
+
+//@ is "$.target.triple" \"x86_64-unknown-linux-gnu\"
+//@ is "$.target.target_features[?(@.name=='sse2')].globally_enabled" true
+//@ is "$.target.target_features[?(@.name=='avx2')].globally_enabled" false
+//@ has "$.target.target_features[?(@.name=='avx2')].implies_features" '["avx"]'
+//@ is "$.target.target_features[?(@.name=='avx2')].unstable_feature_gate" null
+
+// If this breaks due to stabilization, check rustc_target::target_features for a replacement
+//@ is "$.target.target_features[?(@.name=='amx-tile')].unstable_feature_gate" '"x86_amx_intrinsics"'
+//@ is "$.target.target_features[?(@.name=='x87')].unstable_feature_gate" '"x87_target_feature"'
+
+// Ensure we don't look like aarch64
+//@ !has "$.target.target_features[?(@.name=='sve2')]"