Fix location of check for sized floating-point types

src/base.rs

@@ -2,7 +2,7 @@
 use std::env;
 use std::time::Instant;
 
-use gccjit::{FunctionType, GlobalKind};
+use gccjit::{CType, FunctionType, GlobalKind};
 use rustc_codegen_ssa::base::maybe_create_entry_wrapper;
 use rustc_codegen_ssa::mono_item::MonoItemExt;
 use rustc_codegen_ssa::traits::DebugInfoMethods;
@@ -181,7 +181,22 @@ fn module_codegen(
         context.set_allow_unreachable_blocks(true);
 
         {
-            let cx = CodegenCx::new(&context, cgu, tcx, target_info.supports_128bit_int());
+            // TODO: to make it less error-prone (calling get_target_info() will add the flag
+            // -fsyntax-only), forbid the compilation when get_target_info() is called on a
+            // context.
+            let f16_type_supported = target_info.supports_target_dependent_type(CType::Float16);
+            let f32_type_supported = target_info.supports_target_dependent_type(CType::Float32);
+            let f128_type_supported = target_info.supports_target_dependent_type(CType::Float128);
+            // TODO: improve this to avoid passing that many arguments.
+            let cx = CodegenCx::new(
+                &context,
+                cgu,
+                tcx,
+                target_info.supports_128bit_int(),
+                f16_type_supported,
+                f32_type_supported,
+                f128_type_supported,
+            );
 
             let mono_items = cgu.items_in_deterministic_order(tcx);
             for &(mono_item, data) in &mono_items {

src/context.rs

@@ -68,6 +68,9 @@ pub struct CodegenCx<'gcc, 'tcx> {
     pub sizet_type: Type<'gcc>,
 
     pub supports_128bit_integers: bool,
+    pub supports_f16_type: bool,
+    pub supports_f32_type: bool,
+    pub supports_f128_type: bool,
 
     pub float_type: Type<'gcc>,
     pub double_type: Type<'gcc>,
@@ -130,6 +133,9 @@ pub fn new(
         codegen_unit: &'tcx CodegenUnit<'tcx>,
         tcx: TyCtxt<'tcx>,
         supports_128bit_integers: bool,
+        supports_f16_type: bool,
+        supports_f32_type: bool,
+        supports_f128_type: bool,
     ) -> Self {
         let check_overflow = tcx.sess.overflow_checks();
 
@@ -305,6 +311,9 @@ pub fn new(
             sizet_type,
 
             supports_128bit_integers,
+            supports_f16_type,
+            supports_f32_type,
+            supports_f128_type,
 
             float_type,
             double_type,

src/lib.rs

@@ -89,7 +89,6 @@
 use std::sync::Mutex;
 
 use errors::LTONotSupported;
-#[cfg(not(feature = "master"))]
 use gccjit::CType;
 use gccjit::{Context, OptimizationLevel};
 #[cfg(feature = "master")]
@@ -147,6 +146,10 @@ fn cpu_supports(&self, _feature: &str) -> bool {
     fn supports_128bit_int(&self) -> bool {
         self.supports_128bit_integers.load(Ordering::SeqCst)
     }
+
+    fn supports_target_dependent_type(&self, _typ: CType) -> bool {
+        false
+    }
 }
 
 #[derive(Clone)]
@@ -168,6 +171,10 @@ fn cpu_supports(&self, feature: &str) -> bool {
     fn supports_128bit_int(&self) -> bool {
         self.info.lock().expect("lock").supports_128bit_int()
     }
+
+    fn supports_target_dependent_type(&self, typ: CType) -> bool {
+        self.info.lock().expect("lock").supports_target_dependent_type(typ)
+    }
 }
 
 #[derive(Clone)]
@@ -438,7 +445,8 @@ fn run_link(
 pub fn __rustc_codegen_backend() -> Box<dyn CodegenBackend> {
     #[cfg(feature = "master")]
     let info = {
-        // Check whether the target supports 128-bit integers.
+        // Check whether the target supports 128-bit integers, and sized floating point types (like
+        // Float16).
         let context = Context::default();
         Arc::new(Mutex::new(IntoDynSyncSend(context.get_target_info())))
     };

src/type_.rs

@@ -1,6 +1,9 @@
+#[cfg(feature = "master")]
 use std::convert::TryInto;
 
-use gccjit::{CType, RValue, Struct, Type};
+#[cfg(feature = "master")]
+use gccjit::CType;
+use gccjit::{RValue, Struct, Type};
 use rustc_codegen_ssa::common::TypeKind;
 use rustc_codegen_ssa::traits::{BaseTypeMethods, DerivedTypeMethods, TypeMembershipMethods};
 use rustc_middle::ty::layout::TyAndLayout;
@@ -124,7 +127,7 @@ fn type_isize(&self) -> Type<'gcc> {
 
     #[cfg(feature = "master")]
     fn type_f16(&self) -> Type<'gcc> {
-        if self.context.get_target_info().supports_target_dependent_type(CType::Float16) {
+        if self.supports_f16_type {
             return self.context.new_c_type(CType::Float16);
         }
         unimplemented!("f16")
@@ -137,9 +140,9 @@ fn type_f16(&self) -> Type<'gcc> {
 
     #[cfg(feature = "master")]
     fn type_f32(&self) -> Type<'gcc> {
-        // if self.context.get_target_info().supports_target_dependent_type(CType::Float32) {
-        // return self.context.new_c_type(CType::Float32);
-        // }
+        if self.supports_f32_type {
+            return self.context.new_c_type(CType::Float32);
+        }
         self.float_type
     }
 
@@ -154,7 +157,7 @@ fn type_f64(&self) -> Type<'gcc> {
 
     #[cfg(feature = "master")]
     fn type_f128(&self) -> Type<'gcc> {
-        if self.context.get_target_info().supports_target_dependent_type(CType::Float128) {
+        if self.supports_f128_type {
             return self.context.new_c_type(CType::Float128);
         }
         unimplemented!("f128")