Remove Session methods that duplicate DiagCtxt methods.

Also add some `dcx` methods to types that wrap `TyCtxt`, for easier
access.

src/asm.rs

@@ -109,7 +109,7 @@ enum ConstraintOrRegister {
 impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
     fn codegen_inline_asm(&mut self, template: &[InlineAsmTemplatePiece], rust_operands: &[InlineAsmOperandRef<'tcx, Self>], options: InlineAsmOptions, span: &[Span], instance: Instance<'_>, _dest_catch_funclet: Option<(Self::BasicBlock, Self::BasicBlock, Option<&Self::Funclet>)>) {
         if options.contains(InlineAsmOptions::MAY_UNWIND) {
-            self.sess()
+            self.sess().dcx()
                 .create_err(UnwindingInlineAsm { span: span[0] })
                 .emit();
             return;

src/attributes.rs

@@ -80,7 +80,7 @@ pub fn from_fn_attrs<'gcc, 'tcx>(
         let span = cx.tcx
             .get_attr(instance.def_id(), sym::target_feature)
             .map_or_else(|| cx.tcx.def_span(instance.def_id()), |a| a.span);
-        cx.tcx.sess.create_err(TiedTargetFeatures {
+        cx.tcx.dcx().create_err(TiedTargetFeatures {
             features: features.join(", "),
             span,
         })

src/consts.rs

@@ -24,7 +24,7 @@ fn set_global_alignment<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, gv: LValue<'gcc>
         match Align::from_bits(min) {
             Ok(min) => align = align.max(min),
             Err(err) => {
-                cx.sess().emit_err(InvalidMinimumAlignment { err: err.to_string() });
+                cx.sess().dcx().emit_err(InvalidMinimumAlignment { err: err.to_string() });
             }
         }
     }

src/context.rs

@@ -500,9 +500,9 @@ impl<'gcc, 'tcx> LayoutOfHelpers<'tcx> for CodegenCx<'gcc, 'tcx> {
     #[inline]
     fn handle_layout_err(&self, err: LayoutError<'tcx>, span: Span, ty: Ty<'tcx>) -> ! {
         if let LayoutError::SizeOverflow(_) | LayoutError::ReferencesError(_) = err {
-            self.sess().emit_fatal(respan(span, err.into_diagnostic()))
+            self.tcx.dcx().emit_fatal(respan(span, err.into_diagnostic()))
         } else {
-            self.tcx.sess.emit_fatal(ssa_errors::FailedToGetLayout { span, ty, err })
+            self.tcx.dcx().emit_fatal(ssa_errors::FailedToGetLayout { span, ty, err })
         }
     }
 }
@@ -518,7 +518,7 @@ impl<'gcc, 'tcx> FnAbiOfHelpers<'tcx> for CodegenCx<'gcc, 'tcx> {
         fn_abi_request: FnAbiRequest<'tcx>,
     ) -> ! {
         if let FnAbiError::Layout(LayoutError::SizeOverflow(_)) = err {
-            self.sess().emit_fatal(respan(span, err))
+            self.tcx.dcx().emit_fatal(respan(span, err))
         } else {
             match fn_abi_request {
                 FnAbiRequest::OfFnPtr { sig, extra_args } => {

src/gcc_util.rs

@@ -52,7 +52,7 @@ pub(crate) fn global_gcc_features(sess: &Session, diagnostics: bool) -> Vec<Stri
                 Some(c @ ('+' | '-')) => c,
                 Some(_) => {
                     if diagnostics {
-                        sess.emit_warning(UnknownCTargetFeaturePrefix { feature: s });
+                        sess.dcx().emit_warning(UnknownCTargetFeaturePrefix { feature: s });
                     }
                     return None;
                 }
@@ -79,7 +79,7 @@ pub(crate) fn global_gcc_features(sess: &Session, diagnostics: bool) -> Vec<Stri
                     else {
                         UnknownCTargetFeature { feature, rust_feature: PossibleFeature::None }
                     };
-                sess.emit_warning(unknown_feature);
+                sess.dcx().emit_warning(unknown_feature);
             }
 
             if diagnostics {
@@ -114,7 +114,7 @@ pub(crate) fn global_gcc_features(sess: &Session, diagnostics: bool) -> Vec<Stri
 
     if diagnostics {
         if let Some(f) = check_tied_features(sess, &featsmap) {
-            sess.emit_err(TargetFeatureDisableOrEnable {
+            sess.dcx().emit_err(TargetFeatureDisableOrEnable {
                 features: f,
                 span: None,
                 missing_features: None,

src/intrinsic/mod.rs

@@ -262,7 +262,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
                                 _ => bug!(),
                             },
                             None => {
-                                tcx.sess.emit_err(InvalidMonomorphization::BasicIntegerType { span, name, ty });
+                                tcx.dcx().emit_err(InvalidMonomorphization::BasicIntegerType { span, name, ty });
                                 return;
                             }
                         }

src/intrinsic/simd.rs

@@ -34,7 +34,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     // macros for error handling:
     macro_rules! return_error {
         ($err:expr) => {{
-            bx.sess().emit_err($err);
+            bx.tcx.dcx().emit_err($err);
             return Err(());
         }};
     }
@@ -390,7 +390,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     ) -> Result<RValue<'gcc>, ()> {
         macro_rules! return_error {
             ($err:expr) => {{
-                bx.sess().emit_err($err);
+                bx.tcx.dcx().emit_err($err);
                 return Err(());
             }};
         }

src/lib.rs

@@ -191,7 +191,7 @@ impl CodegenBackend for GccCodegenBackend {
         #[cfg(feature="master")]
         gccjit::set_global_personality_function_name(b"rust_eh_personality\0");
         if sess.lto() == Lto::Thin {
-            sess.emit_warning(LTONotSupported {});
+            sess.dcx().emit_warning(LTONotSupported {});
         }
 
         #[cfg(not(feature="master"))]