num_counters to u32, after implementing TypeFoldable

src/librustc_codegen_llvm/intrinsic.rs

@@ -146,7 +146,7 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
                 let (mangled_fn_name, _len_val) = self.const_str(mangled_fn.name);
                 let hash = self.const_u64(coverage_data.hash);
                 let index = args[0].immediate();
-                let num_counters = self.const_u32(coverage_data.num_counters as u32);
+                let num_counters = self.const_u32(coverage_data.num_counters);
                 debug!(
                     "count_code_region to LLVM intrinsic instrprof.increment(fn_name={}, hash={:?}, num_counters={:?}, index={:?})",
                     mangled_fn.name, hash, index, num_counters

src/librustc_middle/mir/mod.rs

@@ -98,7 +98,7 @@ pub struct CoverageData {
     pub hash: u64,
 
     /// The total number of coverage region counters added to this MIR Body.
-    pub num_counters: usize,
+    pub num_counters: u32,
 }
 
 /// The lowered representation of a single function.

src/librustc_middle/ty/structural_impls.rs

@@ -262,6 +262,7 @@ CloneTypeFoldableAndLiftImpls! {
     bool,
     usize,
     ::rustc_target::abi::VariantIdx,
+    u32,
     u64,
     String,
     crate::middle::region::Scope,

src/librustc_mir/transform/instrument_coverage.rs

@@ -21,7 +21,7 @@ pub struct InstrumentCoverage;
 
 struct Instrumentor<'tcx> {
     tcx: TyCtxt<'tcx>,
-    num_counters: usize,
+    num_counters: u32,
 }
 
 impl<'tcx> MirPass<'tcx> for InstrumentCoverage {
@@ -55,12 +55,12 @@ impl<'tcx> Instrumentor<'tcx> {
     }
 
     fn next_counter(&mut self) -> u32 {
-        let next = self.num_counters as u32;
+        let next = self.num_counters;
         self.num_counters += 1;
         next
     }
 
-    fn inject_counters(&mut self, mir_body: &mut mir::Body<'tcx>) -> usize {
+    fn inject_counters(&mut self, mir_body: &mut mir::Body<'tcx>) -> u32 {
         // FIXME(richkadel): As a first step, counters are only injected at the top of each
         // function. The complete solution will inject counters at each conditional code branch.
         let top_of_function = START_BLOCK;