add spans to injected coverage counters

added regions with counter expressions and counters.

Added codegen_llvm/coverageinfo mod for upcoming coverage map

Move coverage region collection to CodegenCx finalization

Moved from `query coverageinfo` (renamed from `query coverage_data`),
as discussed in the PR at:

https://github.com/rust-lang/rust/pull/73684#issuecomment-649882503

Address merge conflict in MIR instrument_coverage test

The MIR test output format changed for int types.

moved debug messages out of block.rs

This makes the block.rs calls to add coverage mapping data to the
CodegenCx much more concise and readable.

move coverage intrinsic handling into llvm impl

I realized that having half of the coverage intrinsic handling in
`rustc_codegen_ssa` and half in `rustc_codegen_llvm` meant that any
non-llvm backend would be bound to the same decisions about how the
coverage-related MIR terminators should be handled.

To fix this, I moved the non-codegen portion of coverage intrinsic
handling into its own trait, and implemented it in `rustc_codegen_llvm`
alongside `codegen_intrinsic_call`.

I also added the (required?) stubs for the new intrinsics to
`IntrepretCx::emulate_intrinsic()`, to ensure calls to this function do
not fail if called with these new but known intrinsics.

address PR Feedback on 28 June 2020 2:48pm PDT

4 files changed, 52 insertions, 0 deletions

diff --git a/src/librustc_codegen_ssa/traits/builder.rs b/src/librustc_codegen_ssa/traits/builder.rs
index 7ffc9f15bff..994d8e0395d 100644
--- a/src/librustc_codegen_ssa/traits/builder.rs
+++ b/src/librustc_codegen_ssa/traits/builder.rs
@@ -1,5 +1,6 @@
 use super::abi::AbiBuilderMethods;
 use super::asm::AsmBuilderMethods;
+use super::coverageinfo::CoverageInfoBuilderMethods;
 use super::debuginfo::DebugInfoBuilderMethods;
 use super::intrinsic::IntrinsicCallMethods;
 use super::type_::ArgAbiMethods;
@@ -29,6 +30,7 @@ pub enum OverflowOp {
 
 pub trait BuilderMethods<'a, 'tcx>:
     HasCodegen<'tcx>
+    + CoverageInfoBuilderMethods<'tcx>
     + DebugInfoBuilderMethods
     + ArgAbiMethods<'tcx>
     + AbiBuilderMethods<'tcx>
diff --git a/src/librustc_codegen_ssa/traits/coverageinfo.rs b/src/librustc_codegen_ssa/traits/coverageinfo.rs
new file mode 100644
index 00000000000..d80f90fa4fa
--- /dev/null
+++ b/src/librustc_codegen_ssa/traits/coverageinfo.rs
@@ -0,0 +1,35 @@
+use super::BackendTypes;
+use crate::coverageinfo::CounterOp;
+use rustc_middle::ty::Instance;
+
+pub trait CoverageInfoMethods: BackendTypes {
+    fn coverageinfo_finalize(&self);
+}
+
+pub trait CoverageInfoBuilderMethods<'tcx>: BackendTypes {
+    fn add_counter_region(
+        &mut self,
+        instance: Instance<'tcx>,
+        index: u32,
+        start_byte_pos: u32,
+        end_byte_pos: u32,
+    );
+
+    fn add_counter_expression_region(
+        &mut self,
+        instance: Instance<'tcx>,
+        index: u32,
+        lhs: u32,
+        op: CounterOp,
+        rhs: u32,
+        start_byte_pos: u32,
+        end_byte_pos: u32,
+    );
+
+    fn add_unreachable_region(
+        &mut self,
+        instance: Instance<'tcx>,
+        start_byte_pos: u32,
+        end_byte_pos: u32,
+    );
+}
diff --git a/src/librustc_codegen_ssa/traits/intrinsic.rs b/src/librustc_codegen_ssa/traits/intrinsic.rs
index f6201949851..e713cc948c1 100644
--- a/src/librustc_codegen_ssa/traits/intrinsic.rs
+++ b/src/librustc_codegen_ssa/traits/intrinsic.rs
@@ -1,5 +1,6 @@
 use super::BackendTypes;
 use crate::mir::operand::OperandRef;
+use rustc_middle::mir::Operand;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::Span;
 use rustc_target::abi::call::FnAbi;
@@ -18,6 +19,16 @@ pub trait IntrinsicCallMethods<'tcx>: BackendTypes {
         caller_instance: ty::Instance<'tcx>,
     );
 
+    /// Intrinsic-specific pre-codegen processing, if any is required. Some intrinsics are handled
+    /// at compile time and do not generate code. Returns true if codegen is required or false if
+    /// the intrinsic does not need code generation.
+    fn is_codegen_intrinsic(
+        &mut self,
+        intrinsic: &str,
+        args: &Vec<Operand<'tcx>>,
+        caller_instance: ty::Instance<'tcx>,
+    ) -> bool;
+
     fn abort(&mut self);
     fn assume(&mut self, val: Self::Value);
     fn expect(&mut self, cond: Self::Value, expected: bool) -> Self::Value;
diff --git a/src/librustc_codegen_ssa/traits/mod.rs b/src/librustc_codegen_ssa/traits/mod.rs
index 6b782731d53..0ac519dd0b1 100644
--- a/src/librustc_codegen_ssa/traits/mod.rs
+++ b/src/librustc_codegen_ssa/traits/mod.rs
@@ -19,6 +19,7 @@ mod asm;
 mod backend;
 mod builder;
 mod consts;
+mod coverageinfo;
 mod debuginfo;
 mod declare;
 mod intrinsic;
@@ -32,6 +33,7 @@ pub use self::asm::{AsmBuilderMethods, AsmMethods, InlineAsmOperandRef};
 pub use self::backend::{Backend, BackendTypes, CodegenBackend, ExtraBackendMethods};
 pub use self::builder::{BuilderMethods, OverflowOp};
 pub use self::consts::ConstMethods;
+pub use self::coverageinfo::{CoverageInfoBuilderMethods, CoverageInfoMethods};
 pub use self::debuginfo::{DebugInfoBuilderMethods, DebugInfoMethods};
 pub use self::declare::{DeclareMethods, PreDefineMethods};
 pub use self::intrinsic::IntrinsicCallMethods;
@@ -56,6 +58,7 @@ pub trait CodegenMethods<'tcx>:
     + MiscMethods<'tcx>
     + ConstMethods<'tcx>
     + StaticMethods
+    + CoverageInfoMethods
     + DebugInfoMethods<'tcx>
     + DeclareMethods<'tcx>
     + AsmMethods
@@ -72,6 +75,7 @@ impl<'tcx, T> CodegenMethods<'tcx> for T where
         + MiscMethods<'tcx>
         + ConstMethods<'tcx>
         + StaticMethods
+        + CoverageInfoMethods
         + DebugInfoMethods<'tcx>
         + DeclareMethods<'tcx>
         + AsmMethods