Allow coverage tests to enable llvm-cov --use-color

src/tools/compiletest/src/header.rs

@@ -178,6 +178,9 @@ pub struct TestProps {
     // Whether to tell `rustc` to remap the "src base" directory to a fake
     // directory.
     pub remap_src_base: bool,
+    // If true, tells the `llvm-cov` tool to produce colored output.
+    // Only used by the "coverage-run" test mode.
+    pub llvm_cov_use_color: bool,
 }
 
 mod directives {
@@ -216,6 +219,7 @@ mod directives {
     pub const MIR_UNIT_TEST: &'static str = "unit-test";
     pub const REMAP_SRC_BASE: &'static str = "remap-src-base";
     pub const COMPARE_OUTPUT_LINES_BY_SUBSET: &'static str = "compare-output-lines-by-subset";
+    pub const LLVM_COV_USE_COLOR: &'static str = "llvm-cov-use-color";
     // This isn't a real directive, just one that is probably mistyped often
     pub const INCORRECT_COMPILER_FLAGS: &'static str = "compiler-flags";
 }
@@ -265,6 +269,7 @@ impl TestProps {
             stderr_per_bitwidth: false,
             mir_unit_test: None,
             remap_src_base: false,
+            llvm_cov_use_color: false,
         }
     }
 
@@ -488,6 +493,8 @@ impl TestProps {
                     COMPARE_OUTPUT_LINES_BY_SUBSET,
                     &mut self.compare_output_lines_by_subset,
                 );
+
+                config.set_name_directive(ln, LLVM_COV_USE_COLOR, &mut self.llvm_cov_use_color);
             });
         }
 

src/tools/compiletest/src/runtest.rs

@@ -565,6 +565,10 @@ impl<'test> TestCx<'test> {
         let proc_res = self.run_llvm_tool("llvm-cov", |cmd| {
             cmd.args(["show", "--format=text", "--show-line-counts-or-regions"]);
 
+            if self.props.llvm_cov_use_color {
+                cmd.arg("--use-color=1");
+            }
+
             cmd.arg("--Xdemangler");
             cmd.arg(self.config.rust_demangler_path.as_ref().unwrap());
 

tests/coverage/color.coverage

@@ -0,0 +1,13 @@
+   LL|       |// edition: 2021
+   LL|       |// ignore-mode-coverage-map
+   LL|       |// ignore-windows
+   LL|       |// llvm-cov-use-color
+   LL|       |
+   LL|       |// Verify that telling `llvm-cov` to use colored output actually works.
+   LL|       |// Ignored on Windows because we can't tell the tool to use ANSI escapes.
+   LL|       |
+   LL|      1|fn main() {
+   LL|      1|    for _i in 0..0 {}
+                      ^0         ^0
+   LL|      1|}
+

tests/coverage/color.rs

@@ -0,0 +1,11 @@
+// edition: 2021
+// ignore-mode-coverage-map
+// ignore-windows
+// llvm-cov-use-color
+
+// Verify that telling `llvm-cov` to use colored output actually works.
+// Ignored on Windows because we can't tell the tool to use ANSI escapes.
+
+fn main() {
+    for _i in 0..0 {}
+}