| # needs-profiler-support |
| |
| -include ../tools.mk |
| |
| # This test makes sure that PGO profiling data leads to cold functions being |
| # marked as `cold` and hot functions with `inlinehint`. |
| # The test program contains an `if` were actual execution only ever takes the |
| # `else` branch. Accordingly, we expect the function that is never called to |
| # be marked as cold. |
| # |
| # The program is compiled with `-Copt-level=s` because this setting disables |
| # LLVM's pre-inlining pass (i.e. a pass that does some inlining before it adds |
| # the profiling instrumentation). Disabling this pass leads to rather |
| # predictable IR which we need for this test to be stable. |
| |
| COMMON_FLAGS=-Copt-level=s -Ccodegen-units=1 |
| |
| # LLVM doesn't support instrumenting binaries that use SEH: |
| # https://github.com/rust-lang/rust/issues/61002 |
| # |
| # Things work fine with -Cpanic=abort though. |
| ifdef IS_MSVC |
| COMMON_FLAGS+= -Cpanic=abort |
| endif |
| |
| ifeq ($(UNAME),Darwin) |
| # macOS does not have the `tac` command, but `tail -r` does the same thing |
| TAC := tail -r |
| else |
| # some other platforms don't support the `-r` flag for `tail`, so use `tac` |
| TAC := tac |
| endif |
| |
| all: |
| # Compile the test program with instrumentation |
| $(RUSTC) $(COMMON_FLAGS) -Cprofile-generate="$(TMPDIR)" main.rs |
| # Run it in order to generate some profiling data |
| $(call RUN,main some-argument) || exit 1 |
| # Postprocess the profiling data so it can be used by the compiler |
| "$(LLVM_BIN_DIR)"/llvm-profdata merge \ |
| -o "$(TMPDIR)"/merged.profdata \ |
| "$(TMPDIR)"/default_*.profraw |
| # Compile the test program again, making use of the profiling data |
| $(RUSTC) $(COMMON_FLAGS) -Cprofile-use="$(TMPDIR)"/merged.profdata --emit=llvm-ir main.rs |
| # Check that the generate IR contains some things that we expect |
| # |
| # We feed the file into LLVM FileCheck tool *in reverse* so that we see the |
| # line with the function name before the line with the function attributes. |
| # FileCheck only supports checking that something matches on the next line, |
| # but not if something matches on the previous line. |
| $(TAC) "$(TMPDIR)"/main.ll | "$(LLVM_FILECHECK)" filecheck-patterns.txt |