diff --git a/src/test/run-make-fulldeps/pgo-indirect-call-promotion/Makefile b/src/test/run-make-fulldeps/pgo-indirect-call-promotion/Makefile new file mode 100644 index 00000000000..e61018752c3 --- /dev/null +++ b/src/test/run-make-fulldeps/pgo-indirect-call-promotion/Makefile @@ -0,0 +1,36 @@ +# needs-profiler-support + +-include ../tools.mk + +# This test makes sure that indirect call promotion is performed. The test +# programs calls the same function a thousand times through a function pointer. +# Only PGO data provides the information that it actually always is the same +# function. We verify that the indirect call promotion pass inserts a check +# whether it can make a direct call instead of the indirect call. + +# 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 + +all: + # We don't compile `opaque` with either optimizations or instrumentation. + # We don't compile `opaque` with either optimizations or instrumentation. + $(RUSTC) $(COMMON_FLAGS) opaque.rs + # Compile the test program with instrumentation + mkdir -p "$(TMPDIR)"/prof_data_dir + $(RUSTC) $(COMMON_FLAGS) interesting.rs \ + -Cprofile-generate="$(TMPDIR)"/prof_data_dir -O -Ccodegen-units=1 + $(RUSTC) $(COMMON_FLAGS) main.rs -Cprofile-generate="$(TMPDIR)"/prof_data_dir -O + # The argument below generates to the expected branch weights + $(call RUN,main) || exit 1 + "$(LLVM_BIN_DIR)"/llvm-profdata merge \ + -o "$(TMPDIR)"/prof_data_dir/merged.profdata \ + "$(TMPDIR)"/prof_data_dir + $(RUSTC) $(COMMON_FLAGS) interesting.rs \ + -Cprofile-use="$(TMPDIR)"/prof_data_dir/merged.profdata -O \ + -Ccodegen-units=1 --emit=llvm-ir + cat "$(TMPDIR)"/interesting.ll | "$(LLVM_FILECHECK)" filecheck-patterns.txt diff --git a/src/test/run-make-fulldeps/pgo-indirect-call-promotion/filecheck-patterns.txt b/src/test/run-make-fulldeps/pgo-indirect-call-promotion/filecheck-patterns.txt new file mode 100644 index 00000000000..934159207e2 --- /dev/null +++ b/src/test/run-make-fulldeps/pgo-indirect-call-promotion/filecheck-patterns.txt @@ -0,0 +1,16 @@ +CHECK: define void @call_a_bunch_of_functions({{.*}} { + +# Make sure that indirect call promotion inserted a check against the most +# frequently called function. +CHECK: %{{.*}} = icmp eq void ()* %{{.*}}, @function_called_always + +# Check that the call to `function_called_always` was inlined, so that we +# directly call `opaque_f1` from the upstream crate. +CHECK: call void @opaque_f1() + + +# Same checks as above, repeated for the trait object case + +CHECK: define void @call_a_bunch_of_trait_methods({{.*}} +CHECK: %{{.*}} = icmp eq void ({}*)* %{{.*}}, {{.*}} @foo +CHECK: tail call void @opaque_f2() diff --git a/src/test/run-make-fulldeps/pgo-indirect-call-promotion/interesting.rs b/src/test/run-make-fulldeps/pgo-indirect-call-promotion/interesting.rs new file mode 100644 index 00000000000..4fd096d626d --- /dev/null +++ b/src/test/run-make-fulldeps/pgo-indirect-call-promotion/interesting.rs @@ -0,0 +1,56 @@ +#![crate_name="interesting"] +#![crate_type="rlib"] + +extern crate opaque; + +#[no_mangle] +pub fn function_called_always() { + opaque::opaque_f1(); +} + +#[no_mangle] +pub fn function_called_never() { + opaque::opaque_f2(); +} + +#[no_mangle] +pub fn call_a_bunch_of_functions(fns: &[fn()]) { + + // Indirect call promotion transforms the below into something like + // + // for f in fns { + // if f == function_called_always { + // function_called_always() + // } else { + // f(); + // } + // } + // + // where `function_called_always` actually gets inlined too. + + for f in fns { + f(); + } +} + + +pub trait Foo { + fn foo(&self); +} + +impl Foo for u32 { + + #[no_mangle] + fn foo(&self) { + opaque::opaque_f2(); + } +} + +#[no_mangle] +pub fn call_a_bunch_of_trait_methods(trait_objects: &[&dyn Foo]) { + + // Same as above, just with vtables in between + for x in trait_objects { + x.foo(); + } +} diff --git a/src/test/run-make-fulldeps/pgo-indirect-call-promotion/main.rs b/src/test/run-make-fulldeps/pgo-indirect-call-promotion/main.rs new file mode 100644 index 00000000000..27181f30710 --- /dev/null +++ b/src/test/run-make-fulldeps/pgo-indirect-call-promotion/main.rs @@ -0,0 +1,14 @@ +extern crate interesting; + +fn main() { + // function pointer case + let fns: Vec<_> = std::iter::repeat(interesting::function_called_always as fn()) + .take(1000) + .collect(); + interesting::call_a_bunch_of_functions(&fns[..]); + + // Trait object case + let trait_objects = vec![0u32; 1000]; + let trait_objects: Vec<_> = trait_objects.iter().map(|x| x as &dyn interesting::Foo).collect(); + interesting::call_a_bunch_of_trait_methods(&trait_objects[..]); +} diff --git a/src/test/run-make-fulldeps/pgo-indirect-call-promotion/opaque.rs b/src/test/run-make-fulldeps/pgo-indirect-call-promotion/opaque.rs new file mode 100644 index 00000000000..9628d711c50 --- /dev/null +++ b/src/test/run-make-fulldeps/pgo-indirect-call-promotion/opaque.rs @@ -0,0 +1,7 @@ +#![crate_name="opaque"] +#![crate_type="rlib"] + +#[no_mangle] +pub fn opaque_f1() {} +#[no_mangle] +pub fn opaque_f2() {}