From 5b800c231f45fcd823a3e958bb942cd620ceb3e0 Mon Sep 17 00:00:00 2001 From: Björn Steinbrink Date: Wed, 3 Jan 2018 10:29:27 +0100 Subject: Don't force-enable frame pointers when generating debug info We apparently used to generate bad/incomplete debug info causing debuggers not to find symbols of stack allocated variables. This was somehow worked around by having frame pointers. With the current codegen, this seems no longer necessary, so we can remove the code that force-enables frame pointers whenever debug info is requested. Since certain situations, like profiling code profit from having frame pointers, we add a -Cforce-frame-pointers flag to always enable frame pointers. Fixes #11906 --- src/test/codegen/force-frame-pointers.rs | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) create mode 100644 src/test/codegen/force-frame-pointers.rs (limited to 'src/test/codegen/force-frame-pointers.rs') diff --git a/src/test/codegen/force-frame-pointers.rs b/src/test/codegen/force-frame-pointers.rs new file mode 100644 index 00000000000..d40406a0476 --- /dev/null +++ b/src/test/codegen/force-frame-pointers.rs @@ -0,0 +1,16 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. +// +// compile-flags: -C no-prepopulate-passes -C force-frame-pointers + +#![crate_type="lib"] + +// CHECK: attributes #{{.*}} "no-frame-pointer-elim"="true" +pub fn foo() {} -- cgit 1.4.1-3-g733a5 From 09d2db4e963c6696f7c22386b6791e419ad75cfb Mon Sep 17 00:00:00 2001 From: Simonas Kazlauskas Date: Tue, 6 Mar 2018 20:27:19 +0200 Subject: Rework force-frame-pointer This reworks the force-frame-pointer PR to explicitly only consider the value of the flag if it is provided, and use a target default otherwise. Something that was tried but not kept was renaming the flag to `frame-pointer`, because for flag `frame-pointer=no`, there is no guarante, that LLVM will elide *all* the frame pointers; oposite of what the literal reading of the flag would suggest. --- src/librustc/session/config.rs | 6 +++--- src/librustc/session/mod.rs | 7 +++++-- src/test/codegen/force-frame-pointers.rs | 2 +- 3 files changed, 9 insertions(+), 6 deletions(-) (limited to 'src/test/codegen/force-frame-pointers.rs') diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs index 023be789222..59b40e9e2dc 100644 --- a/src/librustc/session/config.rs +++ b/src/librustc/session/config.rs @@ -1053,8 +1053,8 @@ options! {CodegenOptions, CodegenSetter, basic_codegen_options, 2 = full debug info with variable and type information"), opt_level: Option = (None, parse_opt_string, [TRACKED], "optimize with possible levels 0-3, s, or z"), - force_frame_pointers: bool = (false, parse_bool, [TRACKED], - "force frame pointers to be used"), + force_frame_pointers: Option = (None, parse_opt_bool, [TRACKED], + "force use of the frame pointers"), debug_assertions: Option = (None, parse_opt_bool, [TRACKED], "explicitly enable the cfg(debug_assertions) directive"), inline_threshold: Option = (None, parse_opt_uint, [TRACKED], @@ -2968,7 +2968,7 @@ mod tests { assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash()); opts = reference.clone(); - opts.cg.force_frame_pointers = true; + opts.cg.force_frame_pointers = Some(false); assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash()); opts = reference.clone(); diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs index 45b7e2d1740..2ab72ba20bf 100644 --- a/src/librustc/session/mod.rs +++ b/src/librustc/session/mod.rs @@ -658,8 +658,11 @@ impl Session { } pub fn must_not_eliminate_frame_pointers(&self) -> bool { - self.opts.debuginfo != DebugInfoLevel::NoDebugInfo - || !self.target.target.options.eliminate_frame_pointer + if let Some(x) = self.opts.cg.force_frame_pointers { + x + } else { + !self.target.target.options.eliminate_frame_pointer + } } /// Returns the symbol name for the registrar function, diff --git a/src/test/codegen/force-frame-pointers.rs b/src/test/codegen/force-frame-pointers.rs index d40406a0476..f70e3667198 100644 --- a/src/test/codegen/force-frame-pointers.rs +++ b/src/test/codegen/force-frame-pointers.rs @@ -8,7 +8,7 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. // -// compile-flags: -C no-prepopulate-passes -C force-frame-pointers +// compile-flags: -C no-prepopulate-passes -C force-frame-pointers=y #![crate_type="lib"] -- cgit 1.4.1-3-g733a5