From 935070a8f182ab92bfca51606e49ee2b62e51e55 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Steinbrink?= Date: Wed, 3 Jan 2018 10:29:27 +0100 Subject: [PATCH 1/2] 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/librustc/session/config.rs | 6 ++++++ src/librustc/session/mod.rs | 2 +- src/librustc_trans/attributes.rs | 2 -- src/test/codegen/force-frame-pointers.rs | 16 ++++++++++++++++ 4 files changed, 23 insertions(+), 3 deletions(-) create mode 100644 src/test/codegen/force-frame-pointers.rs diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs index 736d7f8a1396b..df4ae1e24619a 100644 --- a/src/librustc/session/config.rs +++ b/src/librustc/session/config.rs @@ -1064,6 +1064,8 @@ 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"), debug_assertions: Option = (None, parse_opt_bool, [TRACKED], "explicitly enable the cfg(debug_assertions) directive"), inline_threshold: Option = (None, parse_opt_uint, [TRACKED], @@ -2890,6 +2892,10 @@ mod tests { opts.cg.debuginfo = Some(0xba5eba11); assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash()); + opts = reference.clone(); + opts.cg.force_frame_pointers = true; + assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash()); + opts = reference.clone(); opts.cg.debug_assertions = Some(true); assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash()); diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs index 3f52ecfc0999b..46c69d052301e 100644 --- a/src/librustc/session/mod.rs +++ b/src/librustc/session/mod.rs @@ -20,7 +20,7 @@ use lint::builtin::BuiltinLintDiagnostics; use middle::allocator::AllocatorKind; use middle::dependency_format; use session::search_paths::PathKind; -use session::config::{DebugInfoLevel, OutputType}; +use session::config::{OutputType}; use ty::tls; use util::nodemap::{FxHashMap, FxHashSet}; use util::common::{duration_to_secs_str, ErrorReported}; diff --git a/src/librustc_trans/attributes.rs b/src/librustc_trans/attributes.rs index d5ec8d1b55262..d57e5040045cd 100644 --- a/src/librustc_trans/attributes.rs +++ b/src/librustc_trans/attributes.rs @@ -65,8 +65,6 @@ pub fn naked(val: ValueRef, is_naked: bool) { } pub fn set_frame_pointer_elimination(cx: &CodegenCx, llfn: ValueRef) { - // FIXME: #11906: Omitting frame pointers breaks retrieving the value of a - // parameter. if cx.sess().must_not_eliminate_frame_pointers() { llvm::AddFunctionAttrStringValue( llfn, llvm::AttributePlace::Function, diff --git a/src/test/codegen/force-frame-pointers.rs b/src/test/codegen/force-frame-pointers.rs new file mode 100644 index 0000000000000..d40406a0476f2 --- /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() {} From 7188f4144a2cc25b4ee7aa0df78198ebe8ffe6e8 Mon Sep 17 00:00:00 2001 From: Simonas Kazlauskas Date: Tue, 6 Mar 2018 20:27:19 +0200 Subject: [PATCH 2/2] 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(-) diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs index df4ae1e24619a..3789626d3511a 100644 --- a/src/librustc/session/config.rs +++ b/src/librustc/session/config.rs @@ -1064,8 +1064,8 @@ 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], @@ -2893,7 +2893,7 @@ 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 46c69d052301e..1cfb5700b715d 100644 --- a/src/librustc/session/mod.rs +++ b/src/librustc/session/mod.rs @@ -676,8 +676,11 @@ 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 d40406a0476f2..f70e366719882 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"]