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Auto merge of #38984 - alexcrichton:less-debuginfo, r=brson

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rustbuild: Don't enable debuginfo in rustc

In #37280 we enabled line number debugging information in release artifacts,
primarily to close out #36452 where debugging information was critical for MSVC
builds of Rust to be useful in production. This commit, however, apparently had
some unfortunate side effects.

Namely it was noticed in #37477 that if `RUST_BACKTRACE=1` was set then any
compiler error would take a very long time for the compiler to exit. The cause
of the problem here was somewhat deep:

* For all compiler errors, the compiler will `panic!` with a known value. This
  tears down the main compiler thread and allows cleaning up all the various
  resources. By default, however, this panic output is suppressed for "normal"
  compiler errors.
* When `RUST_BACKTRACE=1` was set this caused every compiler error to generate a
  backtrace.
* The libbacktrace library hits a pathological case where it spends a very long
  time in its custom allocation function, `backtrace_alloc`, because the
  compiler has so much debugging information. More information about this can be
  found in #29293 with a summary at the end of #37477.

To solve this problem this commit simply removes debuginfo from the compiler but
not from the standard library. This should allow us to keep #36452 closed while
also closing #37477. I've measured the difference to be orders of magnitude
faster than it was before, so we should see a much quicker time-to-exit after a
compile error when `RUST_BACKTRACE=1` is set.

Closes #37477
Closes #37571
This commit is contained in:
bors 2017-01-11 13:42:52 +00:00
commit 52c03d1d61
4 changed files with 25 additions and 4 deletions
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13
configure vendored
View File

@ -647,6 +647,7 @@ opt_nosave debug-assertions 0 "build with debugging assertions"
opt_nosave llvm-release-debuginfo 0 "build LLVM with debugger metadata"
opt_nosave debuginfo 0 "build with debugger metadata"
opt_nosave debuginfo-lines 0 "build with line number debugger metadata"
opt_nosave debuginfo-only-std 0 "build only libstd with debugging information"
opt_nosave debug-jemalloc 0 "build jemalloc with --enable-debug --enable-fill"
valopt localstatedir "/var/lib" "local state directory"
@ -733,15 +734,17 @@ case "$CFG_RELEASE_CHANNEL" in
nightly )
msg "overriding settings for $CFG_RELEASE_CHANNEL"
CFG_ENABLE_LLVM_ASSERTIONS=1
# FIXME(#37364) shouldn't have to disable this on windows-gnu
# FIXME(stage0) re-enable this on the next stage0 now that #35566 is
# fixed
case "$CFG_BUILD" in
*-pc-windows-gnu)
;;
*)
CFG_ENABLE_DEBUGINFO_LINES=1
CFG_ENABLE_DEBUGINFO_LINES=1
CFG_ENABLE_DEBUGINFO_ONLY_STD=1
;;
esac
;;
beta | stable)
msg "overriding settings for $CFG_RELEASE_CHANNEL"
@ -749,7 +752,8 @@ case "$CFG_RELEASE_CHANNEL" in
*-pc-windows-gnu)
;;
*)
CFG_ENABLE_DEBUGINFO_LINES=1
CFG_ENABLE_DEBUGINFO_LINES=1
CFG_ENABLE_DEBUGINFO_ONLY_STD=1
;;
esac
;;
@ -785,6 +789,7 @@ if [ -n "$CFG_ENABLE_DEBUG_ASSERTIONS" ]; then putvar CFG_ENABLE_DEBUG_ASSERTION
if [ -n "$CFG_ENABLE_LLVM_RELEASE_DEBUGINFO" ]; then putvar CFG_ENABLE_LLVM_RELEASE_DEBUGINFO; fi
if [ -n "$CFG_ENABLE_DEBUGINFO" ]; then putvar CFG_ENABLE_DEBUGINFO; fi
if [ -n "$CFG_ENABLE_DEBUGINFO_LINES" ]; then putvar CFG_ENABLE_DEBUGINFO_LINES; fi
if [ -n "$CFG_ENABLE_DEBUGINFO_ONLY_STD" ]; then putvar CFG_ENABLE_DEBUGINFO_ONLY_STD; fi
if [ -n "$CFG_ENABLE_DEBUG_JEMALLOC" ]; then putvar CFG_ENABLE_DEBUG_JEMALLOC; fi
step_msg "looking for build programs"

7
src/bootstrap/compile.rs
View File

@ -189,6 +189,13 @@ pub fn rustc(build: &Build, target: &str, compiler: &Compiler) {
.env("CFG_PREFIX", build.config.prefix.clone().unwrap_or(String::new()))
.env("CFG_LIBDIR_RELATIVE", "lib");
// If we're not building a compiler with debugging information then remove
// these two env vars which would be set otherwise.
if build.config.rust_debuginfo_only_std {
cargo.env_remove("RUSTC_DEBUGINFO");
cargo.env_remove("RUSTC_DEBUGINFO_LINES");
}
if let Some(ref ver_date) = build.ver_date {
cargo.env("CFG_VER_DATE", ver_date);
}

4
src/bootstrap/config.rs
View File

@ -63,6 +63,7 @@ pub struct Config {
pub rust_debug_assertions: bool,
pub rust_debuginfo: bool,
pub rust_debuginfo_lines: bool,
pub rust_debuginfo_only_std: bool,
pub rust_rpath: bool,
pub rustc_default_linker: Option<String>,
pub rustc_default_ar: Option<String>,
@ -179,6 +180,7 @@ struct Rust {
debug_assertions: Option<bool>,
debuginfo: Option<bool>,
debuginfo_lines: Option<bool>,
debuginfo_only_std: Option<bool>,
debug_jemalloc: Option<bool>,
use_jemalloc: Option<bool>,
backtrace: Option<bool>,
@ -298,6 +300,7 @@ impl Config {
set(&mut config.rust_debug_assertions, rust.debug_assertions);
set(&mut config.rust_debuginfo, rust.debuginfo);
set(&mut config.rust_debuginfo_lines, rust.debuginfo_lines);
set(&mut config.rust_debuginfo_only_std, rust.debuginfo_only_std);
set(&mut config.rust_optimize, rust.optimize);
set(&mut config.rust_optimize_tests, rust.optimize_tests);
set(&mut config.rust_debuginfo_tests, rust.debuginfo_tests);
@ -390,6 +393,7 @@ impl Config {
("DEBUG_ASSERTIONS", self.rust_debug_assertions),
("DEBUGINFO", self.rust_debuginfo),
("DEBUGINFO_LINES", self.rust_debuginfo_lines),
("DEBUGINFO_ONLY_STD", self.rust_debuginfo_only_std),
("JEMALLOC", self.use_jemalloc),
("DEBUG_JEMALLOC", self.debug_jemalloc),
("RPATH", self.rust_rpath),

5
src/bootstrap/config.toml.example
View File

@ -149,6 +149,11 @@
# Whether or not line number debug information is emitted
#debuginfo-lines = false
# Whether or not to only build debuginfo for the standard library if enabled.
# If enabled, this will not compile the compiler with debuginfo, just the
# standard library.
#debuginfo-only-std = false
# Whether or not jemalloc is built and enabled
#use-jemalloc = true