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rustbuild: Don't enable debuginfo in rustc

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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:
Alex Crichton 2017-01-10 20:01:54 -08:00
parent e4fee525e0
commit 099e7cb120
4 changed files with 25 additions and 4 deletions
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13
configure vendored
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@ -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"