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scons: Raise bin size limit for sanitized builds.

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Sanitizers can enlarge binary size drammatically, north of 2GB. This
can prevent successful linkage due to symbol relocation outside from
the 2GB region allocated by the small x86_64 code model that is
enabled by default (32-bit relative offset limitation). Switching to
the medium model in x86_64 enables 64-bit relative offset for large
objects (>64KB by default) while sticking to 32-bit relative
addressing for code and smaller objects. Note this comes at a
potential performance cost so it should not be enabled in all cases.
This should still be a very happy medium for non-perf-critical
sanitized builds.

Jira issue: https://gem5.atlassian.net/browse/GEM5-1313

Change-Id: I9aceacfcda99cc29c8fb24b7c69aaab019ce97fd
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67451
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
This commit is contained in:
Gabriel Busnot
2023-01-24 08:28:48 +00:00
committed by Gabriel B.
parent 8d0fde1961
commit 534d9dea10
1 changed files with 40 additions and 0 deletions
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@@ -290,6 +290,17 @@ main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
if main['GCC'] + main['CLANG'] > 1:
error('Two compilers enabled at once?')
# Find the gem5 binary target architecture (usually host architecture). The
# "Target: <target>" is consistent accross gcc and clang at the time of
# writting this.
bin_target_arch = readCommand([main['CXX'], '--verbose'], exception=False)
main["BIN_TARGET_ARCH"] = (
"x86_64"
if bin_target_arch.find("Target: x86_64") != -1
else "aarch64"
if bin_target_arch.find("Target: aarch64") != -1
else "unknown"
)
########################################################################
#
@@ -516,6 +527,35 @@ for variant_path in variant_paths:
env.Append(CCFLAGS=['-fsanitize=%s' % sanitizers,
'-fno-omit-frame-pointer'],
LINKFLAGS='-fsanitize=%s' % sanitizers)
if main["BIN_TARGET_ARCH"] == "x86_64":
# Sanitizers can enlarge binary size drammatically, north of
# 2GB. This can prevent successful linkage due to symbol
# relocation outside from the 2GB region allocated by the small
# x86_64 code model that is enabled by default (32-bit relative
# offset limitation). Switching to the medium model in x86_64
# enables 64-bit relative offset for large objects (>64KB by
# default) while sticking to 32-bit relative addressing for
# code and smaller objects. Note this comes at a potential
# performance cost so it should not be enabled in all cases.
# This should still be a very happy medium for
# non-perf-critical sanitized builds.
env.Append(CCFLAGS='-mcmodel=medium')
env.Append(LINKFLAGS='-mcmodel=medium')
elif main["BIN_TARGET_ARCH"] == "aarch64":
# aarch64 default code model is small but with different
# constrains than for x86_64. With aarch64, the small code
# model enables 4GB distance between symbols. This is
# sufficient for the largest ALL/gem5.debug target with all
# sanitizers enabled at the time of writting this. Note that
# the next aarch64 code model is "large" which prevents dynamic
# linkage so it should be avoided when possible.
pass
else:
warning(
"Unknown code model options for your architecture. "
"Linkage might fail for larger binaries "
"(e.g., ALL/gem5.debug with sanitizers enabled)."
)
else:
warning("Don't know how to enable %s sanitizer(s) for your "
"compiler." % sanitizers)