Gabriel B. has submitted this change. (
https://gem5-review.googlesource.com/c/public/gem5/+/67451?usp=email )
Change subject: scons: Raise bin size limit for sanitized builds.
......................................................................
scons: Raise bin size limit for sanitized builds.
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+kok...@google.com>
Reviewed-by: Jason Lowe-Power <power...@gmail.com>
Maintainer: Jason Lowe-Power <power...@gmail.com>
---
M SConstruct
1 file changed, 66 insertions(+), 0 deletions(-)
Approvals:
Jason Lowe-Power: Looks good to me, approved; Looks good to me, approved
kokoro: Regressions pass
diff --git a/SConstruct b/SConstruct
index e08c2984..43ca3ac 100755
--- a/SConstruct
+++ b/SConstruct
@@ -290,6 +290,17 @@
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 @@
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)
--
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Gerrit-Project: public/gem5
Gerrit-Branch: develop
Gerrit-Change-Id: I9aceacfcda99cc29c8fb24b7c69aaab019ce97fd
Gerrit-Change-Number: 67451
Gerrit-PatchSet: 2
Gerrit-Owner: Gabriel B. <gabriel.bus...@arteris.com>
Gerrit-Reviewer: Gabe Black <gabe.bl...@gmail.com>
Gerrit-Reviewer: Gabriel B. <gabriel.bus...@arteris.com>
Gerrit-Reviewer: Jason Lowe-Power <power...@gmail.com>
Gerrit-Reviewer: kokoro <noreply+kok...@google.com>
Gerrit-MessageType: merged
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