scons: Update the Check(Cxx|Link)Flag checks to set their vars.

This avoids boilerplate where we check to see if flag X is supported,
and if so then set flag X. Since there are shared and static versions of
the linker flags but we only explicitly check the static ones, this
change also adds a parameter to CheckLinkFlag to set both flavors. This
defaults to true since I assume most of the time linking flags will
apply to both.

Change-Id: I983222169e9835aeb98570362f7004e2ef0240d0
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40855
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

diff --git a/SConstruct b/SConstruct
index 2e83aa2fae5ce0bfbe4257225f17280517839c0a..6b028ee0e963594a02a82d7c67fc47e2ed3d2d49 100755 (executable)
--- a/SConstruct
+++ b/SConstruct
@@ -512,21 +512,26 @@ timeout_version = timeout_lines[0].split() if timeout_lines else []
 main['TIMEOUT'] =  timeout_version and \
     compareVersions(timeout_version[-1], '8.13') >= 0
 
-def CheckCxxFlag(context, flag):
+def CheckCxxFlag(context, flag, autoadd=True):
     context.Message("Checking for compiler %s support... " % flag)
     last_cxxflags = context.env['CXXFLAGS']
     context.env.Append(CXXFLAGS=[flag])
     ret = context.TryCompile('', '.cc')
-    context.env['CXXFLAGS'] = last_cxxflags
+    if not autoadd:
+        context.env['CXXFLAGS'] = last_cxxflags
     context.Result(ret)
     return ret
 
-def CheckLinkFlag(context, flag):
+def CheckLinkFlag(context, flag, autoadd=True, set_for_shared=True):
     context.Message("Checking for linker %s support... " % flag)
     last_linkflags = context.env['LINKFLAGS']
     context.env.Append(LINKFLAGS=[flag])
     ret = context.TryLink('int main(int, char *[]) { return 0; }', '.cc')
-    context.env['LINKFLAGS'] = last_linkflags
+    if not autoadd:
+        context.env['LINKFLAGS'] = last_linkflags
+    if set_for_shared:
+        assert(autoadd)
+        context.env.Append(SHLINKFLAGS=[flag])
     context.Result(ret)
     return ret
 
@@ -621,13 +626,9 @@ if main['M5_BUILD_CACHE']:
     CacheDir(main['M5_BUILD_CACHE'])
 
 if not GetOption('no_compress_debug'):
-    if conf.CheckCxxFlag('-gz'):
-        main.Append(CXXFLAGS=['-gz'])
-    else:
+    if not conf.CheckCxxFlag('-gz'):
         warning("Can't enable object file debug section compression")
-    if conf.CheckLinkFlag('-gz'):
-        main.Append(LINKFLAGS=['-gz'], SHLINKFLAGS=['-gz'])
-    else:
+    if not conf.CheckLinkFlag('-gz'):
         warning("Can't enable executable debug section compression")
 
 main['USE_PYTHON'] = not GetOption('without_python')