[pseudo][PATCH v3] makewrappers: Allow the wrapper architecture to be set for cross builds

[sunilkumar.dora@windriver.com]

From: Sunil Dora <sunilkumar.dora@windriver.com>

Architecture specific modifiers in wrapfuncs.in, such as
version-aarch64="GLIBC_2.17" on the xattr wrappers, are selected with
platform.machine(), so they follow the machine running the script
rather than the one pseudo is built for. An aarch64 pseudo cross built
on x86_64 ends up with GLIBC_2.3 and the reverse with GLIBC_2.17, which
shows up as pseudo not being reproducible between x86_64 and aarch64
builders.

Add a --target option to configure and pass it on to makewrappers,
which uses the cpu part of the triplet for these modifiers. Without
--target the build machine is used as before.

[YOCTO #16376]

Signed-off-by: Sunil Dora <sunilkumar.dora@windriver.com>
---
v3: I missed the [pseudo] tag in the subject.

v2: use a configure --target option and a makewrappers --target argument
    instead of the MAKEWRAPPERS_ARCH environment variable, as suggested by
    Mark. Without --target the generated wrapper table is unchanged.

 Makefile.in  |  3 ++-
 configure    |  6 ++++++
 makewrappers | 17 +++++++++++++++--
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/Makefile.in b/Makefile.in
index 6640a73..9c6da77 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -34,6 +34,7 @@ BITS=@BITS@
 ARCH_FLAGS=@ARCH_FLAGS@
 MARK64=@MARK64@
 RPATH=@RPATH@
+TARGET=@TARGET@
 VERSION=1.99.0
 
 LIB=@LIB@
@@ -146,7 +147,7 @@ tables: enums/*.in maketables templatefile.py $(TABLES)
 	./maketables enums/*.in
 
 wrappers: makewrappers templatefile.py $(TEMPLATES) ports/*/wrapfuncs.in
-	CC="$(CC) $(CFLAGS) $(CFLAGS_PSEUDO)" ./makewrappers "xattr=$(XATTR)"
+	CC="$(CC) $(CFLAGS) $(CFLAGS_PSEUDO)" ./makewrappers --target="$(TARGET)" "xattr=$(XATTR)"
 
 .SECONDARY: tables wrappers
 
diff --git a/configure b/configure
index 68c9962..b43809e 100755
--- a/configure
+++ b/configure
@@ -10,6 +10,7 @@
 opt_prefix=
 opt_libdir=
 opt_suffix=
+opt_target=
 opt_arch=x86
 opt_bits=
 opt_sqlite=/usr
@@ -32,6 +33,7 @@ usage()
     echo >&2 "  configure --prefix=..."
     echo >&2 "           [--libdir=...]"
     echo >&2 "           [--suffix=...]"
+    echo >&2 "           [--target=...]"
     echo >&2 "           [--enable-memory-db]"
     echo >&2 "           [--enable-epoll]"
     echo >&2 "           [--enable-xattr]"
@@ -153,6 +155,9 @@ do
     --suffix=*)
         opt_suffix=${arg#--suffix=}
         ;;
+    --target=*)
+        opt_target=${arg#--target=}
+        ;;
     --arch=*)
         echo >&2 "WARNING: The --arch option is now deprecated. Use --cflags."
         opt_arch=${arg#--arch=}
@@ -341,6 +346,7 @@ sed -e '
   s,@LIBDIR@,'"$opt_libdir"',g
   s,@LIB@,'"$opt_lib"',g
   s,@SUFFIX@,'"$opt_suffix"',g
+  s,@TARGET@,'"$opt_target"',g
   s,@SQLITE@,'"$opt_sqlite"',g
   s,@ARCH_FLAGS@,'"$arch_flags"',g
   s,@DEFAULT_SQLITE@,'"$default_sqlite"',g
diff --git a/makewrappers b/makewrappers
index 19508fa..7cf2862 100755
--- a/makewrappers
+++ b/makewrappers
@@ -15,6 +15,13 @@ import platform
 import subprocess
 from templatefile import TemplateFile
 
+# Set from --target=, empty means the machine running this script
+target_arch = ""
+
+def wrapper_arch():
+    """Architecture the wrappers are built for: the --target cpu or the build machine."""
+    return target_arch or platform.machine()
+
 class ArgumentList:
     """A (possibly empty) list of arguments"""
 
@@ -319,11 +326,11 @@ class Function:
             # Strip all leading/trailing whitespace
             modifiers = {k.strip():v.strip() for k, v in modifiers.items()}
 
-            arch = "-" + platform.machine()
+            arch = "-" + wrapper_arch()
             # Sorted so that versions-foo appear after versions, so overrides are easy
             for key in sorted(modifiers):
                 value = modifiers[key].replace('<equals>', '==')
-                # If the key is version-arm64 and we're on arm64 then rename this to version
+                # If the key is version-arm64 and we're building for arm64 then rename this to version
                 if key.endswith(arch):
                     key = key.replace(arch, "")
                 setattr(self, key, value)
@@ -669,10 +676,15 @@ def process_wrapfuncs(port):
 
 def main(argv):
     """Read in function definitions, write out files based on templates."""
+    global target_arch
     funcs = []
     sources = []
 
     for arg in argv:
+        if arg.startswith('--target='):
+            # A GNU triplet such as aarch64-poky-linux, only the cpu part is used
+            target_arch = arg[len('--target='):].split('-')[0]
+            continue
         if '=' not in arg:
             print("Invalid argument '%s', must be of the form name=value" % arg)
             exit(1)
@@ -702,6 +714,7 @@ def main(argv):
     port = Port('common', sources)
 
     # the per-function stuff
+    print("Architecture for wrapper modifiers: %s" % wrapper_arch())
     print("Writing functions...")
     all_funcs = port.functions()
     for name in sorted(all_funcs.keys()):
-- 
2.49.0