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gh-101525: configure: Add PIE detection logic for BOLT optimizations compatibility #140203

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gh-101525: configure: Add PIE detection logic for BOLT optimizations compatibility #140203

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74 changes: 70 additions & 4 deletions configure
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52 changes: 48 additions & 4 deletions configure.ac
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Original file line number Diff line number Diff line change
Expand Up @@ -2116,10 +2116,49 @@ if test "$Py_BOLT" = 'true' ; then
# These flags are required for bolt to work:
LDFLAGS_NODIST="$LDFLAGS_NODIST -Wl,--emit-relocs"

# These flags are required to get good performance from bolt:
CFLAGS_NODIST="$CFLAGS_NODIST -fno-pie"
# We want to add these no-pie flags to linking executables but not shared libraries:
LINKCC="$LINKCC -fno-pie -no-pie"
# Detect if PIE is enabled
# Compile-time PIE: -fPIE in CFLAGS (defines __PIE__)
# Link-time PIE: -pie for link (no __PIE__ defined)
# We need to check CFLAGS and LDFLAGS.
AC_MSG_CHECKING([whether PIE is enabled by default])

pie_enabled=no

# Check for compile-time PIE (-fPIE defines __PIE__/__pie__)
# Save original CFLAGS and temporarily add CFLAGS_NODIST to test
save_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS $CFLAGS_NODIST"
AC_PREPROC_IFELSE([AC_LANG_SOURCE([[
#if !defined(__PIE__) && !defined(__pie__)
#error PIE not enabled
#endif
]])],
[pie_enabled=yes],
[])
CFLAGS="$save_CFLAGS"

# Check for link-time PIE (test if linker produces PIE by default)
if test "$pie_enabled" = "no"; then
save_LDFLAGS="$LDFLAGS"
LDFLAGS="$LDFLAGS $LDFLAGS_NODIST"
AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],[[]])],
[if file conftest$EXEEXT 2>/dev/null | grep -q -E 'pie executable|shared object'; then
pie_enabled=yes
fi],
[])
LDFLAGS="$save_LDFLAGS"
fi

AC_MSG_RESULT([$pie_enabled])

# Only add -fno-pie flags if PIE is not enabled by default.
# If PIE is enabled, these flags would conflict with the build system's PIE enforcement.
if test "$pie_enabled" = "no"; then
# These flags are required to get good performance from bolt:
CFLAGS_NODIST="$CFLAGS_NODIST -fno-pie"
# We want to add these no-pie flags to linking executables but not shared libraries:
LINKCC="$LINKCC -fno-pie -no-pie"
fi
AC_SUBST([LLVM_BOLT])
AC_PATH_TOOL([LLVM_BOLT], [llvm-bolt], [''], [${llvm_path}])
if test -n "${LLVM_BOLT}" -a -x "${LLVM_BOLT}"
Expand Down Expand Up @@ -2165,6 +2204,11 @@ then
[-skip-funcs=_PyEval_EvalFrameDefault,sre_ucs1_match/1,sre_ucs2_match/1,sre_ucs4_match/1]
")]
)

# Add --relocs flag if PIE is enabled, as BOLT requires it for PIE binaries
if test "${pie_enabled:-no}" = "yes"; then
BOLT_COMMON_FLAGS="${BOLT_COMMON_FLAGS} --relocs"
fi
fi

AC_ARG_VAR(
Expand Down
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