Bug 1480005 - Move NM to python configure. r=firefox-build-system-reviewers,nalexander

There is only one place where it's used:
config/check_vanilla_allocations.py, which is only executed from
js/src/build/Makefile.in on the condition that the build is targeting
Linux and not LTO. But the LTO test is actually outdated, because we
don't build with `-flto`, but `-flto=thin`, so the exclusion doesn't
work anymore.

There is however no AC_CHECK_PROG, and we currently rely on NM to be
given, or fall back to "nm", which works in most cases, except LTO with
clang. It works on CI because in LTO builds we explicitly set NM to
llvm-nm (which can output symbols from LLVM bitcode objects), but we
could also do that automatically.

So we add a full detection of nm/llvm-nm to python configure, and limit
it to Linux, since we only ever use it there.

Differential Revision: https://phabricator.services.mozilla.com/D101681

build/moz.configure/toolchain.configure

@@ -2898,6 +2898,26 @@ add_old_configure_assignment("AR", ar)
 set_config("AR_FLAGS", ar_config.flags)
 
 
+@depends(toolchain_prefix, c_compiler)
+def nm_names(toolchain_prefix, c_compiler):
+    names = tuple("%s%s" % (p, "nm") for p in (toolchain_prefix or ()) + ("",))
+    if c_compiler.type == "clang":
+        # Get the llvm-nm path as per the output from clang --print-prog-name=llvm-nm
+        # so that we directly get the one under the clang directory, rather than one
+        # that might be in /usr/bin and that might point to one from a different version
+        # of clang.
+        out = check_cmd_output(
+            c_compiler.compiler, "--print-prog-name=llvm-nm", onerror=lambda: None
+        )
+        llvm_nm = out.rstrip() if out else "llvm-nm"
+        names = (llvm_nm,) + names
+
+    return names
+
+
+check_prog("NM", nm_names, paths=toolchain_search_path, when=target_is_linux)
+
+
 option("--enable-cpp-rtti", help="Enable C++ RTTI")
 
 add_old_configure_assignment("_MOZ_USE_RTTI", "1", when="--enable-cpp-rtti")

build/mozconfig.no-compile

@@ -33,7 +33,6 @@ unset MOZ_LTO
 unset MOZ_STDCXX_COMPAT
 unset MOZ_NO_PIE_COMPAT
 
-unset NM
 unset NASM
 
 # Don't unset this on Linux artifact builds so the artifact builds correctly

build/unix/mozconfig.unix

@@ -36,7 +36,6 @@ else
             ac_add_options --with-pgo-jarlog=${MOZ_FETCHES_DIR}/en-US.log
             ac_add_options --with-pgo-profile-path=${MOZ_FETCHES_DIR}/merged.profdata
             export LLVM_PROFDATA="$MOZ_FETCHES_DIR/clang/bin/llvm-profdata"
-            export NM="$MOZ_FETCHES_DIR/clang/bin/llvm-nm"
         fi
     fi
 

js/src/build/Makefile.in

@@ -6,6 +6,7 @@
 
 include $(topsrcdir)/config/rules.mk
 
+ifdef NM
 # check_vanilla_allocations.py is tailored to Linux, so only run it there.
 # That should be enough to catch any problems.
 check-vanilla-allocations:
@@ -16,11 +17,8 @@ check-vanilla-allocations:
 check-vanilla-allocations-aggressive:
 	$(PYTHON3) $(topsrcdir)/config/check_vanilla_allocations.py --aggressive $(REAL_LIBRARY)
 
-ifeq ($(OS_ARCH),Linux)
-ifeq (,$(filter -flto,$(COMPUTED_CFLAGS) $(COMPUTED_CXXFLAGS) $(COMPUTED_LDFLAGS)))
 check:: check-vanilla-allocations
 endif
-endif
 
 $(LIBRARY_NAME).pc: js.pc
 	cp $^ $@

js/src/old-configure.in

@@ -1330,7 +1330,6 @@ dnl = Maintainer debug option (no --enable equivalent)
 dnl =
 dnl ========================================================
 
-AC_SUBST(NM)
 AC_SUBST_LIST(ASFLAGS)
 AC_SUBST(IMPLIB)
 AC_SUBST(FILTER)

mobile/android/config/mozconfigs/android-aarch64/beta

@@ -8,6 +8,4 @@ ac_add_options --with-branding=mobile/android/branding/beta
 
 export MOZILLA_OFFICIAL=1
 
-export NM="$MOZ_FETCHES_DIR/clang/bin/llvm-nm"
-
 . "$topsrcdir/mobile/android/config/mozconfigs/common.override"

mobile/android/config/mozconfigs/android-aarch64/nightly

@@ -10,6 +10,4 @@ export FENNEC_NIGHTLY=1
 
 export MOZILLA_OFFICIAL=1
 
-export NM="$MOZ_FETCHES_DIR/clang/bin/llvm-nm"
-
 . "$topsrcdir/mobile/android/config/mozconfigs/common.override"

mobile/android/config/mozconfigs/android-api-16/beta

@@ -13,6 +13,4 @@ ac_add_options --with-branding=mobile/android/branding/beta
 
 export MOZILLA_OFFICIAL=1
 
-export NM="$MOZ_FETCHES_DIR/clang/bin/llvm-nm"
-
 . "$topsrcdir/mobile/android/config/mozconfigs/common.override"

mobile/android/config/mozconfigs/android-api-16/nightly

@@ -15,6 +15,4 @@ export FENNEC_NIGHTLY=1
 
 export MOZILLA_OFFICIAL=1
 
-export NM="$MOZ_FETCHES_DIR/clang/bin/llvm-nm"
-
 . "$topsrcdir/mobile/android/config/mozconfigs/common.override"

mobile/android/config/mozconfigs/android-x86/beta

@@ -12,6 +12,4 @@ ac_add_options --with-branding=mobile/android/branding/beta
 
 export MOZILLA_OFFICIAL=1
 
-export NM="$MOZ_FETCHES_DIR/clang/bin/llvm-nm"
-
 . "$topsrcdir/mobile/android/config/mozconfigs/common.override"

mobile/android/config/mozconfigs/android-x86/nightly

@@ -15,6 +15,4 @@ export FENNEC_NIGHTLY=1
 
 export MOZILLA_OFFICIAL=1
 
-export NM="$MOZ_FETCHES_DIR/clang/bin/llvm-nm"
-
 . "$topsrcdir/mobile/android/config/mozconfigs/common.override"

mobile/android/config/mozconfigs/android-x86_64/beta

@@ -8,6 +8,4 @@ ac_add_options --with-branding=mobile/android/branding/beta
 
 export MOZILLA_OFFICIAL=1
 
-export NM="$MOZ_FETCHES_DIR/clang/bin/llvm-nm"
-
 . "$topsrcdir/mobile/android/config/mozconfigs/common.override"

mobile/android/config/mozconfigs/android-x86_64/nightly

@@ -10,6 +10,4 @@ export FENNEC_NIGHTLY=1
 
 export MOZILLA_OFFICIAL=1
 
-export NM="$MOZ_FETCHES_DIR/clang/bin/llvm-nm"
-
 . "$topsrcdir/mobile/android/config/mozconfigs/common.override"

old-configure.in

@@ -2470,7 +2470,6 @@ dnl = Maintainer debug option (no --enable equivalent)
 dnl =
 dnl ========================================================
 
-AC_SUBST(NM)
 AC_SUBST_LIST(ASFLAGS)
 AC_SUBST(IMPLIB)
 AC_SUBST(FILTER)