[PATCH 3/4] kbuild: Remove MFS flags from Propeller profile generate builds

[xur@google.com]

From: Rong Xu <xur@google.com>

Propeller profile generation requires Machine Function Splitter (MFS)
to be disabled.

Signed-off-by: Rong Xu <xur@google.com>
---
 scripts/Makefile.propeller | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/scripts/Makefile.propeller b/scripts/Makefile.propeller
index fa018098506b8..8c3e514dbcc04 100644
--- a/scripts/Makefile.propeller
+++ b/scripts/Makefile.propeller
@@ -13,8 +13,14 @@ else
   else
     CFLAGS_PROPELLER_CLANG := -fbasic-block-sections=labels
   endif
+  # Disable Machine Function Splitter for Propeller.
+  # Propeller profile generation requires Machine Function Splitter to be disabled.
+  # We use -fno-split-machine-functions to override any prior AutoFDO/PGO flags
+  #(in Makefile.lib), assuming Propeller options are applied afterward.
+  CFLAGS_PROPELLER_CLANG += -fno-split-machine-functions
 endif
 
+
 # Propeller requires debug information to embed module names in the profiles.
 # If CONFIG_DEBUG_INFO is not enabled, set -gmlt option. Skip this for AutoFDO,
 # as the option should already be set.
@@ -33,6 +39,8 @@ ifdef CONFIG_LTO_CLANG_THIN
     else
        _ldflags_propeller += --lto-basic-block-sections=labels
     endif
+    # Again, we need to disable Machine Function Splitter.
+    LDFLAGS_vmlinux := $(filter-out -plugin-opt=-split-machine-functions, $(LDFLAGS_vmlinux))
   endif
 endif
 
-- 
2.51.0.740.g6adb054d12-goog