From 14f8442d241188909f3a50082260808c9769582b Mon Sep 17 00:00:00 2001
From: jiangning <jiangning26@huawei.com>
Date: Tue, 10 Jun 2025 15:15:16 +0800
Subject: [PATCH] compiler & OS oeaware schedule opt

---
 lld/ELF/Config.h              |  1 +
 lld/ELF/Driver.cpp            |  2 ++
 lld/ELF/SyntheticSections.cpp |  9 +++++++++
 lld/ELF/SyntheticSections.h   | 15 +++++++++++++++
 lld/ELF/Writer.cpp            |  6 ++++++
 lld/test/ELF/oeaware.s        | 17 +++++++++++++++++
 6 files changed, 50 insertions(+)
 create mode 100644 lld/test/ELF/oeaware.s

diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
index 94af8c34beb7..abd9bcf9dc4f 100644
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -317,6 +317,7 @@ struct Config {
   uint8_t zStartStopVisibility;
   bool zText;
   bool zRetpolineplt;
+  int8_t zOeawarePolicy;
   bool zWxneeded;
   DiscardPolicy discard;
   GnuStackKind zGnustack;
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index e65dfa553de0..7bf2361e1b72 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -569,6 +569,7 @@ constexpr const char *knownZFlags[] = {
     "text",
     "undefs",
     "wxneeded",
+    "oe-aware",
 };
 
 static bool isKnownZFlag(StringRef s) {
@@ -1397,6 +1398,7 @@ static void readConfigs(opt::InputArgList &args) {
   config->zStartStopVisibility = getZStartStopVisibility(args);
   config->zText = getZFlag(args, "text", "notext", true);
   config->zWxneeded = hasZOption(args, "wxneeded");
+  config->zOeawarePolicy = args::getZOptionValue(args, OPT_z,  "oeaware-policy", -1);
   setUnresolvedSymbolPolicy(args);
   config->power10Stubs = args.getLastArgValue(OPT_power10_stubs_eq) != "no";
 
diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
index de25750bf9eb..8238cc330276 100644
--- a/lld/ELF/SyntheticSections.cpp
+++ b/lld/ELF/SyntheticSections.cpp
@@ -3900,6 +3900,15 @@ size_t PackageMetadataNote::getSize() const {
          alignTo(config->packageMetadata.size() + 1, 4);
 }
 
+void OeAware::writeTo(uint8_t *buf) {
+  if(config->zOeawarePolicy != -1)
+    write32(buf, config->zOeawarePolicy);
+}
+
+size_t OeAware::getSize() const { return 4; }
+
+void OeAware::finalizeContents() {}
+
 InStruct elf::in;
 
 std::vector<Partition> elf::partitions;
diff --git a/lld/ELF/SyntheticSections.h b/lld/ELF/SyntheticSections.h
index 38d0c80a073d..6215019cc587 100644
--- a/lld/ELF/SyntheticSections.h
+++ b/lld/ELF/SyntheticSections.h
@@ -1245,6 +1245,20 @@ public:
   size_t getSize() const override;
 };
 
+class OeAware : public SyntheticSection {
+public:
+  OeAware()
+      : SyntheticSection(llvm::ELF::SHF_ALLOC | llvm::ELF::SHF_WRITE,
+		         llvm::ELF::SHT_NOTE, /*alignment=*/4, ".LLVM4OE_oeAware")
+        {}
+  void writeTo(uint8_t *buf) override;
+  size_t getSize() const override;
+  void finalizeContents() override;
+
+private:
+  uint64_t size;
+};
+
 InputSection *createInterpSection();
 MergeInputSection *createCommentSection();
 template <class ELFT> void splitSections();
@@ -1323,6 +1337,7 @@ struct InStruct {
   std::unique_ptr<StringTableSection> strTab;
   std::unique_ptr<SymbolTableBaseSection> symTab;
   std::unique_ptr<SymtabShndxSection> symTabShndx;
+  std::unique_ptr<SyntheticSection> oeaware;
 
   void reset();
 };
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index dd37bbbf76c1..33a1046767b0 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -294,6 +294,11 @@ template <class ELFT> void elf::createSyntheticSections() {
   in.bss = std::make_unique<BssSection>(".bss", 0, 1);
   add(*in.bss);
 
+  if (config->zOeawarePolicy != -1) {
+    in.oeaware = std::make_unique<OeAware>();
+    add(*in.oeaware);
+  }
+
   // If there is a SECTIONS command and a .data.rel.ro section name use name
   // .data.rel.ro.bss so that we match in the .data.rel.ro output section.
   // This makes sure our relro is contiguous.
@@ -2067,6 +2072,7 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
     llvm::TimeTraceScope timeScope("Finalize synthetic sections");
 
     finalizeSynthetic(in.bss.get());
+    finalizeSynthetic(in.oeaware.get());
     finalizeSynthetic(in.bssRelRo.get());
     finalizeSynthetic(in.symTabShndx.get());
     finalizeSynthetic(in.shStrTab.get());
diff --git a/lld/test/ELF/oeaware.s b/lld/test/ELF/oeaware.s
new file mode 100644
index 000000000000..50f66c228a34
--- /dev/null
+++ b/lld/test/ELF/oeaware.s
@@ -0,0 +1,17 @@
+# REQUIRES: target=aarch64{{.*}}
+# RUN: llvm-mc -filetype=obj -triple=aarch64-none-linux-gnu %s -o %t.o
+# RUN: ld.lld %t.o -o %ta -z oeaware-policy=1
+# RUN: llvm-objdump -j .LLVM4OE_oeAware %ta -d | FileCheck %s
+
+# CHECK: <.LLVM4OE_oeAware>:
+# CHECK-NEXT: 00000001
+
+# RUN: ld.lld %t.o -o %tb -z oeaware-policy=2
+# RUN: llvm-objdump -j .LLVM4OE_oeAware %tb -d | FileCheck %s --check-prefix=OPTION
+
+# OPTION: <.LLVM4OE_oeAware>:
+# OPTION-NEXT: 00000002
+
+.globl _start
+_start: nop
+.bss; .byte 0
-- 
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