fix: address code review feedback

Author: Colibrow

lld/ELF/BPSectionOrderer.cpp

@@ -42,7 +42,7 @@ struct BPOrdererELF : lld::BPOrderer<BPOrdererELF> {
   }
 
   std::optional<StringRef> static getResolvedLinkageName(llvm::StringRef name) {
-    return name;
+    return {};
   }
 
   static void

lld/ELF/BPSectionOrderer.h

@@ -24,8 +24,9 @@ class InputSectionBase;
 /// Run Balanced Partitioning to find the optimal function and data order to
 /// improve startup time and compressed size.
 ///
-/// It is important that .subsections_via_symbols is used to ensure functions
-/// and data are in their own sections and thus can be reordered.
+/// It is important that -ffunction-sections and -fdata-sections compiler flags
+/// are used to ensure functions and data are in their own sections and thus
+/// can be reordered.
 llvm::DenseMap<const InputSectionBase *, int>
 runBalancedPartitioning(Ctx &ctx, llvm::StringRef profilePath,
                         bool forFunctionCompression, bool forDataCompression,

lld/ELF/Options.td

@@ -141,7 +141,7 @@ def call_graph_profile_sort: JJ<"call-graph-profile-sort=">,
 def : FF<"no-call-graph-profile-sort">, Alias<call_graph_profile_sort>, AliasArgs<["none"]>,
   Flags<[HelpHidden]>;
 
-defm irpgo_profile: Eq<"irpgo-profile",
+defm irpgo_profile: EEq<"irpgo-profile",
     "Read the IRPGO profile for use with -bp-startup-sort and other profile-guided optimizations">;
 
 def bp_startup_sort: JJ<"bp-startup-sort=">,

lld/test/ELF/bp-section-orderer-stress.s

@@ -7,9 +7,9 @@
 # RUN: llvm-mc -filetype=obj -triple=aarch64 %t.s -o %t.o
 # RUN: llvm-profdata merge %t.proftext -o %t.profdata
 
-# RUN: ld.lld --icf=all -o - %t.o --irpgo-profile=%t.profdata --bp-startup-sort=function --bp-compression-sort-startup-functions --bp-compression-sort=both | llvm-nm --numeric-sort --format=just-symbols - > %t.order1.txt
-# RUN: ld.lld --icf=all -o - %t.o --irpgo-profile=%t.profdata --bp-startup-sort=function --bp-compression-sort-startup-functions --bp-compression-sort=both | llvm-nm --numeric-sort --format=just-symbols - > %t.order2.txt
-# RUN: diff %t.order1.txt %t.order2.txt
+# RUN: ld.lld --icf=all -o %t1.o %t.o --irpgo-profile=%t.profdata --bp-startup-sort=function --bp-compression-sort-startup-functions --bp-compression-sort=both
+# RUN: ld.lld --icf=all -o %t2.o %t.o --irpgo-profile=%t.profdata --bp-startup-sort=function --bp-compression-sort-startup-functions --bp-compression-sort=both
+# RUN: cmp %t1.o %t2.o
 
 import random
 import sys

lld/test/ELF/bp-section-orderer.s

@@ -110,39 +110,30 @@ r2
 const char s1[] = "hello world";
 const char s2[] = "i am a string";
 const char s3[] = "this is s3";
-const char* r1 = s1;
-const char** r2 = &r1;
-const char*** r3 = &r2;
-const char* r4 = s2;
-void A() {
-    return;
-}
+const char *r1 = s1;
+const char **r2 = &r1;
+const char ***r3 = &r2;
+const char *r4 = s2;
+void A() { return; }
 
 int B(int a) {
-    A();
-    return a + 1;
+  A();
+  return a + 1;
 }
 
 int C(int a) {
-    A();
-    return a + 2;
+  A();
+  return a + 2;
 }
 
-int D(int a) {
-    return B(a + 2);
-}
+int D(int a) { return B(a + 2); }
 
-int E(int a) {
-    return C(a + 2);
-}
+int E(int a) { return C(a + 2); }
 
-int F(int a) {
-    return C(a + 3);
-}
+int F(int a) { return C(a + 3); }
+
+int _start() { return 0; }
 
-int _start() {
-    return 0;
-}
 #--- gen
 clang --target=aarch64-linux-gnu -O0 -ffunction-sections -fdata-sections -fno-exceptions -fno-rtti -fno-asynchronous-unwind-tables -S a.c -o -
 ;--- a.s