[BOLT] More refactoring of PHDR handling. NFC#148932

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[BOLT] More refactoring of PHDR handling. NFC#148932

maksfb wants to merge1 commit intollvm:mainfrommaksfb:gh-phdrs

+12 −18

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maksfb commentedJul 15, 2025

Replace ad-hoc adjustment of the program header count with info from the new segment list.

[BOLT] More refactoring of PHDR handling. NFC

dff76f6

Replace ad-hoc adjustment of the program header count with info from thenew segment list.

maksfb requested review fromaaupov,rafaelauler,ayermolo,yota9 andpaschalis-mpeis ascode owners

July 15, 2025 19:02

llvmbot added the BOLT label

Jul 15, 2025

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llvmbot commentedJul 15, 2025

@llvm/pr-subscribers-bolt

Author: Maksim Panchenko (maksfb)

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Replace ad-hoc adjustment of the program header count with info from the new segment list.

Full diff:https://github.com/llvm/llvm-project/pull/148932.diff

1 Files Affected:

(modified) bolt/lib/Rewrite/RewriteInstance.cpp (+12-18)

diff --git a/bolt/lib/Rewrite/RewriteInstance.cpp b/bolt/lib/Rewrite/RewriteInstance.cppindex 96045a916232c..f1b94e4a821a6 100644--- a/bolt/lib/Rewrite/RewriteInstance.cpp+++ b/bolt/lib/Rewrite/RewriteInstance.cpp@@ -4260,31 +4260,25 @@ void RewriteInstance::patchELFPHDRTable() {   const ELFFile<ELF64LE> &Obj = ELF64LEFile->getELFFile();   raw_fd_ostream &OS = Out->os();-  // Write/re-write program headers.   Phnum = Obj.getHeader().e_phnum;-  if (PHDRTableOffset) {-    // Writing new pheader table and adding one new entry for R+X segment.-    Phnum += 1;-    if (NewWritableSegmentSize) {-      // Adding one more entry for R+W segment.-      Phnum += 1;-    }-  } else {++  if (BC->NewSegments.empty()) {+    BC->outs() << "BOLT-INFO: not adding new segments\n";+    return;+  }++  if (opts::UseGnuStack) {     assert(!PHDRTableAddress && "unexpected address for program header table");-    PHDRTableOffset = Obj.getHeader().e_phoff;-    if (NewWritableSegmentSize) {+    if (BC->NewSegments.size() > 1) {       BC->errs() << "BOLT-ERROR: unable to add writable segment\n";       exit(1);     }+  } else {+    Phnum += BC->NewSegments.size();   }-  if (opts::Instrument)-    Phnum += 2;--  if (BC->NewSegments.empty()) {-    BC->outs() << "BOLT-INFO: not adding new segments\n";-    return;-  }+  if (!PHDRTableOffset)+    PHDRTableOffset = Obj.getHeader().e_phoff;    const uint64_t SavedPos = OS.tell();   OS.seek(PHDRTableOffset);