[lld] ELF: Introduce --randomize-section-padding option. (PR #117653)

[via llvm-commits]

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@@ -1444,6 +1444,39 @@ static void finalizeSynthetic(Ctx &ctx, SyntheticSection *sec) {
   }
 }
 
+static bool canInsertPadding(OutputSection *sec) {
+  StringRef s = sec->name;
+  return s == ".bss" || s == ".data" || s == ".data.rel.ro" || s == ".rodata" ||
+         s.starts_with(".text");
+}
+
+static void randomizeSectionPadding(Ctx &ctx) {
+  std::mt19937 g(*ctx.arg.randomizeSectionPadding);
+  PhdrEntry *curPtLoad = nullptr;
+  for (OutputSection *os : ctx.outputSections) {
+    if (!canInsertPadding(os))
+      continue;
+    for (SectionCommand *bc : os->commands) {
+      if (auto *isd = dyn_cast<InputSectionDescription>(bc)) {
+        SmallVector<InputSection *, 0> tmp;
+        if (os->ptLoad != curPtLoad) {
+          tmp.push_back(make<RandomizePaddingSection>(
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pcc wrote:

Okay, added a test with a linker script.

https://github.com/llvm/llvm-project/pull/117653