vendor/lld/lld-trunk-r233088

1 files changed, 73 insertions, 0 deletions

diff --git a/lib/ReaderWriter/ELF/Mips/MipsCtorsOrderPass.cpp b/lib/ReaderWriter/ELF/Mips/MipsCtorsOrderPass.cpp
new file mode 100644
index 000000000000..8bf80257fc89
--- /dev/null
+++ b/lib/ReaderWriter/ELF/Mips/MipsCtorsOrderPass.cpp
@@ -0,0 +1,73 @@
+//===- lib/ReaderWriter/ELF/Mips/Mips/CtorsOrderPass.cpp ------------------===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MipsCtorsOrderPass.h"
+#include <algorithm>
+#include <climits>
+
+using namespace lld;
+using namespace lld::elf;
+
+static bool matchCrtObjName(StringRef objName, StringRef objPath) {
+  if (!objPath.endswith(".o"))
+    return false;
+
+  // check *<objName> case
+  objPath = objPath.drop_back(2);
+  if (objPath.endswith(objName))
+    return true;
+
+  // check *<objName>? case
+  return !objPath.empty() && objPath.drop_back(1).endswith(objName);
+}
+
+static int32_t getSectionPriority(StringRef path, StringRef sectionName) {
+  // Arrange .ctors/.dtors sections in the following order:
+  //   .ctors from crtbegin.o or crtbegin?.o
+  //   .ctors from regular object files
+  //   .ctors.* (sorted) from regular object files
+  //   .ctors from crtend.o or crtend?.o
+
+  if (matchCrtObjName("crtbegin", path))
+    return std::numeric_limits<int32_t>::min();
+  if (matchCrtObjName("crtend", path))
+    return std::numeric_limits<int32_t>::max();
+
+  StringRef num = sectionName.drop_front().rsplit('.').second;
+
+  int32_t priority = std::numeric_limits<int32_t>::min() + 1;
+  if (!num.empty())
+    num.getAsInteger(10, priority);
+
+  return priority;
+}
+
+void MipsCtorsOrderPass::perform(std::unique_ptr<MutableFile> &f) {
+  auto definedAtoms = f->definedAtoms();
+
+  auto last = std::stable_partition(definedAtoms.begin(), definedAtoms.end(),
+                                    [](const DefinedAtom *atom) {
+    if (atom->sectionChoice() != DefinedAtom::sectionCustomRequired)
+      return false;
+
+    StringRef name = atom->customSectionName();
+    return name.startswith(".ctors") || name.startswith(".dtors");
+  });
+
+  std::stable_sort(definedAtoms.begin(), last,
+                   [](const DefinedAtom *left, const DefinedAtom *right) {
+    StringRef leftSec = left->customSectionName();
+    StringRef rightSec = right->customSectionName();
+
+    int32_t leftPriority = getSectionPriority(left->file().path(), leftSec);
+    int32_t rightPriority = getSectionPriority(right->file().path(), rightSec);
+
+    return leftPriority < rightPriority;
+  });
+}