Sort sections in relocatable files.

The final section order in relocatable files was just a side effect of the atom sorter. This meant that sections like __data were before __text because __data has RW permissions and __text RX and RW was less than RX in our enum. Final linked images had an actual section/segment sorter. There was no reason for the difference, so simplify a bunch of code and just use the same sorted for everything. Reviewed by Lang Hames. http://reviews.llvm.org/D15868 llvm-svn: 256786
2016-01-04 22:29:36 +00:00 · 2016-01-04 22:29:36 +00:00 · bd364ce694
parent 204efe2de8
commit bd364ce694
4 changed files with 134 additions and 107 deletions
--- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
+++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
@ -406,14 +406,8 @@ bool Util::TextSectionSorter::operator()(const SectionInfo *left,
 }

 void Util::organizeSections() {
-  if (_ctx.outputMachOType() == llvm::MachO::MH_OBJECT) {
-    // Leave sections ordered as normalized file specified.
-    uint32_t sectionIndex = 1;
-    for (SectionInfo *si : _sectionInfos) {
-      si->finalSectionIndex = sectionIndex++;
-    }
-  } else {
-    switch (_ctx.outputMachOType()) {
+  // NOTE!: Keep this in sync with assignAddressesToSections.
+  switch (_ctx.outputMachOType()) {
    case llvm::MachO::MH_EXECUTE:
      // Main executables, need a zero-page segment
      segmentForName("__PAGEZERO");
@ -425,32 +419,30 @@ void Util::organizeSections() {
      break;
    default:
      break;
-    }
-    // Group sections into segments.
-    for (SectionInfo *si : _sectionInfos) {
-      SegmentInfo *seg = segmentForName(si->segmentName);
-      seg->sections.push_back(si);
-    }
-    // Sort segments.
-    std::sort(_segmentInfos.begin(), _segmentInfos.end(), SegmentSorter());
+  }
+  // Group sections into segments.
+  for (SectionInfo *si : _sectionInfos) {
+    SegmentInfo *seg = segmentForName(si->segmentName);
+    seg->sections.push_back(si);
+  }
+  // Sort segments.
+  std::sort(_segmentInfos.begin(), _segmentInfos.end(), SegmentSorter());

-    // Sort sections within segments.
-    for (SegmentInfo *seg : _segmentInfos) {
-      if (seg->name.equals("__TEXT")) {
-        std::sort(seg->sections.begin(), seg->sections.end(),
-                                                          TextSectionSorter());
-      }
+  // Sort sections within segments.
+  for (SegmentInfo *seg : _segmentInfos) {
+    if (seg->name.equals("__TEXT")) {
+      std::sort(seg->sections.begin(), seg->sections.end(),
+                TextSectionSorter());
    }
+  }

-    // Record final section indexes.
-    uint32_t segmentIndex = 0;
-    uint32_t sectionIndex = 1;
-    for (SegmentInfo *seg : _segmentInfos) {
-      seg->normalizedSegmentIndex = segmentIndex++;
-      for (SectionInfo *sect : seg->sections) {
-        sect->finalSectionIndex = sectionIndex++;
-      }
-    }
+  // Record final section indexes.
+  uint32_t segmentIndex = 0;
+  uint32_t sectionIndex = 1;
+  for (SegmentInfo *seg : _segmentInfos) {
+    seg->normalizedSegmentIndex = segmentIndex++;
+    for (SectionInfo *sect : seg->sections)
+      sect->finalSectionIndex = sectionIndex++;
  }
 }

@ -487,54 +479,39 @@ void Util::layoutSectionsInTextSegment(size_t hlcSize, SegmentInfo *seg,
 }

 void Util::assignAddressesToSections(const NormalizedFile &file) {
+  // NOTE!: Keep this in sync with organizeSections.
  size_t hlcSize = headerAndLoadCommandsSize(file);
  uint64_t address = 0;
-  if (_ctx.outputMachOType() != llvm::MachO::MH_OBJECT) {
-    for (SegmentInfo *seg : _segmentInfos) {
-      if (seg->name.equals("__PAGEZERO")) {
-        seg->size = _ctx.pageZeroSize();
-        address += seg->size;
-      }
-      else if (seg->name.equals("__TEXT")) {
-        // _ctx.baseAddress()  == 0 implies it was either unspecified or
-        // pageZeroSize is also 0. In either case resetting address is safe.
-        address = _ctx.baseAddress() ? _ctx.baseAddress() : address;
-        layoutSectionsInTextSegment(hlcSize, seg, address);
-      } else
-        layoutSectionsInSegment(seg, address);
+  for (SegmentInfo *seg : _segmentInfos) {
+    if (seg->name.equals("__PAGEZERO")) {
+      seg->size = _ctx.pageZeroSize();
+      address += seg->size;
+    }
+    else if (seg->name.equals("__TEXT")) {
+      // _ctx.baseAddress()  == 0 implies it was either unspecified or
+      // pageZeroSize is also 0. In either case resetting address is safe.
+      address = _ctx.baseAddress() ? _ctx.baseAddress() : address;
+      layoutSectionsInTextSegment(hlcSize, seg, address);
+    } else
+      layoutSectionsInSegment(seg, address);

-      address = llvm::RoundUpToAlignment(address, _ctx.pageSize());
-    }
-    DEBUG_WITH_TYPE("WriterMachO-norm",
-      llvm::dbgs() << "assignAddressesToSections()\n";
-      for (SegmentInfo *sgi : _segmentInfos) {
-        llvm::dbgs()  << "   address=" << llvm::format("0x%08llX", sgi->address)
-                      << ", size="  << llvm::format("0x%08llX", sgi->size)
-                      << ", segment-name='" << sgi->name
-                      << "'\n";
-        for (SectionInfo *si : sgi->sections) {
-          llvm::dbgs()<< "      addr="  << llvm::format("0x%08llX", si->address)
-                      << ", size="  << llvm::format("0x%08llX", si->size)
-                      << ", section-name='" << si->sectionName
-                      << "\n";
-        }
-      }
-    );
-  } else {
-    for (SectionInfo *sect : _sectionInfos) {
-      sect->address = llvm::RoundUpToAlignment(address, sect->alignment);
-      address = sect->address + sect->size;
-    }
-    DEBUG_WITH_TYPE("WriterMachO-norm",
-      llvm::dbgs() << "assignAddressesToSections()\n";
-      for (SectionInfo *si : _sectionInfos) {
-        llvm::dbgs()  << "      section=" << si->sectionName
-                      << " address= "  << llvm::format("0x%08X", si->address)
-                      << " size= "  << llvm::format("0x%08X", si->size)
-                      << "\n";
-      }
-    );
+    address = llvm::RoundUpToAlignment(address, _ctx.pageSize());
  }
+  DEBUG_WITH_TYPE("WriterMachO-norm",
+    llvm::dbgs() << "assignAddressesToSections()\n";
+    for (SegmentInfo *sgi : _segmentInfos) {
+      llvm::dbgs()  << "   address=" << llvm::format("0x%08llX", sgi->address)
+                    << ", size="  << llvm::format("0x%08llX", sgi->size)
+                    << ", segment-name='" << sgi->name
+                    << "'\n";
+      for (SectionInfo *si : sgi->sections) {
+        llvm::dbgs()<< "      addr="  << llvm::format("0x%08llX", si->address)
+                    << ", size="  << llvm::format("0x%08llX", si->size)
+                    << ", section-name='" << si->sectionName
+                    << "\n";
+      }
+    }
+  );
 }

 void Util::copySegmentInfo(NormalizedFile &file) {
@ -604,16 +581,9 @@ void Util::copySectionContent(NormalizedFile &file) {

 void Util::copySectionInfo(NormalizedFile &file) {
  file.sections.reserve(_sectionInfos.size());
-  // For final linked images, write sections grouped by segment.
-  if (_ctx.outputMachOType() != llvm::MachO::MH_OBJECT) {
-    for (SegmentInfo *sgi : _segmentInfos) {
-      for (SectionInfo *si : sgi->sections) {
-        appendSection(si, file);
-      }
-    }
-  } else {
-    // Object files write sections in default order.
-    for (SectionInfo *si : _sectionInfos) {
+  // Write sections grouped by segment.
+  for (SegmentInfo *sgi : _segmentInfos) {
+    for (SectionInfo *si : sgi->sections) {
      appendSection(si, file);
    }
  }
@ -621,20 +591,12 @@ void Util::copySectionInfo(NormalizedFile &file) {

 void Util::updateSectionInfo(NormalizedFile &file) {
  file.sections.reserve(_sectionInfos.size());
-  if (_ctx.outputMachOType() != llvm::MachO::MH_OBJECT) {
-    // For final linked images, sections grouped by segment.
-    for (SegmentInfo *sgi : _segmentInfos) {
-      Segment *normSeg = &file.segments[sgi->normalizedSegmentIndex];
-      normSeg->address = sgi->address;
-      normSeg->size = sgi->size;
-      for (SectionInfo *si : sgi->sections) {
-        Section *normSect = &file.sections[si->normalizedSectionIndex];
-        normSect->address = si->address;
-      }
-    }
-  } else {
-    // Object files write sections in default order.
-    for (SectionInfo *si : _sectionInfos) {
+  // sections grouped by segment.
+  for (SegmentInfo *sgi : _segmentInfos) {
+    Segment *normSeg = &file.segments[sgi->normalizedSegmentIndex];
+    normSeg->address = sgi->address;
+    normSeg->size = sgi->size;
+    for (SectionInfo *si : sgi->sections) {
      Section *normSect = &file.sections[si->normalizedSectionIndex];
      normSect->address = si->address;
    }
@ -999,11 +961,9 @@ void Util::segIndexForSection(const SectionInfo *sect, uint8_t &segmentIndex,

 uint32_t Util::sectionIndexForAtom(const Atom *atom) {
  uint64_t address = _atomToAddress[atom];
-  uint32_t index = 1;
  for (const SectionInfo *si : _sectionInfos) {
    if ((si->address <= address) && (address < si->address+si->size))
-      return index;
-    ++index;
+      return si->finalSectionIndex;
  }
  llvm_unreachable("atom not in any section");
 }
--- a/lld/test/mach-o/arm64-reloc-negDelta32-fixup.yaml
+++ b/lld/test/mach-o/arm64-reloc-negDelta32-fixup.yaml
@ -6,12 +6,12 @@
 # The reference from FDE->CIE is implicitly created as a negDelta32.
 # We don't emit these in to the binary as relocations, so we need to
 # make sure that the offset in the FDE to the CIE is the correct value.
-# CHECK: 0010 10000000 00000000 017a5200 01781e01
-# CHECK: 0020 100c1f00 20000000 18000000 e4ffffff
+# CHECK: {{[0-9abcdef]*}} 10000000 00000000 017a5200 01781e01
+# CHECK: {{[0-9abcdef]*}} 100c1f00 20000000 18000000 e4ffffff
 # Note, this one that matters   ^~~~~~~~
 # It needs to be 0x18 as that is the offset back to 0 where the CIE is.
-# CHECK: 0030 ffffffff 20000000 00000000 00480e10
-# CHECK: 0040 9e019d02 00000000
+# CHECK: {{[0-9abcdef]*}} ffffffff 20000000 00000000 00480e10
+# CHECK: {{[0-9abcdef]*}} 9e019d02 00000000

 ---  !mach-o
 arch:            arm64
--- a/lld/test/mach-o/arm64-section-order.yaml
+++ b/lld/test/mach-o/arm64-section-order.yaml
@ -0,0 +1,67 @@
+# RUN: lld -flavor darwin -arch arm64 -r -print_atoms %s -o %t
+# RUN: lld -flavor darwin -arch arm64 -r -print_atoms %t -o %t2
+# RUN: llvm-objdump -section-headers %t | FileCheck %s
+# RUN: llvm-objdump -section-headers %t2 | FileCheck %s
+
+# Make sure that the sections are sorted.  Currently we want this order:
+# __text, __unwind_info
+
+# CHECK: Sections:
+# CHECK: 0 __text        {{.*}} TEXT
+# CHECK: 1 __compact_unwind {{.*}}
+
+
+--- !mach-o
+arch:            arm64
+file-type:       MH_OBJECT
+flags:           [ MH_SUBSECTIONS_VIA_SYMBOLS ]
+compat-version:  0.0
+current-version: 0.0
+has-UUID:        false
+OS:              unknown
+sections:
+  - segment:         __TEXT
+    section:         __text
+    type:            S_REGULAR
+    attributes:      [ S_ATTR_PURE_INSTRUCTIONS, S_ATTR_SOME_INSTRUCTIONS ]
+    alignment:       8
+    address:         0x0000000000000000
+    content:         [ 0xC0, 0x03, 0x5F, 0xD6, 0xC0, 0x03, 0x5F, 0xD6 ]
+  - segment:         __LD
+    section:         __compact_unwind
+    type:            S_REGULAR
+    attributes:      [  ]
+    alignment:       8
+    address:         0x0000000000000008
+    content:         [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                       0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03,
+                       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                       0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                       0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03,
+                       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ]
+    relocations:
+      - offset:          0x00000020
+        type:            ARM64_RELOC_UNSIGNED
+        length:          3
+        pc-rel:          false
+        extern:          false
+        symbol:          1
+      - offset:          0x00000000
+        type:            ARM64_RELOC_UNSIGNED
+        length:          3
+        pc-rel:          false
+        extern:          false
+        symbol:          1
+global-symbols:
+  - name:            __Z3fooi
+    type:            N_SECT
+    scope:           [ N_EXT ]
+    sect:            1
+    value:           0x0000000000000000
+  - name:            __Z4foo2i
+    type:            N_SECT
+    scope:           [ N_EXT ]
+    sect:            1
+    value:           0x0000000000000004
--- a/lld/test/mach-o/parse-data-relocs-x86_64.yaml
+++ b/lld/test/mach-o/parse-data-relocs-x86_64.yaml
@ -268,7 +268,7 @@ page-size:       0x00000000
 # CHECK:    type:            data
 # CHECK:    content:         [ 00, 00, 00, 00, 00, 00, 00, 00, 04, 00, 00, 00, 
 # CHECK:                       00, 00, 00, 00, F0, FF, FF, FF, FF, FF, FF, FF, 
-# CHECK:                       {{..}}, 00, 00, 00, 00, 00, 00, 00, {{..}}, 00, 00, 00, 
+# CHECK:                       {{..}}, {{..}}, 00, 00, 00, 00, 00, 00, {{..}}, {{..}}, 00, 00,
 # CHECK:                       00, 00, 00, 00, D8, FF, FF, FF, FF, FF, FF, FF, 
 # CHECK:                       D4, FF, FF, FF, FF, FF, FF, FF, {{..}}, {{..}}, {{..}}, {{..}},
 # CHECK:                       {{..}}, {{..}}, {{..}}, {{..}}, C0, FF, FF, FF, C0, FF, FF, FF,