Add basic section information to darwin procmaps

[fjricci]

Fix backwards conditional

[fjricci]

Merged into D35422

lib/sanitizer_common/sanitizer_procmaps.h

public:
   uptr end;
   uptr offset;
   char *filename;  // owned by caller
   uptr filename_size;
   uptr protection;
   ModuleArch arch;
   u8 uuid[kModuleUUIDSize];
   bool has_sections;
+
+ private:
+#if SANITIZER_MAC
+  friend class MemoryMappingLayout;
+
+  template <typename Section>
+  bool NextSectionLoad(MemoryMappedSection *section);
+  uptr nsects_;
+  char *current_load_cmd_addr_;
+  u32 lc_type_;
+  uptr base_virt_addr_;
+#endif
 };
 
 class MemoryMappingLayout {
  public:
   explicit MemoryMappingLayout(bool cache_enabled);
   ~MemoryMappingLayout();
   bool Next(MemoryMappedSegment *segment);
   void Reset();

lib/sanitizer_common/sanitizer_procmaps_mac.cc

 #ifndef CPU_SUBTYPE_ARM_V7K
 #define CPU_SUBTYPE_ARM_V7K   ((cpu_subtype_t)12)
 #endif
 #ifndef CPU_TYPE_ARM64
 #define CPU_TYPE_ARM64        (CPU_TYPE_ARM | CPU_ARCH_ABI64)
 #endif
 
 namespace __sanitizer {
+template <typename Section>
+bool MemoryMappedSegment::NextSectionLoad(MemoryMappedSection *section) {
+  const Section *sc = (const Section *)current_load_cmd_addr_;
+  current_load_cmd_addr_ += sizeof(Section);
+
+  section->start = sc->addr + base_virt_addr_;
+  section->end = section->start + sc->size;
+  section->offset = sc->offset;
+
+  nsects_--;
+  return true;
+}
+
 bool MemoryMappedSegment::Next(MemoryMappedSection *section) {
-  return false;
+  if (nsects_ == 0) return false;
+
+  bool ret = false;
+  if (lc_type_ == LC_SEGMENT) {
+    ret = NextSectionLoad<struct section>(section);
+#ifdef MH_MAGIC_64
+  } else if (lc_type_ == LC_SEGMENT_64) {
+    ret = NextSectionLoad<struct section_64>(section);
+#endif
+  }
+  return ret;
 }
 
 MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) {
   Reset();
 }
 
 MemoryMappingLayout::~MemoryMappingLayout() {
 }

 // segment.
 // Note that the segment addresses are not necessarily sorted.
 template <u32 kLCSegment, typename SegmentCommand>
 bool MemoryMappingLayout::NextSegmentLoad(MemoryMappedSegment *segment) {
   const char *lc = current_load_cmd_addr_;
   current_load_cmd_addr_ += ((const load_command *)lc)->cmdsize;
   if (((const load_command *)lc)->cmd == kLCSegment) {
     const SegmentCommand* sc = (const SegmentCommand *)lc;
-    segment->has_sections = false;
+    segment->current_load_cmd_addr_ = (char *)lc + sizeof(SegmentCommand);
+    segment->lc_type_ = kLCSegment;
+    segment->nsects_ = sc->nsects;
+
+    // Some macho segments don't contain sections
+    segment->has_sections = segment->nsects_;
 
     if (current_image_ == kDyldImageIdx) {
+      segment->base_virt_addr_ = (uptr)get_dyld_hdr();
       // vmaddr is masked with 0xfffff because on macOS versions < 10.12,
       // it contains an absolute address rather than an offset for dyld.
       // To make matters even more complicated, this absolute address
       // isn't actually the absolute segment address, but the offset portion
       // of the address is accurate when combined with the dyld base address,
       // and the mask will give just this offset.
-      segment->start = (sc->vmaddr & 0xfffff) + (uptr)get_dyld_hdr();
-      segment->end = (sc->vmaddr & 0xfffff) + sc->vmsize + (uptr)get_dyld_hdr();
+      segment->start = (sc->vmaddr & 0xfffff) + segment->base_virt_addr_;
     } else {
-      const sptr dlloff = _dyld_get_image_vmaddr_slide(current_image_);
-      segment->start = sc->vmaddr + dlloff;
-      segment->end = sc->vmaddr + sc->vmsize + dlloff;
+      segment->base_virt_addr_ =
+          (uptr)_dyld_get_image_vmaddr_slide(current_image_);
+      segment->start = sc->vmaddr + segment->base_virt_addr_;
     }
+    segment->end = segment->start + sc->vmsize;
 
     // Return the initial protection.
     segment->protection = sc->initprot;
     segment->offset =
         (current_filetype_ == /*MH_EXECUTE*/ 0x2) ? sc->vmaddr : sc->fileoff;
     if (segment->filename) {
       const char *src = (current_image_ == kDyldImageIdx)
                             ? kDyldPath