Add MachO dump writer to createdump

Instead of the hacky ELF core dumps on MacOS now createdump generates true MachO dumps. Setting the COMPlus_DbgEnableElfDumpOnMacOS environment variable is no longer needed. Add special thread info memory region containing the OS thread ids missing from macho core dumps. This allows SOS to map the thread indexes to thread ids. The address (0x7fffffff00000000) of this special memory region is above the highest user address (0x0007FFFFFFFFF000) and below a kernel reserved address (0xffffff8000xxxxxx) which is kind of moot because dumps don't include any kernel regions. lldb seems just fine with this memory region. The changes include ARM64 support also, but since I don't have a M1 device I can't build/test them. I'm hoping Steve can at least review them. Add --verbose/TRACE_VERBOSE support to tone down all the macho dump generation spew. Issue: dotnet#48664
mikem8361 · Apr 12, 2021 · ef165f2 · ef165f2
1 parent 8d102e3
commit ef165f2
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Showing 21 changed files with 1,166 additions and 927 deletions.
diff --git a/src/coreclr/debug/createdump/CMakeLists.txt b/src/coreclr/debug/createdump/CMakeLists.txt
@@ -63,12 +63,14 @@ if(CLR_CMAKE_HOST_OSX)
     add_executable_clr(createdump
         crashinfomac.cpp
         threadinfomac.cpp
+        dumpwritermacho.cpp
         ${CREATEDUMP_SOURCES}
     )
 else()
     add_executable_clr(createdump
         crashinfounix.cpp
         threadinfounix.cpp
+        dumpwriterelf.cpp
         ${CREATEDUMP_SOURCES}
         ${PAL_REDEFINES_FILE}
     )

diff --git a/src/coreclr/debug/createdump/crashinfo.cpp b/src/coreclr/debug/createdump/crashinfo.cpp
@@ -122,10 +122,13 @@ CrashInfo::GatherCrashInfo(MINIDUMP_TYPE minidumpType)
         return false;
     }
 #endif
-    TRACE("Module addresses:\n");
-    for (const MemoryRegion& region : m_moduleAddresses)
+    if (g_diagnosticsVerbose)
     {
-        region.Trace();
+        TRACE_VERBOSE("Module addresses:\n");
+        for (const MemoryRegion& region : m_moduleAddresses)
+        {
+            region.Trace();
+        }
     }
     // If full memory dump, include everything regardless of permissions
     if (minidumpType & MiniDumpWithFullMemory)
@@ -589,7 +592,7 @@ CrashInfo::CombineMemoryRegions()
 
     TRACE("CombineMemoryRegions: FINISHED\n");
 
-    if (g_diagnostics)
+    if (g_diagnosticsVerbose)
     {
         TRACE("Memory Regions:\n");
         for (const MemoryRegion& region : m_memoryRegions)
@@ -619,7 +622,21 @@ CrashInfo::SearchMemoryRegions(const std::set<MemoryRegion>& regions, const Memo
 void
 CrashInfo::Trace(const char* format, ...)
 {
-    if (g_diagnostics) {
+    if (g_diagnostics)
+    {
+        va_list args;
+        va_start(args, format);
+        vfprintf(stdout, format, args);
+        fflush(stdout);
+        va_end(args);
+    }
+}
+
+void
+CrashInfo::TraceVerbose(const char* format, ...)
+{
+    if (g_diagnosticsVerbose)
+    {
         va_list args;
         va_start(args, format);
         vfprintf(stdout, format, args);

diff --git a/src/coreclr/debug/createdump/crashinfo.h b/src/coreclr/debug/createdump/crashinfo.h
@@ -5,7 +5,6 @@
 #include "../dbgutil/machoreader.h"
 #else
 #include "../dbgutil/elfreader.h"
-#endif
 
 // typedef for our parsing of the auxv variables in /proc/pid/auxv.
 #if TARGET_64BIT
@@ -29,6 +28,8 @@ typedef __typeof__(((elf_aux_entry*) 0)->a_un.a_val) elf_aux_val_t;
 // All interesting auvx entry types are AT_SYSINFO_EHDR and below
 #define AT_MAX (AT_SYSINFO_EHDR + 1)
 
+#endif
+
 class CrashInfo : public ICLRDataEnumMemoryRegionsCallback,
 #ifdef __APPLE__
     public MachOReader
@@ -53,8 +54,8 @@ class CrashInfo : public ICLRDataEnumMemoryRegionsCallback,
     std::set<MemoryRegion> m_allMemoryRegions;      // all memory regions on MacOS
 #else
     std::array<elf_aux_val_t, AT_MAX> m_auxvValues; // auxv values
-#endif
     std::vector<elf_aux_entry> m_auxvEntries;       // full auxv entries
+#endif
     std::vector<ThreadInfo*> m_threads;             // threads found and suspended
     std::set<MemoryRegion> m_moduleMappings;        // module memory mappings
     std::set<MemoryRegion> m_otherMappings;         // other memory mappings
@@ -87,8 +88,10 @@ class CrashInfo : public ICLRDataEnumMemoryRegionsCallback,
     inline const std::set<MemoryRegion> ModuleMappings() const { return m_moduleMappings; }
     inline const std::set<MemoryRegion> OtherMappings() const { return m_otherMappings; }
     inline const std::set<MemoryRegion> MemoryRegions() const { return m_memoryRegions; }
+#ifndef __APPLE__
     inline const std::vector<elf_aux_entry> AuxvEntries() const { return m_auxvEntries; }
     inline size_t GetAuxvSize() const { return m_auxvEntries.size() * sizeof(elf_aux_entry); }
+#endif
 
     // IUnknown
     STDMETHOD(QueryInterface)(___in REFIID InterfaceId, ___out PVOID* Interface);
@@ -122,4 +125,5 @@ class CrashInfo : public ICLRDataEnumMemoryRegionsCallback,
     bool ValidRegion(const MemoryRegion& region);
     void CombineMemoryRegions();
     void Trace(const char* format, ...);
+    void TraceVerbose(const char* format, ...);
 };
diff --git a/src/coreclr/debug/createdump/crashinfomac.cpp b/src/coreclr/debug/createdump/crashinfomac.cpp
@@ -15,8 +15,6 @@ CrashInfo::Initialize()
         fprintf(stderr, "task_for_pid(%d) FAILED %x %s\n", m_pid, result, mach_error_string(result));
         return false;
     }
-    m_auxvEntries.push_back(elf_aux_entry { AT_BASE, { 0 } });
-    m_auxvEntries.push_back(elf_aux_entry { AT_NULL, { 0 } });
     return true;
 }
 
@@ -110,7 +108,7 @@ CrashInfo::EnumerateMemoryRegions()
             TRACE("mach_vm_region_recurse for address %016llx %08llx FAILED %x %s\n", address, size, result, mach_error_string(result));
             break;
         }
-        TRACE("%016llx - %016llx (%06llx) %08llx %s %d %d %d %c%c%c %02x\n",
+        TRACE_VERBOSE("%016llx - %016llx (%06llx) %08llx %s %d %d %d %c%c%c %02x\n",
             address,
             address + size,
             size / PAGE_SIZE,
@@ -291,9 +289,11 @@ void CrashInfo::VisitSegment(MachOModule& module, const segment_command_64& segm
             const auto& found = m_moduleMappings.find(moduleRegion);
             if (found == m_moduleMappings.end())
             {
-                TRACE("VisitSegment: ");
-                moduleRegion.Trace();
-
+                if (g_diagnosticsVerbose)
+                {
+                    TRACE_VERBOSE("VisitSegment: ");
+                    moduleRegion.Trace();
+                }
                 // Add this module segment to the module mappings list
                 m_moduleMappings.insert(moduleRegion);
 
@@ -380,9 +380,3 @@ CrashInfo::ReadProcessMemory(void* address, void* buffer, size_t size, size_t* r
     *read = numberOfBytesRead;
     return size == 0 || numberOfBytesRead > 0;
 }
-
-// For src/inc/llvm/ELF.h
-Elf64_Ehdr::Elf64_Ehdr()
-{
-}
-
diff --git a/src/coreclr/debug/createdump/createdump.h b/src/coreclr/debug/createdump/createdump.h
@@ -11,11 +11,13 @@
 #endif
 
 extern void trace_printf(const char* format, ...);
+extern void trace_verbose_printf(const char* format, ...);
 extern bool g_diagnostics;
+extern bool g_diagnosticsVerbose;
 
 #ifdef HOST_UNIX
 #define TRACE(args...) trace_printf(args)
-#define TRACE_VERBOSE(args...)
+#define TRACE_VERBOSE(args...) trace_verbose_printf(args)
 #else
 #define TRACE(args, ...)
 #define TRACE_VERBOSE(args, ...)
@@ -82,7 +84,8 @@ typedef int T_CONTEXT;
 #include <string>
 #ifdef HOST_UNIX
 #ifdef __APPLE__
-#include "mac.h"
+#include <mach/mach.h>
+#include <mach/mach_vm.h>
 #endif
 #include "datatarget.h"
 #include "threadinfo.h"