[lldb] Pick the correct architecutre when target and core file disagree (#105576)

In f9f3316, Adrian fixed an issue where LLDB wouldn't update the
target's architecture when the process reported a different triple that
only differed in its sub-architecture.

This unintentionally regressed core file debugging when the core file
reports the base architecture (e.g. armv7) while the main binary knows
the correct CPU subtype (e.g. armv7em). After the aforementioned change,
we update the target architecture from armv7em to armv7. Fix the issue
by trusting the target architecture over the ProcessMachCore process.

rdar://133834304

Author: JDevlieghere

lldb/source/Plugins/Process/mach-core/ProcessMachCore.cpp

@@ -562,17 +562,22 @@ Status ProcessMachCore::DoLoadCore() {
 
   SetCanJIT(false);
 
-  // The corefile's architecture is our best starting point.
-  ArchSpec arch(m_core_module_sp->GetArchitecture());
-  if (arch.IsValid())
-    GetTarget().SetArchitecture(arch);
-
   CreateMemoryRegions();
 
   LoadBinariesAndSetDYLD();
 
   CleanupMemoryRegionPermissions();
 
+  ModuleSP exe_module_sp = GetTarget().GetExecutableModule();
+  if (exe_module_sp && exe_module_sp->GetArchitecture().IsValid()) {
+    GetTarget().SetArchitecture(exe_module_sp->GetArchitecture());
+  } else {
+    // The corefile's architecture is our best starting point.
+    ArchSpec arch(m_core_module_sp->GetArchitecture());
+    if (arch.IsValid())
+      GetTarget().SetArchitecture(arch);
+  }
+
   AddressableBits addressable_bits = core_objfile->GetAddressableBits();
   SetAddressableBitMasks(addressable_bits);
 

lldb/test/Shell/Process/Inputs/a.out.yaml

@@ -0,0 +1,62 @@
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACE
+  cputype:         0xC
+  cpusubtype:      0x10
+  filetype:        0x2
+  ncmds:           3
+  sizeofcmds:      272
+  flags:           0x200085
+LoadCommands:
+  - cmd:             LC_SEGMENT
+    cmdsize:         56
+    segname:         __PAGEZERO
+    vmaddr:          0
+    vmsize:          16384
+    fileoff:         0
+    filesize:        0
+    maxprot:         0
+    initprot:        0
+    nsects:          0
+    flags:           0
+  - cmd:             LC_SEGMENT
+    cmdsize:         192
+    segname:         __TEXT
+    vmaddr:          16384
+    vmsize:          32768
+    fileoff:         0
+    filesize:        32768
+    maxprot:         5
+    initprot:        5
+    nsects:          2
+    flags:           0
+    Sections:
+      - sectname:        __text
+        segname:         __TEXT
+        addr:            0xBFB4
+        size:            4
+        offset:          0x7FB4
+        align:           1
+        reloff:          0x0
+        nreloc:          0
+        flags:           0x80000400
+        reserved1:       0x0
+        reserved2:       0x0
+        reserved3:       0x0
+        content:         '00207047'
+      - sectname:        __unwind_info
+        segname:         __TEXT
+        addr:            0xBFB8
+        size:            72
+        offset:          0x7FB8
+        align:           2
+        reloff:          0x0
+        nreloc:          0
+        flags:           0x0
+        reserved1:       0x0
+        reserved2:       0x0
+        reserved3:       0x0
+        content:         010000001C000000000000001C000000000000001C00000002000000B57F00003400000034000000BA7F00000000000034000000030000000C000100100001000000000000000000
+  - cmd:             LC_UUID
+    cmdsize:         24
+    uuid:            C2065535-C63D-3C6A-BF79-19CF960DEF2E

lldb/test/Shell/Process/Inputs/corefile.yaml

@@ -0,0 +1,22 @@
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0xC
+  cpusubtype:      0x9
+  filetype:        0x4
+  ncmds:           1
+  sizeofcmds:      84
+  flags:           0x0
+  reserved:        0x0
+LoadCommands:
+  - cmd:             LC_THREAD
+    cmdsize:         84
+    PayloadBytes:    [ 0x1, 0x0, 0x0, 0x0, 0x11, 0x0, 0x0, 0x0, 0x0, 0x0, 
+                       0x1, 0x0, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0, 0x3, 0x0, 
+                       0x0, 0x0, 0x4, 0x0, 0x0, 0x0, 0x5, 0x0, 0x0, 0x0, 
+                       0x6, 0x0, 0x0, 0x0, 0x7, 0x0, 0x0, 0x0, 0x8, 0x0, 
+                       0x0, 0x0, 0x9, 0x0, 0x0, 0x0, 0xA, 0x0, 0x0, 0x0, 
+                       0xB, 0x0, 0x0, 0x0, 0xC, 0x0, 0x0, 0x0, 0xD, 0x0, 
+                       0x0, 0x0, 0xE, 0x0, 0x0, 0x0, 0xF, 0x0, 0x0, 0x0, 
+                       0x10, 0x0, 0x0, 0x0, 0x11, 0x0 ]
+...

lldb/test/Shell/Process/ProcessMachCoreArch.test

@@ -0,0 +1,8 @@
+# RUN: yaml2obj %S/Inputs/corefile.yaml -o %t.corefile
+# RUN: yaml2obj %S/Inputs/a.out.yaml -o %t.out
+
+# RUN: %lldb -b -c %t.corefile %t.out -o 'target list ' | FileCheck %s --check-prefix BINARY
+# BINARY: target {{.*}} arch=armv7em-apple
+
+# RUN: %lldb -b %t.corefile -o 'target list' | FileCheck %s --check-prefix CORE
+# CORE: target {{.*}} arch=armv7-apple