[Lldb-commits] [PATCH] D153079: Add an llvm::report_fatal_error for when the darwin kernel says we've finished an insn-step but the thread doesn't think it was insn-stepping

[Jason Molenda via Phabricator via lldb-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG6a8e2538afc1: Add a fatal error for debug builds when 
disagreement about stepping (authored by jasonmolenda).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D153079/new/

https://reviews.llvm.org/D153079

Files:
  lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp


Index: lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
===================================================================
--- lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
+++ lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
@@ -708,12 +708,49 @@
 
     case llvm::Triple::aarch64_32:
     case llvm::Triple::aarch64: {
+      // xnu describes three things with type EXC_BREAKPOINT:
+      //
+      //   exc_code 0x102 [EXC_ARM_DA_DEBUG], exc_sub_code addr-of-insn
+      //      Watchpoint access.  exc_sub_code is the address of the
+      //      instruction which trigged the watchpoint trap.
+      //      debugserver may add the watchpoint number that was triggered
+      //      in exc_sub_sub_code.
+      //
+      //   exc_code 1 [EXC_ARM_BREAKPOINT], exc_sub_code 0
+      //      Instruction step has completed.
+      //
+      //   exc_code 1 [EXC_ARM_BREAKPOINT], exc_sub_code address-of-instruction
+      //      Software breakpoint instruction executed.
+
       if (exc_code == 1 && exc_sub_code == 0) // EXC_ARM_BREAKPOINT
       {
         // This is hit when we single instruction step aka MDSCR_EL1 SS bit 0
         // is set
-        is_actual_breakpoint = false;
+        is_actual_breakpoint = true;
         is_trace_if_actual_breakpoint_missing = true;
+#ifndef NDEBUG
+        if (thread.GetTemporaryResumeState() != eStateStepping) {
+          StreamString s;
+          s.Printf("CreateStopReasonWithMachException got EXC_BREAKPOINT [1,0] 
"
+                   "indicating trace event, but thread is not tracing, it has "
+                   "ResumeState %d",
+                   thread.GetTemporaryResumeState());
+          if (RegisterContextSP regctx = thread.GetRegisterContext()) {
+            if (const RegisterInfo *ri = regctx->GetRegisterInfoByName("esr")) 
{
+              uint32_t esr =
+                  (uint32_t)regctx->ReadRegisterAsUnsigned(ri, UINT32_MAX);
+              if (esr != UINT32_MAX) {
+                s.Printf(" esr value: 0x%" PRIx32, esr);
+              }
+            }
+          }
+          llvm::report_fatal_error(s.GetData());
+          lldbassert(
+              false &&
+              "CreateStopReasonWithMachException got EXC_BREAKPOINT [1,0] "
+              "indicating trace event, but thread was not doing a step.");
+        }
+#endif
       }
       if (exc_code == 0x102) // EXC_ARM_DA_DEBUG
       {



Index: lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
===================================================================
--- lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
+++ lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
@@ -708,12 +708,49 @@
 
     case llvm::Triple::aarch64_32:
     case llvm::Triple::aarch64: {
+      // xnu describes three things with type EXC_BREAKPOINT:
+      //
+      //   exc_code 0x102 [EXC_ARM_DA_DEBUG], exc_sub_code addr-of-insn
+      //      Watchpoint access.  exc_sub_code is the address of the
+      //      instruction which trigged the watchpoint trap.
+      //      debugserver may add the watchpoint number that was triggered
+      //      in exc_sub_sub_code.
+      //
+      //   exc_code 1 [EXC_ARM_BREAKPOINT], exc_sub_code 0
+      //      Instruction step has completed.
+      //
+      //   exc_code 1 [EXC_ARM_BREAKPOINT], exc_sub_code address-of-instruction
+      //      Software breakpoint instruction executed.
+
       if (exc_code == 1 && exc_sub_code == 0) // EXC_ARM_BREAKPOINT
       {
         // This is hit when we single instruction step aka MDSCR_EL1 SS bit 0
         // is set
-        is_actual_breakpoint = false;
+        is_actual_breakpoint = true;
         is_trace_if_actual_breakpoint_missing = true;
+#ifndef NDEBUG
+        if (thread.GetTemporaryResumeState() != eStateStepping) {
+          StreamString s;
+          s.Printf("CreateStopReasonWithMachException got EXC_BREAKPOINT [1,0] "
+                   "indicating trace event, but thread is not tracing, it has "
+                   "ResumeState %d",
+                   thread.GetTemporaryResumeState());
+          if (RegisterContextSP regctx = thread.GetRegisterContext()) {
+            if (const RegisterInfo *ri = regctx->GetRegisterInfoByName("esr")) {
+              uint32_t esr =
+                  (uint32_t)regctx->ReadRegisterAsUnsigned(ri, UINT32_MAX);
+              if (esr != UINT32_MAX) {
+                s.Printf(" esr value: 0x%" PRIx32, esr);
+              }
+            }
+          }
+          llvm::report_fatal_error(s.GetData());
+          lldbassert(
+              false &&
+              "CreateStopReasonWithMachException got EXC_BREAKPOINT [1,0] "
+              "indicating trace event, but thread was not doing a step.");
+        }
+#endif
       }
       if (exc_code == 0x102) // EXC_ARM_DA_DEBUG
       {

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