[Lldb-commits] [lldb] [lldb][riscv] Fix setting breakpoint for undecoded instruction (PR #90075)

[Jason Molenda via lldb-commits]

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@@ -115,8 +148,23 @@ Status NativeProcessSoftwareSingleStep::SetupSoftwareSingleStepping(
   emulator_up->SetWriteMemCallback(&WriteMemoryCallback);
   emulator_up->SetWriteRegCallback(&WriteRegisterCallback);
 
-  if (!emulator_up->ReadInstruction())
-    return Status("Read instruction failed!");
+  if (!emulator_up->ReadInstruction()) {
+    // try to get at least the size of next instruction to set breakpoint.
+    auto instrSizeOpt = emulator_up->GetLastInstrSize();
+    if (!instrSizeOpt)
+      return Status("Read instruction failed!");
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jasonmolenda wrote:

We've defined the new GetLastInstrSize() method for the RISCV EmulateInstruction plugin, but others like AArch64 won't have that, so this will error out on them, won't it?  What we really want to express is "if `arch.GetTriple().isRISCV()` and we couldn't decode the length of the last instruction, then error out" isn't it? 

https://github.com/llvm/llvm-project/pull/90075