SPMI: Fix repPrintObjectDescription and repGetStringLiteral (#77372)

repPrintObjectDescription was not null-terminating when the map was
null. There is SPMI error trap on the JIT side so we can just make it
fail on missing data.

repGetStringLiteral should not succeed on missing data, it is used for
optimization purposes.

src/coreclr/tools/superpmi/superpmi-shared/methodcontext.cpp

@@ -4881,35 +4881,24 @@ void MethodContext::dmpGetStringLiteral(DLDD key, DD value)
 
 int MethodContext::repGetStringLiteral(CORINFO_MODULE_HANDLE module, unsigned metaTOK, char16_t* buffer, int bufferSize)
 {
-    if (GetStringLiteral == nullptr)
-    {
-        return -1;
-    }
-
     DLDD key;
     ZeroMemory(&key, sizeof(key)); // Zero key including any struct padding
     key.A = CastHandle(module);
     key.B = (DWORD)metaTOK;
     key.C = (DWORD)bufferSize;
 
-    int itemIndex = GetStringLiteral->GetIndex(key);
-    if (itemIndex < 0)
-    {
-        return -1;
-    }
-    else
+    AssertMapAndKeyExist(GetStringLiteral, key, ": key handle-%016llX token-%X bufferSize-%d", key.A, key.B, key.C);
+
+    DD value = GetStringLiteral->Get(key);
+    DEBUG_REP(dmpGetStringLiteral(key, value));
+    int srcBufferLength = (int)value.A;
+    if (buffer != nullptr && srcBufferLength > 0)
     {
-        DD value = GetStringLiteral->Get(key);
-        DEBUG_REP(dmpGetStringLiteral(key, value));
-        int srcBufferLength = (int)value.A;
-        if (buffer != nullptr && srcBufferLength > 0)
-        {
-            char16_t* srcBuffer = (char16_t*)GetStringLiteral->GetBuffer(value.B);
-            Assert(srcBuffer != nullptr);
-            memcpy(buffer, srcBuffer, min(srcBufferLength, bufferSize) * sizeof(char16_t));
-        }
-        return srcBufferLength;
+        char16_t* srcBuffer = (char16_t*)GetStringLiteral->GetBuffer(value.B);
+        Assert(srcBuffer != nullptr);
+        memcpy(buffer, srcBuffer, min(srcBufferLength, bufferSize) * sizeof(char16_t));
     }
+    return srcBufferLength;
 }
 
 void MethodContext::recPrintObjectDescription(void* handle, char* buffer, size_t bufferSize, size_t* pRequiredBufferSize, size_t bytesWritten)
@@ -4943,44 +4932,31 @@ void MethodContext::dmpPrintObjectDescription(DLDL key, Agnostic_PrintObjectDesc
 }
 size_t MethodContext::repPrintObjectDescription(void* handle, char* buffer, size_t bufferSize, size_t* pRequiredBufferSize)
 {
-    if (PrintObjectDescription == nullptr)
-    {
-        return 0;
-    }
-
     DLDL key;
     key.A = CastHandle(handle);
     key.B = (DWORDLONG)bufferSize;
 
-    int itemIndex = PrintObjectDescription->GetIndex(key);
-    if (itemIndex < 0)
+    AssertMapAndKeyExist(PrintObjectDescription, key, ": key handle-%016llX bufferSize-%016llX", key.A, key.B);
+
+    Agnostic_PrintObjectDescriptionResult value = PrintObjectDescription->Get(key);
+    DEBUG_REP(dmpPrintObjectDescription(key, value));
+    if (pRequiredBufferSize != nullptr)
     {
-        return 0;
+        *pRequiredBufferSize = (size_t)value.requiredBufferSize;
     }
-    else
-    {
-        Agnostic_PrintObjectDescriptionResult value = PrintObjectDescription->Get(key);
-        DEBUG_REP(dmpPrintObjectDescription(key, value));
-        if (pRequiredBufferSize != nullptr)
-        {
-            *pRequiredBufferSize = (size_t)value.requiredBufferSize;
-        }
 
-        size_t bytesWritten = 0;
-
-        BYTE* srcBuffer = (BYTE*)PrintObjectDescription->GetBuffer(value.buffer);
-        Assert(srcBuffer != nullptr);
+    size_t bytesWritten = 0;
 
-        if (bufferSize > 0)
-        {
-            bytesWritten = min(bufferSize - 1, (size_t)value.bytesWritten);
-            memcpy(buffer, srcBuffer, bytesWritten);
+    BYTE* srcBuffer = (BYTE*)PrintObjectDescription->GetBuffer(value.buffer);
+    if (bufferSize > 0)
+    {
+        bytesWritten = min(bufferSize - 1, (size_t)value.bytesWritten);
+        memcpy(buffer, srcBuffer, bytesWritten);
 
-            // Always null-terminate
-            buffer[bytesWritten] = 0;
-        }
-        return bytesWritten;
+        // Always null-terminate
+        buffer[bytesWritten] = 0;
     }
+    return bytesWritten;
 }
 
 void MethodContext::recGetHelperName(CorInfoHelpFunc funcNum, const char* result)