From 5185822dcfcff08d63695633b281e1bbe7325958 Mon Sep 17 00:00:00 2001
From: peace-maker <peace-maker@wcfan.de>
Date: Sun, 5 Jan 2025 22:51:00 +0100
Subject: [PATCH] Support pre-RTTI debug symbol information

Allow to use the API on old .smx binaries too.
---
 vm/smx-v1-image.cpp | 68 +++++++++++++++++++++++++++++++++++++++++++--
 vm/smx-v1-image.h   |  4 +++
 2 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/vm/smx-v1-image.cpp b/vm/smx-v1-image.cpp
index bdabc60e..5a5ae0f5 100644
--- a/vm/smx-v1-image.cpp
+++ b/vm/smx-v1-image.cpp
@@ -1060,12 +1060,71 @@ SmxV1Image::GetFileName(size_t index) const
   return debug_names_ + debug_files_[index].name;
 }
 
+template <typename SymbolType, typename DimType>
+uint32_t
+SmxV1Image::getFunctionCount(const SymbolType* syms) const {
+  const uint8_t* cursor = reinterpret_cast<const uint8_t*>(syms);
+  const uint8_t* cursor_end = cursor + debug_symbols_section_->size;
+  uint32_t func_count = 0;
+  for (uint32_t i = 0; i < debug_info_->num_syms; i++) {
+    if (cursor + sizeof(SymbolType) > cursor_end)
+      break;
+
+    const SymbolType* sym = reinterpret_cast<const SymbolType*>(cursor);
+    if (sym->ident == sp::IDENT_FUNCTION)
+        func_count++;
+
+    if (sym->dimcount > 0)
+      cursor += sizeof(DimType) * sym->dimcount;
+    cursor += sizeof(SymbolType);
+  }
+  return func_count;
+}
+
 size_t
 SmxV1Image::NumFunctions() const {
 	if (rtti_methods_) {
 		return rtti_methods_->row_count;
 	}
-  return 0;
+
+  // Count function symbols once.
+  static uint32_t num_debug_functions = 0;
+  if (num_debug_functions == 0) {
+    if (debug_syms_)
+      num_debug_functions = getFunctionCount<sp_fdbg_symbol_t, sp_fdbg_arraydim_t>(debug_syms_);
+    else
+      num_debug_functions = getFunctionCount<sp_u_fdbg_symbol_t, sp_u_fdbg_arraydim_t>(debug_syms_unpacked_);
+  }
+  return num_debug_functions;
+}
+
+template <typename SymbolType, typename DimType>
+const char*
+SmxV1Image::getFunctionName(const SymbolType* syms, const char** filename, uint32_t index) const {
+  const uint8_t* cursor = reinterpret_cast<const uint8_t*>(syms);
+  const uint8_t* cursor_end = cursor + debug_symbols_section_->size;
+  uint32_t func_count = 0;
+  for (uint32_t i = 0; i < debug_info_->num_syms; i++) {
+    if (cursor + sizeof(SymbolType) > cursor_end)
+      break;
+
+    const SymbolType* sym = reinterpret_cast<const SymbolType*>(cursor);
+    if (sym->ident == sp::IDENT_FUNCTION) {
+      if (func_count == index) {
+        if (filename)
+          *filename = LookupFile(sym->addr);
+        if (sym->name < debug_names_section_->size)
+          return debug_names_ + sym->name;
+        return nullptr;
+      }
+      func_count++;
+    }
+
+    if (sym->dimcount > 0)
+      cursor += sizeof(DimType) * sym->dimcount;
+    cursor += sizeof(SymbolType);
+  }
+  return nullptr;
 }
 
 const char*
@@ -1079,7 +1138,12 @@ SmxV1Image::GetFunctionName(size_t index, const char** filename) const {
       *filename = LookupFile(method->pcode_start);
     return names_ + method->name;
   }
-  return nullptr;
+
+  if (debug_syms_) {
+    return getFunctionName<sp_fdbg_symbol_t, sp_fdbg_arraydim_t>(debug_syms_, filename, index);
+  } else {
+    return getFunctionName<sp_u_fdbg_symbol_t, sp_u_fdbg_arraydim_t>(debug_syms_unpacked_, filename, index);
+  }
 }
 
 template <typename SymbolType, typename DimType>
diff --git a/vm/smx-v1-image.h b/vm/smx-v1-image.h
index 454b33c7..6764196d 100644
--- a/vm/smx-v1-image.h
+++ b/vm/smx-v1-image.h
@@ -221,6 +221,10 @@ class SmxV1Image
   template <typename SymbolType, typename DimType>
   const char* lookupFunction(const SymbolType* syms, uint32_t addr) const;
   template <typename SymbolType, typename DimType>
+  uint32_t getFunctionCount(const SymbolType* syms) const;
+  template <typename SymbolType, typename DimType>
+  const char* getFunctionName(const SymbolType* syms, const char** filename, uint32_t index) const;
+  template <typename SymbolType, typename DimType>
   bool getFunctionAddress(const SymbolType* syms, const char* function, ucell_t* funcaddr, uint32_t& index) const;
 
   const smx_rtti_table_header* findRttiSection(const char* name) const {