From 47d6416189fd87cddc5c5ce0e3907d3d7d76742e Mon Sep 17 00:00:00 2001
From: Luke Drummond <luke.drummond@codeplay.com>
Date: Wed, 4 Jan 2017 12:11:04 +0000
Subject: Add a debuginfo version check for RenderScript modules

Added an extra field parser to the `RSModuleDescriptor` class enabling us to
check whether the versions of LLVM used to generated the debug symbols match
across the RenderScript compiler frontend (llvm-rs-cc) and backend (bcc); if
they do not, we warn the user that the debugging experience may be suboptimal
as LLVM IR debug information has no compatibility guarantees.

llvm-svn: 290957
---
 .../RenderScriptRuntime/RenderScriptRuntime.cpp    | 47 +++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

(limited to 'lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.cpp')

diff --git a/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.cpp b/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.cpp
index 82473fba065..ae907ac8dfb 100644
--- a/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.cpp
@@ -2854,6 +2854,11 @@ bool RenderScriptRuntime::LoadModule(const lldb::ModuleSP &module_sp) {
       module_desc.reset(new RSModuleDescriptor(module_sp));
       if (module_desc->ParseRSInfo()) {
         m_rsmodules.push_back(module_desc);
+        module_desc->WarnIfVersionMismatch(GetProcess()
+                                               ->GetTarget()
+                                               .GetDebugger()
+                                               .GetAsyncOutputStream()
+                                               .get());
         module_loaded = true;
       }
       if (module_loaded) {
@@ -2923,6 +2928,25 @@ void RenderScriptRuntime::Update() {
   }
 }
 
+void RSModuleDescriptor::WarnIfVersionMismatch(lldb_private::Stream *s) const {
+  if (!s)
+    return;
+
+  if (m_slang_version.empty() || m_bcc_version.empty()) {
+    s->PutCString("WARNING: Unknown bcc or slang (llvm-rs-cc) version; debug "
+                  "experience may be unreliable");
+    s->EOL();
+  } else if (m_slang_version != m_bcc_version) {
+    s->Printf("WARNING: The debug info emitted by the slang frontend "
+              "(llvm-rs-cc) used to build this module (%s) does not match the "
+              "version of bcc used to generate the debug information (%s). "
+              "This is an unsupported configuration and may result in a poor "
+              "debugging experience; proceed with caution",
+              m_slang_version.c_str(), m_bcc_version.c_str());
+    s->EOL();
+  }
+}
+
 bool RSModuleDescriptor::ParsePragmaCount(llvm::StringRef *lines,
                                           size_t n_lines) {
   // Skip the pragma prototype line
@@ -2990,6 +3014,22 @@ bool RSModuleDescriptor::ParseExportReduceCount(llvm::StringRef *lines,
   return true;
 }
 
+bool RSModuleDescriptor::ParseVersionInfo(llvm::StringRef *lines,
+                                          size_t n_lines) {
+  // Skip the versionInfo line
+  ++lines;
+  for (; n_lines--; ++lines) {
+    // We're only interested in bcc and slang versions, and ignore all other
+    // versionInfo lines
+    const auto kv_pair = lines->split(" - ");
+    if (kv_pair.first == "slang")
+      m_slang_version = kv_pair.second.str();
+    else if (kv_pair.first == "bcc")
+      m_bcc_version = kv_pair.second.str();
+  }
+  return true;
+}
+
 bool RSModuleDescriptor::ParseExportForeachCount(llvm::StringRef *lines,
                                                  size_t n_lines) {
   // Skip the exportForeachCount line
@@ -3054,7 +3094,8 @@ bool RSModuleDescriptor::ParseRSInfo() {
     eExportReduce,
     ePragma,
     eBuildChecksum,
-    eObjectSlot
+    eObjectSlot,
+    eVersionInfo,
   };
 
   const auto rs_info_handler = [](llvm::StringRef name) -> int {
@@ -3070,6 +3111,7 @@ bool RSModuleDescriptor::ParseRSInfo() {
         // script
         .Case("pragmaCount", ePragma)
         .Case("objectSlotCount", eObjectSlot)
+        .Case("versionInfo", eVersionInfo)
         .Default(-1);
   };
 
@@ -3108,6 +3150,9 @@ bool RSModuleDescriptor::ParseRSInfo() {
     case ePragma:
       success = ParsePragmaCount(line, n_lines);
       break;
+    case eVersionInfo:
+      success = ParseVersionInfo(line, n_lines);
+      break;
     default: {
       if (log)
         log->Printf("%s - skipping .rs.info field '%s'", __FUNCTION__,
-- 
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