diff --git a/renderdoc/driver/shaders/spirv/spirv_common.h b/renderdoc/driver/shaders/spirv/spirv_common.h
index 24f5b5d14..101d59625 100644
--- a/renderdoc/driver/shaders/spirv/spirv_common.h
+++ b/renderdoc/driver/shaders/spirv/spirv_common.h
@@ -231,9 +231,28 @@ private:
   uint32_t value;
 };
 
+// need to do this in a separate struct because you can't specialise a member function in a
+// templated class. Blech
+struct OpExtInstHelper
+{
+  rdcarray<uint32_t> params;
+
+  template <typename T>
+  T arg(uint32_t idx)
+  {
+    return T(params[idx]);
+  }
+};
+
+template <>
+inline Id OpExtInstHelper::arg<Id>(uint32_t idx)
+{
+  return Id::fromWord(params[idx]);
+}
+
 // helper in the style of the auto-generated one for ext insts
 template <typename InstType>
-struct OpExtInstGeneric
+struct OpExtInstGeneric : public OpExtInstHelper
 {
   OpExtInstGeneric(IdResultType resultType, IdResult result, Id set, InstType inst,
                    const rdcarray<IdOrWord> &params)
@@ -279,7 +298,6 @@ struct OpExtInstGeneric
   IdResult result;
   Id set;
   InstType inst;
-  rdcarray<uint32_t> params;
 };
 
 struct OpExtInst : public OpExtInstGeneric<uint32_t>
diff --git a/renderdoc/driver/shaders/spirv/spirv_debug_setup.cpp b/renderdoc/driver/shaders/spirv/spirv_debug_setup.cpp
index 902caee9f..8d919bf2c 100644
--- a/renderdoc/driver/shaders/spirv/spirv_debug_setup.cpp
+++ b/renderdoc/driver/shaders/spirv/spirv_debug_setup.cpp
@@ -2413,7 +2413,7 @@ void Debugger::RegisterOp(Iter it)
   {
     OpExtInst extinst(it);
 
-    if(extSets[extinst.set] == "GLSL.std.450")
+    if(knownExtSet[ExtSet_GLSL450] == extinst.set)
     {
       // all parameters to GLSL.std.450 are Ids, extend idDeathOffset appropriately
       for(const uint32_t param : extinst.params)
@@ -2422,7 +2422,7 @@ void Debugger::RegisterOp(Iter it)
         idDeathOffset[id] = RDCMAX(it.offs() + 1, idDeathOffset[id]);
       }
     }
-    else if(extSets[extinst.set] == "NonSemantic.DebugPrintf")
+    else if(knownExtSet[ExtSet_Printf] == extinst.set)
     {
       // all parameters to NonSemantic.DebugPrintf are Ids, extend idDeathOffset appropriately
       for(const uint32_t param : extinst.params)
diff --git a/renderdoc/driver/shaders/spirv/spirv_disassemble.cpp b/renderdoc/driver/shaders/spirv/spirv_disassemble.cpp
index 22111a461..7e6f5c0ba 100644
--- a/renderdoc/driver/shaders/spirv/spirv_disassemble.cpp
+++ b/renderdoc/driver/shaders/spirv/spirv_disassemble.cpp
@@ -1534,44 +1534,74 @@ rdcstr Reflector::Disassemble(const rdcstr &entryPoint,
           break;
         }
 
-        // need to handle this by hand anyway
         case Op::ExtInst:
         {
-          OpDecoder decoded(it);
-          ret += indent;
-          ret += StringFormat::Fmt("%s = ", declName(decoded.resultType, decoded.result).c_str());
+          OpExtInst decoded(it);
 
-          rdcstr setname = extSets.find(Id::fromWord(it.word(3)))->second;
+          rdcstr setname = extSets.find(decoded.set)->second;
           uint32_t inst = it.word(4);
 
-          const bool IsGLSL450 = (setname == "GLSL.std.450");
-          const bool IsDebugPrintf = (setname == "NonSemantic.DebugPrintf");
+          const bool IsGLSL450 = knownExtSet[ExtSet_GLSL450] == decoded.set;
+          const bool IsDebugPrintf = knownExtSet[ExtSet_Printf] == decoded.set;
+          const bool IsShaderDbg = knownExtSet[ExtSet_ShaderDbg] == decoded.set;
           // GLSL.std.450 all parameters are Ids
           const bool idParams = IsGLSL450 || setname.beginsWith("NonSemantic.");
 
-          if(IsGLSL450)
-            ret += StringFormat::Fmt("%s::%s(", setname.c_str(), ToStr(GLSLstd450(inst)).c_str());
-          else if(IsDebugPrintf)
-            ret += "DebugPrintf(";
-          else
-            ret += StringFormat::Fmt("%s::[%u](", setname.c_str(), inst);
-
-          for(size_t i = 5; i < it.size(); i++)
+          // most vulkan debug info instructions don't get printed explicitly, and those that do
+          // have no return value that we print
+          if(IsShaderDbg)
           {
-            if(i == 5 && IsDebugPrintf)
-              ret += "\"";
+            OpShaderDbg dbg(it);
 
-            // TODO could generate this from the instruction set grammar.
-            ret += idParams ? idName(Id::fromWord(it.word(i))) : ToStr(it.word(i));
-
-            if(i == 5 && IsDebugPrintf)
-              ret += "\"";
-
-            if(i + 1 < it.size())
+            if(dbg.inst == ShaderDbg::Source)
+            {
+              dynamicNames[dbg.result] = idName(dbg.arg<Id>(0));
+              continue;
+            }
+            else if(dbg.inst == ShaderDbg::CompilationUnit)
+            {
+              uint32_t lang = EvaluateConstant(dbg.arg<Id>(3), {}).value.u32v[0];
+              ret += indent;
+              ret += "DebugCompilationUnit(";
+              ret += idName(dbg.arg<Id>(2));
               ret += ", ";
+              ret += ToStr(rdcspv::SourceLanguage(lang));
+              ret += ")";
+            }
+            else
+            {
+              continue;
+            }
           }
+          else
+          {
+            ret += indent;
+            ret += StringFormat::Fmt("%s = ", declName(decoded.resultType, decoded.result).c_str());
 
-          ret += ")";
+            if(IsGLSL450)
+              ret += StringFormat::Fmt("%s::%s(", setname.c_str(), ToStr(GLSLstd450(inst)).c_str());
+            else if(IsDebugPrintf)
+              ret += "DebugPrintf(";
+            else
+              ret += StringFormat::Fmt("%s::[%u](", setname.c_str(), inst);
+
+            for(uint32_t i = 0; i < decoded.params.size(); i++)
+            {
+              if(i == 5 && IsDebugPrintf)
+                ret += "\"";
+
+              // TODO could generate this from the instruction set grammar.
+              ret += idParams ? idName(decoded.arg<Id>(i)) : ToStr(decoded.arg<uint32_t>(i));
+
+              if(i == 5 && IsDebugPrintf)
+                ret += "\"";
+
+              if(i + 1 < decoded.params.size())
+                ret += ", ";
+            }
+
+            ret += ")";
+          }
           break;
         }
 
diff --git a/renderdoc/driver/shaders/spirv/spirv_processor.cpp b/renderdoc/driver/shaders/spirv/spirv_processor.cpp
index c3e394aa9..d38d596c3 100644
--- a/renderdoc/driver/shaders/spirv/spirv_processor.cpp
+++ b/renderdoc/driver/shaders/spirv/spirv_processor.cpp
@@ -526,6 +526,13 @@ void Processor::RegisterOp(Iter it)
   {
     OpExtInstImport decoded(it);
     extSets[decoded.result] = decoded.name;
+
+    if(decoded.name == "GLSL.std.450")
+      knownExtSet[ExtSet_GLSL450] = decoded.result;
+    else if(decoded.name == "NonSemantic.DebugPrintf")
+      knownExtSet[ExtSet_Printf] = decoded.result;
+    else if(decoded.name == "NonSemantic.Shader.DebugInfo.100")
+      knownExtSet[ExtSet_ShaderDbg] = decoded.result;
   }
   else if(opdata.op == Op::EntryPoint)
   {
diff --git a/renderdoc/driver/shaders/spirv/spirv_processor.h b/renderdoc/driver/shaders/spirv/spirv_processor.h
index 690ea7ebe..901351ced 100644
--- a/renderdoc/driver/shaders/spirv/spirv_processor.h
+++ b/renderdoc/driver/shaders/spirv/spirv_processor.h
@@ -567,7 +567,16 @@ protected:
   SparseIdMap<SampledImage> sampledImageTypes;
   SparseIdMap<FunctionType> functionTypes;
 
+  enum ExtSet
+  {
+    ExtSet_GLSL450 = 0,
+    ExtSet_Printf = 1,
+    ExtSet_ShaderDbg = 2,
+    ExtSet_Count,
+  };
+
   std::map<Id, rdcstr> extSets;
+  Id knownExtSet[ExtSet_Count];
 
   struct LogicalSection
   {