Warnings for uninitialized values (#4530)

This extends the code for handling uninitialized output parameters.
Still needs to handle generic templates and assignment of uninitialized
values more carefully.

The file containing the relevant code are now in

    source/slang/slang-ir-use-uninitialized-values.cpp

rather than the previous

    source/slang/slang-ir-use-uninitialized-out-param.h

and the top-level function is now checkForUsingUinitializedValues.

Additionally a rudimentary test shader has been added for this case, which replaces the old file for out params only; tests/diagnositcs/uninitialized-out.slang becomes tests/diagnositcs/uninitialized.slang.

What this does not implement (could be future PRs):
* Checking uninitialized fields within constructors
* Partially uninitialized values with respect to data structure (e.g. arrays/structs/vector types)
* Partially uninitialized values with respect to control flow (e.g. if/else/loop)

build/visual-studio/slang/slang.vcxproj

@@ -492,7 +492,7 @@ IF EXIST ..\..\..\external\slang-glslang\bin\windows-aarch64\release\slang-glsla
     <ClInclude Include="..\..\..\source\slang\slang-ir-synthesize-active-mask.h" />
     <ClInclude Include="..\..\..\source\slang\slang-ir-translate-glsl-global-var.h" />
     <ClInclude Include="..\..\..\source\slang\slang-ir-uniformity.h" />
-    <ClInclude Include="..\..\..\source\slang\slang-ir-use-uninitialized-out-param.h" />
+    <ClInclude Include="..\..\..\source\slang\slang-ir-use-uninitialized-values.h" />
     <ClInclude Include="..\..\..\source\slang\slang-ir-user-type-hint.h" />
     <ClInclude Include="..\..\..\source\slang\slang-ir-util.h" />
     <ClInclude Include="..\..\..\source\slang\slang-ir-validate.h" />
@@ -737,7 +737,7 @@ IF EXIST ..\..\..\external\slang-glslang\bin\windows-aarch64\release\slang-glsla
     <ClCompile Include="..\..\..\source\slang\slang-ir-synthesize-active-mask.cpp" />
     <ClCompile Include="..\..\..\source\slang\slang-ir-translate-glsl-global-var.cpp" />
     <ClCompile Include="..\..\..\source\slang\slang-ir-uniformity.cpp" />
-    <ClCompile Include="..\..\..\source\slang\slang-ir-use-uninitialized-out-param.cpp" />
+    <ClCompile Include="..\..\..\source\slang\slang-ir-use-uninitialized-values.cpp" />
     <ClCompile Include="..\..\..\source\slang\slang-ir-user-type-hint.cpp" />
     <ClCompile Include="..\..\..\source\slang\slang-ir-util.cpp" />
     <ClCompile Include="..\..\..\source\slang\slang-ir-validate.cpp" />

build/visual-studio/slang/slang.vcxproj.filters

@@ -564,7 +564,7 @@
     <ClInclude Include="..\..\..\source\slang\slang-ir-uniformity.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="..\..\..\source\slang\slang-ir-use-uninitialized-out-param.h">
+    <ClInclude Include="..\..\..\source\slang\slang-ir-use-uninitialized-values.h">
       <Filter>Header Files</Filter>
     </ClInclude>
     <ClInclude Include="..\..\..\source\slang\slang-ir-user-type-hint.h">
@@ -1295,7 +1295,7 @@
     <ClCompile Include="..\..\..\source\slang\slang-ir-uniformity.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="..\..\..\source\slang\slang-ir-use-uninitialized-out-param.cpp">
+    <ClCompile Include="..\..\..\source\slang\slang-ir-use-uninitialized-values.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="..\..\..\source\slang\slang-ir-user-type-hint.cpp">

source/slang/slang-diagnostic-defs.h

@@ -598,7 +598,7 @@ DIAGNOSTIC(39999, Error, unableToFindSymbolInModule, "unable to find the mangled
 
 DIAGNOSTIC(39999, Error, overloadedParameterToHigherOrderFunction, "passing overloaded functions to higher order functions is not supported")
 
-// 38xxx 
+// 38xxx
 
 DIAGNOSTIC(38000, Error, entryPointFunctionNotFound, "no function found matching entry point name '$0'")
 DIAGNOSTIC(38001, Error, ambiguousEntryPoint, "more than one function matches entry point name '$0'")
@@ -735,9 +735,11 @@ DIAGNOSTIC(41010, Warning, missingReturn, "control flow may reach end of non-'vo
 DIAGNOSTIC(41011, Error, profileIncompatibleWithTargetSwitch, "__target_switch has no compatable target with current profile '$0'")
 DIAGNOSTIC(41012, Warning, profileImplicitlyUpgraded, "user set `profile` had an implicit upgrade applied to it, atoms added: '$0'")
 DIAGNOSTIC(41012, Error, profileImplicitlyUpgradedRestrictive, "user set `profile` had an implicit upgrade applied to it, atoms added: '$0'")
-DIAGNOSTIC(41015, Error, usingUninitializedValue, "use of uninitialized value '$0'")
-DIAGNOSTIC(41016, Warning, returningWithUninitializedOut, "returning without initializing out parameter '$0'")
-DIAGNOSTIC(41017, Warning, returningWithPartiallyUninitializedOut, "returning without fully initializing out parameter '$0'")
+DIAGNOSTIC(41015, Warning, usingUninitializedOut, "use of uninitialized out parameter '$0'")
+DIAGNOSTIC(41016, Warning, usingUninitializedVariable, "use of uninitialized variable '$0'")
+DIAGNOSTIC(41017, Warning, usingUninitializedGlobalVariable, "use of uninitialized global variable '$0'")
+DIAGNOSTIC(41018, Warning, returningWithUninitializedOut, "returning without initializing out parameter '$0'")
+DIAGNOSTIC(41019, Warning, returningWithPartiallyUninitializedOut, "returning without fully initializing out parameter '$0'")
 
 DIAGNOSTIC(41011, Error, typeDoesNotFitAnyValueSize, "type '$0' does not fit in the size required by its conforming interface.")
 DIAGNOSTIC(41012, Note, typeAndLimit, "sizeof($0) is $1, limit is $2")