[llvm] [SPIRV] Emit NonSemantic DebugGlobalVariable (PR #207230)

[Manuel Carrasco via llvm-commits]

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@@ -256,6 +273,42 @@ class SPIRVNonSemanticDebugHandler : public DebugHandlerBase {
                                MCRegister I32TypeReg, MCRegister ExtInstSetReg,
                                SPIRV::ModuleAnalysisInfo &MAI);
 
+  /// Emit \c DebugGlobalVariable for the source global variable \p GV.
+  ///
+  /// (\c SPIRVDebug::Operand::GlobalVariable): Name, Type, Source, Line,
+  /// Column, Parent, Linkage Name, Variable, Flags, and an optional Static
+  /// Member Declaration. Line, Column, and Flags are emitted as \c OpConstant
+  /// ids as required for non-semantic debug info.
+  ///
+  /// \c DebugInfoNone is used for two operands when LLVM has no value to
+  /// supply:
+  /// \c Type when \p GV is a declaration with no DI type (e.g. \c extern void;
+  /// valid IR, \c isDefinition: false); \c Variable when no \c
+  /// llvm::GlobalVariable in this module carries \p GV in its \c !dbg metadata.
+  ///
+  /// \returns The result id register on success. Returns \c std::nullopt and
+  /// emits nothing if a non-null \p GV type was not emitted in \c
+  /// DebugTypeRegs,
+  /// \p GV has a static data member declaration that was not emitted in
+  /// \c DebugTypeRegs, or \c resolveGlobalVariableParent returns no id for the
+  /// \c Parent operand.
+  std::optional<MCRegister>
+  emitDebugGlobalVariable(const DIGlobalVariable *GV, MCRegister VoidTypeReg,
+                          MCRegister I32TypeReg, MCRegister ExtInstSetReg,
+                          SPIRV::ModuleAnalysisInfo &MAI);
+
+  /// Resolve the \c Parent operand for \c DebugGlobalVariable.
+  std::optional<MCRegister>
+  resolveGlobalVariableParent(const DIGlobalVariable *GV) const;
+
+  /// Emit \c DebugExpression for \p Expr. Unimplemented: defined as a no-op
+  /// (\returns \c std::nullopt, emits nothing) so \c emitDebugGlobalVariable
+  /// can complete Variable-operand resolution for the opcodes we support today.
+  std::optional<MCRegister> emitDebugExpression(const DIExpression *Expr,
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mgcarrasco wrote:

I was already implementing the handler for `DebugGlobalVariable` support, and wanted it to leave its logic ready for when DIExpression can be supported. Once DIExpressions are supported it won't require changing anything in the `DebugGlobalVariable` handler.

https://github.com/llvm/llvm-project/pull/207230