[bindings/go] Add methods to read debuginfo for globals

[aykevl]

Summary

This adds methods to read debug info for functions (subprograms) and global variables. It is related to D72206 (but for reading back debug info that was previously put into the IR) and requires D72207 to be actually useful.

[aykevl]

Not relevant anymore since D135436.

llvm/bindings/go/llvm/dibuilder.go

 
 // FileSource returns the source of a DIFile metadata node.
 func (md Metadata) FileSource() string {
   var length C.unsigned
   ptr := C.LLVMDIFileGetSource(md.C, &length)
   return string(((*[1 << 20]byte)(unsafe.Pointer(ptr)))[:length:length])
 }
 
+// GlobalVariableExpressionVariable returns the DIVariable associated with this
+// global variable expression.
+func (md Metadata) GlobalVariableExpressionVariable() Metadata {
+  return Metadata{C.LLVMDIGlobalVariableExpressionGetVariable(md.C)}
+}
+
 // LocationLine returns the line number of a DILocation.
 func (md Metadata) LocationLine() uint {
   return uint(C.LLVMDILocationGetLine(md.C))
 }
 
 // LocationColumn returns the column (offset from the start of the line) of a
 // DILocation.
 func (md Metadata) LocationColumn() uint {

 func (md Metadata) LocationInlinedAt() Metadata {
   return Metadata{C.LLVMDILocationGetInlinedAt(md.C)}
 }
 
 // ScopeFile returns the file (DIFile) of a given scope.
 func (md Metadata) ScopeFile() Metadata {
   return Metadata{C.LLVMDIScopeGetFile(md.C)}
 }
+
+// SubprogramLine returns the line number of a DISubprogram.
+func (md Metadata) SubprogramLine() uint {
+  return uint(C.LLVMDISubprogramGetLine(md.C))
+}
+
+// VariableFile returns the file (DIFile) of a given variable.
+func (md Metadata) VariableFile() Metadata {
+  return Metadata{C.LLVMDIVariableGetFile(md.C)}
+}
+
+// VariableLine returns the line number of a DIVariable.
+func (md Metadata) VariableLine() uint {
+  return uint(C.LLVMDIVariableGetLine(md.C))
+}
+
+// VariableScope returns the metadata of the scope associated with this
+// variable.
+func (md Metadata) VariableScope() Metadata {
+  return Metadata{C.LLVMDIVariableGetScope(md.C)}
+}