Method setDebugLocation

compiler/compiler.go:697–739

setDebugLocation sets the current debug location for the builder.

(pos token.Pos)

// setDebugLocation sets the current debug location for the builder.
func (b *builder) setDebugLocation(pos token.Pos) {
	if pos == token.NoPos {
		// No debug information available for this instruction.
		b.SetCurrentDebugLocation(0, 0, b.difunc, llvm.Metadata{})
		return
	}

	position := b.program.Fset.Position(pos)
	if b.fn.Synthetic == "package initializer" {
		// Package initializers are treated specially, because while individual
		// Go SSA instructions have file/line/col information, the parent
		// function does not. LLVM doesn't store filename information per
		// instruction, only per function. We work around this difference by
		// creating a fake DIFunction for each Go file and say that the
		// instruction really came from that (fake) function but was inlined in
		// the package initializer function.
		position := b.program.Fset.Position(pos)
		name := filepath.Base(position.Filename)
		difunc, ok := b.initPseudoFuncs[name]
		if !ok {
			diFuncType := b.dibuilder.CreateSubroutineType(llvm.DISubroutineType{
				File: b.getDIFile(position.Filename),
			})
			difunc = b.dibuilder.CreateFunction(b.getDIFile(position.Filename), llvm.DIFunction{
				Name:         b.fn.RelString(nil) + "#" + name,
				File:         b.getDIFile(position.Filename),
				Line:         0,
				Type:         diFuncType,
				LocalToUnit:  true,
				IsDefinition: true,
				ScopeLine:    0,
				Flags:        llvm.FlagPrototyped,
				Optimized:    true,
			})
			b.initPseudoFuncs[name] = difunc
		}
		b.SetCurrentDebugLocation(uint(position.Line), uint(position.Column), difunc, b.initInlinedAt)
		return
	}

	// Regular debug information.
	b.SetCurrentDebugLocation(uint(position.Line), uint(position.Column), b.difunc, llvm.Metadata{})
}

// getLocalVariable returns a debug info entry for a local variable, which may
// either be a parameter or a regular variable. It will create a new metadata