func()

in tool/instrument/optimize.go [241:306]
45 lines of code
12 McCabe index (conditional complexity)

func (rp *RuleProcessor) optimizeTJumps() (err error) {
	for _, tjump := range rp.trampolineJumps {
		mustTJump(tjump.ifStmt)
		// Strip the trampoline-jump-if anchor label as no longer needed
		stripTJumpLabel(tjump)

		// No onExit hook present? Simply remove defer call to onExit trampoline.
		// Why we dont remove the whole else block of trampoline-jump-if? Well,
		// because there might be more than one trampoline-jump-if in the same
		// function, they are nested in the else block. See findJumpPoint for
		// more details.
		// TODO: Remove corresponding CallContextImpl methods
		rule := tjump.rule
		removedOnExit := false
		if rule.OnExit == "" {
			err = rp.removeOnExitTrampolineCall(tjump)
			if err != nil {
				return err
			}
			removedOnExit = true
		}

		// No onEnter hook present? Construct CallContext on the fly and pass it
		// to onExit trampoline defer call and rewrite the whole condition to
		// always false, then null out its initialization statement.
		if rule.OnEnter == "" {
			err = rp.removeOnEnterTrampolineCall(tjump)
			if err != nil {
				return err
			}
		}

		// No SkipCall used in onEnter hook? Rewrite cond of trampoline-jump-if
		// to always false, and remove return statement in then block, they are
		// memory aware and may generate memory SSA values during compilation.
		// This further simplifies the trampoline-jump-if and gives more chances
		// for optimization passes to kick in.
		if rule.OnEnter != "" {
			onEnterHook, err := getHookFunc(rule, true)
			if err != nil {
				return err
			}
			foundPoison := false
			const poison = "SkipCall"
			// FIXME: We should traverse the call graph to find all possible
			// usage of SkipCall, but for now, we just check the onEnter hook
			// function body.
			dst.Inspect(onEnterHook, func(node dst.Node) bool {
				if ident, ok := node.(*dst.Ident); ok {
					if strings.Contains(ident.Name, poison) {
						foundPoison = true
						return false
					}
				}
				if foundPoison {
					return false
				}
				return true
			})
			if !foundPoison {
				flattenTJump(tjump, removedOnExit)
			}
		}
	}
	return nil
}