How Function Return Values Get Back: From rax to Return Value Optimization

A return statement looks like one line of source; underneath it there are three routes: rax, a hidden pointer, and RVO. This topic measures when each route triggers and what it looks like in assembly, so after reading you can judge which route a large object will take.

STARTFINISHFunction Return Values: the rax Family and Register Pairs→STARTFINISHLarge Objects Return Through a Hidden Pointer: The sret Route and the Routing Criteria→STARTFINISHNRVO: The Copy on the Return Path Never Existed→STARTFINISHReturning Multiple Values: pair Packing and the Full Picture of the Three Routes→