fomit-frame-pointer, Oy

Architecture Restrictions

Option /Oy[-] is only available on IA-32 architecture

Syntax

Arguments

None

Default

Description

These options determine whether EBP is used as a general-purpose register in optimizations. Options -fomit-frame-pointer and /Oy allow this use. Options -fno-omit-frame-pointer and /Oy- disallow it.

Some debuggers expect EBP to be used as a stack frame pointer, and cannot produce a stack backtrace unless this is so. The -fno-omit-frame-pointer and /Oy- options direct the compiler to generate code that maintains and uses EBP as a stack frame pointer for all functions so that a debugger can still produce a stack backtrace without doing the following:

• For -fno-omit-frame-pointer: turning off optimizations with -O0

• For /Oy-: turning off /O1, /O2, or /O3 optimizations

The -fno-omit-frame-pointer option is set when you specify option -O0 or the -g option. The -fomit-frame-pointer option is set when you specify option -O1, -O2, or -O3.

The /Oy option is set when you specify the /O1, /O2, or /O3 option. Option /Oy- is set when you specify the /Od option.

Using the -fno-omit-frame-pointer or /Oy- option reduces the number of available general-purpose registers by 1, and can result in slightly less efficient code.

IDE Equivalent

Windows: Optimization > Omit Frame Pointers

Linux: Optimization > Provide Frame Pointer

OS X: Optimization > Provide Frame Pointer

Alternate Options

Linux and OS X: -fp (this is a deprecated option)

Windows: None