HP-UX Linker and Libraries User's Guide

Segment Flags.................................................................................................................196
Mapfile Segment Declaration Examples..............................................................................197
Defining Mapfile Section Mapping Directives...........................................................................197
Internal Map Structure...........................................................................................................198
Placement of Segments in an Executable.............................................................................198
Mapping Input Sections to Segments..................................................................................198
Interaction between User-defined and Default Mapfile Directives.............................................200
Mapfile Option Error Messages..............................................................................................200
Fatal Errors.....................................................................................................................200
Warnings ......................................................................................................................201
10 Improving Your Application Performance..................................................202
Linker Optimizations..............................................................................................................202
Invoking Linker Optimizations from the Compile Line.............................................................202
Incompatibilities with other Options ...................................................................................203
Unused Procedure Elimination with +Oprocelim...................................................................203
Complete Executables..................................................................................................203
Incomplete Executables................................................................................................204
Shared Libraries..........................................................................................................204
Retain Unreferenced Symbols with +noprocelim_sym........................................................204
Relocatable Objects....................................................................................................204
Affects on Symbolic Debugging....................................................................................204
Profile-Based Optimization (PA-RISC)..................................................................................204
General Information about PBO....................................................................................204
Using PBO ................................................................................................................205
When to Use PBO.......................................................................................................205
How to Use PBO.........................................................................................................205
Instrumenting (+I/-I).....................................................................................................206
The Startup File icrt0.o............................................................................................207
The -I Linker Option.................................................................................................207
Code Generation from I-SOMs.................................................................................207
Building Portable Code with Linker Optimization.........................................................208
Profiling.....................................................................................................................208
Choosing Input Data...............................................................................................208
The flow.data File...................................................................................................208
Storing Profile Information for Multiple Programs.........................................................209
Sharing the flow.data File Among Multiple Processes..................................................209
Forking an Instrumented Application.........................................................................210
Optimizing Based on Profile Data (+P/-P).......................................................................210
The -P Linker Option................................................................................................210
Using The flow.data File..........................................................................................211
Specifying a Different flow.data File with +df..............................................................211
Specifying a Different flow.data with FLOW_DATA......................................................211
Interaction between FLOW_DATA and +df ................................................................211
Specifying a Different Program Name (+pgm)............................................................211
Selecting an Optimization Level with PBO.......................................................................212
Using PBO to Optimize Shared Libraries........................................................................212
Using PBO with ld -r....................................................................................................213
Restrictions and Limitations of PBO................................................................................214
Temporary Files......................................................................................................214
Source Code Changes and PBO..............................................................................214
Profile-Based Optimization (PBO) and High-Level Optimization (HLO)............................214
I-SOM File Restrictions.............................................................................................215
Compatibility with 9.0 PBO.....................................................................................216
Compatibility with 9.0 PBO..........................................................................................216
Contents 11