clang  6.0.0svn
Macros | Enumerations | Functions
CodeGenPGO.cpp File Reference
#include "CodeGenPGO.h"
#include "CodeGenFunction.h"
#include "CoverageMappingGen.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/StmtVisitor.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MD5.h"
Include dependency graph for CodeGenPGO.cpp:

Go to the source code of this file.

Macros

#define DEFINE_NESTABLE_TRAVERSAL(N)
 

Enumerations

enum  PGOHashVersion : unsigned { PGO_HASH_V1, PGO_HASH_V2, PGO_HASH_LATEST = PGO_HASH_V2 }
 The version of the PGO hash algorithm. More...
 

Functions

static llvm::cl::opt< boolEnableValueProfiling ("enable-value-profiling", llvm::cl::ZeroOrMore, llvm::cl::desc("Enable value profiling"), llvm::cl::Hidden, llvm::cl::init(false))
 
static uint64_t calculateWeightScale (uint64_t MaxWeight)
 Calculate what to divide by to scale weights. More...
 
static uint32_t scaleBranchWeight (uint64_t Weight, uint64_t Scale)
 Scale an individual branch weight (and add 1). More...
 

Macro Definition Documentation

◆ DEFINE_NESTABLE_TRAVERSAL

#define DEFINE_NESTABLE_TRAVERSAL (   N)
Value:
bool Traverse##N(N *S) { \
Base::Traverse##N(S); \
if (Hash.getHashVersion() != PGO_HASH_V1) \
Hash.combine(PGOHash::EndOfScope); \
return true; \
}

Definition at line 231 of file CodeGenPGO.cpp.

Enumeration Type Documentation

◆ PGOHashVersion

enum PGOHashVersion : unsigned

The version of the PGO hash algorithm.

Enumerator
PGO_HASH_V1 
PGO_HASH_V2 
PGO_HASH_LATEST 

Definition at line 52 of file CodeGenPGO.cpp.

Function Documentation

◆ calculateWeightScale()

static uint64_t calculateWeightScale ( uint64_t  MaxWeight)
static

Calculate what to divide by to scale weights.

Given the maximum weight, calculate a divisor that will scale all the weights to strictly less than UINT32_MAX.

Definition at line 985 of file CodeGenPGO.cpp.

Referenced by scaleBranchWeight().

◆ EnableValueProfiling()

static llvm::cl::opt<bool> EnableValueProfiling ( "enable-value-profiling"  ,
llvm::cl::ZeroOrMore  ,
llvm::cl::desc("Enable value profiling")  ,
llvm::cl::Hidden  ,
llvm::cl::init(false  
)
static

◆ scaleBranchWeight()

static uint32_t scaleBranchWeight ( uint64_t  Weight,
uint64_t  Scale 
)
static

Scale an individual branch weight (and add 1).

Scale a 64-bit weight down to 32-bits using Scale.

According to Laplace's Rule of Succession, it is better to compute the weight based on the count plus 1, so universally add 1 to the value.

Precondition
Scale was calculated by calculateWeightScale() with a weight no greater than Weight.

Definition at line 998 of file CodeGenPGO.cpp.

References calculateWeightScale(), and max().