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/CommandLine.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MD5.h"
#include <optional>

Go to the source code of this file.

Namespaces
namespace	llvm
	Diagnostic wrappers for TextAPI types for error reporting.

Macros
#define	DEFINE_NESTABLE_TRAVERSAL(N)

Enumerations
enum	PGOHashVersion : unsigned { PGO_HASH_V1 , PGO_HASH_V2 , PGO_HASH_V3 , PGO_HASH_LATEST = PGO_HASH_V3 }
	The version of the PGO hash algorithm. More...

Functions
static llvm::cl::opt< bool >	EnableValueProfiling ("enable-value-profiling", 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.
static uint32_t	scaleBranchWeight (uint64_t Weight, uint64_t Scale)
	Scale an individual branch weight (and add 1).

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 475 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_V3
PGO_HASH_LATEST

Definition at line 57 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 1433 of file CodeGenPGO.cpp.

EnableValueProfiling()

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

static

Referenced by clang::CodeGen::CodeGenPGO::setValueProfilingFlag(), and clang::CodeGen::CodeGenPGO::valueProfile().

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 1446 of file CodeGenPGO.cpp.