From 1fc08f5e9ef733ef1ce6f363fecedc2260e78974 Mon Sep 17 00:00:00 2001
From: dim <dim@FreeBSD.org>
Date: Sat, 14 Apr 2012 13:54:10 +0000
Subject: Vendor import of llvm trunk r154661:
http://llvm.org/svn/llvm-project/llvm/trunk@r154661
---
lib/Analysis/CodeMetrics.cpp | 184 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 184 insertions(+)
create mode 100644 lib/Analysis/CodeMetrics.cpp
(limited to 'lib/Analysis/CodeMetrics.cpp')
diff --git a/lib/Analysis/CodeMetrics.cpp b/lib/Analysis/CodeMetrics.cpp
new file mode 100644
index 0000000..316e7bc9
--- /dev/null
+++ b/lib/Analysis/CodeMetrics.cpp
@@ -0,0 +1,184 @@
+//===- CodeMetrics.cpp - Code cost measurements ---------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements code cost measurement utilities.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/CodeMetrics.h"
+#include "llvm/Function.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/Target/TargetData.h"
+
+using namespace llvm;
+
+/// callIsSmall - If a call is likely to lower to a single target instruction,
+/// or is otherwise deemed small return true.
+/// TODO: Perhaps calls like memcpy, strcpy, etc?
+bool llvm::callIsSmall(const Function *F) {
+ if (!F) return false;
+
+ if (F->hasLocalLinkage()) return false;
+
+ if (!F->hasName()) return false;
+
+ StringRef Name = F->getName();
+
+ // These will all likely lower to a single selection DAG node.
+ if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" ||
+ Name == "fabs" || Name == "fabsf" || Name == "fabsl" ||
+ Name == "sin" || Name == "sinf" || Name == "sinl" ||
+ Name == "cos" || Name == "cosf" || Name == "cosl" ||
+ Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl" )
+ return true;
+
+ // These are all likely to be optimized into something smaller.
+ if (Name == "pow" || Name == "powf" || Name == "powl" ||
+ Name == "exp2" || Name == "exp2l" || Name == "exp2f" ||
+ Name == "floor" || Name == "floorf" || Name == "ceil" ||
+ Name == "round" || Name == "ffs" || Name == "ffsl" ||
+ Name == "abs" || Name == "labs" || Name == "llabs")
+ return true;
+
+ return false;
+}
+
+bool llvm::isInstructionFree(const Instruction *I, const TargetData *TD) {
+ if (isa<PHINode>(I))
+ return true;
+
+ // If a GEP has all constant indices, it will probably be folded with
+ // a load/store.
+ if (const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I))
+ return GEP->hasAllConstantIndices();
+
+ if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
+ switch (II->getIntrinsicID()) {
+ default:
+ return false;
+ case Intrinsic::dbg_declare:
+ case Intrinsic::dbg_value:
+ case Intrinsic::invariant_start:
+ case Intrinsic::invariant_end:
+ case Intrinsic::lifetime_start:
+ case Intrinsic::lifetime_end:
+ case Intrinsic::objectsize:
+ case Intrinsic::ptr_annotation:
+ case Intrinsic::var_annotation:
+ // These intrinsics don't count as size.
+ return true;
+ }
+ }
+
+ if (const CastInst *CI = dyn_cast<CastInst>(I)) {
+ // Noop casts, including ptr <-> int, don't count.
+ if (CI->isLosslessCast() || isa<IntToPtrInst>(CI) || isa<PtrToIntInst>(CI))
+ return true;
+ // trunc to a native type is free (assuming the target has compare and
+ // shift-right of the same width).
+ if (TD && isa<TruncInst>(CI) &&
+ TD->isLegalInteger(TD->getTypeSizeInBits(CI->getType())))
+ return true;
+ // Result of a cmp instruction is often extended (to be used by other
+ // cmp instructions, logical or return instructions). These are usually
+ // nop on most sane targets.
+ if (isa<CmpInst>(CI->getOperand(0)))
+ return true;
+ }
+
+ return false;
+}
+
+/// analyzeBasicBlock - Fill in the current structure with information gleaned
+/// from the specified block.
+void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB,
+ const TargetData *TD) {
+ ++NumBlocks;
+ unsigned NumInstsBeforeThisBB = NumInsts;
+ for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
+ II != E; ++II) {
+ if (isInstructionFree(II, TD))
+ continue;
+
+ // Special handling for calls.
+ if (isa<CallInst>(II) || isa<InvokeInst>(II)) {
+ ImmutableCallSite CS(cast<Instruction>(II));
+
+ if (const Function *F = CS.getCalledFunction()) {
+ // If a function is both internal and has a single use, then it is
+ // extremely likely to get inlined in the future (it was probably
+ // exposed by an interleaved devirtualization pass).
+ if (!CS.isNoInline() && F->hasInternalLinkage() && F->hasOneUse())
+ ++NumInlineCandidates;
+
+ // If this call is to function itself, then the function is recursive.
+ // Inlining it into other functions is a bad idea, because this is
+ // basically just a form of loop peeling, and our metrics aren't useful
+ // for that case.
+ if (F == BB->getParent())
+ isRecursive = true;
+ }
+
+ if (!isa<IntrinsicInst>(II) && !callIsSmall(CS.getCalledFunction())) {
+ // Each argument to a call takes on average one instruction to set up.
+ NumInsts += CS.arg_size();
+
+ // We don't want inline asm to count as a call - that would prevent loop
+ // unrolling. The argument setup cost is still real, though.
+ if (!isa<InlineAsm>(CS.getCalledValue()))
+ ++NumCalls;
+ }
+ }
+
+ if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
+ if (!AI->isStaticAlloca())
+ this->usesDynamicAlloca = true;
+ }
+
+ if (isa<ExtractElementInst>(II) || II->getType()->isVectorTy())
+ ++NumVectorInsts;
+
+ ++NumInsts;
+ }
+
+ if (isa<ReturnInst>(BB->getTerminator()))
+ ++NumRets;
+
+ // We never want to inline functions that contain an indirectbr. This is
+ // incorrect because all the blockaddress's (in static global initializers
+ // for example) would be referring to the original function, and this indirect
+ // jump would jump from the inlined copy of the function into the original
+ // function which is extremely undefined behavior.
+ // FIXME: This logic isn't really right; we can safely inline functions
+ // with indirectbr's as long as no other function or global references the
+ // blockaddress of a block within the current function. And as a QOI issue,
+ // if someone is using a blockaddress without an indirectbr, and that
+ // reference somehow ends up in another function or global, we probably
+ // don't want to inline this function.
+ if (isa<IndirectBrInst>(BB->getTerminator()))
+ containsIndirectBr = true;
+
+ // Remember NumInsts for this BB.
+ NumBBInsts[BB] = NumInsts - NumInstsBeforeThisBB;
+}
+
+void CodeMetrics::analyzeFunction(Function *F, const TargetData *TD) {
+ // If this function contains a call that "returns twice" (e.g., setjmp or
+ // _setjmp) and it isn't marked with "returns twice" itself, never inline it.
+ // This is a hack because we depend on the user marking their local variables
+ // as volatile if they are live across a setjmp call, and they probably
+ // won't do this in callers.
+ exposesReturnsTwice = F->callsFunctionThatReturnsTwice() &&
+ !F->hasFnAttr(Attribute::ReturnsTwice);
+
+ // Look at the size of the callee.
+ for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
+ analyzeBasicBlock(&*BB, TD);
+}
--
cgit v1.1