[sancov] Leave llvm.localescape in the entry block
Summary: Similar to the change we applied to ASan. The same test case works.
Reviewers: samsonov
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11961
llvm-svn: 245067
diff --git a/llvm/lib/Transforms/Instrumentation/Instrumentation.cpp b/llvm/lib/Transforms/Instrumentation/Instrumentation.cpp
index 2750585..68aee22 100644
--- a/llvm/lib/Transforms/Instrumentation/Instrumentation.cpp
+++ b/llvm/lib/Transforms/Instrumentation/Instrumentation.cpp
@@ -12,12 +12,47 @@
//
//===----------------------------------------------------------------------===//
-#include "llvm/InitializePasses.h"
+#include "llvm/Transforms/Instrumentation.h"
#include "llvm-c/Initialization.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/InitializePasses.h"
#include "llvm/PassRegistry.h"
using namespace llvm;
+/// Moves I before IP. Returns new insert point.
+static BasicBlock::iterator moveBeforeInsertPoint(BasicBlock::iterator I, BasicBlock::iterator IP) {
+ // If I is IP, move the insert point down.
+ if (I == IP)
+ return ++IP;
+ // Otherwise, move I before IP and return IP.
+ I->moveBefore(IP);
+ return IP;
+}
+
+/// Instrumentation passes often insert conditional checks into entry blocks.
+/// Call this function before splitting the entry block to move instructions
+/// that must remain in the entry block up before the split point. Static
+/// allocas and llvm.localescape calls, for example, must remain in the entry
+/// block.
+BasicBlock::iterator llvm::PrepareToSplitEntryBlock(BasicBlock &BB,
+ BasicBlock::iterator IP) {
+ assert(&BB.getParent()->getEntryBlock() == &BB);
+ for (auto I = IP, E = BB.end(); I != E; ++I) {
+ bool KeepInEntry = false;
+ if (auto *AI = dyn_cast<AllocaInst>(I)) {
+ if (AI->isStaticAlloca())
+ KeepInEntry = true;
+ } else if (auto *II = dyn_cast<IntrinsicInst>(I)) {
+ if (II->getIntrinsicID() == llvm::Intrinsic::localescape)
+ KeepInEntry = true;
+ }
+ if (KeepInEntry)
+ IP = moveBeforeInsertPoint(I, IP);
+ }
+ return IP;
+}
+
/// initializeInstrumentation - Initialize all passes in the TransformUtils
/// library.
void llvm::initializeInstrumentation(PassRegistry &Registry) {
diff --git a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index b6829ae..8a6ab4b 100644
--- a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -438,20 +438,16 @@
if (isa<UnreachableInst>(BB.getTerminator()))
return;
BasicBlock::iterator IP = BB.getFirstInsertionPt(), BE = BB.end();
- // Skip static allocas at the top of the entry block so they don't become
- // dynamic when we split the block. If we used our optimized stack layout,
- // then there will only be one alloca and it will come first.
- for (; IP != BE; ++IP) {
- AllocaInst *AI = dyn_cast<AllocaInst>(IP);
- if (!AI || !AI->isStaticAlloca())
- break;
- }
bool IsEntryBB = &BB == &F.getEntryBlock();
DebugLoc EntryLoc;
if (IsEntryBB) {
if (auto SP = getDISubprogram(&F))
EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP);
+ // Keep static allocas and llvm.localescape calls in the entry block. Even
+ // if we aren't splitting the block, it's nice for allocas to be before
+ // calls.
+ IP = PrepareToSplitEntryBlock(BB, IP);
} else {
EntryLoc = IP->getDebugLoc();
}