[HotColdSplit] Disable splitting for sanitized functions

Splitting can make sanitizer errors harder to understand, as the
trapping instruction may not be in the function where the bug was
detected.

rdar://48142697

llvm-svn: 354931

llvm/lib/Transforms/IPO/HotColdSplitting.cpp

@@ -111,10 +111,11 @@ bool unlikelyExecuted(BasicBlock &BB) {
  if (BB.isEHPad() || isa<ResumeInst>(BB.getTerminator()))
  return true;
 
- // The block is cold if it calls/invokes a cold function.
+ // The block is cold if it calls/invokes a cold function. However, do not
+ // mark sanitizer traps as cold.
  for (Instruction &I : BB)
  if (auto CS = CallSite(&I))
- if (CS.hasFnAttr(Attribute::Cold))
+ if (CS.hasFnAttr(Attribute::Cold) && !CS->getMetadata("nosanitize"))
  return true;
 
  // The block is cold if it has an unreachable terminator, unless it's
@@ -235,6 +236,12 @@ bool HotColdSplitting::shouldOutlineFrom(const Function &F) const {
  if (F.hasFnAttribute(Attribute::NoInline))
  return false;
 
+ if (F.hasFnAttribute(Attribute::SanitizeAddress) ||
+ F.hasFnAttribute(Attribute::SanitizeHWAddress) ||
+ F.hasFnAttribute(Attribute::SanitizeThread) ||
+ F.hasFnAttribute(Attribute::SanitizeMemory))
+ return false;
+
  return true;
 }
 

llvm/test/Transforms/HotColdSplit/X86/do-not-split.ll

@@ -110,6 +110,78 @@ if.end: ; preds = %entry
  ret void
 }
 
+; CHECK-LABEL: @sanitize_address
+; CHECK-NOT: sanitize_address.cold.1
+define void @sanitize_address() sanitize_address {
+entry:
+ br i1 undef, label %if.then, label %if.end
+
+if.then: ; preds = %entry
+ call void @sink()
+ ret void
+
+if.end: ; preds = %entry
+ ret void
+}
+
+; CHECK-LABEL: @sanitize_hwaddress
+; CHECK-NOT: sanitize_hwaddress.cold.1
+define void @sanitize_hwaddress() sanitize_hwaddress {
+entry:
+ br i1 undef, label %if.then, label %if.end
+
+if.then: ; preds = %entry
+ call void @sink()
+ ret void
+
+if.end: ; preds = %entry
+ ret void
+}
+
+; CHECK-LABEL: @sanitize_thread
+; CHECK-NOT: sanitize_thread.cold.1
+define void @sanitize_thread() sanitize_thread {
+entry:
+ br i1 undef, label %if.then, label %if.end
+
+if.then: ; preds = %entry
+ call void @sink()
+ ret void
+
+if.end: ; preds = %entry
+ ret void
+}
+
+; CHECK-LABEL: @sanitize_memory
+; CHECK-NOT: sanitize_memory.cold.1
+define void @sanitize_memory() sanitize_memory {
+entry:
+ br i1 undef, label %if.then, label %if.end
+
+if.then: ; preds = %entry
+ call void @sink()
+ ret void
+
+if.end: ; preds = %entry
+ ret void
+}
+
+declare void @llvm.trap() cold noreturn
+
+; CHECK-LABEL: @nosanitize_call
+; CHECK-NOT: nosanitize_call.cold.1
+define void @nosanitize_call() sanitize_memory {
+entry:
+ br i1 undef, label %if.then, label %if.end
+
+if.then: ; preds = %entry
+ call void @llvm.trap(), !nosanitize !2
+ unreachable
+
+if.end: ; preds = %entry
+ ret void
+}
+
 declare void @llvm.dbg.value(metadata, metadata, metadata)
 
 declare void @sink() cold