[sancov] Don't instrument blocks with no insertion point

This prevents crashes when attempting to instrument functions containing
C++ try.

Sanitizer coverage will still fail at runtime when an exception is
thrown through a sancov instrumented function, but that seems marginally
better than what we have now. The full solution is to color the blocks
in LLVM IR and only instrument blocks that have an unambiguous color,
using the appropriate token.

llvm-svn: 298662

2 files changed, 116 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index 8f7ac9c971e..59a926150ff 100644
--- a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -445,6 +445,11 @@ static bool shouldInstrumentBlock(const Function& F, const BasicBlock *BB, const
   if (isa<UnreachableInst>(BB->getTerminator()))
     return false;
 
+  // Don't insert coverage into blocks without a valid insertion point
+  // (catchswitch blocks).
+  if (BB->getFirstInsertionPt() == BB->end())
+    return false;
+
   if (!ClPruneBlocks || &F.getEntryBlock() == BB)
     return true;
 
diff --git a/llvm/test/Instrumentation/SanitizerCoverage/wineh.ll b/llvm/test/Instrumentation/SanitizerCoverage/wineh.ll
new file mode 100644
index 00000000000..87b44be5544
--- /dev/null
+++ b/llvm/test/Instrumentation/SanitizerCoverage/wineh.ll
@@ -0,0 +1,111 @@
+; RUN: opt < %s -sancov -sanitizer-coverage-level=3 -sanitizer-coverage-trace-pc -S | FileCheck %s --check-prefix=CHECK
+
+; Generated from this C++ source:
+; $ clang -O2 t.cpp -S -emit-llvm
+; void g();
+; struct Foo { Foo(); ~Foo(); };
+; int f() {
+;   Foo v;
+;   g();
+;   try {
+;     g();
+;   } catch (int e) {
+;     g();
+;   } catch (...) {
+;     g();
+;   }
+;   return 0;
+; }
+
+; FIXME: We need to do more than this. In particular, __sanitizer_cov callbacks
+; in funclets need token bundles.
+
+; CHECK-LABEL: define i32 @"\01?f@@YAHXZ"()
+; CHECK: catch.dispatch:
+; CHECK-NEXT: catchswitch within none [label %catch3, label %catch] unwind label %ehcleanup
+
+; ModuleID = 't.cpp'
+source_filename = "t.cpp"
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.10.24728"
+
+%rtti.TypeDescriptor2 = type { i8**, i8*, [3 x i8] }
+%struct.Foo = type { i8 }
+
+$"\01??_R0H@8" = comdat any
+
+@"\01??_7type_info@@6B@" = external constant i8*
+@"\01??_R0H@8" = linkonce_odr global %rtti.TypeDescriptor2 { i8** @"\01??_7type_info@@6B@", i8* null, [3 x i8] c".H\00" }, comdat
+
+; Function Attrs: uwtable
+define i32 @"\01?f@@YAHXZ"() local_unnamed_addr #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+entry:
+  %v = alloca %struct.Foo, align 1
+  %e = alloca i32, align 4
+  %0 = getelementptr inbounds %struct.Foo, %struct.Foo* %v, i64 0, i32 0
+  call void @llvm.lifetime.start(i64 1, i8* nonnull %0) #4
+  %call = call %struct.Foo* @"\01??0Foo@@QEAA@XZ"(%struct.Foo* nonnull %v)
+  invoke void @"\01?g@@YAXXZ"()
+          to label %invoke.cont unwind label %ehcleanup
+
+invoke.cont:                                      ; preds = %entry
+  invoke void @"\01?g@@YAXXZ"()
+          to label %try.cont unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %invoke.cont
+  %1 = catchswitch within none [label %catch3, label %catch] unwind label %ehcleanup
+
+catch3:                                           ; preds = %catch.dispatch
+  %2 = catchpad within %1 [%rtti.TypeDescriptor2* @"\01??_R0H@8", i32 0, i32* %e]
+  invoke void @"\01?g@@YAXXZ"() [ "funclet"(token %2) ]
+          to label %invoke.cont4 unwind label %ehcleanup
+
+invoke.cont4:                                     ; preds = %catch3
+  catchret from %2 to label %try.cont
+
+try.cont:                                         ; preds = %invoke.cont, %invoke.cont2, %invoke.cont4
+  call void @"\01??1Foo@@QEAA@XZ"(%struct.Foo* nonnull %v) #4
+  call void @llvm.lifetime.end(i64 1, i8* nonnull %0) #4
+  ret i32 0
+
+catch:                                            ; preds = %catch.dispatch
+  %3 = catchpad within %1 [i8* null, i32 64, i8* null]
+  invoke void @"\01?g@@YAXXZ"() [ "funclet"(token %3) ]
+          to label %invoke.cont2 unwind label %ehcleanup
+
+invoke.cont2:                                     ; preds = %catch
+  catchret from %3 to label %try.cont
+
+ehcleanup:                                        ; preds = %catch3, %catch, %catch.dispatch, %entry
+  %4 = cleanuppad within none []
+  call void @"\01??1Foo@@QEAA@XZ"(%struct.Foo* nonnull %v) #4 [ "funclet"(token %4) ]
+  call void @llvm.lifetime.end(i64 1, i8* nonnull %0) #4
+  cleanupret from %4 unwind to caller
+}
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.start(i64, i8* nocapture) #1
+
+declare %struct.Foo* @"\01??0Foo@@QEAA@XZ"(%struct.Foo* returned) unnamed_addr #2
+
+declare void @"\01?g@@YAXXZ"() local_unnamed_addr #2
+
+declare i32 @__CxxFrameHandler3(...)
+
+; Function Attrs: nounwind
+declare void @"\01??1Foo@@QEAA@XZ"(%struct.Foo*) unnamed_addr #3
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end(i64, i8* nocapture) #1
+
+attributes #0 = { uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind }
+attributes #2 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #3 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #4 = { nounwind }
+
+!llvm.module.flags = !{!0}
+!llvm.ident = !{!1}
+
+!0 = !{i32 1, !"PIC Level", i32 2}
+!1 = !{!"clang version 5.0.0 "}