[WinEH] Add llvm.eh.exceptionpointer intrinsic

Summary:
This intrinsic can be used to extract a pointer to the exception caught by
a given catchpad.  Its argument has token type and must be a `catchpad`.

Also clarify ExtendingLLVM documentation regarding overloaded intrinsics.


Reviewers: majnemer, andrew.w.kaylor, sanjoy, rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12533

llvm-svn: 246752

2 files changed, 72 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/WinEH/wineh-intrinsics-invalid.ll b/llvm/test/CodeGen/WinEH/wineh-intrinsics-invalid.ll
new file mode 100644
index 00000000000..17d6e70ad1e
--- /dev/null
+++ b/llvm/test/CodeGen/WinEH/wineh-intrinsics-invalid.ll
@@ -0,0 +1,26 @@
+; RUN: sed -e s/.T1:// %s | not opt -lint -disable-output 2>&1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: sed -e s/.T2:// %s | not opt -lint -disable-output 2>&1 | FileCheck --check-prefix=CHECK2 %s
+
+target triple = "x86_64-pc-windows-msvc"
+
+declare void @f()
+
+;T1: declare i8* @llvm.eh.exceptionpointer.p0i8(i32)
+;T1:
+;T1: define void @test1() personality i32 (...)* @__CxxFrameHandler3 {
+;T1:   call i8* @llvm.eh.exceptionpointer.p0i8(i32 0)
+;T1:   ret void
+;T1: }
+;CHECK1: Intrinsic has incorrect argument type!
+;CHECK1-NEXT: i8* (i32)* @llvm.eh.exceptionpointer.p0i8
+
+;T2: declare i8* @llvm.eh.exceptionpointer.p0i8(token)
+;T2:
+;T2: define void @test2() personality i32 (...)* @__CxxFrameHandler3 {
+;T2:   call i8* @llvm.eh.exceptionpointer.p0i8(token undef)
+;T2:   ret void
+;T2: }
+;CHECK2: eh.exceptionpointer argument must be a catchpad
+;CHECK2-NEXT:  call i8* @llvm.eh.exceptionpointer.p0i8(token undef)
+
+declare i32 @__CxxFrameHandler3(...)
diff --git a/llvm/test/CodeGen/WinEH/wineh-intrinsics.ll b/llvm/test/CodeGen/WinEH/wineh-intrinsics.ll
new file mode 100644
index 00000000000..acdeb796ac1
--- /dev/null
+++ b/llvm/test/CodeGen/WinEH/wineh-intrinsics.ll
@@ -0,0 +1,46 @@
+; RUN: opt -lint -disable-output < %s
+
+; This test is meant to prove that the verifier does not report errors for correct
+; use of the llvm.eh.exceptionpointer intrinsic.
+
+target triple = "x86_64-pc-windows-msvc"
+
+declare i8* @llvm.eh.exceptionpointer.p0i8(token)
+declare i8 addrspace(1)* @llvm.eh.exceptionpointer.p1i8(token)
+
+declare void @f(...)
+
+define void @test1() personality i32 (...)* @__CxxFrameHandler3 {
+entry:
+  invoke void (...) @f(i32 1)
+     to label %exit unwind label %catchpad
+catchpad:
+  %catch = catchpad [i32 1] to label %do_catch unwind label %catchend
+do_catch:
+  %exn = call i8* @llvm.eh.exceptionpointer.p0i8(token %catch)
+  call void (...) @f(i8* %exn)
+  catchret %catch to label %exit
+catchend:
+  catchendpad unwind to caller
+exit:
+  ret void
+}
+
+define void @test2() personality i32 (...)* @ProcessManagedException {
+entry:
+  invoke void (...) @f(i32 1)
+     to label %exit unwind label %catchpad
+catchpad:
+  %catch = catchpad [i32 1] to label %do_catch unwind label %catchend
+do_catch:
+  %exn = call i8 addrspace(1)* @llvm.eh.exceptionpointer.p1i8(token %catch)
+  call void (...) @f(i8 addrspace(1)* %exn)
+  catchret %catch to label %exit
+catchend:
+  catchendpad unwind to caller
+exit:
+  ret void
+}
+
+declare i32 @__CxxFrameHandler3(...)
+declare i32 @ProcessManagedException(...)