[WebAssembly] Fix immediate of rethrow when throwing to caller

Summary:
Currently when assigning depths 'rethrow' does not take the whole
control flow stack into accounts but only considers EH pad stacks. When
assigning depth immmediates to rethrows, in normal cases it is done
correctly but when a rethrow instruction throws up to a caller, i.e., we
convert a pseudo RETHROW_TO_CALLER instruction to a rethrow, it
mistakenly compute the whole stack depth.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53619

llvm-svn: 345223

2 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
index 93ca670bbdb..a3b3901f019 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
@@ -767,7 +767,7 @@ void WebAssemblyCFGStackify::rewriteDepthImmediates(MachineFunction &MF) {
       case WebAssembly::RETHROW_TO_CALLER: {
         MachineInstr *Rethrow =
             BuildMI(MBB, MI, MI.getDebugLoc(), TII.get(WebAssembly::RETHROW))
-                .addImm(Stack.size());
+                .addImm(EHPadStack.size());
         MI.eraseFromParent();
         I = MachineBasicBlock::reverse_iterator(Rethrow);
         break;
diff --git a/llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.mir b/llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.mir
index 9038f68966b..b67579087fa 100644
--- a/llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.mir
+++ b/llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.mir
@@ -180,7 +180,7 @@ body: |
     RETHROW_TO_CALLER implicit-def $arguments
   ; CHECK-LABEL: bb.7:
     ; CHECK-NEXT: END_TRY
-    ; CHECK: RETHROW 3
+    ; CHECK: RETHROW 0
 
   bb.8:
   ; predecessors: %bb.2, %bb.4