[WebAssembly] Error out when block/loop markers mismatch
Summary:
Currently InstPrinter ignores if there are mismatches between block/loop
and end markers by skipping the case if ControlFlowStack is empty. I
guess it is better to explicitly error out in this case, because this
signals invalid input.
Reviewers: aardappel
Subscribers: dschuff, sbc100, jgravelle-google, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D53620
llvm-svn: 345333
diff --git a/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp b/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
index 08c1155..e26cf1d 100644
--- a/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
+++ b/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
@@ -85,16 +85,16 @@
break;
case WebAssembly::END_LOOP:
case WebAssembly::END_LOOP_S:
- // Have to guard against an empty stack, in case of mismatched pairs
- // in assembly parsing.
- if (!ControlFlowStack.empty())
- ControlFlowStack.pop_back();
+ if (ControlFlowStack.empty())
+ report_fatal_error("End marker mismatch!");
+ ControlFlowStack.pop_back();
break;
case WebAssembly::END_BLOCK:
case WebAssembly::END_BLOCK_S:
- if (!ControlFlowStack.empty())
- printAnnotation(
- OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':');
+ if (ControlFlowStack.empty())
+ report_fatal_error("END marker mismatch!");
+ printAnnotation(
+ OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':');
break;
}
diff --git a/llvm/test/CodeGen/WebAssembly/block-mismatch.mir b/llvm/test/CodeGen/WebAssembly/block-mismatch.mir
new file mode 100644
index 0000000..0da58e9
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/block-mismatch.mir
@@ -0,0 +1,18 @@
+# RUN: not llc -mtriple=wasm32-unknown-unknown -start-after xray-instrumentation %s -o /dev/null 2>&1 | FileCheck %s
+
+# This tests if there are block/loop marker mismatches, the program crashes.
+
+---
+name: block_mismatch
+liveins:
+ - { reg: '$arguments', reg: '$value_stack' }
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $arguments, $value_stack
+ BLOCK 64, implicit-def $value_stack, implicit $value_stack
+ END_BLOCK implicit-def $value_stack, implicit $value_stack
+ ; CHECK: LLVM ERROR: END marker mismatch!
+ END_BLOCK implicit-def $value_stack, implicit $value_stack
+ RETURN_VOID implicit-def dead $arguments
+...