MIR Parser: Report an error when parsing machine function with an empty body.

This commit adds a new error which is reported when the MIR Parser encounters
a machine function without any machine basic blocks. The machine verifier
expects that the machine functions have at least one MBB, and this error will
prevent machine functions without MBBs from reaching the machine verifier and
crashing with an assertion.

llvm-svn: 241862

8 files changed, 42 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
index e505ab4baeb..e5ba0322235 100644
--- a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
@@ -275,6 +275,9 @@ bool MIRParserImpl::initializeMachineFunction(MachineFunction &MF) {
                    Twine(YamlMBB.ID));
   }
 
+  if (YamlMF.BasicBlocks.empty())
+    return error(Twine("machine function '") + Twine(MF.getName()) +
+                 "' requires at least one machine basic block in its body");
   // Initialize the machine basic blocks after creating them all so that the
   // machine instructions parser can resolve the MBB references.
   unsigned I = 0;
diff --git a/llvm/test/CodeGen/MIR/llvmIR.mir b/llvm/test/CodeGen/MIR/llvmIR.mir
index 4d7fde240c5..3c084ad7d39 100644
--- a/llvm/test/CodeGen/MIR/llvmIR.mir
+++ b/llvm/test/CodeGen/MIR/llvmIR.mir
@@ -32,4 +32,6 @@
 ...
 ---
 name: foo
+body:
+  - id: 0
 ...
diff --git a/llvm/test/CodeGen/MIR/llvmIRMissing.mir b/llvm/test/CodeGen/MIR/llvmIRMissing.mir
index 83d846ba44c..80cea5a6fda 100644
--- a/llvm/test/CodeGen/MIR/llvmIRMissing.mir
+++ b/llvm/test/CodeGen/MIR/llvmIRMissing.mir
@@ -4,4 +4,6 @@
 ---
 # CHECK: name: foo
 name: foo
+body:
+  - id: 0
 ...
diff --git a/llvm/test/CodeGen/MIR/machine-function-missing-body-error.mir b/llvm/test/CodeGen/MIR/machine-function-missing-body-error.mir
new file mode 100644
index 00000000000..0dc7477f627
--- /dev/null
+++ b/llvm/test/CodeGen/MIR/machine-function-missing-body-error.mir
@@ -0,0 +1,15 @@
+# RUN: not llc -start-after branch-folder -stop-after branch-folder -o /dev/null %s 2>&1 | FileCheck %s
+# This test ensures that the MIR parser reports an error when it encounters a
+# machine function with an empty body.
+
+--- |
+
+  define i32 @foo() {
+    ret i32 0
+  }
+
+...
+---
+# CHECK: machine function 'foo' requires at least one machine basic block in its body
+name:            foo
+...
diff --git a/llvm/test/CodeGen/MIR/machine-function-missing-function.mir b/llvm/test/CodeGen/MIR/machine-function-missing-function.mir
index eed4142d659..424c34aae84 100644
--- a/llvm/test/CodeGen/MIR/machine-function-missing-function.mir
+++ b/llvm/test/CodeGen/MIR/machine-function-missing-function.mir
@@ -12,8 +12,12 @@
 ...
 ---
 name:            foo
+body:
+  - id: 0
 ...
 ---
 # CHECK: function 'faa' isn't defined in the provided LLVM IR
 name:            faa
+body:
+  - id: 0
 ...
diff --git a/llvm/test/CodeGen/MIR/machine-function-missing-name.mir b/llvm/test/CodeGen/MIR/machine-function-missing-name.mir
index b16156e54bd..a868a65d35f 100644
--- a/llvm/test/CodeGen/MIR/machine-function-missing-name.mir
+++ b/llvm/test/CodeGen/MIR/machine-function-missing-name.mir
@@ -16,7 +16,11 @@
 ---
 # CHECK: [[@LINE+1]]:1: missing required key 'name'
 nme:             foo
+body:
+  - id: 0
 ...
 ---
 name:            bar
+body:
+  - id: 0
 ...
diff --git a/llvm/test/CodeGen/MIR/machine-function.mir b/llvm/test/CodeGen/MIR/machine-function.mir
index 8f053adc22b..afd10ab02c2 100644
--- a/llvm/test/CodeGen/MIR/machine-function.mir
+++ b/llvm/test/CodeGen/MIR/machine-function.mir
@@ -27,6 +27,8 @@
 # CHECK-NEXT: hasInlineAsm: false
 # CHECK: ...
 name:            foo
+body:
+  - id: 0
 ...
 ---
 # CHECK: name: bar
@@ -35,6 +37,8 @@ name:            foo
 # CHECK-NEXT: hasInlineAsm: false
 # CHECK: ...
 name:            bar
+body:
+  - id: 0
 ...
 ---
 # CHECK: name: func
@@ -44,6 +48,8 @@ name:            bar
 # CHECK: ...
 name:            func
 alignment:       8
+body:
+  - id: 0
 ...
 ---
 # CHECK: name: func2
@@ -55,4 +61,6 @@ name:            func2
 alignment:       16
 exposesReturnsTwice: true
 hasInlineAsm:    true
+body:
+  - id: 0
 ...
diff --git a/llvm/test/CodeGen/MIR/register-info.mir b/llvm/test/CodeGen/MIR/register-info.mir
index c01997b4685..9585faa9622 100644
--- a/llvm/test/CodeGen/MIR/register-info.mir
+++ b/llvm/test/CodeGen/MIR/register-info.mir
@@ -22,6 +22,8 @@
 # CHECK-NEXT: tracksSubRegLiveness: false
 # CHECK: ...
 name:            foo
+body:
+  - id: 0
 ...
 ---
 # CHECK: name: bar
@@ -33,4 +35,6 @@ name: bar
 isSSA: false
 tracksRegLiveness: true
 tracksSubRegLiveness: true
+body:
+  - id: 0
 ...