From 9362698450d1843e7fde98d8012a7308244c2d79 Mon Sep 17 00:00:00 2001
From: David Truby <david.truby@arm.com>
Date: Wed, 6 May 2020 18:38:28 +0100
Subject: [PATCH] [flang] Change DIE("unreachable") cases to use
 llvm_unreachable

Reviewers: sscalpone

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79507
---
 flang/lib/Semantics/check-declarations.cpp |  5 +++-
 flang/lib/Semantics/resolve-names.cpp      | 32 ++++++++++++++++------
 2 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/flang/lib/Semantics/check-declarations.cpp b/flang/lib/Semantics/check-declarations.cpp
index 55cf8cdb3896..871bb8283543 100644
--- a/flang/lib/Semantics/check-declarations.cpp
+++ b/flang/lib/Semantics/check-declarations.cpp
@@ -1455,7 +1455,10 @@ void SubprogramMatchHelper::CheckDummyArg(const Symbol &symbol1,
                        "Dummy argument '%s' is a procedure; the corresponding"
                        " argument in the interface body is not"_err_en_US);
                  },
-                 [&](const auto &, const auto &) { DIE("can't happen"); },
+                 [&](const auto &, const auto &) {
+                   llvm_unreachable("Dummy arguments are not data objects or"
+                                    "procedures");
+                 },
              },
       arg1.u, arg2.u);
 }
diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index 4e159b5d2f77..0cf93c6f0344 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -287,7 +287,7 @@ protected:
     case parser::AccessSpec::Kind::Private:
       return Attr::PRIVATE;
     }
-    common::die("unreachable"); // suppress g++ warning
+    llvm_unreachable("Switch covers all cases"); // suppress g++ warning
   }
   Attr IntentSpecToAttr(const parser::IntentSpec &x) {
     switch (x.v) {
@@ -298,7 +298,7 @@ protected:
     case parser::IntentSpec::Intent::InOut:
       return Attr::INTENT_INOUT;
     }
-    common::die("unreachable"); // suppress g++ warning
+    llvm_unreachable("Switch covers all cases"); // suppress g++ warning
   }
 
 private:
@@ -1398,13 +1398,27 @@ public:
   void Post(const parser::AssignedGotoStmt &);
 
   // These nodes should never be reached: they are handled in ProgramUnit
-  bool Pre(const parser::MainProgram &) { DIE("unreachable"); }
-  bool Pre(const parser::FunctionSubprogram &) { DIE("unreachable"); }
-  bool Pre(const parser::SubroutineSubprogram &) { DIE("unreachable"); }
-  bool Pre(const parser::SeparateModuleSubprogram &) { DIE("unreachable"); }
-  bool Pre(const parser::Module &) { DIE("unreachable"); }
-  bool Pre(const parser::Submodule &) { DIE("unreachable"); }
-  bool Pre(const parser::BlockData &) { DIE("unreachable"); }
+  bool Pre(const parser::MainProgram &) {
+    llvm_unreachable("This node is handled in ProgramUnit");
+  }
+  bool Pre(const parser::FunctionSubprogram &) {
+    llvm_unreachable("This node is handled in ProgramUnit");
+  }
+  bool Pre(const parser::SubroutineSubprogram &) {
+    llvm_unreachable("This node is handled in ProgramUnit");
+  }
+  bool Pre(const parser::SeparateModuleSubprogram &) {
+    llvm_unreachable("This node is handled in ProgramUnit");
+  }
+  bool Pre(const parser::Module &) {
+    llvm_unreachable("This node is handled in ProgramUnit");
+  }
+  bool Pre(const parser::Submodule &) {
+    llvm_unreachable("This node is handled in ProgramUnit");
+  }
+  bool Pre(const parser::BlockData &) {
+    llvm_unreachable("This node is handled in ProgramUnit");
+  }
 
   void NoteExecutablePartCall(Symbol::Flag, const parser::Call &);