DI: Rewrite the DIBuilder local variable API

Replace the general `createLocalVariable()` with two more specific
functions: `createParameterVariable()` and `createAutoVariable()`, and
rewrite the documentation.

Besides cleaning up the API, this avoids exposing the fake DWARF tags
`DW_TAG_arg_variable` and `DW_TAG_auto_variable` to frontends, and is
preparation for removing them completely.

llvm-svn: 243764

1 files changed, 23 insertions, 3 deletions

diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index 28a8d567c22..7a4c5203965 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -602,15 +602,18 @@ DIGlobalVariable *DIBuilder::createTempGlobalVariableFwdDecl(
       .release();
 }
 
-DILocalVariable *DIBuilder::createLocalVariable(
-    unsigned Tag, DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNo,
-    DIType *Ty, bool AlwaysPreserve, unsigned Flags, unsigned ArgNo) {
+static DILocalVariable *createLocalVariable(
+    LLVMContext &VMContext,
+    DenseMap<MDNode *, std::vector<TrackingMDNodeRef>> &PreservedVariables,
+    DIScope *Scope, StringRef Name, unsigned ArgNo, DIFile *File,
+    unsigned LineNo, DIType *Ty, bool AlwaysPreserve, unsigned Flags) {
   // FIXME: Why getNonCompileUnitScope()?
   // FIXME: Why is "!Context" okay here?
   // FIXME: Why doesn't this check for a subprogram or lexical block (AFAICT
   // the only valid scopes)?
   DIScope *Context = getNonCompileUnitScope(Scope);
 
+  dwarf::Tag Tag = ArgNo ? dwarf::DW_TAG_arg_variable : dwarf::DW_TAG_auto_variable;
   auto *Node = DILocalVariable::get(
       VMContext, Tag, cast_or_null<DILocalScope>(Context), Name, File, LineNo,
       DITypeRef::get(Ty), ArgNo, Flags);
@@ -625,6 +628,23 @@ DILocalVariable *DIBuilder::createLocalVariable(
   return Node;
 }
 
+DILocalVariable *DIBuilder::createAutoVariable(DIScope *Scope, StringRef Name,
+                                               DIFile *File, unsigned LineNo,
+                                               DIType *Ty, bool AlwaysPreserve,
+                                               unsigned Flags) {
+  return createLocalVariable(VMContext, PreservedVariables, Scope, Name,
+                             /* ArgNo */ 0, File, LineNo, Ty, AlwaysPreserve,
+                             Flags);
+}
+
+DILocalVariable *DIBuilder::createParameterVariable(
+    DIScope *Scope, StringRef Name, unsigned ArgNo, DIFile *File,
+    unsigned LineNo, DIType *Ty, bool AlwaysPreserve, unsigned Flags) {
+  assert(ArgNo && "Expected non-zero argument number for parameter");
+  return createLocalVariable(VMContext, PreservedVariables, Scope, Name, ArgNo,
+                             File, LineNo, Ty, AlwaysPreserve, Flags);
+}
+
 DIExpression *DIBuilder::createExpression(ArrayRef<uint64_t> Addr) {
   return DIExpression::get(VMContext, Addr);
 }