Add support for DW_TAG_thrown_type.

For Swift we would like to be able to encode the error types that a
function may throw, so the debugger can display them alongside the
function's return value when finish-ing a function.

DWARF defines DW_TAG_thrown_type (intended to be used for C++ throw()
declarations) that is a perfect fit for this purpose. This patch wires
up support for DW_TAG_thrown_type in LLVM by adding a list of thrown
types to DISubprogram.

To offset the cost of the extra pointer, there is a follow-up patch
that turns DISubprogram into a variable-length node.

rdar://problem/29481673

Differential Revision: https://reviews.llvm.org/D32559

llvm-svn: 301489

1 files changed, 8 insertions, 4 deletions

diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index 0ee0b9c0da2..d2c4b021026 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -552,6 +552,7 @@ template <> struct MDNodeKeyImpl<DISubprogram> {
   Metadata *TemplateParams;
   Metadata *Declaration;
   Metadata *Variables;
+  Metadata *ThrownTypes;
 
   MDNodeKeyImpl(Metadata *Scope, MDString *Name, MDString *LinkageName,
                 Metadata *File, unsigned Line, Metadata *Type,
@@ -559,7 +560,8 @@ template <> struct MDNodeKeyImpl<DISubprogram> {
                 Metadata *ContainingType, unsigned Virtuality,
                 unsigned VirtualIndex, int ThisAdjustment, unsigned Flags,
                 bool IsOptimized, Metadata *Unit, Metadata *TemplateParams,
-                Metadata *Declaration, Metadata *Variables)
+                Metadata *Declaration, Metadata *Variables,
+                Metadata *ThrownTypes)
       : Scope(Scope), Name(Name), LinkageName(LinkageName), File(File),
         Line(Line), Type(Type), IsLocalToUnit(IsLocalToUnit),
         IsDefinition(IsDefinition), ScopeLine(ScopeLine),
@@ -567,7 +569,7 @@ template <> struct MDNodeKeyImpl<DISubprogram> {
         VirtualIndex(VirtualIndex), ThisAdjustment(ThisAdjustment),
         Flags(Flags), IsOptimized(IsOptimized), Unit(Unit),
         TemplateParams(TemplateParams), Declaration(Declaration),
-        Variables(Variables) {}
+        Variables(Variables), ThrownTypes(ThrownTypes) {}
   MDNodeKeyImpl(const DISubprogram *N)
       : Scope(N->getRawScope()), Name(N->getRawName()),
         LinkageName(N->getRawLinkageName()), File(N->getRawFile()),
@@ -578,7 +580,8 @@ template <> struct MDNodeKeyImpl<DISubprogram> {
         ThisAdjustment(N->getThisAdjustment()), Flags(N->getFlags()),
         IsOptimized(N->isOptimized()), Unit(N->getRawUnit()),
         TemplateParams(N->getRawTemplateParams()),
-        Declaration(N->getRawDeclaration()), Variables(N->getRawVariables()) {}
+        Declaration(N->getRawDeclaration()), Variables(N->getRawVariables()),
+        ThrownTypes(N->getRawThrownTypes()) {}
 
   bool isKeyOf(const DISubprogram *RHS) const {
     return Scope == RHS->getRawScope() && Name == RHS->getRawName() &&
@@ -595,7 +598,8 @@ template <> struct MDNodeKeyImpl<DISubprogram> {
            Unit == RHS->getUnit() &&
            TemplateParams == RHS->getRawTemplateParams() &&
            Declaration == RHS->getRawDeclaration() &&
-           Variables == RHS->getRawVariables();
+           Variables == RHS->getRawVariables() &&
+           ThrownTypes == RHS->getRawThrownTypes();
   }
   unsigned getHashValue() const {
     // If this is a declaration inside an ODR type, only hash the type and the