PR14492: Debug Info: Support for values of non-integer non-type template parameters.

This is only tested for global variables at the moment (& includes tests
for the unnamed parameter case, since apparently this entire function
was completely untested previously)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181632 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/DIBuilder.h

@@ -332,10 +332,9 @@ namespace llvm {
     /// @param LineNo       Line number.
     /// @param ColumnNo     Column Number.
     DITemplateValueParameter
-    createTemplateValueParameter(DIDescriptor Scope, StringRef Name, DIType Ty,
+    createTemplateValueParameter(DIDescriptor Scope, StringRef Name,
-                                 uint64_t Value,
+                                 DIType Ty, Value *Val, MDNode *File = 0,
-                                 MDNode *File = 0, unsigned LineNo = 0,
+                                 unsigned LineNo = 0, unsigned ColumnNo = 0);
-                                 unsigned ColumnNo = 0);
 
     /// createArrayType - Create debugging information entry for an array.
     /// @param Size         Array size.

include/llvm/DebugInfo.h

@@ -401,7 +401,7 @@ namespace llvm {
     DIScope getContext() const       { return getFieldAs<DIScope>(1); }
     StringRef getName() const        { return getStringField(2); }
     DIType getType() const           { return getFieldAs<DIType>(3); }
-    uint64_t getValue() const         { return getUInt64Field(4); }
+    Value *getValue() const;
     StringRef getFilename() const    {
       return getFieldAs<DIFile>(5).getFilename();
     }

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

@@ -588,6 +588,9 @@ static bool isTypeSigned(DIType Ty, int *SizeInBits) {
 /// addConstantValue - Add constant value entry in variable DIE.
 bool CompileUnit::addConstantValue(DIE *Die, const MachineOperand &MO,
                                    DIType Ty) {
+  // FIXME: This is a bit conservative/simple - it emits negative values at
+  // their maximum bit width which is a bit unfortunate (& doesn't prefer
+  // udata/sdata over dataN as suggested by the DWARF spec)
   assert(MO.isImm() && "Invalid machine operand!");
   DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
   int SizeInBits = -1;
@@ -1095,8 +1098,21 @@ CompileUnit::getOrCreateTemplateValueParameterDIE(DITemplateValueParameter TPV){
   addType(ParamDIE, TPV.getType());
   if (!TPV.getName().empty())
     addString(ParamDIE, dwarf::DW_AT_name, TPV.getName());
-  addUInt(ParamDIE, dwarf::DW_AT_const_value, dwarf::DW_FORM_udata,
+  if (Value *Val = TPV.getValue()) {
-          TPV.getValue());
+    if (ConstantInt *CI = dyn_cast<ConstantInt>(Val))
+      addConstantValue(ParamDIE, CI, TPV.getType().isUnsignedDIType());
+    else if (GlobalValue *GV = dyn_cast<GlobalValue>(Val)) {
+      // For declaration non-type template parameters (such as global values and
+      // functions)
+      DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
+      addOpAddress(Block, Asm->Mang->getSymbol(GV));
+      // Emit DW_OP_stack_value to use the address as the immediate value of the
+      // parameter, rather than a pointer to it.
+      addUInt(Block, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_stack_value);
+      addBlock(ParamDIE, dwarf::DW_AT_location, 0, Block);
+    }
+  }
+
   return ParamDIE;
 }
 

lib/IR/DIBuilder.cpp

@@ -502,7 +502,7 @@ DIBuilder::createTemplateTypeParameter(DIDescriptor Context, StringRef Name,
 /// value parameter.
 DITemplateValueParameter
 DIBuilder::createTemplateValueParameter(DIDescriptor Context, StringRef Name,
-                                        DIType Ty, uint64_t Val,
+                                        DIType Ty, Value *Val,
                                         MDNode *File, unsigned LineNo,
                                         unsigned ColumnNo) {
   Value *Elts[] = {
@@ -510,7 +510,7 @@ DIBuilder::createTemplateValueParameter(DIDescriptor Context, StringRef Name,
     getNonCompileUnitScope(Context),
     MDString::get(VMContext, Name),
     Ty,
-    ConstantInt::get(Type::getInt64Ty(VMContext), Val),
+    Val,
     File,
     ConstantInt::get(Type::getInt32Ty(VMContext), LineNo),
     ConstantInt::get(Type::getInt32Ty(VMContext), ColumnNo)

lib/IR/DebugInfo.cpp

@@ -695,6 +695,10 @@ DIArray DISubprogram::getVariables() const {
   return DIArray();
 }
 
+Value *DITemplateValueParameter::getValue() const {
+  return getField(DbgNode, 4);
+}
+
 void DIScope::setFilename(StringRef Name, LLVMContext &Context) {
   if (!DbgNode)
     return;

test/DebugInfo/template.ll

@@ -0,0 +1,84 @@
+; REQUIRES: object-emission
+
+; RUN: llc -O0 -filetype=obj < %s > %t
+; RUN: llvm-dwarfdump %t | FileCheck %s
+
+; IR generated with `clang++ -g -emit-llvm -S` from the following code:
+; template<int, int* x>  func() { }
+; int glbl = func<3, &glbl>();
+
+; CHECK: [[INT:0x[0-9a-f]*]]:{{ *}}DW_TAG_base_type
+; CHECK-NEXT: DW_AT_name{{.*}} = "int"
+
+; CHECK: DW_AT_name{{.*}}"func<3, &glbl>"
+; CHECK-NOT: NULL
+; CHECK: DW_TAG_template_value_parameter
+; CHECK-NEXT: DW_AT_type{{.*}}=> {[[INT]]}
+; CHECK-NEXT: DW_AT_name{{.*}}= "x"
+
+; This could be made shorter by encoding it as _sdata rather than data4, or
+; even as data1. DWARF strongly urges implementations to prefer 
+; _sdata/_udata rather than dataN
+
+; CHECK-NEXT: DW_AT_const_value [DW_FORM_data4]{{.*}}(0x00000003)
+
+; CHECK: DW_TAG_template_value_parameter
+; CHECK-NEXT: DW_AT_type{{.*}}=> {[[INTPTR:0x[0-9a-f]*]]}
+
+; The address of the global 'glbl', followed by DW_OP_stack_value (9f), to use
+; the value immediately, rather than indirecting through the address.
+
+; CHECK-NEXT: DW_AT_location [DW_FORM_block1]{{ *}}(<0x0a> 03 00 00 00 00 00 00 00 00 9f )
+
+; CHECK: [[INTPTR]]:{{ *}}DW_TAG_pointer_type
+; CHECK-NEXT: DW_AT_type{{.*}} => {[[INT]]}
+
+@glbl = global i32 0, align 4
+@llvm.global_ctors = appending global [1 x { i32, void ()* }] [{ i32, void ()* } { i32 65535, void ()* @_GLOBAL__I_a }]
+
+define internal void @__cxx_global_var_init() section ".text.startup" {
+entry:
+  %call = call i32 @_Z4funcILi3EXadL_Z4glblEEEiv(), !dbg !20
+  store i32 %call, i32* @glbl, align 4, !dbg !20
+  ret void, !dbg !20
+}
+
+; Function Attrs: nounwind uwtable
+define linkonce_odr i32 @_Z4funcILi3EXadL_Z4glblEEEiv() #0 {
+entry:
+  ret i32 3, !dbg !21
+}
+
+define internal void @_GLOBAL__I_a() section ".text.startup" {
+entry:
+  call void @__cxx_global_var_init(), !dbg !22
+  ret void, !dbg !22
+}
+
+attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+
+!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.4 ", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !18, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ] [/usr/local/google/home/blaikie/dev/scratch/templ.cpp] [DW_LANG_C_plus_plus]
+!1 = metadata !{metadata !"templ.cpp", metadata !"/usr/local/google/home/blaikie/dev/scratch"}
+!2 = metadata !{i32 0}
+!3 = metadata !{metadata !4, metadata !8, metadata !16}
+!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"__cxx_global_var_init", metadata !"__cxx_global_var_init", metadata !"", i32 2, metadata !6, i1 true, i1 true, i32 0, i32 0, null, i32 256, i1 false, void ()* @__cxx_global_var_init, null, null, metadata !2, i32 2} ; [ DW_TAG_subprogram ] [line 2] [local] [def] [__cxx_global_var_init]
+!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [/usr/local/google/home/blaikie/dev/scratch/templ.cpp]
+!6 = metadata !{i32 786453, i32 0, i32 0, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, i32 0} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!7 = metadata !{null}
+!8 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"func<3, &glbl>", metadata !"func<3, &glbl>", metadata !"_Z4funcILi3EXadL_Z4glblEEEiv", i32 1, metadata !9, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 ()* @_Z4funcILi3EXadL_Z4glblEEEiv, metadata !12, null, metadata !2, i32 1} ; [ DW_TAG_subprogram ] [line 1] [def] [func<3, &glbl>]
+!9 = metadata !{i32 786453, i32 0, i32 0, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !10, i32 0, i32 0} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!10 = metadata !{metadata !11}
+!11 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!12 = metadata !{metadata !13, metadata !14}
+!13 = metadata !{i32 786480, null, metadata !"x", metadata !11, i32 3, null, i32 0, i32 0} ; [ DW_TAG_template_value_parameter ]
+!14 = metadata !{i32 786480, null, metadata !"", metadata !15, i32* @glbl, null, i32 0, i32 0} ; [ DW_TAG_template_value_parameter ]
+!15 = metadata !{i32 786447, null, null, metadata !"", i32 0, i64 64, i64 64, i64 0, i32 0, metadata !11} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from int]
+!16 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"_GLOBAL__I_a", metadata !"_GLOBAL__I_a", metadata !"", i32 1, metadata !17, i1 true, i1 true, i32 0, i32 0, null, i32 64, i1 false, void ()* @_GLOBAL__I_a, null, null, metadata !2, i32 1} ; [ DW_TAG_subprogram ] [line 1] [local] [def] [_GLOBAL__I_a]
+!17 = metadata !{i32 786453, i32 0, i32 0, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !2, i32 0, i32 0} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!18 = metadata !{metadata !19}
+!19 = metadata !{i32 786484, i32 0, null, metadata !"glbl", metadata !"glbl", metadata !"", metadata !5, i32 2, metadata !11, i32 0, i32 1, i32* @glbl, null} ; [ DW_TAG_variable ] [glbl] [line 2] [def]
+!20 = metadata !{i32 2, i32 0, metadata !4, null}
+!21 = metadata !{i32 1, i32 0, metadata !8, null}
+!22 = metadata !{i32 1, i32 0, metadata !16, null}