[Core] Remove use of ClangASTContext in DumpDataExtractor

Summary:
DumpDataExtractor uses ClangASTContext in order to get the proper llvm
fltSemantics for the type it needs so that it can dump floats in a more
precise way. However, there's no reason that this behavior needs to be
specific ClangASTContext. Instead, I think it makes sense to ask
TypeSystems for the float semantics for a type of a given size.

Differential Revision: https://reviews.llvm.org/D67239

llvm-svn: 371258

Author: bulbazord

lldb/include/lldb/Symbol/ClangASTContext.h

@@ -694,6 +694,8 @@ class ClangASTContext : public TypeSystem {
 
   // Exploring the type
 
+  const llvm::fltSemantics &GetFloatTypeSemantics(size_t byte_size) override;
+
   llvm::Optional<uint64_t> GetByteSize(lldb::opaque_compiler_type_t type,
                        ExecutionContextScope *exe_scope) {
     if (llvm::Optional<uint64_t> bit_size = GetBitSize(type, exe_scope))

lldb/include/lldb/Symbol/TypeSystem.h

@@ -14,6 +14,7 @@
 #include <mutex>
 #include <string>
 
+#include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/APSInt.h"
 #include "llvm/ADT/SmallBitVector.h"
 #include "llvm/Support/Casting.h"
@@ -276,6 +277,8 @@ class TypeSystem : public PluginInterface {
 
   // Exploring the type
 
+  virtual const llvm::fltSemantics &GetFloatTypeSemantics(size_t byte_size) = 0;
+
   virtual llvm::Optional<uint64_t>
   GetBitSize(lldb::opaque_compiler_type_t type,
              ExecutionContextScope *exe_scope) = 0;

lldb/source/Core/DumpDataExtractor.cpp

@@ -14,7 +14,6 @@
 #include "lldb/Core/Address.h"
 #include "lldb/Core/Disassembler.h"
 #include "lldb/Core/ModuleList.h"
-#include "lldb/Symbol/ClangASTContext.h"
 #include "lldb/Target/ExecutionContext.h"
 #include "lldb/Target/ExecutionContextScope.h"
 #include "lldb/Target/SectionLoadList.h"
@@ -69,6 +68,9 @@ static float half2float(uint16_t half) {
 static llvm::Optional<llvm::APInt> GetAPInt(const DataExtractor &data,
                                             lldb::offset_t *offset_ptr,
                                             lldb::offset_t byte_size) {
+  if (byte_size == 0)
+    return llvm::None;
+
   llvm::SmallVector<uint64_t, 2> uint64_array;
   lldb::offset_t bytes_left = byte_size;
   uint64_t u64;
@@ -556,57 +558,31 @@ lldb::offset_t lldb_private::DumpDataExtractor(
       if (exe_scope)
         target_sp = exe_scope->CalculateTarget();
       if (target_sp) {
-        ClangASTContext *clang_ast = target_sp->GetScratchClangASTContext();
-        if (clang_ast) {
-          clang::ASTContext *ast = clang_ast->getASTContext();
-          if (ast) {
-            llvm::SmallVector<char, 256> sv;
-            // Show full precision when printing float values
-            const unsigned format_precision = 0;
-            const unsigned format_max_padding =
-                target_sp->GetMaxZeroPaddingInFloatFormat();
-            size_t item_bit_size = item_byte_size * 8;
-
-            if (item_bit_size == ast->getTypeSize(ast->FloatTy)) {
-              llvm::Optional<llvm::APInt> apint =
-                  GetAPInt(DE, &offset, item_byte_size);
-              if (apint.hasValue()) {
-                llvm::APFloat apfloat(ast->getFloatTypeSemantics(ast->FloatTy),
-                                      apint.getValue());
-                apfloat.toString(sv, format_precision, format_max_padding);
-              }
-            } else if (item_bit_size == ast->getTypeSize(ast->DoubleTy)) {
-              llvm::Optional<llvm::APInt> apint =
-                  GetAPInt(DE, &offset, item_byte_size);
-              if (apint.hasValue()) {
-                llvm::APFloat apfloat(ast->getFloatTypeSemantics(ast->DoubleTy),
-                                      apint.getValue());
-                apfloat.toString(sv, format_precision, format_max_padding);
-              }
-            } else if (item_bit_size == ast->getTypeSize(ast->LongDoubleTy)) {
-              const auto &semantics =
-                  ast->getFloatTypeSemantics(ast->LongDoubleTy);
-
-              offset_t byte_size = item_byte_size;
-              if (&semantics == &llvm::APFloatBase::x87DoubleExtended())
-                byte_size = (llvm::APFloat::getSizeInBits(semantics) + 7) / 8;
-
-              llvm::Optional<llvm::APInt> apint =
-                  GetAPInt(DE, &offset, byte_size);
-              if (apint.hasValue()) {
-                llvm::APFloat apfloat(semantics, apint.getValue());
-                apfloat.toString(sv, format_precision, format_max_padding);
-              }
-            } else if (item_bit_size == ast->getTypeSize(ast->HalfTy)) {
-              llvm::Optional<llvm::APInt> apint =
-                  GetAPInt(DE, &offset, item_byte_size);
-              if (apint.hasValue()) {
-                llvm::APFloat apfloat(ast->getFloatTypeSemantics(ast->HalfTy),
-                                      apint.getValue());
-                apfloat.toString(sv, format_precision, format_max_padding);
-              }
-            }
-
+        auto type_system_or_err =
+            target_sp->GetScratchTypeSystemForLanguage(eLanguageTypeC);
+        if (!type_system_or_err) {
+          llvm::consumeError(type_system_or_err.takeError());
+        } else {
+          auto &type_system = *type_system_or_err;
+          llvm::SmallVector<char, 256> sv;
+          // Show full precision when printing float values
+          const unsigned format_precision = 0;
+          const unsigned format_max_padding =
+              target_sp->GetMaxZeroPaddingInFloatFormat();
+
+          const auto &semantics =
+              type_system.GetFloatTypeSemantics(item_byte_size);
+
+          // Recalculate the byte size in case of a difference. This is possible
+          // when item_byte_size is 16 (128-bit), because you could get back the
+          // x87DoubleExtended semantics which has a byte size of 10 (80-bit).
+          const size_t semantics_byte_size =
+              (llvm::APFloat::getSizeInBits(semantics) + 7) / 8;
+          llvm::Optional<llvm::APInt> apint =
+              GetAPInt(DE, &offset, semantics_byte_size);
+          if (apint.hasValue()) {
+            llvm::APFloat apfloat(semantics, apint.getValue());
+            apfloat.toString(sv, format_precision, format_max_padding);
             if (!sv.empty()) {
               s->Printf("%*.*s", (int)sv.size(), (int)sv.size(), sv.data());
               used_upfloat = true;

lldb/source/Symbol/ClangASTContext.cpp

@@ -4991,6 +4991,22 @@ CompilerType ClangASTContext::GetBasicTypeFromAST(lldb::BasicType basic_type) {
 }
 // Exploring the type
 
+const llvm::fltSemantics &
+ClangASTContext::GetFloatTypeSemantics(size_t byte_size) {
+  if (auto *ast = getASTContext()) {
+    const size_t bit_size = byte_size * 8;
+    if (bit_size == ast->getTypeSize(ast->FloatTy))
+      return ast->getFloatTypeSemantics(ast->FloatTy);
+    else if (bit_size == ast->getTypeSize(ast->DoubleTy))
+      return ast->getFloatTypeSemantics(ast->DoubleTy);
+    else if (bit_size == ast->getTypeSize(ast->LongDoubleTy))
+      return ast->getFloatTypeSemantics(ast->LongDoubleTy);
+    else if (bit_size == ast->getTypeSize(ast->HalfTy))
+      return ast->getFloatTypeSemantics(ast->HalfTy);
+  }
+  return llvm::APFloatBase::Bogus();
+}
+
 Optional<uint64_t>
 ClangASTContext::GetBitSize(lldb::opaque_compiler_type_t type,
                             ExecutionContextScope *exe_scope) {