Clang: Change the default DWARF version to 5

(except on platforms that already opt in to specific versions - SCE,
Android, and Darwin using DWARFv4 explicitly, for instance)

clang/docs/ReleaseNotes.rst

@@ -252,6 +252,14 @@ X86 Support in Clang
 
 - Support for ``AVX512-FP16`` instructions has been added.
 
+DWARF Support in Clang
+----------------------
+
+- The default DWARF version has increased from DWARFv4 to DWARFv5.  You can opt
+  back in to the old behavior with -gdwarf-4. Some platforms (Darwin, Android,
+  and SCE for instance) already opt out of this version bump as is suitable for
+  the platform
+
 Arm and AArch64 Support in Clang
 --------------------------------
 

clang/include/clang/Driver/ToolChain.h

@@ -510,7 +510,7 @@ public:
 
   // Return the DWARF version to emit, in the absence of arguments
   // to the contrary.
-  virtual unsigned GetDefaultDwarfVersion() const { return 4; }
+  virtual unsigned GetDefaultDwarfVersion() const { return 5; }
 
   // Some toolchains may have different restrictions on the DWARF version and
   // may need to adjust it. E.g. NVPTX may need to enforce DWARF2 even when host

clang/lib/Driver/ToolChains/Linux.h

@@ -40,6 +40,7 @@ public:
   void AddIAMCUIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                            llvm::opt::ArgStringList &CC1Args) const override;
   RuntimeLibType GetDefaultRuntimeLibType() const override;
+  unsigned GetDefaultDwarfVersion() const override;
   CXXStdlibType GetDefaultCXXStdlibType() const override;
   bool
   IsAArch64OutlineAtomicsDefault(const llvm::opt::ArgList &Args) const override;

clang/test/CodeGen/debug-info-extern-call.c

@@ -12,13 +12,13 @@
 // decls so that the dwarf generator can describe information needed for tail
 // call frame reconstrution.
 //
-// RUN: %clang -g -O2 -target x86_64-none-linux-gnu -ggdb -S -emit-llvm %s -o - \
+// RUN: %clang -gdwarf-4 -O2 -target x86_64-none-linux-gnu -ggdb -S -emit-llvm %s -o - \
 // RUN:   | FileCheck %s -check-prefix=DECLS-FOR-EXTERN
 //
 // Do not emit a subprogram for extern decls when entry values are disabled and
 // the tuning is not set to gdb.
 //
-// RUN: %clang -g -O2 -target x86_64-none-linux-gnu -gsce -S -emit-llvm %s -o - \
+// RUN: %clang -gdwarf-4 -O2 -target x86_64-none-linux-gnu -gsce -S -emit-llvm %s -o - \
 // RUN:   | FileCheck %s -check-prefix=NO-DECLS-FOR-EXTERN
 
 // DECLS-FOR-EXTERN-NOT: !DICompileUnit({{.*}}retainedTypes: !{{[0-9]+}}

clang/test/CodeGen/dwarf-version.c

@@ -2,8 +2,8 @@
 // RUN: %clang -target x86_64-linux-gnu -gdwarf-3 -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER3
 // RUN: %clang -target x86_64-linux-gnu -gdwarf-4 -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER4
 // RUN: %clang -target x86_64-linux-gnu -gdwarf-5 -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER5
-// RUN: %clang -target x86_64-linux-gnu -g -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER4
-// RUN: %clang -target x86_64-linux-gnu -gdwarf -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER4
+// RUN: %clang -target x86_64-linux-gnu -g -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER5
+// RUN: %clang -target x86_64-linux-gnu -gdwarf -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER5
 
 // The -isysroot is used as a hack to avoid LIT messing with the SDKROOT
 // environment variable which indirecty overrides the version in the target
@@ -28,10 +28,10 @@
 // RUN:     | FileCheck %s --check-prefixes=NODWARF,CODEVIEW
 //     Explicitly request DWARF.
 // RUN: %clang -target i686-pc-windows-msvc -gdwarf -S -emit-llvm -o - %s \
-// RUN:     | FileCheck %s --check-prefixes=VER4,NOCODEVIEW
+// RUN:     | FileCheck %s --check-prefixes=VER5,NOCODEVIEW
 //     Explicitly request both.
 // RUN: %clang -target i686-pc-windows-msvc -gdwarf -gcodeview -S -emit-llvm -o - %s \
-// RUN:     | FileCheck %s --check-prefixes=VER4,CODEVIEW
+// RUN:     | FileCheck %s --check-prefixes=VER5,CODEVIEW
 // RUN: %clang -target powerpc-ibm-aix-xcoff -g -S -emit-llvm -o - %s | \
 // RUN:   FileCheck %s --check-prefix=VER3
 // RUN: %clang -target powerpc-ibm-aix-xcoff -gdwarf-2 -S -emit-llvm -o - %s | \

clang/test/Driver/cl-options.c

@@ -596,7 +596,7 @@
 // RUN: %clang_cl /Z7 -gdwarf /c -### -- %s 2>&1 | FileCheck -check-prefix=Z7_gdwarf %s
 // Z7_gdwarf: "-gcodeview"
 // Z7_gdwarf: "-debug-info-kind=constructor"
-// Z7_gdwarf: "-dwarf-version=4"
+// Z7_gdwarf: "-dwarf-version=
 
 // RUN: %clang_cl -fmsc-version=1800 -TP -### -- %s 2>&1 | FileCheck -check-prefix=CXX11 %s
 // CXX11: -std=c++11

clang/test/Driver/clang-g-opts.c

@@ -32,7 +32,7 @@
 
 // CHECK-WITHOUT-G-NOT: -debug-info-kind
 // CHECK-WITH-G: "-debug-info-kind=constructor"
-// CHECK-WITH-G: "-dwarf-version=4"
+// CHECK-WITH-G: "-dwarf-version=5"
 // CHECK-WITH-G-DWARF2: "-dwarf-version=2"
 
 // CHECK-WITH-G-STANDALONE: "-debug-info-kind=standalone"

clang/test/Driver/ve-toolchain.c

@@ -6,7 +6,7 @@
 /// Checking dwarf-version
 
 // RUN: %clang -### -g -target ve %s 2>&1 | FileCheck -check-prefix=DWARF_VER %s
-// DWARF_VER: "-dwarf-version=4"
+// DWARF_VER: "-dwarf-version=5"
 
 ///-----------------------------------------------------------------------------
 /// Checking include-path

clang/test/Driver/ve-toolchain.cpp

@@ -7,7 +7,7 @@
 
 // RUN: %clangxx -### -g -target ve-unknown-linux-gnu \
 // RUN:     %s 2>&1 | FileCheck -check-prefix=DWARF_VER %s
-// DWARF_VER: "-dwarf-version=4"
+// DWARF_VER: "-dwarf-version=5"
 
 ///-----------------------------------------------------------------------------
 /// Checking include-path