[DWARF] Allow toolchain to adjust specified DWARF version.

Artem-B · Artem-B · commit 016e4ebfde28 · 2020-12-09T16:34:34.000-08:00
This is needed for CUDA compilation where NVPTX back-end only supports DWARF2, but host compilation should be allowed to use newer DWARF versions. Differential Revision: https://reviews.llvm.org/D92617
diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -292,6 +292,9 @@ def warn_drv_unsupported_opt_for_target : Warning<
 def warn_drv_unsupported_debug_info_opt_for_target : Warning<
   "debug information option '%0' is not supported for target '%1'">,
   InGroup<UnsupportedTargetOpt>;
+def warn_drv_dwarf_version_limited_by_target : Warning<
+  "debug information option '%0' is not supported. It needs DWARF-%2 but target '%1' only provides DWARF-%3.">,
+  InGroup<UnsupportedTargetOpt>;
 def warn_c_kext : Warning<
   "ignoring -fapple-kext which is valid for C++ and Objective-C++ only">;
 def warn_ignoring_fdiscard_for_bitcode : Warning<
diff --git a/clang/include/clang/Driver/ToolChain.h b/clang/include/clang/Driver/ToolChain.h
@@ -27,6 +27,7 @@
 #include "llvm/Support/VersionTuple.h"
 #include "llvm/Target/TargetOptions.h"
 #include <cassert>
+#include <climits>
 #include <memory>
 #include <string>
 #include <utility>
@@ -489,6 +490,11 @@ class ToolChain {
   // to the contrary.
   virtual unsigned GetDefaultDwarfVersion() const { return 4; }
 
+  // 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
+  // compilation uses DWARF5.
+  virtual unsigned getMaxDwarfVersion() const { return UINT_MAX; }
+
   // True if the driver should assume "-fstandalone-debug"
   // in the absence of an option specifying otherwise,
   // provided that debugging was requested in the first place.
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -3821,26 +3821,33 @@ static void RenderDebugOptions(const ToolChain &TC, const Driver &D,
     }
   }
 
-  unsigned DWARFVersion = 0;
+  unsigned RequestedDWARFVersion = 0; // DWARF version requested by the user
+  unsigned EffectiveDWARFVersion = 0; // DWARF version TC can generate. It may
+                                      // be lower than what the user wanted.
   unsigned DefaultDWARFVersion = ParseDebugDefaultVersion(TC, Args);
   if (EmitDwarf) {
     // Start with the platform default DWARF version
-    DWARFVersion = TC.GetDefaultDwarfVersion();
-    assert(DWARFVersion && "toolchain default DWARF version must be nonzero");
+    RequestedDWARFVersion = TC.GetDefaultDwarfVersion();
+    assert(RequestedDWARFVersion &&
+           "toolchain default DWARF version must be nonzero");
 
     // If the user specified a default DWARF version, that takes precedence
     // over the platform default.
     if (DefaultDWARFVersion)
-      DWARFVersion = DefaultDWARFVersion;
+      RequestedDWARFVersion = DefaultDWARFVersion;
 
     // Override with a user-specified DWARF version
     if (GDwarfN)
       if (auto ExplicitVersion = DwarfVersionNum(GDwarfN->getSpelling()))
-        DWARFVersion = ExplicitVersion;
+        RequestedDWARFVersion = ExplicitVersion;
+    // Clamp effective DWARF version to the max supported by the toolchain.
+    EffectiveDWARFVersion =
+        std::min(RequestedDWARFVersion, TC.getMaxDwarfVersion());
   }
 
   // -gline-directives-only supported only for the DWARF debug info.
-  if (DWARFVersion == 0 && DebugInfoKind == codegenoptions::DebugDirectivesOnly)
+  if (RequestedDWARFVersion == 0 &&
+      DebugInfoKind == codegenoptions::DebugDirectivesOnly)
     DebugInfoKind = codegenoptions::NoDebugInfo;
 
   // We ignore flag -gstrict-dwarf for now.
@@ -3900,9 +3907,15 @@ static void RenderDebugOptions(const ToolChain &TC, const Driver &D,
     // fallen back to the target default, so if this is still not at least 5
     // we emit an error.
     const Arg *A = Args.getLastArg(options::OPT_gembed_source);
-    if (DWARFVersion < 5)
+    if (RequestedDWARFVersion < 5)
       D.Diag(diag::err_drv_argument_only_allowed_with)
           << A->getAsString(Args) << "-gdwarf-5";
+    else if (EffectiveDWARFVersion < 5)
+      // The toolchain has reduced allowed dwarf version, so we can't enable
+      // -gembed-source.
+      D.Diag(diag::warn_drv_dwarf_version_limited_by_target)
+          << A->getAsString(Args) << TC.getTripleString() << 5
+          << EffectiveDWARFVersion;
     else if (checkDebugInfoOption(A, Args, D, TC))
       CmdArgs.push_back("-gembed-source");
   }
@@ -3931,7 +3944,7 @@ static void RenderDebugOptions(const ToolChain &TC, const Driver &D,
       DebugInfoKind <= codegenoptions::DebugDirectivesOnly)
     DebugInfoKind = codegenoptions::DebugLineTablesOnly;
 
-  RenderDebugEnablingArgs(Args, CmdArgs, DebugInfoKind, DWARFVersion,
+  RenderDebugEnablingArgs(Args, CmdArgs, DebugInfoKind, EffectiveDWARFVersion,
                           DebuggerTuning);
 
   // -fdebug-macro turns on macro debug info generation.
diff --git a/clang/lib/Driver/ToolChains/Cuda.h b/clang/lib/Driver/ToolChains/Cuda.h
@@ -185,6 +185,8 @@ class LLVM_LIBRARY_VISIBILITY CudaToolChain : public ToolChain {
                      const llvm::opt::ArgList &Args) const override;
 
   unsigned GetDefaultDwarfVersion() const override { return 2; }
+  // NVPTX supports only DWARF2.
+  unsigned getMaxDwarfVersion() const override { return 2; }
 
   const ToolChain &HostTC;
   CudaInstallationDetector CudaInstallation;
diff --git a/clang/test/Driver/cuda-omp-unsupported-debug-options.cu b/clang/test/Driver/cuda-omp-unsupported-debug-options.cu
@@ -0,0 +1,65 @@
+// REQUIRES: clang-driver
+// REQUIRES: x86-registered-target
+// REQUIRES: nvptx-registered-target
+// REQUIRES: zlib
+
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -g -gz 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -gdwarf -fdebug-info-for-profiling 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -gdwarf-2 -gsplit-dwarf 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -gdwarf-3 -glldb 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -gdwarf-4 -gcodeview 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -gdwarf-5 -gmodules 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -ggdb1 -fdebug-macro 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -ggdb2 -ggnu-pubnames 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -ggdb3 -gdwarf-aranges 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -g -gcolumn-info -fdebug-types-section 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN,COMMON
+
+// Same tests for OpenMP
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -g -gz 2>&1 | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -gdwarf -fdebug-info-for-profiling 2>&1 | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -gdwarf-2 -gsplit-dwarf 2>&1 | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -gdwarf-3 -glldb 2>&1 | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -gdwarf-4 -gcodeview 2>&1 | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -gdwarf-5 -gmodules 2>&1 | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -ggdb1 -fdebug-macro 2>&1 | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -ggdb2 -ggnu-pubnames 2>&1 | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -ggdb3 -gdwarf-aranges 2>&1 | FileCheck %s --check-prefixes WARN,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -g -gcolumn-info -fdebug-types-section 2>&1 | FileCheck %s --check-prefixes WARN,COMMON
+
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -gdwarf-5 -gembed-source 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN-GES,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -ggdb -gembed-source -gdwarf-5 2>&1 \
+// RUN: | FileCheck %s --check-prefixes WARN-GES,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -gdwarf-5 -gembed-source 2>&1 | FileCheck %s --check-prefixes WARN-GES,COMMON
+// RUN: %clang -### -target x86_64-linux-gnu -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -c %s \
+// RUN:   -ggdb -gembed-source -gdwarf-5 2>&1 | FileCheck %s --check-prefixes WARN-GES,COMMON
+
+// COMMON: warning: debug information option '{{-gz|-fdebug-info-for-profiling|-gsplit-dwarf|-glldb|-gcodeview|-gmodules|-gembed-source|-fdebug-macro|-ggnu-pubnames|-gdwarf-aranges|-fdebug-types-section}}' is not supported
+// WARN-SAME: for target 'nvptx64-nvidia-cuda' [-Wunsupported-target-opt]
+// WARN-GES-SAME: It needs DWARF-5 but target 'nvptx64-nvidia-cuda' only provides DWARF-2. [-Wunsupported-target-opt]
+// COMMON-NOT: debug information option '{{.*}}' is not supported for target 'x86
+// COMMON: "-triple" "nvptx64-nvidia-cuda"
+// COMMON-NOT: {{-compress-debug|-fdebug-info-for-profiling|lldb|codeview|module-format|embed-source|debug-info-macro|gnu-pubnames|generate-arange-section|generate-type-units}}
+// COMMON: "-triple" "x86_64
+// COMMON-SAME: {{-compress-debug|-fdebug-info-for-profiling|split-dwarf|lldb|codeview|module-format|embed-source|debug-info-macro|gnu-pubnames|generate-arange-section|generate-type-units}}
diff --git a/clang/test/Driver/cuda-unsupported-debug-options.cu b/clang/test/Driver/cuda-unsupported-debug-options.cu
diff --git a/clang/test/Driver/dwarf-target-version-clamp.cu b/clang/test/Driver/dwarf-target-version-clamp.cu
@@ -0,0 +1,14 @@
+// REQUIRES: clang-driver
+// REQUIRES: x86-registered-target
+// REQUIRES: nvptx-registered-target
+
+// Verify that DWARF version is properly clamped for nvptx, but not for the host.
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -gdwarf-5 -gembed-source 2>&1 \
+// RUN: | FileCheck %s --check-prefix=DWARF-CLAMP
+// RUN: %clang -### -target x86_64-linux-gnu -c %s -ggdb -gembed-source -gdwarf-5 2>&1 \
+// RUN: | FileCheck %s --check-prefix=DWARF-CLAMP
+
+// DWARF-CLAMP: "-triple" "nvptx64-nvidia-cuda"
+// DWARF-CLAMP-SAME: -dwarf-version=2
+// DWARF-CLAMP: "-triple" "x86_64
+// DWARF-CLAMP-SAME: -dwarf-version=5
diff --git a/clang/test/Driver/openmp-unsupported-debug-options.c b/clang/test/Driver/openmp-unsupported-debug-options.c
