Merge commit '58b71bb621fe' from apple/stable/20200714 into swift/main

Author: git apple-llvm automerger

llvm/cmake/modules/AddLLVM.cmake

@@ -2104,6 +2104,13 @@ function(setup_dependency_debugging name)
   set_target_properties(${name} PROPERTIES RULE_LAUNCH_COMPILE ${sandbox_command})
 endfunction()
 
+# If the sources at the given `path` are under version control, set `out_var`
+# to the the path of a file which will be modified when the VCS revision
+# changes, attempting to create that file if it does not exist; if no such
+# file exists and one cannot be created, instead set `out_var` to the
+# empty string.
+#
+# If the sources are not under version control, do not define `out_var`.
 function(find_first_existing_vc_file path out_var)
   if(NOT EXISTS "${path}")
     return()
@@ -2125,6 +2132,7 @@ function(find_first_existing_vc_file path out_var)
           RESULT_VARIABLE touch_head_result
           ERROR_QUIET)
         if (NOT touch_head_result EQUAL 0)
+          set(${out_var} "" PARENT_SCOPE)
           return()
         endif()
       endif()

llvm/include/llvm/Support/CMakeLists.txt

@@ -11,7 +11,7 @@ if(LLVM_APPEND_VC_REV)
   # A fake version file and is not expected to exist. It is being used to
   # force regeneration of VCSRevision.h for source directory with no write
   # permission available.
-  if (NOT llvm_vc)
+  if (llvm_vc STREQUAL "")
     set(fake_version_inc "${CMAKE_CURRENT_BINARY_DIR}/__FakeVCSRevision.h")
   endif()
 endif()

llvm/lib/DebugInfo/DWARF/DWARFDebugArangeSet.cpp

@@ -132,19 +132,20 @@ Error DWARFDebugArangeSet::extract(DWARFDataExtractor data,
 
   uint64_t end_offset = Offset + full_length;
   while (*offset_ptr < end_offset) {
+    uint64_t EntryOffset = *offset_ptr;
     arangeDescriptor.Address = data.getUnsigned(offset_ptr, HeaderData.AddrSize);
     arangeDescriptor.Length = data.getUnsigned(offset_ptr, HeaderData.AddrSize);
 
-    if (arangeDescriptor.Length == 0) {
-      // Each set of tuples is terminated by a 0 for the address and 0
-      // for the length.
-      if (arangeDescriptor.Address == 0 && *offset_ptr == end_offset)
+    // Each set of tuples is terminated by a 0 for the address and 0
+    // for the length.
+    if (arangeDescriptor.Length == 0 && arangeDescriptor.Address == 0) {
+      if (*offset_ptr == end_offset)
         return ErrorSuccess();
       return createStringError(
           errc::invalid_argument,
           "address range table at offset 0x%" PRIx64
-          " has an invalid tuple (length = 0) at offset 0x%" PRIx64,
-          Offset, *offset_ptr - tuple_size);
+          " has a premature terminator entry at offset 0x%" PRIx64,
+          Offset, EntryOffset);
     }
 
     ArangeDescriptors.push_back(arangeDescriptor);

llvm/unittests/DebugInfo/DWARF/DWARFDebugArangeSetTest.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h"
+#include "llvm/Testing/Support/Error.h"
 #include "gtest/gtest.h"
 
 using namespace llvm;
@@ -166,24 +167,78 @@ TEST(DWARFDebugArangeSet, UnevenLength) {
       "of the tuple size");
 }
 
-TEST(DWARFDebugArangeSet, ZeroLengthEntry) {
+TEST(DWARFDebugArangeSet, ZeroAddressEntry) {
   static const char DebugArangesSecRaw[] =
-      "\x24\x00\x00\x00" // Length
+      "\x1c\x00\x00\x00" // Length
       "\x02\x00"         // Version
       "\x00\x00\x00\x00" // Debug Info Offset
       "\x04"             // Address Size
       "\x00"             // Segment Selector Size
       "\x00\x00\x00\x00" // Padding
       "\x00\x00\x00\x00" // Entry1: Address
       "\x01\x00\x00\x00" //         Length
+      "\x00\x00\x00\x00" // Termination tuple
+      "\x00\x00\x00\x00";
+  DWARFDataExtractor Extractor(
+      StringRef(DebugArangesSecRaw, sizeof(DebugArangesSecRaw) - 1),
+      /*IsLittleEndian=*/true,
+      /*AddressSize=*/4);
+  DWARFDebugArangeSet Set;
+  uint64_t Offset = 0;
+  ASSERT_THAT_ERROR(Set.extract(Extractor, &Offset),
+                    Succeeded());
+  auto Range = Set.descriptors();
+  auto Iter = Range.begin();
+  ASSERT_EQ(std::distance(Iter, Range.end()), 1u);
+  EXPECT_EQ(Iter->Address, 0u);
+  EXPECT_EQ(Iter->Length, 1u);
+}
+
+TEST(DWARFDebugArangeSet, ZeroLengthEntry) {
+  static const char DebugArangesSecRaw[] =
+      "\x1c\x00\x00\x00" // Length
+      "\x02\x00"         // Version
+      "\x00\x00\x00\x00" // Debug Info Offset
+      "\x04"             // Address Size
+      "\x00"             // Segment Selector Size
+      "\x00\x00\x00\x00" // Padding
+      "\x01\x00\x00\x00" // Entry1: Address
+      "\x00\x00\x00\x00" //         Length
+      "\x00\x00\x00\x00" // Termination tuple
+      "\x00\x00\x00\x00";
+  DWARFDataExtractor Extractor(
+      StringRef(DebugArangesSecRaw, sizeof(DebugArangesSecRaw) - 1),
+      /*IsLittleEndian=*/true,
+      /*AddressSize=*/4);
+  DWARFDebugArangeSet Set;
+  uint64_t Offset = 0;
+  ASSERT_THAT_ERROR(Set.extract(Extractor, &Offset),
+                    Succeeded());
+  auto Range = Set.descriptors();
+  auto Iter = Range.begin();
+  ASSERT_EQ(std::distance(Iter, Range.end()), 1u);
+  EXPECT_EQ(Iter->Address, 1u);
+  EXPECT_EQ(Iter->Length, 0u);
+}
+
+TEST(DWARFDebugArangesSet, PrematureTerminator) {
+  static const char DebugArangesSecRaw[] =
+      "\x24\x00\x00\x00" // Length
+      "\x02\x00"         // Version
+      "\x00\x00\x00\x00" // Debug Info Offset
+      "\x04"             // Address Size
+      "\x00"             // Segment Selector Size
+      "\x00\x00\x00\x00" // Padding
+      "\x00\x00\x00\x00" // Entry1: Premature
+      "\x00\x00\x00\x00" //         terminator
       "\x01\x00\x00\x00" // Entry2: Address
-      "\x00\x00\x00\x00" //         Length (invalid)
+      "\x01\x00\x00\x00" //         Length
       "\x00\x00\x00\x00" // Termination tuple
       "\x00\x00\x00\x00";
   ExpectExtractError(
       DebugArangesSecRaw,
-      "address range table at offset 0x0 has an invalid tuple (length = 0) "
-      "at offset 0x18");
+      "address range table at offset 0x0 has a premature "
+      "terminator entry at offset 0x10");
 }
 
 } // end anonymous namespace