Revert "Round up zero-sized symbols to 1 byte in .debug_aranges."

This reverts commit 256a52d (and also the follow-up commit 38eb4fe that moved a test case to a different directory). As discussed in https://reviews.llvm.org/D126257 there is a suspicion that something was wrong with this commit as text section range was shortened to 1 byte rather than rounded up as shown in the llvm/test/DebugInfo/X86/dwarf-aranges.ll test case.
llvm · May 31, 2022 · 86caa03 · 86caa03
1 parent f199b2b
commit 86caa03
Show file tree

Hide file tree

Showing 4 changed files with 5 additions and 32 deletions.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -3042,17 +3042,13 @@ void DwarfDebug::emitDebugARanges() {
     for (const ArangeSpan &Span : List) {
       Asm->emitLabelReference(Span.Start, PtrSize);
 
-      // Calculate the size as being from the span start to its end.
-      //
-      // If the size is zero, then round it up to one byte. The DWARF
-      // specification requires that entries in this table have nonzero
-      // lengths.
-      uint64_t Size = SymSize[Span.Start];
-      if (Size != 0 && Span.End) {
+      // Calculate the size as being from the span start to it's end.
+      if (Span.End) {
         Asm->emitLabelDifference(Span.End, Span.Start, PtrSize);
       } else {
         // For symbols without an end marker (e.g. common), we
         // write a single arange entry containing just that one symbol.
+        uint64_t Size = SymSize[Span.Start];
         if (Size == 0)
           Size = 1;
 

diff --git a/llvm/test/CodeGen/X86/dwarf-aranges-zero-size.ll b/llvm/test/CodeGen/X86/dwarf-aranges-zero-size.ll
diff --git a/llvm/test/DebugInfo/MSP430/dwarf-basics-v5.ll b/llvm/test/DebugInfo/MSP430/dwarf-basics-v5.ll
@@ -98,7 +98,7 @@
 
 ; CHECK:      .debug_aranges contents:
 ; CHECK-NEXT: Address Range Header: length = 0x{{.*}}, format = DWARF32, version = 0x0002, cu_offset = 0x00000000, addr_size = 0x02, seg_size = 0x00
-; CHECK-NEXT: [0x0000, 0x0001)
+; CHECK-NEXT: [0x0000, 0x0006)
 
 ; CHECK:      .debug_addr contents:
 ; CHECK-NEXT: Address table header: length = 0x{{.*}}, format = DWARF32, version = 0x0005, addr_size = 0x02, seg_size = 0x00

diff --git a/llvm/test/DebugInfo/X86/dwarf-aranges.ll b/llvm/test/DebugInfo/X86/dwarf-aranges.ll
@@ -22,7 +22,7 @@
 
 ; <text section> - it should have made one span covering all functions in this CU.
 ; CHECK-NEXT: .quad .Lfunc_begin0
-; CHECK-NEXT: .quad 1
+; CHECK-NEXT: .quad .Lsec_end2-.Lfunc_begin0
 
 ; -- finish --
 ; CHECK-NEXT: # ARange terminator