Revert "Symbolize line zero as if no source info is available (#124846)"

This commit creates an inconsistency on `__sanitizer_symbolize_pc` API. Before this change, this API always uses the filename from debug info when the line number is 0. After this change, the filename becomes invalid when line number is 0. The sanitizer might fall back to use base filename from symbol table. So, this API may return either `??:0` or `{filename from symbol table}:0` depending on if the symbol table has the filename for it. Make sure this inconsistency is resolved before relanding the commit.

Author: ZequanWu

llvm/lib/DebugInfo/DWARF/DWARFContext.cpp

@@ -1869,7 +1869,7 @@ DWARFContext::getInliningInfoForAddress(object::SectionedAddress Address,
           LineTable->getFileLineInfoForAddress(
               {Address.Address, Address.SectionIndex}, Spec.ApproximateLine,
               CU->getCompilationDir(), Spec.FLIKind, Frame);
-      } else if (CallLine != 0) {
+      } else {
         // Otherwise, use call file, call line and call column from
         // previous DIE in inlined chain.
         if (LineTable)

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

@@ -1539,8 +1539,7 @@ bool DWARFDebugLine::LineTable::getFileLineInfoForAddress(
     return false;
   // Take file number and line/column from the row.
   const auto &Row = Rows[RowIndex];
-  if (Row.Line == 0 ||
-      !getFileNameByIndex(Row.File, CompDir, Kind, Result.FileName))
+  if (!getFileNameByIndex(Row.File, CompDir, Kind, Result.FileName))
     return false;
   Result.Line = Row.Line;
   Result.Column = Row.Column;

llvm/test/tools/llvm-symbolizer/skip-line-zero.s

@@ -20,13 +20,13 @@
 ## Check that without '--skip-line-zero', line zero is displayed for a line-table entry which has no source correspondence.
 # RUN: llvm-symbolizer --obj=%t.o -f=none 0x16d4 | FileCheck --strict-whitespace --match-full-lines --check-prefix=DISABLE %s
 
-# DISABLE:??:0:0
+# DISABLE:main.c:0:0
 
 ## Check that the '--skip-line-zero' does not cross sequence boundaries.
 ## If it fails to find in the current sequence then line zero is returned for the queried address.
 # RUN: llvm-symbolizer --obj=%t.o -f=none --skip-line-zero 0x16c0 | FileCheck --strict-whitespace --match-full-lines --check-prefix=FAIL-ACROSS-SEQ %s
 
-# FAIL-ACROSS-SEQ:??:0:0
+# FAIL-ACROSS-SEQ:main.c:0:0
 
 ## Check that with '--skip-line-zero', the last non-zero line in the current sequence is displayed.
 # RUN: llvm-symbolizer --obj=%t.o -f=none --skip-line-zero 0x1717 | FileCheck --strict-whitespace --match-full-lines --check-prefix=WITHIN-SEQ %s

llvm/test/tools/llvm-symbolizer/sym-verbose.test

@@ -50,12 +50,13 @@ CHECK-NEXT: Column: 0
 
 CHECK: 0x4005ad
 CHECK-NEXT: foo
-CHECK-NEXT: Filename: ??
+CHECK-NEXT: Filename: /tmp{{[\\/]}}discrim.c
 CHECK-NEXT: Function start filename: /tmp{{[\\/]}}discrim.c
 CHECK-NEXT: Function start line: 4
 CHECK-NEXT: Function start address: 0x400590
 CHECK-NEXT: Line: 0
-CHECK-NEXT: Column: 0
+CHECK-NEXT: Column: 30
+CHECK-NEXT: Discriminator: 4
 CHECK-NEXT: main
 CHECK-NEXT: Filename: /tmp{{[\\/]}}discrim.c
 CHECK-NEXT: Function start filename: /tmp{{[\\/]}}discrim.c