[llvm] r345740 - MachineModuleInfo: Initialize DbgInfoAvailable depending on debug_cus existing

[Matthias Braun via llvm-commits]

Author: matze
Date: Wed Oct 31 10:18:41 2018
New Revision: 345740

URL: http://llvm.org/viewvc/llvm-project?rev=345740&view=rev
Log:
MachineModuleInfo: Initialize DbgInfoAvailable depending on debug_cus existing

Before this patch DbgInfoAvailable was set to true in
DwarfDebug::beginModule() or CodeViewDebug::CodeViewDebug(). This made
MIR testing weird since passes would suddenly stop dealing with debug
info just because we stopped the pipeline before the debug printers.

This patch changes the logic to initialize DbgInfoAvailable based on the
fact that debug_compile_units exist in the llvm Module. The debug
printers may then override it with false in case of debug printing being
disabled.

Differential Revision: https://reviews.llvm.org/D53885

Added:
    llvm/trunk/test/CodeGen/AArch64/fast-isel-dbg.ll
Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
    llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp?rev=345740&r1=345739&r2=345740&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp Wed Oct 31 10:18:41 2018
@@ -117,6 +117,7 @@ CodeViewDebug::CodeViewDebug(AsmPrinter
   if (!MMI->getModule()->getNamedMetadata("llvm.dbg.cu") ||
       !AP->getObjFileLowering().getCOFFDebugSymbolsSection()) {
     Asm = nullptr;
+    MMI->setDebugInfoAvailability(false);
     return;
   }
   // Tell MMI that we have debug info.

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=345740&r1=345739&r2=345740&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Wed Oct 31 10:18:41 2018
@@ -701,15 +701,18 @@ sortGlobalExprs(SmallVectorImpl<DwarfCom
 void DwarfDebug::beginModule() {
   NamedRegionTimer T(DbgTimerName, DbgTimerDescription, DWARFGroupName,
                      DWARFGroupDescription, TimePassesIsEnabled);
-  if (DisableDebugInfoPrinting)
+  if (DisableDebugInfoPrinting) {
+    MMI->setDebugInfoAvailability(false);
     return;
+  }
 
   const Module *M = MMI->getModule();
 
   unsigned NumDebugCUs = std::distance(M->debug_compile_units_begin(),
                                        M->debug_compile_units_end());
   // Tell MMI whether we have debug info.
-  MMI->setDebugInfoAvailability(NumDebugCUs > 0);
+  assert(MMI->hasDebugInfo() == (NumDebugCUs > 0) &&
+         "DebugInfoAvailabilty initialized unexpectedly");
   SingleCU = NumDebugCUs == 1;
   DenseMap<DIGlobalVariable *, SmallVector<DwarfCompileUnit::GlobalExpr, 1>>
       GVMap;

Modified: llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp?rev=345740&r1=345739&r2=345740&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp Wed Oct 31 10:18:41 2018
@@ -206,10 +206,11 @@ MachineModuleInfo::~MachineModuleInfo()
 bool MachineModuleInfo::doInitialization(Module &M) {
   ObjFileMMI = nullptr;
   CurCallSite = 0;
-  DbgInfoAvailable = UsesVAFloatArgument = UsesMorestackAddr = false;
+  UsesVAFloatArgument = UsesMorestackAddr = false;
   HasSplitStack = HasNosplitStack = false;
   AddrLabelSymbols = nullptr;
   TheModule = &M;
+  DbgInfoAvailable = !empty(M.debug_compile_units());
   return false;
 }
 

Added: llvm/trunk/test/CodeGen/AArch64/fast-isel-dbg.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/fast-isel-dbg.ll?rev=345740&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/fast-isel-dbg.ll (added)
+++ llvm/trunk/test/CodeGen/AArch64/fast-isel-dbg.ll Wed Oct 31 10:18:41 2018
@@ -0,0 +1,26 @@
+; RUN: llc -o - %s -fast-isel -stop-before=expand-isel-pseudos | FileCheck %s
+; Make sure fast-isel produces DBG_VALUE instructions even if no debug printer
+; is scheduled because of -stop-before.
+target triple="aarch64--"
+
+; CHECK-LABEL: name: func
+; CHECK: DBG_VALUE
+define void @func(i32 %a) !dbg !4 {
+  call void @llvm.dbg.declare(metadata i32 %a, metadata !5, metadata !DIExpression()), !dbg !7
+  ret void
+}
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #0
+attributes #0 = { nounwind readnone speculatable }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2, !3}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly)
+!1 = !DIFile(filename: "fast-isel-dbg.ll", directory: "/")
+!2 = !{i32 2, !"Dwarf Version", i32 4}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = distinct !DISubprogram(name: "func", scope: null, isLocal: false, isDefinition: true, isOptimized: false, unit: !0)
+!5 = !DILocalVariable(name: "a", arg: 1, scope: !4, file: !1, line: 17, type: !6)
+!6 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
+!7 = !DILocation(line: 17, scope: !4)