10 files changed, 184 insertions, 11 deletions
diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def
index 0a47869af61..99559b5abe7 100644
--- a/clang/include/clang/Basic/CodeGenOptions.def
+++ b/clang/include/clang/Basic/CodeGenOptions.def
@@ -138,6 +138,8 @@ CODEGENOPT(FatalWarnings     , 1, 0) ///< Set when -Wa,--fatal-warnings is
                                      ///< enabled.
 CODEGENOPT(NoWarn            , 1, 0) ///< Set when -Wa,--no-warn is enabled.
 CODEGENOPT(EnableSegmentedStacks , 1, 0) ///< Set when -fsplit-stack is enabled.
+CODEGENOPT(NoInlineLineTables, 1, 0) ///< Whether debug info should contain
+                                     ///< inline line tables.
 CODEGENOPT(NoImplicitFloat   , 1, 0) ///< Set when -mno-implicit-float is enabled.
 CODEGENOPT(NoInfsFPMath      , 1, 0) ///< Assume FP arguments, results not +-Inf.
 CODEGENOPT(NoSignedZeros     , 1, 0) ///< Allow ignoring the signedness of FP zero
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 3093dc65fce..47e8bbf3eb1 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -1998,6 +1998,9 @@ def gcodeview_ghash : Flag<["-"], "gcodeview-ghash">,
   HelpText<"Emit type record hashes in a .debug$H section">,
   Flags<[CC1Option, CoreOption]>;
 def gno_codeview_ghash : Flag<["-"], "gno-codeview-ghash">, Flags<[CoreOption]>;
+def ginline_line_tables : Flag<["-"], "ginline-line-tables">, Flags<[CoreOption]>;
+def gno_inline_line_tables : Flag<["-"], "gno-inline-line-tables">,
+  Flags<[CC1Option, CoreOption]>, HelpText<"Don't emit inline line tables">;
 
 def gfull : Flag<["-"], "gfull">, Group<g_Group>;
 def gused : Flag<["-"], "gused">, Group<g_Group>;
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 3f9a52ab763..1b1d391a63d 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -764,6 +764,10 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
   Fn->addFnAttr("no-jump-tables",
                 llvm::toStringRef(CGM.getCodeGenOpts().NoUseJumpTables));
 
+  // Add no-inline-line-tables value.
+  if (CGM.getCodeGenOpts().NoInlineLineTables)
+    Fn->addFnAttr("no-inline-line-tables");
+
   // Add profile-sample-accurate value.
   if (CGM.getCodeGenOpts().ProfileSampleAccurate)
     Fn->addFnAttr("profile-sample-accurate");
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 529c33a1674..369d8cc1aa9 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -3312,6 +3312,12 @@ static void RenderDebugOptions(const ToolChain &TC, const Driver &D,
     }
   }
 
+  // Omit inline line tables if requested.
+  if (Args.hasFlag(options::OPT_gno_inline_line_tables,
+                   options::OPT_ginline_line_tables, false)) {
+    CmdArgs.push_back("-gno-inline-line-tables");
+  }
+
   // Adjust the debug info kind for the given toolchain.
   TC.adjustDebugInfoKind(DebugInfoKind, Args);
 
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 0775d1021c5..c935ce5ebab 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -809,6 +809,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.RecordCommandLine = Args.getLastArgValue(OPT_record_command_line);
   Opts.MergeAllConstants = Args.hasArg(OPT_fmerge_all_constants);
   Opts.NoCommon = Args.hasArg(OPT_fno_common);
+  Opts.NoInlineLineTables = Args.hasArg(OPT_gno_inline_line_tables);
   Opts.NoImplicitFloat = Args.hasArg(OPT_no_implicit_float);
   Opts.OptimizeSize = getOptimizationLevelSize(Args);
   Opts.SimplifyLibCalls = !(Args.hasArg(OPT_fno_builtin) ||
diff --git a/clang/test/CodeGen/debug-info-no-inline-line-tables.c b/clang/test/CodeGen/debug-info-no-inline-line-tables.c
new file mode 100644
index 00000000000..ac9216247c8
--- /dev/null
+++ b/clang/test/CodeGen/debug-info-no-inline-line-tables.c
@@ -0,0 +1,31 @@
+// RUN: %clang_cc1 -triple x86_64-windows-msvc -debug-info-kind=limited \
+// RUN:   -gno-inline-line-tables -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang -gno-inline-line-tables -S -emit-llvm -o - %s | FileCheck %s \
+// RUN:   -check-prefix=INLINE-FLAG
+// RUN: %clang -S -emit-llvm -o - %s | FileCheck %s -check-prefix=NO-FLAG
+
+int x;
+__attribute((always_inline)) void f() {
+  x += 1;
+}
+int main() {
+  f();
+  x += 2;
+  return x;
+}
+
+// Check that clang emits the location of the call site and not the inlined
+// function in the debug info.
+// CHECK: define dso_local i32 @main()
+// CHECK: %{{.+}} = load i32, i32* @x, align 4, !dbg [[DbgLoc:![0-9]+]]
+
+// Check that the no-inline-line-tables attribute is added.
+// CHECK: attributes #0 = {{.*}}"no-inline-line-tables"{{.*}}
+// CHECK: attributes #1 = {{.*}}"no-inline-line-tables"{{.*}}
+
+// CHECK: [[DbgLoc]] = !DILocation(line: 12,
+// CHECK-NOT:  inlinedAt:
+
+// INLINE-FLAG: attributes #0 = {{.*}}"no-inline-line-tables"{{.*}}
+// INLINE-FLAG: attributes #1 = {{.*}}"no-inline-line-tables"{{.*}}
+// NO-FLAG-NOT: "no-inline-line-tables"
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 6e99f25b572..b6b94dd3078 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -1456,6 +1456,13 @@ example:
 ``naked``
     This attribute disables prologue / epilogue emission for the
     function. This can have very system-specific consequences.
+``"no-inline-line-tables"``
+    When this attribute is set to true, the inliner discards source locations
+    when inlining code and instead uses the source location of the call site.
+    Breakpoints set on code that was inlined into the current function will
+    not fire during the execution of the inlined call sites. If the debugger
+    stops inside an inlined call site, it will appear to be stopped at the
+    outermost inlined call site.
 ``no-jump-tables``
     When this attribute is set to true, the jump tables and lookup tables that
     can be generated from a switch case lowering are disabled.
diff --git a/llvm/include/llvm/IR/Attributes.td b/llvm/include/llvm/IR/Attributes.td
index 153046d2311..5d4a5f6743b 100644
--- a/llvm/include/llvm/IR/Attributes.td
+++ b/llvm/include/llvm/IR/Attributes.td
@@ -220,6 +220,7 @@ def NoInfsFPMath : StrBoolAttr<"no-infs-fp-math">;
 def NoNansFPMath : StrBoolAttr<"no-nans-fp-math">;
 def UnsafeFPMath : StrBoolAttr<"unsafe-fp-math">;
 def NoJumpTables : StrBoolAttr<"no-jump-tables">;
+def NoInlineLineTables : StrBoolAttr<"no-inline-line-tables">;
 def ProfileSampleAccurate : StrBoolAttr<"profile-sample-accurate">;
 
 class CompatRule<string F> {
diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index 7e08da35563..b522dd2b631 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -1405,6 +1405,10 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
   // other.
   DenseMap<const MDNode *, MDNode *> IANodes;
 
+  // Check if we are not generating inline line tables and want to use
+  // the call site location instead.
+  bool NoInlineLineTables = Fn->hasFnAttribute("no-inline-line-tables");
+
   for (; FI != Fn->end(); ++FI) {
     for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
          BI != BE; ++BI) {
@@ -1416,20 +1420,22 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
         BI->setMetadata(LLVMContext::MD_loop, NewLoopID);
       }
 
-      if (DebugLoc DL = BI->getDebugLoc()) {
-        DebugLoc IDL =
-            inlineDebugLoc(DL, InlinedAtNode, BI->getContext(), IANodes);
-        BI->setDebugLoc(IDL);
-        continue;
-      }
+      if (!NoInlineLineTables)
+        if (DebugLoc DL = BI->getDebugLoc()) {
+          DebugLoc IDL =
+              inlineDebugLoc(DL, InlinedAtNode, BI->getContext(), IANodes);
+          BI->setDebugLoc(IDL);
+          continue;
+        }
 
-      if (CalleeHasDebugInfo)
+      if (CalleeHasDebugInfo && !NoInlineLineTables)
         continue;
 
-      // If the inlined instruction has no line number, make it look as if it
-      // originates from the call location. This is important for
-      // ((__always_inline__, __nodebug__)) functions which must use caller
-      // location for all instructions in their function body.
+      // If the inlined instruction has no line number, or if inline info
+      // is not being generated, make it look as if it originates from the call
+      // location. This is important for ((__always_inline, __nodebug__))
+      // functions which must use caller location for all instructions in their
+      // function body.
 
       // Don't update static allocas, as they may get moved later.
       if (auto *AI = dyn_cast<AllocaInst>(BI))
@@ -1438,6 +1444,19 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
 
       BI->setDebugLoc(TheCallDL);
     }
+
+    // Remove debug info intrinsics if we're not keeping inline info.
+    if (NoInlineLineTables) {
+      BasicBlock::iterator BI = FI->begin();
+      while (BI != FI->end()) {
+        if (isa<DbgInfoIntrinsic>(BI)) {
+          BI = BI->eraseFromParent();
+          continue;
+        }
+        ++BI;
+      }
+    }
+
   }
 }
 
diff --git a/llvm/test/Transforms/Inline/no-inline-line-tables.ll b/llvm/test/Transforms/Inline/no-inline-line-tables.ll
new file mode 100644
index 00000000000..b20f6b75888
--- /dev/null
+++ b/llvm/test/Transforms/Inline/no-inline-line-tables.ll
@@ -0,0 +1,99 @@
+; RUN: opt < %s -inline -S | FileCheck %s
+
+; This tests that functions with the attribute `no-inline-line-tables` have the
+; correct debug information when they are inlined.
+
+; ModuleID = 't.c'
+source_filename = "t.c"
+target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-windows-msvc"
+
+; Function Attrs: alwaysinline nounwind
+define dso_local i32 @f(i32 %x) #0 !dbg !7 {
+entry:
+  %x.addr = alloca i32, align 4
+  store i32 %x, i32* %x.addr, align 4
+  call void @llvm.dbg.declare(metadata i32* %x.addr, metadata !12, metadata !DIExpression()), !dbg !13
+  %0 = load i32, i32* %x.addr, align 4, !dbg !14
+  ret i32 %0, !dbg !14
+}
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: alwaysinline nounwind
+define i32 @g(i32 %x) #0 !dbg !15 {
+entry:
+  %x.addr = alloca i32, align 4
+  store i32 %x, i32* %x.addr, align 4
+  call void @llvm.dbg.declare(metadata i32* %x.addr, metadata !16, metadata !DIExpression()), !dbg !17
+  br label %L, !dbg !17
+
+L:                                                ; preds = %entry
+  call void @llvm.dbg.label(metadata !18), !dbg !19
+  store i32 42, i32* %x.addr, align 4, !dbg !20
+  %0 = load i32, i32* %x.addr, align 4, !dbg !21
+  ret i32 %0, !dbg !21
+}
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.label(metadata) #1
+
+; Check that debug info for inlined code uses the call location and that debug
+; intrinsics are removed.
+; Function Attrs: noinline nounwind optnone
+define i32 @main() #2 !dbg !22 {
+entry:
+; CHECK-LABEL: @main()
+; CHECK-NOT: @f
+; CHECK-NOT: @llvm.dbg.declare
+; CHECK: %{{[0-9]+}} = load i32, i32* %x.addr.i, align 4, !dbg ![[VAR1:[0-9]+]]
+  %call = call i32 @f(i32 3), !dbg !25
+
+; Another test for inlining debug intrinsics where the intrinsic appears at the
+; start of the basic block.
+; CHECK-NOT: @g
+; CHECK-NOT: @llvm.dbg.label
+; CHECK: %{{[0-9]+}} = load i32, i32* %x.addr.i1, align 4, !dbg ![[VAR2:[0-9]+]]
+  %call1 = call i32 @g(i32 340), !dbg !26
+  ret i32 0, !dbg !27
+}
+
+; CHECK: ![[VAR1]] = !DILocation(line: 10, scope: ![[SCOPE:[0-9]+]])
+; CHECK: ![[VAR2]] = !DILocation(line: 11, scope: ![[SCOPE]])
+
+attributes #0 = { alwaysinline nounwind "no-inline-line-tables" }
+attributes #2 = { noinline nounwind optnone "no-inline-line-tables"}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0 (https://github.com/llvm/llvm-project.git 03ec3a12a94bbbaa11999b6da3a43221a5aa54a5)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "<stdin>", directory: "/usr/local/google/home/akhuang/testing/inline-line-tables", checksumkind: CSK_MD5, checksum: "38a4785b48742d3ea655b8f3461436a4")
+!2 = !{}
+!3 = !{i32 2, !"CodeView", i32 1}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 10.0.0 (https://github.com/llvm/llvm-project.git 03ec3a12a94bbbaa11999b6da3a43221a5aa54a5)"}
+!7 = distinct !DISubprogram(name: "f", scope: !8, file: !8, line: 1, type: !9, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!8 = !DIFile(filename: "t.c", directory: "/usr/local/google/home/akhuang/testing/inline-line-tables", checksumkind: CSK_MD5, checksum: "38a4785b48742d3ea655b8f3461436a4")
+!9 = !DISubroutineType(types: !10)
+!10 = !{!11, !11}
+!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!12 = !DILocalVariable(name: "x", arg: 1, scope: !7, file: !8, line: 1, type: !11)
+!13 = !DILocation(line: 1, scope: !7)
+!14 = !DILocation(line: 2, scope: !7)
+!15 = distinct !DISubprogram(name: "g", scope: !8, file: !8, line: 4, type: !9, scopeLine: 4, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!16 = !DILocalVariable(name: "x", arg: 1, scope: !15, file: !8, line: 4, type: !11)
+!17 = !DILocation(line: 4, scope: !15)
+!18 = !DILabel(scope: !15, name: "L", file: !8, line: 5)
+!19 = !DILocation(line: 5, scope: !15)
+!20 = !DILocation(line: 6, scope: !15)
+!21 = !DILocation(line: 7, scope: !15)
+!22 = distinct !DISubprogram(name: "main", scope: !8, file: !8, line: 9, type: !23, scopeLine: 9, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!23 = !DISubroutineType(types: !24)
+!24 = !{!11}
+!25 = !DILocation(line: 10, scope: !22)
+!26 = !DILocation(line: 11, scope: !22)
+!27 = !DILocation(line: 12, scope: !22)