Add IR debug info support for Elemental, Pure, and Recursive Procedures.

Patch by Eric Schweitz! Differential Revision: https://reviews.llvm.org/D54043 llvm-svn: 356163
llvm · Mar 14, 2019 · e69917f · e69917f
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commit e69917f
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Showing 5 changed files with 57 additions and 3 deletions.
diff --git a/llvm/docs/SourceLevelDebugging.rst b/llvm/docs/SourceLevelDebugging.rst
@@ -670,6 +670,37 @@ a C/C++ front-end would generate the following descriptors:
   ...
   }
 
+Fortran specific debug information
+==================================
+
+Fortran function information
+----------------------------
+
+There are a few DWARF attributes defined to support client debugging of Fortran programs.  LLVM can generate (or omit) the appropriate DWARF attributes for the prefix-specs of ELEMENTAL, PURE, IMPURE, RECURSIVE, and NON_RECURSIVE.  This is done by using the spFlags values: DISPFlagElemental, DISPFlagPure, and DISPFlagRecursive.
+
+.. code-block:: fortran
+
+  elemental function elem_func(a)
+
+a Fortran front-end would generate the following descriptors:
+
+.. code-block:: text
+
+  !11 = distinct !DISubprogram(name: "subroutine2", scope: !1, file: !1,
+          line: 5, type: !8, scopeLine: 6,
+          spFlags: DISPFlagDefinition | DISPFlagElemental, unit: !0,
+          retainedNodes: !2)
+
+and this will materialize an additional DWARF attribute as:
+
+.. code-block:: text
+
+  DW_TAG_subprogram [3]  
+     DW_AT_low_pc [DW_FORM_addr]     (0x0000000000000010 ".text")
+     DW_AT_high_pc [DW_FORM_data4]   (0x00000001)
+     ...
+     DW_AT_elemental [DW_FORM_flag_present]  (true)
+
 Debugging information format
 ============================
 

diff --git a/llvm/include/llvm/IR/DebugInfoFlags.def b/llvm/include/llvm/IR/DebugInfoFlags.def
@@ -85,11 +85,14 @@ HANDLE_DISP_FLAG(2u, PureVirtual)
 HANDLE_DISP_FLAG((1u << 2), LocalToUnit)
 HANDLE_DISP_FLAG((1u << 3), Definition)
 HANDLE_DISP_FLAG((1u << 4), Optimized)
+HANDLE_DISP_FLAG((1u << 5), Pure)
+HANDLE_DISP_FLAG((1u << 6), Elemental)
+HANDLE_DISP_FLAG((1u << 7), Recursive)
 
 #ifdef DISP_FLAG_LARGEST_NEEDED
 // Intended to be used with ADT/BitmaskEnum.h.
 // NOTE: Always must be equal to largest flag, check this when adding new flags.
-HANDLE_DISP_FLAG((1 << 4), Largest)
+HANDLE_DISP_FLAG((1 << 7), Largest)
 #undef DISP_FLAG_LARGEST_NEEDED
 #endif
 

diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -1801,6 +1801,9 @@ class DISubprogram : public DILocalScope {
     return getFlags() & FlagAllCallsDescribed;
   }
   bool isMainSubprogram() const { return getFlags() & FlagMainSubprogram; }
+  bool isPure() const { return getSPFlags() & SPFlagPure; }
+  bool isElemental() const { return getSPFlags() & SPFlagElemental; }
+  bool isRecursive() const { return getSPFlags() & SPFlagRecursive; }
 
   /// Check if this is reference-qualified.
   ///

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1267,6 +1267,12 @@ void DwarfUnit::applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
 
   if (SP->isMainSubprogram())
     addFlag(SPDie, dwarf::DW_AT_main_subprogram);
+  if (SP->isPure())
+    addFlag(SPDie, dwarf::DW_AT_pure);
+  if (SP->isElemental())
+    addFlag(SPDie, dwarf::DW_AT_elemental);
+  if (SP->isRecursive())
+    addFlag(SPDie, dwarf::DW_AT_recursive);
 }
 
 void DwarfUnit::constructSubrangeDIE(DIE &Buffer, const DISubrange *SR,

diff --git a/llvm/test/Assembler/disubprogram.ll b/llvm/test/Assembler/disubprogram.ll
@@ -6,8 +6,8 @@ define void @_Z3foov() !dbg !9 {
   ret void
 }
 
-; CHECK: !named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9, !10, !11, !12, !13, !14, !15}
-!named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9, !10, !11, !12, !13, !14, !15}
+; CHECK: !named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9, !10, !11, !12, !13, !14, !15, !16, !17, !18, !19}
+!named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9, !10, !11, !12, !13, !14, !15, !17, !19, !20, !21}
 
 !0 = !{null}
 !1 = distinct !DICompositeType(tag: DW_TAG_structure_type)
@@ -81,3 +81,14 @@ define void @_Z3foov() !dbg !9 {
 !16 = !{i32 1, !"Debug Info Version", i32 3}
 !llvm.module.flags = !{!16}
 !llvm.dbg.cu = !{!8}
+
+; CHECK: !DISubprogram({{.*}}subroutine1{{.*}}, spFlags: DISPFlagDefinition | DISPFlagPure,
+; CHECK: !DISubprogram({{.*}}subroutine2{{.*}}, spFlags: DISPFlagDefinition | DISPFlagElemental,
+; CHECK: !DISubprogram({{.*}}subroutine3{{.*}}, spFlags: DISPFlagDefinition | DISPFlagRecursive,
+; CHECK: !DISubprogram({{.*}}subroutine4{{.*}}, spFlags: DISPFlagDefinition | DISPFlagPure | DISPFlagElemental | DISPFlagRecursive,
+
+!17 = distinct !DISubprogram(name: "subroutine1", scope: !1, file: !2, line: 1, type: !18, scopeLine: 2, spFlags: DISPFlagDefinition | DISPFlagPure, unit: !8, retainedNodes: !6)
+!18 = !DISubroutineType(types: !0)
+!19 = distinct !DISubprogram(name: "subroutine2", scope: !1, file: !2, line: 5, type: !18, scopeLine: 6, spFlags: DISPFlagDefinition | DISPFlagElemental, unit: !8, retainedNodes: !6)
+!20 = distinct !DISubprogram(name: "subroutine3", scope: !1, file: !2, line: 9, type: !18, scopeLine: 10, spFlags: DISPFlagDefinition | DISPFlagRecursive, unit: !8, retainedNodes: !6)
+!21 = distinct !DISubprogram(name: "subroutine4", scope: !1, file: !2, line: 13, type: !18, scopeLine: 14, spFlags: DISPFlagDefinition | DISPFlagPure | DISPFlagElemental | DISPFlagRecursive, unit: !8, retainedNodes: !6)