From 6ed5706a2beab0bcde2a24e36751ea30cd5b4009 Mon Sep 17 00:00:00 2001 From: Adrian Prantl Date: Mon, 8 Apr 2019 19:13:55 +0000 Subject: Add LLVM IR debug info support for Fortran COMMON blocks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit COMMON blocks are a feature of Fortran that has no direct analog in C languages, but they are similar to data sections in assembly language programming. A COMMON block is a named area of memory that holds a collection of variables. Fortran subprograms may map the COMMON block memory area to their own, possibly distinct, non-empty list of variables. A Fortran COMMON block might look like the following example. COMMON /ALPHA/ I, J For this construct, the compiler generates a new scope-like DI construct (!DICommonBlock) into which variables (see I, J above) can be placed. As the common block implies a range of storage with global lifetime, the !DICommonBlock refers to a !DIGlobalVariable. The Fortran variable that comprise the COMMON block are also linked via metadata to offsets within the global variable that stands for the entire common block. @alpha_ = common global %alphabytes_ zeroinitializer, align 64, !dbg !27, !dbg !30, !dbg !33 !14 = distinct !DISubprogram(…) !20 = distinct !DICommonBlock(scope: !14, declaration: !25, name: "alpha") !25 = distinct !DIGlobalVariable(scope: !20, name: "common alpha", type: !24) !27 = !DIGlobalVariableExpression(var: !25, expr: !DIExpression()) !29 = distinct !DIGlobalVariable(scope: !20, name: "i", file: !3, type: !28) !30 = !DIGlobalVariableExpression(var: !29, expr: !DIExpression()) !31 = distinct !DIGlobalVariable(scope: !20, name: "j", file: !3, type: !28) !32 = !DIExpression(DW_OP_plus_uconst, 4) !33 = !DIGlobalVariableExpression(var: !31, expr: !32) The DWARF generated for this is as follows. DW_TAG_common_block: DW_AT_name: alpha DW_AT_location: @alpha_+0 DW_TAG_variable: DW_AT_name: common alpha DW_AT_type: array of 8 bytes DW_AT_location: @alpha_+0 DW_TAG_variable: DW_AT_name: i DW_AT_type: integer*4 DW_AT_location: @Alpha+0 DW_TAG_variable: DW_AT_name: j DW_AT_type: integer*4 DW_AT_location: @Alpha+4 Patch by Eric Schweitz! Differential Revision: https://reviews.llvm.org/D54327 llvm-svn: 357934 --- llvm/lib/Bitcode/Writer/BitcodeWriter.cpp | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'llvm/lib/Bitcode/Writer/BitcodeWriter.cpp') diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp index 1d6480c..c835976 100644 --- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp +++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp @@ -317,6 +317,8 @@ private: void writeDILexicalBlockFile(const DILexicalBlockFile *N, SmallVectorImpl &Record, unsigned Abbrev); + void writeDICommonBlock(const DICommonBlock *N, + SmallVectorImpl &Record, unsigned Abbrev); void writeDINamespace(const DINamespace *N, SmallVectorImpl &Record, unsigned Abbrev); void writeDIMacro(const DIMacro *N, SmallVectorImpl &Record, @@ -1686,6 +1688,20 @@ void ModuleBitcodeWriter::writeDILexicalBlockFile( Record.clear(); } +void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N, + SmallVectorImpl &Record, + unsigned Abbrev) { + Record.push_back(N->isDistinct()); + Record.push_back(VE.getMetadataOrNullID(N->getScope())); + Record.push_back(VE.getMetadataOrNullID(N->getDecl())); + Record.push_back(VE.getMetadataOrNullID(N->getRawName())); + Record.push_back(VE.getMetadataOrNullID(N->getFile())); + Record.push_back(N->getLineNo()); + + Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev); + Record.clear(); +} + void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N, SmallVectorImpl &Record, unsigned Abbrev) { -- cgit v1.1