[LLVM-C] Add DIFile Field Accesssors

[CodaFi]

Summary

Add accessors for the file, directory, source file name (curiously, an Optional value?), of a DIFile.

This is intended to replace the LLVMValueRef-based accessors used in D52239

[CodaFi]

@jberdine Are these bindings missing anything for your current use-case? I want to make sure you're covered before I deprecate them.

[whitequark]

LGTM

[CodaFi]

Retarget from DIScope to DIFile since we can retrieve the file object for a scope now.

[jberdine]

@CodaFi thanks! For Instructions, I have modified my client to use these functions and tested. For reference, the callers look like:

CAMLprim value llvm_instr_get_debug_loc_filename(LLVMValueRef Instr) {
  CAMLparam0();
  CAMLlocal2(Option, String);
  LLVMMetadataRef Loc = LLVMInstructionGetDebugLoc(Instr);
  if (!Loc) CAMLreturn(Val_int(0));
  LLVMMetadataRef Scope = LLVMDILocationGetScope(Loc);
  if (!Scope) CAMLreturn(Val_int(0));
  LLVMMetadataRef File = LLVMDIScopeGetFile(Scope);
  if (!File) CAMLreturn(Val_int(0));
  unsigned Length;
  const char *Chars;
  if ((Chars = LLVMDIFileGetFilename(File, &Length))) {
    String = caml_alloc_string(Length);
    memcpy(String_val(String), Chars, Length);
    Option = caml_alloc_small(1, 0);
    Store_field(Option, 0, String);
    CAMLreturn(Option);
  }
  CAMLreturn(Val_int(0));
}

So for instructions, it seems to work well to use LLVMInstructionGetDebugLoc and then LLVMDILocationGetLine, LLVMDILocationGetColumn, LLVMDILocationGetScope and this diff's functions.

But so far I have not found analogues of LLVMInstructionGetDebugLoc for GlobalVariables and Functions. To be concrete, the function extracting the line number I'm using is:

unsigned LLVMGetDebugLocLine(LLVMValueRef Val) {
  unsigned L = 0;
  if (const auto *I = dyn_cast<Instruction>(unwrap(Val))) {
    if (const auto &DL = I->getDebugLoc()) {
      L = DL->getLine();
    }
  } else if (const auto *GV = dyn_cast<GlobalVariable>(unwrap(Val))) {
    SmallVector<DIGlobalVariableExpression *, 1> GVEs;
    GV->getDebugInfo(GVEs);
    if (GVEs.size())
      if (const DIGlobalVariable *DGV = GVEs[0]->getVariable())
        L = DGV->getLine();
  } else if (const auto *F = dyn_cast<Function>(unwrap(Val))) {
    if (const DISubprogram *DSP = F->getSubprogram())
      L = DSP->getLine();
  } else {
    assert(0 && "Expected Instruction, GlobalVariable or Function");
    return -1;
  }
  return L;
}

Am I overlooking something, or is exposing more needed to cover what the above is doing on GlobalVariables and Functions?

llvm/include/llvm-c/DebugInfo.h

464 ↗

(On Diff #194415)

s/Scope/File ?

473 ↗

(On Diff #194415)

s/Scope/File ?

482 ↗

(On Diff #194415)

s/Scope/File ?

llvm/lib/IR/DebugInfo.cpp

913 ↗

(On Diff #194415)

Dir ?

919 ↗

(On Diff #194415)

Dir ?

[CodaFi]

A DISubprogram is a kind of DIScope so you can use LLVMDIScopeGetFile and the rest of the accessors to poke at their metadata. For Global Variables, the idea should be to add corresponding accessors for the scope, file, name, source, and directory since these nodes do not store DILocations. It seems like the latter is pressing, so I'll make a patch for it in a bit.

[jberdine]

Modulo the names seemingly left over from copy-paste, this looks good to me and is working in my tests.

[CodaFi]

@jberdine Any further comments?

[jberdine]

No, looks good, thanks!

llvm/trunk/include/llvm-c/DebugInfo.h

 /**
  * Get the "inline at" location associated with this debug location.
  * \param Location     The debug location.
  *
  * @see DILocation::getInlinedAt()
  */
 LLVMMetadataRef LLVMDILocationGetInlinedAt(LLVMMetadataRef Location);
 
+/**
+ * Get the metadata of the file associated with a given scope.
+ * \param Scope     The scope object.
+ *
+ * @see DIScope::getFile()
+ */
+LLVMMetadataRef LLVMDIScopeGetFile(LLVMMetadataRef Scope);
+
+/**
+ * Get the directory of a given file.
+ * \param File     The file object.
+ * \param Len      The length of the returned string.
+ *
+ * @see DIFile::getDirectory()
+ */
+const char *LLVMDIFileGetDirectory(LLVMMetadataRef File, unsigned *Len);
+
+/**
+ * Get the name of a given file.
+ * \param File     The file object.
+ * \param Len      The length of the returned string.
+ *
+ * @see DIFile::getFilename()
+ */
+const char *LLVMDIFileGetFilename(LLVMMetadataRef File, unsigned *Len);
+
+/**
+ * Get the source of a given file.
+ * \param File     The file object.
+ * \param Len      The length of the returned string.
+ *
+ * @see DIFile::getSource()
+ */
+const char *LLVMDIFileGetSource(LLVMMetadataRef File, unsigned *Len);
 
 /**
  * Create a type array.
  * \param Builder        The DIBuilder.
  * \param Data           The type elements.
  * \param NumElements    Number of type elements.
  */
 LLVMMetadataRef LLVMDIBuilderGetOrCreateTypeArray(LLVMDIBuilderRef Builder,

llvm/trunk/lib/IR/DebugInfo.cpp

 LLVMMetadataRef LLVMDILocationGetScope(LLVMMetadataRef Location) {
   return wrap(unwrapDI<DILocation>(Location)->getScope());
 }
 
 LLVMMetadataRef LLVMDILocationGetInlinedAt(LLVMMetadataRef Location) {
   return wrap(unwrapDI<DILocation>(Location)->getInlinedAt());
 }
 
+LLVMMetadataRef LLVMDIScopeGetFile(LLVMMetadataRef Scope) {
+  return wrap(unwrapDI<DIScope>(Scope)->getFile());
+}
+
+const char *LLVMDIFileGetDirectory(LLVMMetadataRef File, unsigned *Len) {
+  auto Dir = unwrapDI<DIFile>(File)->getDirectory();
+  *Len = Dir.size();
+  return Dir.data();
+}
+
+const char *LLVMDIFileGetFilename(LLVMMetadataRef File, unsigned *Len) {
+  auto Name = unwrapDI<DIFile>(File)->getFilename();
+  *Len = Name.size();
+  return Name.data();
+}
+
+const char *LLVMDIFileGetSource(LLVMMetadataRef File, unsigned *Len) {
+  if (auto Src = unwrapDI<DIFile>(File)->getSource()) {
+    *Len = Src->size();
+    return Src->data();
+  }
+  *Len = 0;
+  return "";
+}
+
 LLVMMetadataRef LLVMDIBuilderCreateEnumerator(LLVMDIBuilderRef Builder,
                                               const char *Name, size_t NameLen,
                                               int64_t Value,
                                               LLVMBool IsUnsigned) {
   return wrap(unwrap(Builder)->createEnumerator({Name, NameLen}, Value,
                                                 IsUnsigned != 0));
 }