[llvm-commits] DebugInfoBuilder

[Evan Cheng]

Very nice! This is sorely needed. Some comments:

+    // Calculate the size of the specified LLVM type.
+    Constant * Sizeof(const Type * type);
+
+    // Calculate the alignment of the specified LLVM type.
+    Constant * Alignof(const Type * type);

I find these names confusing. Perhaps getSize and getAlignment? That  
follows the convention which are used elsewhere in LLVM.

+    /// Set the reference to the module where we will insert  
debugging information.
+    /// Also defines the debug info types for the module and creates  
the initial anchors.
+    /// Also changes the current context to the global context for  
that module.
+    void SetModule(Module * m);

80 column please. :-)

+// 
= 
= 
=---------------------------------------------------------------------- 
===//
+// Debug version -- copied from MachineModuleInfo (for now), in order  
to avoid
+// creating a dependency on CodeGen. These declarations really should  
be moved
+// to a better place where modules can get at them without being  
dependent on
+// CodeGen.
+enum {
+  LLVMDebugVersion = (6 << 16),         // Current version of debug  
information.
+  LLVMDebugVersion5 = (5 << 16),        // Constant for version 5.
+  LLVMDebugVersion4 = (4 << 16),        // Constant for version 4.
+  LLVMDebugVersionMask = 0xffff0000     // Mask for version number.
+};

What are the different versions?

+GlobalVariable *  
DebugInfoBuilder::CreateCompileUnitDescriptor(unsigned langId,
+    const sys::Path & srcPath, const std::string & producer) {
+
+    if (compileUnit == NULL) {
+        std::vector<Constant *> values;
+        values.push_back(ConstantInt::get(Type::Int32Ty,  
LLVMDebugVersion + dwarf::DW_TAG_compile_unit));
+        values.push_back(ConstantExpr::getBitCast(compileUnitAnchor,  
anyPtrType));
+        values.push_back(ConstantInt::get(Type::Int32Ty, langId));
+        values.push_back(ConstantArray::get(srcPath.getLast()));
+        values.push_back(ConstantArray::get(srcPath.getDirname() +  
"/"));
+        values.push_back(ConstantArray::get(producer));
+
+        Constant * structVal = ConstantStruct::get(values, false);

It would be nice if there is a ConstantStruct::get that takes  
SmallVectorImpl instead (hint :-). Then we can avoid heap allocation  
for a small vector.


Thanks,

Evan
On Aug 5, 2008, at 11:35 AM, Talin wrote:

> The attached patch file contains an initial implementation of  
> DebugInfoBuilder, which is intended to help generate DWARF debugging  
> information. Currently it only has support for creating global  
> descriptors, I have not yet implemented descriptors for aggregate  
> types or stop points.
>
> The API tries to simplify the task of creating descriptors by using  
> the IR types. For example, instead of having to manually specify the  
> size and alignment of an integer, you can just pass an IntegerType  
> to CreateIntegerTypeDescriptor and it will figure that out for you.  
> However, in some cases you'll need to pass extra information which  
> is not represented in the IR - so for example  
> CreateIntegerTypeDescriptor takes an argument indicating whether the  
> type is intended to be signed or unsigned (since the IR integer type  
> has no concept of signed-ness.)
>
> -- 
> -- Talin
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