DI: Reverse direction of subprogram -> function edge.
Previously, subprograms contained a metadata reference to the function they
described. Because most clients need to get or set a subprogram for a given
function rather than the other way around, this created unneeded inefficiency.
For example, many passes needed to call the function llvm::makeSubprogramMap()
to build a mapping from functions to subprograms, and the IR linker needed to
fix up function references in a way that caused quadratic complexity in the IR
linking phase of LTO.
This change reverses the direction of the edge by storing the subprogram as
function-level metadata and removing DISubprogram's function field.
Since this is an IR change, a bitcode upgrade has been provided.
Fixes PR23367. An upgrade script for textual IR for out-of-tree clients is
attached to the PR.
Differential Revision: http://reviews.llvm.org/D14265
llvm-svn: 252219
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index a9dca44..477ebe1 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -476,8 +476,6 @@
const Module *M = MMI->getModule();
- FunctionDIs = makeSubprogramMap(*M);
-
NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
if (!CU_Nodes)
return;
@@ -1113,8 +1111,8 @@
if (!MMI->hasDebugInfo())
return;
- auto DI = FunctionDIs.find(MF->getFunction());
- if (DI == FunctionDIs.end())
+ auto DI = MF->getFunction()->getSubprogram();
+ if (!DI)
return;
// Grab the lexical scopes for the function, if we don't have any of those
@@ -1205,7 +1203,7 @@
"endFunction should be called with the same function as beginFunction");
if (!MMI->hasDebugInfo() || LScopes.empty() ||
- !FunctionDIs.count(MF->getFunction())) {
+ !MF->getFunction()->getSubprogram()) {
// If we don't have a lexical scope for this function then there will
// be a hole in the range information. Keep note of this by setting the
// previously used section to nullptr.