[PATCH] D88667: [GlobalISel] Change asserting conditions when initializing call site info

[Mateja Marjanovic via Phabricator via llvm-commits]

matejam created this revision.
matejam added a reviewer: djtodoro.
matejam added projects: debug-info, LLVM.
Herald added subscribers: llvm-commits, hiraditya, rovka.
matejam requested review of this revision.

IRTranslator's method runOnMachineFunction is used to translate from IR to MIR when using GlobalISel as an instruction selector.
When all IR instructions are translated, we move all the instructions from the current entry block to it's only successor, which leaves the current entry block empty and useless, we then delete it from the machine function.
The only issue is that the surviving entry block's number is greater by 1 than the minimal entry block number, which is fixed by changing the condition in MIRParserImpl::initializeCallSiteInfo, the idea is to have a special case when using GlobalISel. One way to figure out is GlobalISel the current selector is by not finding "bb.0" in the body of the machine function, the reason for that is beacuse GlobalISel will always start from bb.1, unlike SDAGISel or FastISel.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D88667

Files:
  llvm/lib/CodeGen/MIRParser/MIRParser.cpp
  llvm/test/CodeGen/X86/globalisel-entry-block-enumeration.ll


Index: llvm/test/CodeGen/X86/globalisel-entry-block-enumeration.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/X86/globalisel-entry-block-enumeration.ll
@@ -0,0 +1,39 @@
+;; Test enumeration of entry basic blocks when using GlobalISel.
+;; When using other instruction selectors entry blocks will start
+;; from 0, in case of GlobalISel they start from 1.
+; RUN: llc -emit-call-site-info -global-isel %s -stop-after=finalize-isel -o %t.mir
+; RUN: cat %t.mir | FileCheck %s
+; CHECK: name: fn1
+; CHECK-NOT: bb.0.entry
+; CHECK: name: fn3
+; CHECK-NOT: bb.0.entry
+; CHECK: name: fn2
+; CHECK-NOT: bb.0.entry
+
+; Function Attrs: noinline nounwind uwtable
+define dso_local i32 @fn1(i32 %a) local_unnamed_addr {
+entry:
+	%c = add i32 %a, 2
+	ret i32 %c
+}
+
+; Function Attrs: noinline nounwind uwtable
+define dso_local i32 @fn3(i32 %a, i32 %b, i32 %c) local_unnamed_addr {
+entry:
+	%d = add i32 %a, %b
+	%e = mul i32 %d, %c
+	%f = call i32 @fn1(i32 %e)
+	ret i32 %f
+}
+
+; Function Attrs: noinline nounwind uwtable
+define dso_local i64 @fn2(i32 %a, i32 %b, i32 %c) local_unnamed_addr {
+entry:
+  %call = call i32 @fn1(i32 5)
+  %add = mul i32 %a, 3
+  %sub = sub i32 %add, %b
+  %add2 = add i32 %sub, %c
+  %conv4 = sext i32 %add2 to i64
+  %call2 = call i32 @fn3(i32 5, i32 %add2, i32 %add2)
+  ret i64 %conv4
+}
Index: llvm/lib/CodeGen/MIRParser/MIRParser.cpp
===================================================================
--- llvm/lib/CodeGen/MIRParser/MIRParser.cpp
+++ llvm/lib/CodeGen/MIRParser/MIRParser.cpp
@@ -368,22 +368,27 @@
   const LLVMTargetMachine &TM = MF.getTarget();
   for (auto YamlCSInfo : YamlMF.CallSitesInfo) {
     yaml::CallSiteInfo::MachineInstrLoc MILoc = YamlCSInfo.CallLocation;
-    if (MILoc.BlockNum >= MF.size())
+    unsigned BlockNum = MILoc.BlockNum;
+    // In case of using GlobalISel, entry block enumeration doesn't start
+    // from 0, but from 1.
+    if (YamlMF.Body.Value.Value.find("bb.0") == std::string::npos)
+      BlockNum -= 1;
+    if (BlockNum >= MF.size())
       return error(Twine(MF.getName()) +
                    Twine(" call instruction block out of range.") +
-                   " Unable to reference bb:" + Twine(MILoc.BlockNum));
-    auto CallB = std::next(MF.begin(), MILoc.BlockNum);
+                   " Unable to reference bb:" + Twine(BlockNum));
+    auto CallB = std::next(MF.begin(), BlockNum);
     if (MILoc.Offset >= CallB->size())
       return error(Twine(MF.getName()) +
                    Twine(" call instruction offset out of range.") +
                    " Unable to reference instruction at bb: " +
-                   Twine(MILoc.BlockNum) + " at offset:" + Twine(MILoc.Offset));
+                   Twine(BlockNum) + " at offset:" + Twine(MILoc.Offset));
     auto CallI = std::next(CallB->instr_begin(), MILoc.Offset);
     if (!CallI->isCall(MachineInstr::IgnoreBundle))
       return error(Twine(MF.getName()) +
                    Twine(" call site info should reference call "
                          "instruction. Instruction at bb:") +
-                   Twine(MILoc.BlockNum) + " at offset:" + Twine(MILoc.Offset) +
+                   Twine(BlockNum) + " at offset:" + Twine(MILoc.Offset) +
                    " is not a call instruction");
     MachineFunction::CallSiteInfo CSInfo;
     for (auto ArgRegPair : YamlCSInfo.ArgForwardingRegs) {


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