[GlobalISel] Ensure that translateInvoke adds all successors for inlineasm

The existing code didn't add all necessary successors, which resulted in
disjoint basic blocks. These would end up not being legalized which, in the
best case, caused a fallback only in assert builds.

Here's an example:

https://godbolt.org/z/ndx15Enfj

We also end up getting weird codegen here as well.

Refactoring the code here allows us to correctly attach all successors. With
this patch, the above example gives correct codegen at -O0 with and without
asserts.

Also autogen the testcase to show that we add all the successors now.

Differential Revision: https://reviews.llvm.org/D113437

Author: Jessica Paquette

llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp

@@ -2502,41 +2502,31 @@ bool IRTranslator::translateInvoke(const User &U,
   if (!isa<LandingPadInst>(EHPadBB->getFirstNonPHI()))
     return false;
 
-  bool LowerInlineAsm = false;
-  if (I.isInlineAsm()) {
-    const InlineAsm *IA = cast<InlineAsm>(I.getCalledOperand());
-    if (!IA->canThrow()) {
-      // Fast path without emitting EH_LABELs.
-
-      if (!translateInlineAsm(I, MIRBuilder))
-        return false;
-
-      MachineBasicBlock *InvokeMBB = &MIRBuilder.getMBB(),
-                        *ReturnMBB = &getMBB(*ReturnBB);
-
-      // Update successor info.
-      addSuccessorWithProb(InvokeMBB, ReturnMBB, BranchProbability::getOne());
-
-      MIRBuilder.buildBr(*ReturnMBB);
-      return true;
-    } else {
-      LowerInlineAsm = true;
-    }
-  }
+  bool LowerInlineAsm = I.isInlineAsm();
+  bool NeedEHLabel = true;
+  // If it can't throw then use a fast-path without emitting EH labels.
+  if (LowerInlineAsm)
+    NeedEHLabel = (cast<InlineAsm>(I.getCalledOperand()))->canThrow();
 
   // Emit the actual call, bracketed by EH_LABELs so that the MF knows about
   // the region covered by the try.
-  MCSymbol *BeginSymbol = Context.createTempSymbol();
-  MIRBuilder.buildInstr(TargetOpcode::EH_LABEL).addSym(BeginSymbol);
+  MCSymbol *BeginSymbol = nullptr;
+  if (NeedEHLabel) {
+    BeginSymbol = Context.createTempSymbol();
+    MIRBuilder.buildInstr(TargetOpcode::EH_LABEL).addSym(BeginSymbol);
+  }
 
   if (LowerInlineAsm) {
     if (!translateInlineAsm(I, MIRBuilder))
       return false;
   } else if (!translateCallBase(I, MIRBuilder))
     return false;
 
-  MCSymbol *EndSymbol = Context.createTempSymbol();
-  MIRBuilder.buildInstr(TargetOpcode::EH_LABEL).addSym(EndSymbol);
+  MCSymbol *EndSymbol = nullptr;
+  if (NeedEHLabel) {
+    EndSymbol = Context.createTempSymbol();
+    MIRBuilder.buildInstr(TargetOpcode::EH_LABEL).addSym(EndSymbol);
+  }
 
   SmallVector<std::pair<MachineBasicBlock *, BranchProbability>, 1> UnwindDests;
   BranchProbabilityInfo *BPI = FuncInfo.BPI;
@@ -2558,7 +2548,12 @@ bool IRTranslator::translateInvoke(const User &U,
   }
   InvokeMBB->normalizeSuccProbs();
 
-  MF->addInvoke(&EHPadMBB, BeginSymbol, EndSymbol);
+  if (NeedEHLabel) {
+    assert(BeginSymbol && "Expected a begin symbol!");
+    assert(EndSymbol && "Expected an end symbol!");
+    MF->addInvoke(&EHPadMBB, BeginSymbol, EndSymbol);
+  }
+
   MIRBuilder.buildBr(ReturnMBB);
   return true;
 }

llvm/test/CodeGen/AArch64/GlobalISel/irtranslator-unwind-inline-asm.ll

@@ -1,3 +1,4 @@
+; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
 ; RUN: llc -O0 -global-isel -stop-after=irtranslator < %s | FileCheck %s
 
 target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
@@ -6,19 +7,45 @@ target triple = "aarch64-unknown-linux-gnu"
 @.str.2 = private unnamed_addr constant [7 x i8] c"Boom!\0A\00", align 1
 
 define dso_local void @trap() {
+  ; CHECK-LABEL: name: trap
+  ; CHECK: bb.1.entry:
 entry:
   unreachable
 }
 
 define dso_local void @test() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+  ; CHECK-LABEL: name: test
+  ; CHECK: bb.1.entry:
+  ; CHECK-NEXT:   successors: %bb.2(0x40000000), %bb.3(0x40000000)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[GV:%[0-9]+]]:_(p0) = G_GLOBAL_VALUE @.str.2
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:_(p0) = COPY [[GV]](p0)
+  ; CHECK-NEXT:   EH_LABEL <mcsymbol >
+  ; CHECK-NEXT:   INLINEASM &"bl trap", 1 /* sideeffect attdialect */
+  ; CHECK-NEXT:   EH_LABEL <mcsymbol >
+  ; CHECK-NEXT:   G_BR %bb.2
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.2.invoke.cont:
+  ; CHECK-NEXT:   RET_ReallyLR
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.3.lpad (landing-pad):
+  ; CHECK-NEXT:   liveins: $x0, $x1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   EH_LABEL <mcsymbol >
+  ; CHECK-NEXT:   [[DEF:%[0-9]+]]:_(s128) = G_IMPLICIT_DEF
+  ; CHECK-NEXT:   [[COPY1:%[0-9]+]]:_(p0) = COPY $x0
+  ; CHECK-NEXT:   [[COPY2:%[0-9]+]]:_(p0) = COPY $x1
+  ; CHECK-NEXT:   [[PTRTOINT:%[0-9]+]]:_(s32) = G_PTRTOINT [[COPY2]](p0)
+  ; CHECK-NEXT:   ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+  ; CHECK-NEXT:   $x0 = COPY [[COPY]](p0)
+  ; CHECK-NEXT:   BL @printf, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $x0
+  ; CHECK-NEXT:   ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+  ; CHECK-NEXT:   ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+  ; CHECK-NEXT:   $x0 = COPY [[COPY1]](p0)
+  ; CHECK-NEXT:   BL @_Unwind_Resume, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $x0
+  ; CHECK-NEXT:   ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
 entry:
 
-; CHECK-LABEL: name: test
-; CHECK: body:
-; CHECK-NEXT: bb.1.entry
-; CHECK: EH_LABEL
-; CHECK-NEXT: INLINEASM
-; CHECK-NEXT: EH_LABEL
 
   invoke void asm sideeffect unwind "bl trap", ""()
           to label %invoke.cont unwind label %lpad
@@ -27,8 +54,6 @@ invoke.cont:
   ret void
 
 lpad:
-; CHECK: bb.3.lpad
-; CHECK: EH_LABEL
 
   %0 = landingpad { i8*, i32 }
           cleanup
@@ -37,6 +62,40 @@ lpad:
 
 }
 
+define void @test2() #0 personality i32 (...)* @__gcc_personality_v0 {
+  ; CHECK-LABEL: name: test2
+  ; CHECK: bb.1 (%ir-block.0):
+  ; CHECK-NEXT:   successors: %bb.2(0x40000000), %bb.3(0x40000000)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[DEF:%[0-9]+]]:_(p0) = G_IMPLICIT_DEF
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:gpr64common = COPY [[DEF]](p0)
+  ; CHECK-NEXT:   INLINEASM &"", 1 /* sideeffect attdialect */, 1572873 /* reguse:GPR64common */, [[COPY]]
+  ; CHECK-NEXT:   G_BR %bb.2
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.2.a:
+  ; CHECK-NEXT:   RET_ReallyLR
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.3.b (landing-pad):
+  ; CHECK-NEXT:   liveins: $x0, $x1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   EH_LABEL <mcsymbol >
+  ; CHECK-NEXT:   [[DEF1:%[0-9]+]]:_(s128) = G_IMPLICIT_DEF
+  ; CHECK-NEXT:   [[COPY1:%[0-9]+]]:_(p0) = COPY $x0
+  ; CHECK-NEXT:   [[COPY2:%[0-9]+]]:_(p0) = COPY $x1
+  ; CHECK-NEXT:   [[PTRTOINT:%[0-9]+]]:_(s32) = G_PTRTOINT [[COPY2]](p0)
+  ; CHECK-NEXT:   ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+  ; CHECK-NEXT:   $x0 = COPY [[COPY1]](p0)
+  ; CHECK-NEXT:   BL @_Unwind_Resume, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $x0
+  ; CHECK-NEXT:   ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+  invoke void asm sideeffect "", "r"(i64* undef) to label %a unwind label %b
+a:
+  ret void
+b:
+  %landing_pad = landingpad { i8*, i32 } cleanup
+  resume { i8*, i32 } %landing_pad
+}
+
+declare i32 @__gcc_personality_v0(...)
 declare dso_local i32 @__gxx_personality_v0(...)
 
 declare dso_local void @printf(i8*, ...)