[X86] Fix invalid instructions on x32 with large stack frames (#124041)

`X86FrameLowering::emitSPUpdate()` assumes that 64-bit targets use a
64-bit stack pointer, but that's not true on x32.
When checking the stack pointer size, we need to look at
`Uses64BitFramePtr` rather than `Is64Bit`. This avoids generating
invalid instructions like `add esp, rcx`.

For impossibly-large stack frames (4 GiB or larger with a 32-bit stack
pointer), we were also generating invalid instructions like `mov eax,
5000000000`. The inline stack probe code already had a check for that
situation; I've moved the check into `emitSPUpdate()`, so any attempt to
allocate a 4 GiB stack frame with a 32-bit stack pointer will now trap
rather than adjusting ESP by the wrong amount. This also fixes the
"can't have 32-bit 16GB stack frame" assertion, which used to be
triggerable by user code but is now correct.

To help catch situations like this in the future, I've added
`-verify-machineinstrs` to the stack clash tests that generate large
stack frames.

This fixes the expensive-checks buildbot failure caused by #113219.

Author: mconst

llvm/lib/Target/X86/X86FrameLowering.cpp

@@ -253,17 +253,19 @@ void X86FrameLowering::emitSPUpdate(MachineBasicBlock &MBB,
     // Rather than emit a long series of instructions for large offsets,
     // load the offset into a register and do one sub/add
     unsigned Reg = 0;
-    unsigned Rax = (unsigned)(Is64Bit ? X86::RAX : X86::EAX);
+    unsigned Rax = (unsigned)(Uses64BitFramePtr ? X86::RAX : X86::EAX);
 
     if (isSub && !isEAXLiveIn(MBB))
       Reg = Rax;
     else
-      Reg = TRI->findDeadCallerSavedReg(MBB, MBBI);
+      Reg = getX86SubSuperRegister(TRI->findDeadCallerSavedReg(MBB, MBBI),
+                                   Uses64BitFramePtr ? 64 : 32);
 
-    unsigned AddSubRROpc =
-        isSub ? getSUBrrOpcode(Is64Bit) : getADDrrOpcode(Is64Bit);
+    unsigned AddSubRROpc = isSub ? getSUBrrOpcode(Uses64BitFramePtr)
+                                 : getADDrrOpcode(Uses64BitFramePtr);
     if (Reg) {
-      BuildMI(MBB, MBBI, DL, TII.get(getMOVriOpcode(Is64Bit, Offset)), Reg)
+      BuildMI(MBB, MBBI, DL, TII.get(getMOVriOpcode(Uses64BitFramePtr, Offset)),
+              Reg)
           .addImm(Offset)
           .setMIFlag(Flag);
       MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(AddSubRROpc), StackPtr)
@@ -279,7 +281,7 @@ void X86FrameLowering::emitSPUpdate(MachineBasicBlock &MBB,
       //   addq %rsp, %rax
       //   xchg %rax, (%rsp)
       //   movq (%rsp), %rsp
-      assert(Is64Bit && "can't have 32-bit 16GB stack frame");
+      assert(Uses64BitFramePtr && "can't have 32-bit 16GB stack frame");
       BuildMI(MBB, MBBI, DL, TII.get(X86::PUSH64r))
           .addReg(Rax, RegState::Kill)
           .setMIFlag(Flag);
@@ -289,7 +291,8 @@ void X86FrameLowering::emitSPUpdate(MachineBasicBlock &MBB,
         Offset = -(Offset - SlotSize);
       else
         Offset = Offset + SlotSize;
-      BuildMI(MBB, MBBI, DL, TII.get(getMOVriOpcode(Is64Bit, Offset)), Rax)
+      BuildMI(MBB, MBBI, DL, TII.get(getMOVriOpcode(Uses64BitFramePtr, Offset)),
+              Rax)
           .addImm(Offset)
           .setMIFlag(Flag);
       MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(X86::ADD64rr), Rax)

llvm/test/CodeGen/X86/stack-clash-extra-huge.ll

@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --no_x86_scrub_sp
-; RUN: llc -mtriple=x86_64-linux-android < %s | FileCheck -check-prefix=CHECK-X64 %s
-; RUN: llc -mtriple=i686-linux-android < %s | FileCheck -check-prefix=CHECK-X86 %s
-; RUN: llc -mtriple=x86_64-linux-gnux32 < %s | FileCheck -check-prefix=CHECK-X32 %s
+; RUN: llc -mtriple=x86_64-linux-android -verify-machineinstrs < %s | FileCheck -check-prefix=CHECK-X64 %s
+; RUN: llc -mtriple=i686-linux-android -verify-machineinstrs < %s | FileCheck -check-prefix=CHECK-X86 %s
+; RUN: llc -mtriple=x86_64-linux-gnux32 -verify-machineinstrs < %s | FileCheck -check-prefix=CHECK-X32 %s
 
 define i32 @foo() local_unnamed_addr #0 {
 ; CHECK-X64-LABEL: foo:
@@ -66,8 +66,8 @@ define i32 @foo() local_unnamed_addr #0 {
 ; CHECK-X32-NEXT:    movl $1, 264(%esp)
 ; CHECK-X32-NEXT:    movl $1, 28664(%esp)
 ; CHECK-X32-NEXT:    movl -128(%esp), %eax
-; CHECK-X32-NEXT:    movabsq $4799999880, %rcx # imm = 0x11E1A2F88
-; CHECK-X32-NEXT:    addq %rcx, %esp
+; CHECK-X32-NEXT:    movl $4799999880, %ecx # imm = 0x11E1A2F88
+; CHECK-X32-NEXT:    addl %ecx, %esp
 ; CHECK-X32-NEXT:    .cfi_def_cfa_offset 8
 ; CHECK-X32-NEXT:    retq
   %a = alloca i32, i64 1200000000, align 16

llvm/test/CodeGen/X86/stack-clash-huge.ll

@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --no_x86_scrub_sp
-; RUN: llc -mtriple=x86_64-linux-android < %s | FileCheck -check-prefix=CHECK-X64 %s
-; RUN: llc -mtriple=i686-linux-android < %s | FileCheck -check-prefix=CHECK-X86 %s
-; RUN: llc -mtriple=x86_64-linux-gnux32 < %s | FileCheck -check-prefix=CHECK-X32 %s
+; RUN: llc -mtriple=x86_64-linux-android -verify-machineinstrs < %s | FileCheck -check-prefix=CHECK-X64 %s
+; RUN: llc -mtriple=i686-linux-android -verify-machineinstrs < %s | FileCheck -check-prefix=CHECK-X86 %s
+; RUN: llc -mtriple=x86_64-linux-gnux32 -verify-machineinstrs < %s | FileCheck -check-prefix=CHECK-X32 %s
 
 define i32 @foo() local_unnamed_addr #0 {
 ; CHECK-X64-LABEL: foo:
@@ -69,7 +69,7 @@ define i32 @foo() local_unnamed_addr #0 {
 ; CHECK-X32-NEXT:    movl $1, 28664(%esp)
 ; CHECK-X32-NEXT:    movl -128(%esp), %eax
 ; CHECK-X32-NEXT:    movl $2399999880, %ecx # imm = 0x8F0D1788
-; CHECK-X32-NEXT:    addq %rcx, %esp
+; CHECK-X32-NEXT:    addl %ecx, %esp
 ; CHECK-X32-NEXT:    .cfi_def_cfa_offset 8
 ; CHECK-X32-NEXT:    retq
   %a = alloca i32, i64 600000000, align 16