[GlobalISel] Diagnose inline assembly constraint lowering errors #135782
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@llvm/pr-subscribers-backend-aarch64 @llvm/pr-subscribers-llvm-globalisel Author: Pierre van Houtryve (Pierre-vh) ChangesInstead of printing something to dbgs (which is not visible to all users), In a future patch we could also recover from the error like the DAG does, so the Full diff: https://github.com/llvm/llvm-project/pull/135782.diff 1 Files Affected:
diff --git a/llvm/lib/CodeGen/GlobalISel/InlineAsmLowering.cpp b/llvm/lib/CodeGen/GlobalISel/InlineAsmLowering.cpp
index 81f25b21a0409..97d665c8fbf94 100644
--- a/llvm/lib/CodeGen/GlobalISel/InlineAsmLowering.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/InlineAsmLowering.cpp
@@ -16,6 +16,7 @@
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Module.h"
#define DEBUG_TYPE "inline-asm-lowering"
@@ -212,6 +213,17 @@ static bool buildAnyextOrCopy(Register Dst, Register Src,
return true;
}
+static bool reportInlineAsmConstraintError(const CallBase &Call,
+ const GISelAsmOperandInfo &Info,
+ Twine Msg) {
+ LLVMContext &Ctx = Call.getContext();
+ Ctx.diagnose(DiagnosticInfoInlineAsm(
+ Call, "invalid constraint '" + Info.ConstraintCode + "': " + Msg));
+ // TODO(?): Allow selection to continue by recovering/leaving the gMIR in a
+ // good state, like the DAG does.
+ return false;
+}
+
bool InlineAsmLowering::lowerInlineAsm(
MachineIRBuilder &MIRBuilder, const CallBase &Call,
std::function<ArrayRef<Register>(const Value &Val)> GetOrCreateVRegs)
@@ -243,8 +255,8 @@ bool InlineAsmLowering::lowerInlineAsm(
OpInfo.CallOperandVal = const_cast<Value *>(Call.getArgOperand(ArgNo));
if (isa<BasicBlock>(OpInfo.CallOperandVal)) {
- LLVM_DEBUG(dbgs() << "Basic block input operands not supported yet\n");
- return false;
+ return reportInlineAsmConstraintError(
+ Call, OpInfo, "basic block input operands not supported yet");
}
Type *OpTy = OpInfo.CallOperandVal->getType();
@@ -258,9 +270,8 @@ bool InlineAsmLowering::lowerInlineAsm(
// FIXME: Support aggregate input operands
if (!OpTy->isSingleValueType()) {
- LLVM_DEBUG(
- dbgs() << "Aggregate input operands are not supported yet\n");
- return false;
+ return reportInlineAsmConstraintError(
+ Call, OpInfo, "aggregate input operands not supported yet");
}
OpInfo.ConstraintVT =
@@ -344,9 +355,8 @@ bool InlineAsmLowering::lowerInlineAsm(
// Find a register that we can use.
if (OpInfo.Regs.empty()) {
- LLVM_DEBUG(dbgs()
- << "Couldn't allocate output register for constraint\n");
- return false;
+ return reportInlineAsmConstraintError(
+ Call, OpInfo, "couldn't allocate output register for constraint");
}
// Add information to the INLINEASM instruction to know that this
@@ -389,13 +399,14 @@ bool InlineAsmLowering::lowerInlineAsm(
const InlineAsm::Flag MatchedOperandFlag(Inst->getOperand(InstFlagIdx).getImm());
if (MatchedOperandFlag.isMemKind()) {
- LLVM_DEBUG(dbgs() << "Matching input constraint to mem operand not "
- "supported. This should be target specific.\n");
- return false;
+ return reportInlineAsmConstraintError(
+ Call, OpInfo,
+ "matching input constraint to mem operand not supported; this "
+ "should be target specific");
}
if (!MatchedOperandFlag.isRegDefKind() && !MatchedOperandFlag.isRegDefEarlyClobberKind()) {
- LLVM_DEBUG(dbgs() << "Unknown matching constraint\n");
- return false;
+ return reportInlineAsmConstraintError(Call, OpInfo,
+ "unknown matching constraint");
}
// We want to tie input to register in next operand.
@@ -425,9 +436,10 @@ bool InlineAsmLowering::lowerInlineAsm(
if (OpInfo.ConstraintType == TargetLowering::C_Other &&
OpInfo.isIndirect) {
- LLVM_DEBUG(dbgs() << "Indirect input operands with unknown constraint "
- "not supported yet\n");
- return false;
+ return reportInlineAsmConstraintError(
+ Call, OpInfo,
+ "indirect input operands with unknown constraint not supported "
+ "yet");
}
if (OpInfo.ConstraintType == TargetLowering::C_Immediate ||
@@ -437,9 +449,8 @@ bool InlineAsmLowering::lowerInlineAsm(
if (!lowerAsmOperandForConstraint(OpInfo.CallOperandVal,
OpInfo.ConstraintCode, Ops,
MIRBuilder)) {
- LLVM_DEBUG(dbgs() << "Don't support constraint: "
- << OpInfo.ConstraintCode << " yet\n");
- return false;
+ return reportInlineAsmConstraintError(Call, OpInfo,
+ "unsupported constraint");
}
assert(Ops.size() > 0 &&
@@ -456,9 +467,9 @@ bool InlineAsmLowering::lowerInlineAsm(
if (OpInfo.ConstraintType == TargetLowering::C_Memory) {
if (!OpInfo.isIndirect) {
- LLVM_DEBUG(dbgs()
- << "Cannot indirectify memory input operands yet\n");
- return false;
+ return reportInlineAsmConstraintError(
+ Call, OpInfo,
+ "indirect memory input operands are not supported yet");
}
assert(OpInfo.isIndirect && "Operand must be indirect to be a mem!");
@@ -482,18 +493,15 @@ bool InlineAsmLowering::lowerInlineAsm(
"Unknown constraint type!");
if (OpInfo.isIndirect) {
- LLVM_DEBUG(dbgs() << "Can't handle indirect register inputs yet "
- "for constraint '"
- << OpInfo.ConstraintCode << "'\n");
- return false;
+ return reportInlineAsmConstraintError(
+ Call, OpInfo, "indirect register inputs are not supported yet");
}
// Copy the input into the appropriate registers.
if (OpInfo.Regs.empty()) {
- LLVM_DEBUG(
- dbgs()
- << "Couldn't allocate input register for register constraint\n");
- return false;
+ return reportInlineAsmConstraintError(
+ Call, OpInfo,
+ "couldn't allocate input register for register constraint");
}
unsigned NumRegs = OpInfo.Regs.size();
@@ -503,9 +511,10 @@ bool InlineAsmLowering::lowerInlineAsm(
"source registers");
if (NumRegs > 1) {
- LLVM_DEBUG(dbgs() << "Input operands with multiple input registers are "
- "not supported yet\n");
- return false;
+ return reportInlineAsmConstraintError(
+ Call, OpInfo,
+ "input operands with multiple input registers are not supported "
+ "yet");
}
InlineAsm::Flag Flag(InlineAsm::Kind::RegUse, NumRegs);
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tgymnich
approved these changes
Apr 17, 2025
arsenm
reviewed
Apr 18, 2025
Comment on lines
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to
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| // TODO(?): Allow selection to continue by recovering/leaving the gMIR in a | ||
| // good state, like the DAG does. |
arsenm
reviewed
Apr 18, 2025
Until we have some form of error recovery testing will be difficult because the compiler crashes on failure |
It certainly should not crash |
I just realized it doesn't have to crash, I can just enable the fallback path. And for recovery, I'm thinking of just using |
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I added some tests, do you want me to test every message? |
arsenm
reviewed
Apr 25, 2025
Comment on lines
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| Call, "invalid constraint '" + Info.ConstraintCode + "' in '" + | ||
| MF.getName() + "': " + Msg)); |
There was a problem hiding this comment.
Avoid using getName, it's broken for anonymous functions. The context should be reported by the caller based on the context instructions, you shouldn't need to include it here
Comprehensive tests are always best
Should fix those too |
|
✅ With the latest revision this PR passed the undef deprecator. |
arsenm
approved these changes
May 5, 2025
llvm/test/CodeGen/AMDGPU/GlobalISel/inline-asm-lowering-errors.ll
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Instead of printing something to dbgs (which is not visible to all users), emit a diagnostic like the DAG does. We still crash later because we fail to select the inline assembly, but at least now users will know why it's crashing. In a future patch we could also recover from the error like the DAG does, so the lowering can keep going until it either crashes or gives a different error later.
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I had to update some tests. Is this still good to land? |
arsenm
approved these changes
May 7, 2025
Merge activity
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/51/builds/15701 Here is the relevant piece of the build log for the reference |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/18/builds/15617 Here is the relevant piece of the build log for the reference |
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Reverted this because I wonder if this should be a warning instead, so compilation keeps going? |
Pierre-vh
added a commit
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May 8, 2025
…rors (#135782) The initial patch caused issues because it emits an error, and llc is sensitive to it. It also caused compiler-rt/lib/scudo/standalone/tests/wrappers_cpp_test.cpp to fail. Use warnings instead + reject lowering. That way, the fallback path is used without llc/clang returning a failure code. If fallback isn't enabled then the warnings provide context as to why lowering failed. Original commit description: --- Instead of printing something to dbgs (which is not visible to all users), emit a diagnostic like the DAG does. We still crash later because we fail to select the inline assembly, but at least now users will know why it's crashing. In a future patch we could also recover from the error like the DAG does, so the lowering can keep going until it either crashes or gives a different error later.
Pierre-vh
added a commit
that referenced
this pull request
May 8, 2025
…rors (#139049) The initial patch (#135782 caused issues because it emits an error, and llc is sensitive to it. It also caused compiler-rt/lib/scudo/standalone/tests/wrappers_cpp_test.cpp to fail. Use warnings instead + reject lowering. That way, the fallback path is used without llc/clang returning a failure code. If fallback isn't enabled then the warnings provide context as to why lowering failed. Original commit description for #135782: Instead of printing something to dbgs (which is not visible to all users), emit a diagnostic like the DAG does. We still crash later because we fail to select the inline assembly, but at least now users will know why it's crashing. In a future patch we could also recover from the error like the DAG does, so the lowering can keep going until it either crashes or gives a different error later.
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Instead of printing something to dbgs (which is not visible to all users),
emit a diagnostic like the DAG does. We still crash later because we fail to
select the inline assembly, but at least now users will know why it's crashing.
In a future patch we could also recover from the error like the DAG does, so the
lowering can keep going until it either crashes or gives a different error later.