[llvm] [AMDGPU] Add `.amdgpu.info` section for per-function metadata (PR #192384)

[Shilei Tian via llvm-commits]

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@@ -6741,6 +6747,110 @@ bool AMDGPUAsmParser::ParseDirectiveAMDGPULDS() {
   return false;
 }
 
+bool AMDGPUAsmParser::ParseDirectiveAMDGPUInfo() {
+  if (getParser().checkForValidSection())
+    return true;
+
+  StringRef FuncName;
+  if (getParser().parseIdentifier(FuncName))
+    return TokError("expected symbol name after .amdgpu_info");
+
+  MCSymbol *FuncSym = getContext().getOrCreateSymbol(FuncName);
+  AMDGPU::FuncInfo FI;
+  FI.Sym = FuncSym;
+  bool HasScalarAttrs = false;
+
+  while (true) {
+    while (trySkipToken(AsmToken::EndOfStatement))
+      ;
+
+    StringRef ID;
+    SMLoc IDLoc = getLoc();
+    if (!parseId(ID, "expected directive or .end_amdgpu_info"))
+      return true;
+
+    if (ID == ".end_amdgpu_info")
+      break;
+
+    // Every per-entry directive shares the `.amdgpu_` namespace prefix; strip
+    // it once and dispatch on the distinguishing suffix below. The unstripped
+    // ID is preserved for diagnostics.
+    StringRef Dir = ID;
+    if (!Dir.consume_front(".amdgpu_"))
+      return Error(IDLoc, "unknown .amdgpu_info directive '" + ID + "'");
+
+    if (Dir == "flags") {
+      int64_t Val;
+      if (getParser().parseAbsoluteExpression(Val))
+        return true;
+      auto Flags = static_cast<AMDGPU::FuncInfoFlags>(Val);
+      FI.UsesVCC = !!(Flags & AMDGPU::FuncInfoFlags::FUNC_USES_VCC);
+      FI.UsesFlatScratch =
+          !!(Flags & AMDGPU::FuncInfoFlags::FUNC_USES_FLAT_SCRATCH);
+      FI.HasDynStack = !!(Flags & AMDGPU::FuncInfoFlags::FUNC_HAS_DYN_STACK);
+      HasScalarAttrs = true;
+    } else if (Dir == "num_sgpr") {
+      int64_t Val;
+      if (getParser().parseAbsoluteExpression(Val))
+        return true;
+      FI.NumSGPR = static_cast<uint32_t>(Val);
+      HasScalarAttrs = true;
+    } else if (Dir == "num_vgpr") {
+      int64_t Val;
+      if (getParser().parseAbsoluteExpression(Val))
+        return true;
+      FI.NumArchVGPR = static_cast<uint32_t>(Val);
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shiltian wrote:

It will be in the linker.

https://github.com/llvm/llvm-project/pull/192384