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[ASTWriter] Do not allocate source location space for module maps used only for textual headers #116374

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Merged
merged 6 commits into from
Dec 5, 2024
Merged

[ASTWriter] Do not allocate source location space for module maps used only for textual headers #116374

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ff328f2
[ASTWriter] Do not allocate source location space for module maps use…
ilya-biryukov Nov 15, 2024
e0a1835
fixup! [ASTWriter] Do not allocate source location space for module m…
ilya-biryukov Nov 15, 2024
5611185
fixup! [ASTWriter] Do not allocate source location space for module m…
ilya-biryukov Nov 29, 2024
9cad088
fixup! [ASTWriter] Do not allocate source location space for module m…
ilya-biryukov Nov 29, 2024
441efe6
fixup! [ASTWriter] Do not allocate source location space for module m…
ilya-biryukov Nov 29, 2024
8899db3
Merge branch 'main' into dedup3
ilya-biryukov Dec 5, 2024
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47 changes: 33 additions & 14 deletions clang/lib/Serialization/ASTWriter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -184,14 +184,30 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {
const SourceManager &SM = PP.getSourceManager();
const ModuleMap &MM = HS.getModuleMap();

llvm::DenseSet<FileID> ModuleMaps;

llvm::DenseSet<const Module *> ProcessedModules;
auto CollectModuleMapsForHierarchy = [&](const Module *M) {
// Module maps used only by textual headers are special. Their FileID is
// non-affecting, but their FileEntry is (i.e. must be written as InputFile).
enum AffectedReason : bool {
AR_TextualHeader = 0,
AR_ImportOrTextualHeader = 1,
};
auto AssignMostImportant = [](AffectedReason &LHS, AffectedReason RHS) {
LHS = std::max(LHS, RHS);
};
llvm::DenseMap<FileID, AffectedReason> ModuleMaps;
llvm::DenseMap<const Module *, AffectedReason> ProcessedModules;
auto CollectModuleMapsForHierarchy = [&](const Module *M,
AffectedReason Reason) {
M = M->getTopLevelModule();

if (!ProcessedModules.insert(M).second)
// We need to process the header either when it was not present or when we
// previously flagged module map as textual headers and now we found a
// proper import.
if (auto [It, Inserted] = ProcessedModules.insert({M, Reason});
!Inserted && Reason <= It->second) {
return;
} else {
It->second = Reason;
}
Comment on lines +208 to +210
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Avoid else after return.

Suggested change
} else {
It->second = Reason;
}
}
It->second = Reason;

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I cannot in that case, because It is only valid for the scope of the if.
Increasing the visibility scope of It seems like a worse trade-off. But let me know if you have other suggestions how to rewrite the code better, I might be missing some ideas.


std::queue<const Module *> Q;
Q.push(M);
Expand All @@ -202,12 +218,12 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {
// The containing module map is affecting, because it's being pointed
// into by Module::DefinitionLoc.
if (auto F = MM.getContainingModuleMapFileID(Mod); F.isValid())
ModuleMaps.insert(F);
AssignMostImportant(ModuleMaps[F], Reason);
// For inferred modules, the module map that allowed inferring is not
// related to the virtual containing module map file. It did affect the
// compilation, though.
if (auto UniqF = MM.getModuleMapFileIDForUniquing(Mod); UniqF.isValid())
ModuleMaps.insert(UniqF);
AssignMostImportant(ModuleMaps[UniqF], Reason);

for (auto *SubM : Mod->submodules())
Q.push(SubM);
Expand All @@ -216,7 +232,7 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {

// Handle all the affecting modules referenced from the root module.

CollectModuleMapsForHierarchy(RootModule);
CollectModuleMapsForHierarchy(RootModule, AR_ImportOrTextualHeader);

std::queue<const Module *> Q;
Q.push(RootModule);
Expand All @@ -225,9 +241,9 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {
Q.pop();

for (const Module *ImportedModule : CurrentModule->Imports)
CollectModuleMapsForHierarchy(ImportedModule);
CollectModuleMapsForHierarchy(ImportedModule, AR_ImportOrTextualHeader);
for (const Module *UndeclaredModule : CurrentModule->UndeclaredUses)
CollectModuleMapsForHierarchy(UndeclaredModule);
CollectModuleMapsForHierarchy(UndeclaredModule, AR_ImportOrTextualHeader);

for (auto *M : CurrentModule->submodules())
Q.push(M);
Expand Down Expand Up @@ -256,7 +272,7 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {

for (const auto &KH : HS.findResolvedModulesForHeader(*File))
if (const Module *M = KH.getModule())
CollectModuleMapsForHierarchy(M);
CollectModuleMapsForHierarchy(M, AR_TextualHeader);
}

// FIXME: This algorithm is not correct for module map hierarchies where
Expand All @@ -278,13 +294,16 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {
// includes a module map defining a module that's not a submodule of X.

llvm::DenseSet<const FileEntry *> ModuleFileEntries;
for (FileID MM : ModuleMaps) {
if (auto *FE = SM.getFileEntryForID(MM))
llvm::DenseSet<FileID> ModuleFileIDs;
for (auto [FID, Reason] : ModuleMaps) {
if (Reason == AR_ImportOrTextualHeader)
ModuleFileIDs.insert(FID);
if (auto *FE = SM.getFileEntryForID(FID))
ModuleFileEntries.insert(FE);
}

AffectingModuleMaps R;
R.DefinitionFileIDs = std::move(ModuleMaps);
R.DefinitionFileIDs = std::move(ModuleFileIDs);
R.DefinitionFiles = std::move(ModuleFileEntries);
return std::move(R);
}
Expand Down
104 changes: 104 additions & 0 deletions clang/test/Modules/prune-non-affecting-module-map-repeated-textual.cpp
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Original file line number Diff line number Diff line change
@@ -0,0 +1,104 @@
// Same as prune-non-affecting-module-map-repeated.cpp, but check that textual-only
// inclusions do not cause duplication of the module map files they are defined in.

// RUN: rm -rf %t && mkdir %t
// RUN: split-file %s %t

// RUN: %clang_cc1 -xc++ -fmodules -fno-implicit-modules \
// RUN: -fmodule-map-file=%t/base.map -fmodule-map-file=%t/mixed.map\
// RUN: -fmodule-map-file=%t/mod1.map \
// RUN: -fmodule-name=mod1 -emit-module %t/mod1.map -o %t/mod1.pcm
// RUN: %clang_cc1 -xc++ -fmodules -fno-implicit-modules \
// RUN: -fmodule-map-file=%t/mixed.map\
// RUN: -fmodule-name=mixed -emit-module %t/mixed.map -o %t/mixed.pcm
// RUN: %clang_cc1 -xc++ -fmodules -fno-implicit-modules \
// RUN: -fmodule-map-file=%t/base.map -fmodule-map-file=%t/mod1.map -fmodule-map-file=%t/mod2.map \
// RUN: -fmodule-file=%t/mod1.pcm -fmodule-file=%t/mixed.pcm \
// RUN: -fmodule-name=mod2 -emit-module %t/mod2.map -o %t/mod2.pcm
// RUN: %clang_cc1 -xc++ -fmodules -fno-implicit-modules \
// RUN: -fmodule-map-file=%t/base.map -fmodule-map-file=%t/mod2.map -fmodule-map-file=%t/mod3.map \
// RUN: -fmodule-file=%t/mod2.pcm -fmodule-file=%t/mixed.pcm \
// RUN: -fmodule-name=mod3 -emit-module %t/mod3.map -o %t/mod3.pcm
// RUN: %clang_cc1 -xc++ -fmodules -fno-implicit-modules \
// RUN: -fmodule-map-file=%t/base.map -fmodule-map-file=%t/mod3.map -fmodule-map-file=%t/mod4.map \
// RUN: -fmodule-file=%t/mod3.pcm \
// RUN: -fmodule-name=mod4 -emit-module %t/mod4.map -o %t/mod4.pcm
// RUN: %clang_cc1 -xc++ -fmodules -fno-implicit-modules -fmodule-map-file=%t/base.map -fmodule-map-file=%t/mod4.map -fmodule-file=%t/mod4.pcm -fsyntax-only -verify %t/check_slocs.cc

//--- base.map
module base { textual header "vector.h" }
//--- mixed.map
module mixed { textual header "mixed_text.h" header "mixed_mod.h"}
//--- mod1.map
module mod1 { header "mod1.h" }
//--- mod2.map
module mod2 { header "mod2.h" }
//--- mod3.map
module mod3 { header "mod3.h" }
//--- mod4.map
module mod4 { header "mod4.h" }
//--- check_slocs.cc
#include "mod4.h"
#include "vector.h"
#pragma clang __debug sloc_usage // expected-remark {{source manager location address space usage}}
// expected-note@* {{% of available space}}

// base.map must only be present once, despite being used in each module.
// Because its location in every module compile should be non-affecting.

// [email protected]:1 {{file entered 1 time}}

// different modules use either only textual header from mixed.map or both textual and modular
// headers. Either combination must lead to only 1 use at the end, because the module is ultimately
// in the import chain and any textual uses should not change that.

// [email protected]:1 {{file entered 1 time}}

// expected-note@* + {{file entered}}


//--- vector.h
#ifndef VECTOR_H
#define VECTOR_H
#endif

//--- mixed_text.h
#ifndef MIXED_TEXT_H
#define MIXED_TEXT_H
#endif
//--- mixed_mod.h
#ifndef MIXED_MOD_H
#define MIXED_MOD_H
#endif

//--- mod1.h
#ifndef MOD1
#define MOD1
#include "vector.h"
#include "mixed_text.h"
int mod1();
#endif
//--- mod2.h
#ifndef MOD2
#define MOD2
#include "vector.h"
#include "mod1.h"
#include "mixed_mod.h"
int mod2();
#endif
//--- mod3.h
#ifndef MOD3
#define MOD3
#include "vector.h"
#include "mod2.h"
#include "mixed_text.h"
#include "mixed_mod.h"
int mod3();
#endif
//--- mod4.h
#ifndef MOD4
#define MOD4
#include "vector.h"
#include "mod3.h"
int mod4();
#endif
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